WorldWideScience

Sample records for aerosol source identification

  1. Bio aerosol Generation at wastewater treatment plants: Identification of main bio aerosols sources

    International Nuclear Information System (INIS)

    Sanchez Monedero, M. A.; Aguilar, M. I.; Fenoll, R.; Roig, A.

    2009-01-01

    Typical operations taking place at wastewater treatment plants, especially those involving aeration and mechanical agitation of raw wastewater, represent one of the main sources of bio aerosols that, if inhaled, could pose a biologic hazard to site workers and local residents. Six different wastewater treatment plants from southeast Spain were monitories in order to identify the main bio aerosol sources and to evaluate the airborne microorganisms levels to which workers may be exposed to. Air samples were taken from selected locations by using a single stage impactor. (Author)

  2. Identification of the sources of primary organic aerosols at urban schools: A molecular marker approach

    International Nuclear Information System (INIS)

    Crilley, Leigh R.; Qadir, Raeed M.; Ayoko, Godwin A.; Schnelle-Kreis, Jürgen; Abbaszade, Gülcin; Orasche, Jürgen; Zimmermann, Ralf; Morawska, Lidia

    2014-01-01

    Children are particularly susceptible to air pollution and schools are examples of urban microenvironments that can account for a large portion of children's exposure to airborne particles. Thus this paper aimed to determine the sources of primary airborne particles that children are exposed to at school by analyzing selected organic molecular markers at 11 urban schools in Brisbane, Australia. Positive matrix factorization analysis identified four sources at the schools: vehicle emissions, biomass burning, meat cooking and plant wax emissions accounting for 45%, 29%, 16% and 7%, of the organic carbon respectively. Biomass burning peaked in winter due to prescribed burning of bushland around Brisbane. Overall, the results indicated that both local (traffic) and regional (biomass burning) sources of primary organic aerosols influence the levels of ambient particles that children are exposed at the schools. These results have implications for potential control strategies for mitigating exposure at schools. - Highlights: • Selected organic molecular markers at 11 urban schools were analyzed. • Four sources of primary organic aerosols were identified by PMF at the schools. • Both local and regional sources were found to influence exposure at the schools. • The results have implications for mitigation of children's exposure at schools. - The identification of the most important sources of primary organic aerosols at urban schools has implications for control strategies for mitigating children's exposure at schools

  3. Arctic Aerosols and Sources

    DEFF Research Database (Denmark)

    Nielsen, Ingeborg Elbæk

    2017-01-01

    Since the Industrial Revolution, the anthropogenic emission of greenhouse gases has been increasing, leading to a rise in the global temperature. Particularly in the Arctic, climate change is having serious impact where the average temperature has increased almost twice as much as the global during......, ammonium, black carbon, and trace metals. This PhD dissertation studies Arctic aerosols and their sources, with special focus on black carbon, attempting to increase the knowledge about aerosols’ effect on the climate in an Arctic content. The first part of the dissertation examines the diversity...... of aerosol emissions from an important anthropogenic aerosol source: residential wood combustion. The second part, characterizes the chemical and physical composition of aerosols while investigating sources of aerosols in the Arctic. The main instrument used in this research has been the state...

  4. Identification of sources of aerosol particles in three locations in eastern Botswana

    Science.gov (United States)

    Chimidza, S.; Moloi, K.

    2000-07-01

    Airborne particles have been collected using a dichotomous virtual impactor at three different locations in the eastern part of Botswana: Serowe, Selibe-Phikwe, and Francistown. The particles were separated into two fractions (fine and coarse). Sampling at the three locations was done consecutively during the months of July and August, which are usually dry and stable. The sampling time for each sample was 12 hours during the day. For elemental composition, energy-dispersive x-ray fluorescence technique was used. Correlations and principal component analysis with varimax rotation were used to identify major sources of aerosol particles. In all the three places, soil was found to be the main source of aerosol particles. A copper-nickel mine and smelter at Selibe-Phikwe was found to be not only a source of copper and nickel particles in Selibe-Phikwe but also a source of these particles in far places like Serowe. In Selibe-Phikwe and Francistown, car exhaust was found to be the major source of fine particles of lead and bromine.

  5. Calibration of aerosol radiometers. Special aerosol sources

    International Nuclear Information System (INIS)

    Belkina, S.K.; Zalmanzon, Yu.E.; Kuznetsov, Yu.V.; Fertman, D.E.

    1988-01-01

    Problems of calibration of artificial aerosol radiometry and information-measurement systems of radiometer radiation control, in particular, are considered. Special aerosol source is suggested, which permits to perform certification and testing of aerosol channels of the systems in situ without the dismantling

  6. Final report of the IAEA advisory group meeting on accelerator-based nuclear analytical techniques for characterization and source identification of aerosol particles

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-07-01

    The field of aerosol characterization and source identification covers a wide range of scientific and technical activities in many institutions, in both developed and developing countries. This field includes research and applications on urban air pollution, source apportionment of suspended particulate matter, radioactive aerosol particles, organic compounds carried on particulate matter, elemental characterization of particles, and other areas. The subject of this AGM focused on the use of accelerator-based nuclear analytical techniques for determination of elemental composition of particles (by either bulk or single particle analysis) and the use of accumulated knowledge for source identification.

  7. Final report of the IAEA advisory group meeting on accelerator-based nuclear analytical techniques for characterization and source identification of aerosol particles

    International Nuclear Information System (INIS)

    1995-01-01

    The field of aerosol characterization and source identification covers a wide range of scientific and technical activities in many institutions, in both developed and developing countries. This field includes research and applications on urban air pollution, source apportionment of suspended particulate matter, radioactive aerosol particles, organic compounds carried on particulate matter, elemental characterization of particles, and other areas. The subject of this AGM focused on the use of accelerator-based nuclear analytical techniques for determination of elemental composition of particles (by either bulk or single particle analysis) and the use of accumulated knowledge for source identification

  8. Optical, microphysical and radiative properties of aerosols over a tropical rural site in Kenya, East Africa: Source identification, modification and aerosol type discrimination

    Science.gov (United States)

    Boiyo, Richard; Kumar, K. Raghavendra; Zhao, Tianliang

    2018-03-01

    A better understanding of aerosol optical, microphysical and radiative properties is a crucial challenge for climate change studies. In the present study, column-integrated aerosol optical and radiative properties observed at a rural site, Mbita (0.42°S, 34.20 °E, and 1125 m above sea level) located in Kenya, East Africa (EA) are investigated using ground-based Aerosol Robotic Network (AERONET) data retrieved during January, 2007 to December, 2015. The annual mean aerosol optical depth (AOD500 nm), Ångström exponent (AE440-870 nm), fine mode fraction of AOD500 nm (FMF500 nm), and columnar water vapor (CWV, cm) were found to be 0.23 ± 0.08, 1.01 ± 0.16, 0.60 ± 0.07, and 2.72 ± 0.20, respectively. The aerosol optical properties exhibited a unimodal distribution with substantial seasonal heterogeneity in their peak values being low (high) during the local wet (dry) seasons. The observed data showed that Mbita and its environs are significantly influenced by various types of aerosols, with biomass burning and/or urban-industrial (BUI), mixed (MXD), and desert dust (DDT) aerosol types contributing to 37.72%, 32.81%, and 1.40%, respectively during the local dry season (JJA). The aerosol volume size distribution (VSD) exhibited bimodal lognormal structure with a geometric mean radius of 0.15 μm and 3.86-5.06 μm for fine- and coarse-mode aerosols, respectively. Further, analysis of single scattering albedo (SSA), asymmetry parameter (ASY) and refractive index (RI) revealed dominance of fine-mode absorbing aerosols during JJA. The averaged aerosol direct radiative forcing (ARF) retrieved from the AERONET showed a strong cooling effect at the bottom of the atmosphere (BOA) and significant warming within the atmosphere (ATM), representing the important role of aerosols played in this rural site of Kenya. Finally, the Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) model revealed that aerosols from distinct sources resulted in enhanced loading

  9. Special aerosol sources for certification and test of aerosol radiometers

    International Nuclear Information System (INIS)

    Belkina, S.K.; Zalmanzon, Y.E.; Kuznetsov, Y.V.; Rizin, A.I.; Fertman, D.E.

    1991-01-01

    The results are presented of the development and practical application of new radionuclide source types (Special Aerosol Sources (SAS)), that meet the international standard recommendations, which are used for certification and test of aerosol radiometers (monitors) using model aerosols of plutonium-239, strontium-yttrium-90 or uranium of natural isotope composition and certified against Union of Soviet Socialist Republics USSR national radioactive aerosol standard or by means of a reference radiometer. The original technology for source production allows the particular features of sampling to be taken into account as well as geometry and conditions of radionuclides radiation registration in the sample for the given type of radiometer. (author)

  10. Special aerosol sources for certification and test of aerosol radiometers

    Energy Technology Data Exchange (ETDEWEB)

    Belkina, S.K.; Zalmanzon, Y.E.; Kuznetsov, Y.V.; Rizin, A.I.; Fertman, D.E. (Union Research Institute of Instrumentation, Moscow (USSR))

    1991-01-01

    The results are presented of the development and practical application of new radionuclide source types (Special Aerosol Sources (SAS)), that meet the international standard recommendations, which are used for certification and test of aerosol radiometers (monitors) using model aerosols of plutonium-239, strontium-yttrium-90 or uranium of natural isotope composition and certified against Union of Soviet Socialist Republics USSR national radioactive aerosol standard or by means of a reference radiometer. The original technology for source production allows the particular features of sampling to be taken into account as well as geometry and conditions of radionuclides radiation registration in the sample for the given type of radiometer. (author).

  11. Source identification of water-soluble organic aerosols at a roadway site using a positive matrix factorization analysis.

    Science.gov (United States)

    Park, Seungshik; Cho, Sung Yong; Bae, Min-Suk

    2015-11-15

    Daily PM2.5 measurements were carried out at a local roadway every sixth day from May 2011 to August 2013 to obtain seasonal quantitative information on the primary and secondary sources of two water-soluble organic carbon (WSOC) fractions. Filter samples were analyzed for OC, elemental carbon (EC), WSOC, hydrophilic and hydrophobic WSOC fractions (WSOC(HPI) and WSOC(HPO)), and ionic species. An XAD solid phase extraction method and a total organic carbon analyzer were used to isolate the two WSOC fractions and determine their amounts, respectively. The WSOC/OC and WSOC(HPI)/WSOC ratios were 0.62±0.13 and 0.47±0.14, respectively. Similar seasonal profiles in EC, OC, and WSOC concentrations were observed, with higher concentrations occurring in the cold season and lower concentrations in the warm season. However, opposite results were obtained in WSOC/OC and WSOC(HPI)/WSOC ratios, with the higher in the warm season and the lower in the cold season. Correlation analyses indicated that two WSOC fractions in winter were likely attributed to secondary formation processes, biomass burning (BB), and traffic emissions, while WSOC(HPI) observed in other seasons were associated with secondary formation processes similar to those of oxalate and secondary inorganic species. A positive matrix factorization (PMF) model was employed to investigate the sources of two WSOC fractions. PMF indicated that concentrations of WSOC fractions were affected by five sources: secondary NO3(-) related, secondary SO4(2-) and oxalate related, traffic emissions, BB emissions, and sea-salt. Throughout the study period, secondary organic aerosols were estimated to be the most dominant contributor of WSOC fractions, with higher contributions occurring in the warm seasons. The contribution of secondary aerosol formation processes (NO3(-) related+SO4(2-) and oxalate related) to WSOC(HPI) and WSOC(HPO) was on an average 56.2% (45.0-73.8%) and 47.7% (39.6-52.1%), respectively. The seasonal average

  12. Long-term chemical analysis and organic aerosol source apportionment at nine sites in central Europe: source identification and uncertainty assessment

    Science.gov (United States)

    Daellenbach, Kaspar R.; Stefenelli, Giulia; Bozzetti, Carlo; Vlachou, Athanasia; Fermo, Paola; Gonzalez, Raquel; Piazzalunga, Andrea; Colombi, Cristina; Canonaco, Francesco; Hueglin, Christoph; Kasper-Giebl, Anne; Jaffrezo, Jean-Luc; Bianchi, Federico; Slowik, Jay G.; Baltensperger, Urs; El-Haddad, Imad; Prévôt, André S. H.

    2017-11-01

    Long-term monitoring of organic aerosol is important for epidemiological studies, validation of atmospheric models, and air quality management. In this study, we apply a recently developed filter-based offline methodology using an aerosol mass spectrometer (AMS) to investigate the regional and seasonal differences of contributing organic aerosol sources. We present offline AMS measurements for particulate matter smaller than 10 µm at nine stations in central Europe with different exposure characteristics for the entire year of 2013 (819 samples). The focus of this study is a detailed source apportionment analysis (using positive matrix factorization, PMF) including in-depth assessment of the related uncertainties. Primary organic aerosol (POA) is separated in three components: hydrocarbon-like OA related to traffic emissions (HOA), cooking OA (COA), and biomass burning OA (BBOA). We observe enhanced production of secondary organic aerosol (SOA) in summer, following the increase in biogenic emissions with temperature (summer oxygenated OA, SOOA). In addition, a SOA component was extracted that correlated with an anthropogenic secondary inorganic species that is dominant in winter (winter oxygenated OA, WOOA). A factor (sulfur-containing organic, SC-OA) explaining sulfur-containing fragments (CH3SO2+), which has an event-driven temporal behaviour, was also identified. The relative yearly average factor contributions range from 4 to 14 % for HOA, from 3 to 11 % for COA, from 11 to 59 % for BBOA, from 5 to 23 % for SC-OA, from 14 to 27 % for WOOA, and from 15 to 38 % for SOOA. The uncertainty of the relative average factor contribution lies between 2 and 12 % of OA. At the sites north of the alpine crest, the sum of HOA, COA, and BBOA (POA) contributes less to OA (POA / OA = 0.3) than at the southern alpine valley sites (0.6). BBOA is the main contributor to POA with 87 % in alpine valleys and 42 % north of the alpine crest. Furthermore, the influence of primary

  13. Source identification and airborne chemical characterisation of aerosol pollution from long-range transport over Greenland during POLARCAT summer campaign 2008

    Directory of Open Access Journals (Sweden)

    J. Schmale

    2011-10-01

    Full Text Available We deployed an aerosol mass spectrometer during the POLARCAT (Polar Study using Aircraft, Remote Sensing, Surface Measurements and Models, of Climate, Chemistry, Aerosols, and Transport summer campaign in Greenland in June/July 2008 on the research aircraft ATR-42. Online size resolved chemical composition data of submicron aerosol were collected up to 7.6 km altitude in the region 60 to 71° N and 40 to 60° W. Biomass burning (BB and fossil fuel combustion (FF plumes originating from North America, Asia, Siberia and Europe were sampled. Transport pathways of detected plumes included advection below 700 hPa, air mass uplifting in warm conveyor belts, and high altitude transport in the upper troposphere. By means of the Lagrangian particle dispersion model FLEXPART, trace gas analysis of O3 and CO, particle size distributions and aerosol chemical composition 48 pollution events were identified and classified into five chemically distinct categories. Aerosol from North American BB consisted of 22% particulate sulphate, while with increasing anthropogenic and Asian influence aerosol in Asian FF dominated plumes was composed of up to 37% sulphate category mean value. Overall, it was found that the organic matter fraction was larger (85% in pollution plumes than for background conditions (71%. Despite different source regions and emission types the particle oxygen to carbon ratio of all plume classes was around 1 indicating low-volatility highly oxygenated aerosol. The volume size distribution of out-of-plume aerosol showed markedly smaller modes than all other distributions with two Aitken mode diameters of 24 and 43 nm and a geometric standard deviation σg of 1.12 and 1.22, respectively, while another very broad mode was found at 490 nm (σg = 2.35. Nearly pure BB particles from North America exhibited an Aitken mode at 66 nm (σg = 1.46 and an accumulation mode diameter of 392 nm (σg = 1

  14. Source identification and airborne chemical characterisation of aerosol pollution from long-range transport over Greenland during POLARCAT summer campaign 2008

    Science.gov (United States)

    Schmale, J.; Schneider, J.; Ancellet, G.; Quennehen, B.; Stohl, A.; Sodemann, H.; Burkhart, J. F.; Hamburger, T.; Arnold, S. R.; Schwarzenboeck, A.; Borrmann, S.; Law, K. S.

    2011-10-01

    We deployed an aerosol mass spectrometer during the POLARCAT (Polar Study using Aircraft, Remote Sensing, Surface Measurements and Models, of Climate, Chemistry, Aerosols, and Transport) summer campaign in Greenland in June/July 2008 on the research aircraft ATR-42. Online size resolved chemical composition data of submicron aerosol were collected up to 7.6 km altitude in the region 60 to 71° N and 40 to 60° W. Biomass burning (BB) and fossil fuel combustion (FF) plumes originating from North America, Asia, Siberia and Europe were sampled. Transport pathways of detected plumes included advection below 700 hPa, air mass uplifting in warm conveyor belts, and high altitude transport in the upper troposphere. By means of the Lagrangian particle dispersion model FLEXPART, trace gas analysis of O3 and CO, particle size distributions and aerosol chemical composition 48 pollution events were identified and classified into five chemically distinct categories. Aerosol from North American BB consisted of 22% particulate sulphate, while with increasing anthropogenic and Asian influence aerosol in Asian FF dominated plumes was composed of up to 37% sulphate category mean value. Overall, it was found that the organic matter fraction was larger (85%) in pollution plumes than for background conditions (71%). Despite different source regions and emission types the particle oxygen to carbon ratio of all plume classes was around 1 indicating low-volatility highly oxygenated aerosol. The volume size distribution of out-of-plume aerosol showed markedly smaller modes than all other distributions with two Aitken mode diameters of 24 and 43 nm and a geometric standard deviation σg of 1.12 and 1.22, respectively, while another very broad mode was found at 490 nm (σg = 2.35). Nearly pure BB particles from North America exhibited an Aitken mode at 66 nm (σg = 1.46) and an accumulation mode diameter of 392 nm (σg = 1.76). An aerosol lifetime, including all processes from emission to

  15. Meteorological support for aerosol radiometers: special aerosol sources

    Energy Technology Data Exchange (ETDEWEB)

    Belkina, S.K.; Zalmanzon, Yu.E.; Kuznetsov, Yu.V.; Fertman, D.E.

    1988-07-01

    A new method is described for transfer of the measure of unit volume activity of radioactive aerosols from the state special standard to the working instruments in the stage of regular operation. The differences from existing methods are examined. The principal distinction of the new method is the possibility of direct (rather than through the conversion factor) determination and subsequent testing of the fundamental meteorological characteristics of the instrument by means of special aerosol sources, which fosters a significant reduction in individual components of the indicated errors.

  16. Retrieving global aerosol sources from satellites using inverse modeling

    Directory of Open Access Journals (Sweden)

    O. Dubovik

    2008-01-01

    Full Text Available Understanding aerosol effects on global climate requires knowing the global distribution of tropospheric aerosols. By accounting for aerosol sources, transports, and removal processes, chemical transport models simulate the global aerosol distribution using archived meteorological fields. We develop an algorithm for retrieving global aerosol sources from satellite observations of aerosol distribution by inverting the GOCART aerosol transport model.

    The inversion is based on a generalized, multi-term least-squares-type fitting, allowing flexible selection and refinement of a priori algorithm constraints. For example, limitations can be placed on retrieved quantity partial derivatives, to constrain global aerosol emission space and time variability in the results. Similarities and differences between commonly used inverse modeling and remote sensing techniques are analyzed. To retain the high space and time resolution of long-period, global observational records, the algorithm is expressed using adjoint operators.

    Successful global aerosol emission retrievals at 2°×2.5 resolution were obtained by inverting GOCART aerosol transport model output, assuming constant emissions over the diurnal cycle, and neglecting aerosol compositional differences. In addition, fine and coarse mode aerosol emission sources were inverted separately from MODIS fine and coarse mode aerosol optical thickness data, respectively. These assumptions are justified, based on observational coverage and accuracy limitations, producing valuable aerosol source locations and emission strengths. From two weeks of daily MODIS observations during August 2000, the global placement of fine mode aerosol sources agreed with available independent knowledge, even though the inverse method did not use any a priori information about aerosol sources, and was initialized with a "zero aerosol emission" assumption. Retrieving coarse mode aerosol emissions was less successful

  17. Characterization, Long-Range Transport and Source Identification of Carbonaceous Aerosols during Spring and Autumn Periods at a High Mountain Site in South China

    Directory of Open Access Journals (Sweden)

    Hong-yan Jia

    2016-09-01

    Full Text Available PM10 (particulate matter samples were collected at Mount Lu, a high elevation mountain site in south China (August and September of 2011; and March, April and May of 2012. Eight carbonaceous fractions of particles were analyzed to characterize the possible carbonaceous emission sources. During the sampling events, daily average concentrations of PM10 at Mount Lu were 97.87 μg/m3 and 73.40 μg/m3 in spring and autumn, respectively. The observed mean organic carbon (OC and element carbon (EC concentrations during spring in PM10 were 10.58 μg/m3 and 2.58 μg/m3, respectively, and those in autumn were 6.89 μg/m3 and 2.40 μg/m3, respectively. Secondary organic carbon concentration was 4.77 μg/m3 and 2.93 μg/m3 on average, accounting for 28.0% and 31.0% of the total OC in spring and autumn, respectively. Relationships between carbonaceous species and results of principal component analysis showed that there were multiple sources contributing to the carbonaceous aerosols at the observation site. Through back trajectory analysis, it was found that air masses in autumn were mainly transported from the south of China, and these have the highest OC but lowest EC concentrations. Air masses in spring transported from northwest China bring 7.77 μg/m3 OC and 2.28 μg/m3 EC to the site, with lower levels coming from other sites. These air mass sources were featured by the effective carbon ratio (ECR.

  18. Sources and composition of urban aerosol particles

    Science.gov (United States)

    Vogt, M.; Johansson, C.; Mårtensson, M.; Struthers, H.; Ahlm, L.; Nilsson, D.

    2011-09-01

    From May 2008 to March 2009 aerosol emissions were measured using the eddy covariance method covering the size range 0.25 to 2.5 μm diameter (Dp) from a 105 m tower, in central Stockholm, Sweden. Supporting chemical aerosol data were collected at roof and street level. Results show that the inorganic fraction of sulfate, nitrate, ammonium and sea salt accounts for approximately 15% of the total aerosol mass removed at 0.6 μm Dp. Further heating to 300 °C caused very little additional losses road traffic (as inferred from the ratio of the incremental concentrations of nitrogen oxides (NOx) and BC measured on a densely trafficked street) and the fluxes of non-volatile material at tower level are in close agreement, suggesting a traffic source of BC. We have estimated the emission factors (EFs) for non-volatile particles <0.6 μm Dp to be 2.4±1.4 mg veh-1 km-1 based on either CO2 fluxes or traffic activity data. Light (LDV) and heavy duty vehicle (HDV) EFs were estimated using multiple linear regression and reveal that for non-volatile particulate matter in the 0.25 to 0.6 μm Dp range, the EFHDV is approximately twice as high as the EFLDV, the difference not being statistically significant.

  19. Selective structural source identification

    Science.gov (United States)

    Totaro, Nicolas

    2018-04-01

    In the field of acoustic source reconstruction, the inverse Patch Transfer Function (iPTF) has been recently proposed and has shown satisfactory results whatever the shape of the vibrating surface and whatever the acoustic environment. These two interesting features are due to the virtual acoustic volume concept underlying the iPTF methods. The aim of the present article is to show how this concept of virtual subsystem can be used in structures to reconstruct the applied force distribution. Some virtual boundary conditions can be applied on a part of the structure, called virtual testing structure, to identify the force distribution applied in that zone regardless of the presence of other sources outside the zone under consideration. In the present article, the applicability of the method is only demonstrated on planar structures. However, the final example show how the method can be applied to a complex shape planar structure with point welded stiffeners even in the tested zone. In that case, if the virtual testing structure includes the stiffeners the identified force distribution only exhibits the positions of external applied forces. If the virtual testing structure does not include the stiffeners, the identified force distribution permits to localize the forces due to the coupling between the structure and the stiffeners through the welded points as well as the ones due to the external forces. This is why this approach is considered here as a selective structural source identification method. It is demonstrated that this approach clearly falls in the same framework as the Force Analysis Technique, the Virtual Fields Method or the 2D spatial Fourier transform. Even if this approach has a lot in common with these latters, it has some interesting particularities like its low sensitivity to measurement noise.

  20. Natural Radionuclides and Isotopic Signatures for Determining Carbonaceous Aerosol Sources, Aerosol Lifetimes, and Washout Processes

    International Nuclear Information System (INIS)

    Gaffney, Jeffrey

    2012-01-01

    This is the final technical report. The project description is as follows: to determine the role of aerosol radiative forcing on climate, the processes that control their atmospheric concentrations must be understood, and aerosol sources need to be determined for mitigation. Measurements of naturally occurring radionuclides and stable isotopic signatures allow the sources, removal and transport processes, as well as atmospheric lifetimes of fine carbonaceous aerosols, to be evaluated.

  1. Natural Radionuclides and Isotopic Signatures for Determining Carbonaceous Aerosol Sources, Aerosol Lifetimes, and Washout Processes

    Energy Technology Data Exchange (ETDEWEB)

    Gaffney, Jeffrey [Univ. of Arkansas, Little Rock, AR (United States)

    2012-12-12

    This is the final technical report. The project description is as follows: to determine the role of aerosol radiative forcing on climate, the processes that control their atmospheric concentrations must be understood, and aerosol sources need to be determined for mitigation. Measurements of naturally occurring radionuclides and stable isotopic signatures allow the sources, removal and transport processes, as well as atmospheric lifetimes of fine carbonaceous aerosols, to be evaluated.

  2. Identification of southern radio sources

    International Nuclear Information System (INIS)

    Savage, A.; Bolton, J.G.; Wright, A.E.

    1977-01-01

    Identifications are suggested for 53 radio sources from the southern zones of the Parkes 2700-MHz survey, 32 with galaxies, 11 with suggested QSOs and 10 with confirmed QSOs. The identifications were made from the ESO quick blue survey plates, the SRC IIIa-J deep survey plates and the Palomar Sky Survey prints. Accurate optical positions have been measured for four of the new identifications and for two previously suggested identifications. A further nine previously suggested QSO identifications have also been confirmed by two-colour photography or spectroscopy. (author)

  3. Advanced source apportionment of carbonaceous aerosols by coupling offline AMS and radiocarbon size-segregated measurements over a nearly 2-year period

    OpenAIRE

    Vlachou, Athanasia; Daellenbach, Kaspar R.; Bozzetti, Carlo; Chazeau, Benjamin; Salazar Quintero, Gary Abdiel; Szidat, Sönke; Jaffrezo, Jean-Luc; Hueglin, Christoph; Baltensperger, Urs; Haddad, Imad El; Prévôt, André S. H.

    2018-01-01

    Carbonaceous aerosols are related to adverse human health effects. Therefore, identification of their sources and analysis of their chemical composition is important. The offline AMS (aerosol mass spectrometer) technique offers quantitative separation of organic aerosol (OA) factors which can be related to major OA sources, either primary or secondary. While primary OA can be more clearly separated into sources, secondary (SOA) source apportionment is more challenging because different source...

  4. Identification of southern radio sources

    International Nuclear Information System (INIS)

    Savage, A.; Bolton, J.G.; Wright, A.E.

    1976-01-01

    Identifications are suggested for 36 radio sources from the southern zones of the Parkes 2700 MHz survey, 28 with galaxies, six with confirmed and two with suggested quasi-stellar objects. The identifications were made from the ESO quick blue survey plates, the SRC IIIa-J deep survey plates and the Palomar sky survey prints. Accurate optical positions have also been measured for nine of the objects and for five previously suggested identifications. (author)

  5. Advanced source apportionment of carbonaceous aerosols by coupling offline AMS and radiocarbon size-segregated measurements over a nearly 2-year period

    OpenAIRE

    A. Vlachou; K. R. Daellenbach; C. Bozzetti; B. Chazeau; G. A. Salazar; S. Szidat; J.-L. Jaffrezo; C. Hueglin; U. Baltensperger; I. E. Haddad; A. S. H. Prévôt

    2018-01-01

    Carbonaceous aerosols are related to adverse human health effects. Therefore, identification of their sources and analysis of their chemical composition is important. The offline AMS (aerosol mass spectrometer) technique offers quantitative separation of organic aerosol (OA) factors which can be related to major OA sources, either primary or secondary. While primary OA can be more clearly separated into sources, secondary (SOA) source apportionment is more challenging because d...

  6. Aerosol composition and source apportionment in Santiago de Chile

    Science.gov (United States)

    Artaxo, Paulo; Oyola, Pedro; Martinez, Roberto

    1999-04-01

    Santiago de Chile, São Paulo and Mexico City are Latin American urban areas that suffer from heavy air pollution. In order to study air pollution in Santiago area, an aerosol source apportionment study was designed to measure ambient aerosol composition and size distribution for two downtown sampling sites in Santiago. The aerosol monitoring stations were operated in Gotuzo and Las Condes during July and August 1996. The study employed stacked filter units (SFU) for aerosol sampling, collecting fine mode aerosol (dpsource apportionment was performed using Absolute Principal Factor Analysis (APFA). Very high aerosol concentrations were observed (up to 400 μg/m 3 PM 10). The main aerosol particle sources in Santiago are resuspended soil dust and traffic emissions. Coarse particles account for 63% of PM 10 aerosol in Gotuzo and 53% in Las Condes. A major part of this component is resuspended soil dust. In the fine fraction, resuspended soil dust accounts for 15% of fine mass, and the aerosols associated with transportation activities account for a high 64% of the fine particle mass. Sulfate particle is an important component of the aerosol in Santiago, mainly originating from gas-to-particle conversion from SO 2. In the Gotuzo site, sulfates are the highest aerosol component, accounting for 64.5% of fine mass. Direct traffic emissions are generally mixed with resuspended soil dust. It is difficult to separate the two components, because the soil dust in downtown Santiago is contaminated with Pb, Br, Cl, and other heavy metals that are also tracers for traffic emissions. Residual oil combustion is observed, with the presence of V, S and Ni. An aerosol components from industrial emissions is also present, with the presence of several heavy metals such as Zn, Cu and others. A factor with molybdenum, arsenic, copper and sulfur was observed frequently, and it results from emissions of copper smelters.

  7. A technique for rapid source apportionment applied to ambient organic aerosol measurements from a thermal desorption aerosol gas chromatograph (TAG

    Directory of Open Access Journals (Sweden)

    Y. Zhang

    2016-11-01

    Full Text Available We present a rapid method for apportioning the sources of atmospheric organic aerosol composition measured by gas chromatography–mass spectrometry methods. Here, we specifically apply this new analysis method to data acquired on a thermal desorption aerosol gas chromatograph (TAG system. Gas chromatograms are divided by retention time into evenly spaced bins, within which the mass spectra are summed. A previous chromatogram binning method was introduced for the purpose of chromatogram structure deconvolution (e.g., major compound classes (Zhang et al., 2014. Here we extend the method development for the specific purpose of determining aerosol samples' sources. Chromatogram bins are arranged into an input data matrix for positive matrix factorization (PMF, where the sample number is the row dimension and the mass-spectra-resolved eluting time intervals (bins are the column dimension. Then two-dimensional PMF can effectively do three-dimensional factorization on the three-dimensional TAG mass spectra data. The retention time shift of the chromatogram is corrected by applying the median values of the different peaks' shifts. Bin width affects chemical resolution but does not affect PMF retrieval of the sources' time variations for low-factor solutions. A bin width smaller than the maximum retention shift among all samples requires retention time shift correction. A six-factor PMF comparison among aerosol mass spectrometry (AMS, TAG binning, and conventional TAG compound integration methods shows that the TAG binning method performs similarly to the integration method. However, the new binning method incorporates the entirety of the data set and requires significantly less pre-processing of the data than conventional single compound identification and integration. In addition, while a fraction of the most oxygenated aerosol does not elute through an underivatized TAG analysis, the TAG binning method does have the ability to achieve molecular level

  8. ISS Ambient Air Quality: Updated Inventory of Known Aerosol Sources

    Science.gov (United States)

    Meyer, Marit

    2014-01-01

    Spacecraft cabin air quality is of fundamental importance to crew health, with concerns encompassing both gaseous contaminants and particulate matter. Little opportunity exists for direct measurement of aerosol concentrations on the International Space Station (ISS), however, an aerosol source model was developed for the purpose of filtration and ventilation systems design. This model has successfully been applied, however, since the initial effort, an increase in the number of crewmembers from 3 to 6 and new processes on board the ISS necessitate an updated aerosol inventory to accurately reflect the current ambient aerosol conditions. Results from recent analyses of dust samples from ISS, combined with a literature review provide new predicted aerosol emission rates in terms of size-segregated mass and number concentration. Some new aerosol sources have been considered and added to the existing array of materials. The goal of this work is to provide updated filtration model inputs which can verify that the current ISS filtration system is adequate and filter lifetime targets are met. This inventory of aerosol sources is applicable to other spacecraft, and becomes more important as NASA considers future long term exploration missions, which will preclude the opportunity for resupply of filtration products.

  9. Identification of southern radio sources

    International Nuclear Information System (INIS)

    Savage, A.

    1976-01-01

    Identifications are suggested for 32 radio sources from the southern zones of the Parkes 2700 MHz survey, 18 with galaxies, one with a confirmed and 12 with possible quasistellar objects, and one with a supernova remnant in the Large Magellanic Cloud. The identifications were made from the ESO IIa-O quick blue survey plates, the SRC IIIa-J deep survey plates and the Palomar sky survey prints. Accurate optical positions have also been measured for 10 of the objects and for five previously suggested QSOs. (author)

  10. Aerosol composition and source apportionment in Santiago de Chile

    International Nuclear Information System (INIS)

    Artaxo, Paulo; Oyola, Pedro; Martinez, Roberto

    1999-01-01

    Santiago de Chile, Sao Paulo and Mexico City are Latin American urban areas that suffer from heavy air pollution. In order to study air pollution in Santiago area, an aerosol source apportionment study was designed to measure ambient aerosol composition and size distribution for two downtown sampling sites in Santiago. The aerosol monitoring stations were operated in Gotuzo and Las Condes during July and August 1996. The study employed stacked filter units (SFU) for aerosol sampling, collecting fine mode aerosol (dp 10 mass of particles smaller than 10 μm) and black carbon concentration were also measured. Particle-Induced X-ray Emission (PIXE) was used to measure the concentration of 22 trace elements at levels below 0.5 ng m -3 . Quantitative aerosol source apportionment was performed using Absolute Principal Factor Analysis (APFA). Very high aerosol concentrations were observed (up to 400 μg/m 3 PM 10 ). The main aerosol particle sources in Santiago are resuspended soil dust and traffic emissions. Coarse particles account for 63% of PM 10 aerosol in Gotuzo and 53% in Las Condes. A major part of this component is resuspended soil dust. In the fine fraction, resuspended soil dust accounts for 15% of fine mass, and the aerosols associated with transportation activities account for a high 64% of the fine particle mass. Sulfate particle is an important component of the aerosol in Santiago, mainly originating from gas-to-particle conversion from SO 2 . In the Gotuzo site, sulfates are the highest aerosol component, accounting for 64.5% of fine mass. Direct traffic emissions are generally mixed with resuspended soil dust. It is difficult to separate the two components, because the soil dust in downtown Santiago is contaminated with Pb, Br, Cl, and other heavy metals that are also tracers for traffic emissions. Residual oil combustion is observed, with the presence of V, S and Ni. An aerosol components from industrial emissions is also present, with the presence of

  11. Receptor models for source apportionment of remote aerosols in Brazil

    International Nuclear Information System (INIS)

    Artaxo Netto, P.E.

    1985-11-01

    The PIXE (particle induced X-ray emission), and PESA (proton elastic scattering analysis) method were used in conjunction with receptor models for source apportionment of remote aerosols in Brazil. The PIXE used in the determination of concentration for elements with Z >- 11, has a detection limit of about 1 ng/m 3 . The concentrations of carbon, nitrogen and oxygen in the fine fraction of Amazon Basin aerosols was measured by PESA. We sampled in Jureia (SP), Fernando de Noronha, Arembepe (BA), Firminopolis (GO), Itaberai (GO) and Amazon Basin. For collecting the airbone particles we used cascade impactors, stacked filter units, and streaker samplers. Three receptor models were used: chemical mass balance, stepwise multiple regression analysis and principal factor analysis. The elemental and gravimetric concentrations were explained by the models within the experimental errors. Three sources of aerosol were quantitatively distinguished: marine aerosol, soil dust and aerosols related to forests. The emission of aerosols by vegetation is very clear for all the sampling sites. In Amazon Basin and Jureia it is the major source, responsible for 60 to 80% of airborne concentrations. (Author) [pt

  12. Aerosol behavior and light water reactor source terms

    International Nuclear Information System (INIS)

    Abbey, F.; Schikarski, W.O.

    1988-01-01

    The major developments in nuclear aerosol modeling following the accident to pressurized water reactor Unit 2 at Three Mile Island are briefly reviewed and the state of the art summarized. The importance and implications of these developments for severe accident source terms for light water reactors are then discussed in general terms. The treatment is not aimed at identifying specific source term values but is intended rather to illustrate trends, to assess the adequacy of the understanding of major aspects of aerosol behavior for source term prediction, and demonstrate in qualitative terms the effect of various aspects of reactor design. Areas where improved understanding of aerosol behavior might lead to further reductions in current source terms predictions are also considered

  13. Identification of petroleum pollution sources

    International Nuclear Information System (INIS)

    Begak, O.Yu.; Syroezhko, A.M.

    2001-01-01

    A possibility of preliminary identification of petroleum pollution sources was investigated on specimens of the Khanty-Mansi autonomous district six deposits and specimens of soil and water polluted by these petroleums. Investigations were conducted using IR Fourier spectroscopy and gamma spectrometry, as well as methods of chromato-mass spectrometry and capillary gas liquid chromatography. Every of studied samples of petroleum from different deposits have an individual radiation impression. Insignificant total content of radionuclides in samples is specific to the Khanty-Mansi petroleum region. Gamma spectrometry admits to identify potential source of petroleum pollution using radionuclides of uranium and thorium series [ru

  14. Sources of carbonaceous aerosol in the Amazon basin

    Directory of Open Access Journals (Sweden)

    S. Gilardoni

    2011-03-01

    Full Text Available The quantification of sources of carbonaceous aerosol is important to understand their atmospheric concentrations and regulating processes and to study possible effects on climate and air quality, in addition to develop mitigation strategies.

    In the framework of the European Integrated Project on Aerosol Cloud Climate Interactions (EUCAARI fine (Dp < 2.5 μm and coarse (2.5 μm < Dp <10 μm aerosol particles were sampled from February to June (wet season and from August to September (dry season 2008 in the central Amazon basin. The mass of fine particles averaged 2.4 μg m−3 during the wet season and 4.2 μg m−3 during the dry season. The average coarse aerosol mass concentration during wet and dry periods was 7.9 and 7.6 μg m−3, respectively. The overall chemical composition of fine and coarse mass did not show any seasonality with the largest fraction of fine and coarse aerosol mass explained by organic carbon (OC; the average OC to mass ratio was 0.4 and 0.6 in fine and coarse aerosol modes, respectively. The mass absorbing cross section of soot was determined by comparison of elemental carbon and light absorption coefficient measurements and it was equal to 4.7 m2 g−1 at 637 nm. Carbon aerosol sources were identified by Positive Matrix Factorization (PMF analysis of thermograms: 44% of fine total carbon mass was assigned to biomass burning, 43% to secondary organic aerosol (SOA, and 13% to volatile species that are difficult to apportion. In the coarse mode, primary biogenic aerosol particles (PBAP dominated the carbonaceous aerosol mass. The results confirmed the importance of PBAP in forested areas.

    The source apportionment results were employed to evaluate the ability of global chemistry transport models to simulate carbonaceous aerosol sources in a regional tropical background site. The comparison showed an overestimation

  15. Characterization of selenium in ambient aerosols and primary emission sources.

    Science.gov (United States)

    De Santiago, Arlette; Longo, Amelia F; Ingall, Ellery D; Diaz, Julia M; King, Laura E; Lai, Barry; Weber, Rodney J; Russell, Armistead G; Oakes, Michelle

    2014-08-19

    Atmospheric selenium (Se) in aerosols was investigated using X-ray absorption near-edge structure (XANES) spectroscopy and X-ray fluorescence (XRF) microscopy. These techniques were used to determine the oxidation state and elemental associations of Se in common primary emission sources and ambient aerosols collected from the greater Atlanta area. In the majority of ambient aerosol and primary emission source samples, the spectroscopic patterns as well as the absence of elemental correlations suggest Se is in an elemental, organic, or oxide form. XRF microscopy revealed numerous Se-rich particles, or hotspots, accounting on average for ∼16% of the total Se in ambient aerosols. Hotspots contained primarily Se(0)/Se(-II). However, larger, bulk spectroscopic characterizations revealed Se(IV) as the dominant oxidation state in ambient aerosol, followed by Se(0)/Se(-II) and Se(VI). Se(IV) was the only observed oxidation state in gasoline, diesel, and coal fly ash, while biomass burning contained a combination of Se(0)/Se(-II) and Se(IV). Although the majority of Se in aerosols was in the most toxic form, the Se concentration is well below the California Environmental Protection Agency chronic exposure limit (∼20000 ng/m(3)).

  16. Aerosol composition and sources during the Chinese Spring Festival: fireworks, secondary aerosol, and holiday effects

    Science.gov (United States)

    Jiang, Q.; Sun, Y. L.; Wang, Z.; Yin, Y.

    2015-06-01

    Aerosol particles were characterized by an Aerodyne aerosol chemical speciation monitor along with various collocated instruments in Beijing, China, to investigate the role of fireworks (FW) and secondary aerosol in particulate pollution during the Chinese Spring Festival of 2013. Three FW events, exerting significant and short-term impacts on fine particles (PM2.5), were observed on the days of Lunar New Year, Lunar Fifth Day, and Lantern Festival. The FW were shown to have a large impact on non-refractory potassium, chloride, sulfate, and organics in submicron aerosol (PM1), of which FW organics appeared to be emitted mainly in secondary, with its mass spectrum resembling that of secondary organic aerosol (SOA). Pollution events (PEs) and clean periods (CPs) alternated routinely throughout the study. Secondary particulate matter (SPM = SOA + sulfate + nitrate + ammonium) dominated the total PM1 mass on average, accounting for 63-82% during nine PEs in this study. The elevated contributions of secondary species during PEs resulted in a higher mass extinction efficiency of PM1 (6.4 m2 g-1) than during CPs (4.4 m2 g-1). The Chinese Spring Festival also provides a unique opportunity to study the impact of reduced anthropogenic emissions on aerosol chemistry in the city. Primary species showed ubiquitous reductions during the holiday period with the largest reduction being in cooking organic aerosol (OA; 69%), in nitrogen monoxide (54%), and in coal combustion OA (28%). Secondary sulfate, however, remained only slightly changed, and the SOA and the total PM2.5 even slightly increased. Our results have significant implications for controlling local primary source emissions during PEs, e.g., cooking and traffic activities. Controlling these factors might have a limited effect on improving air quality in the megacity of Beijing, due to the dominance of SPM from regional transport in aerosol particle composition.

  17. Source apportionment of carbonaceous aerosol in southern Sweden

    Directory of Open Access Journals (Sweden)

    J. Genberg

    2011-11-01

    Full Text Available A one-year study was performed at the Vavihill background station in southern Sweden to estimate the anthropogenic contribution to the carbonaceous aerosol. Weekly samples of the particulate matter PM10 were collected on quartz filters, and the amounts of organic carbon, elemental carbon, radiocarbon (14C and levoglucosan were measured. This approach enabled source apportionment of the total carbon in the PM10 fraction using the concentration ratios of the sources. The sources considered in this study were emissions from the combustion of fossil fuels and biomass, as well as biogenic sources. During the summer, the carbonaceous aerosol mass was dominated by compounds of biogenic origin (80%, which are associated with biogenic primary and secondary organic aerosols. During the winter months, biomass combustion (32% and fossil fuel combustion (28% were the main contributors to the carbonaceous aerosol. Elemental carbon concentrations in winter were about twice as large as during summer, and can be attributed to biomass combustion, probably from domestic wood burning. The contribution of fossil fuels to elemental carbon was stable throughout the year, although the fossil contribution to organic carbon increased during the winter. Thus, the organic aerosol originated mainly from natural sources during the summer and from anthropogenic sources during the winter. The result of this source apportionment was compared with results from the EMEP MSC-W chemical transport model. The model and measurements were generally consistent for total atmospheric organic carbon, however, the contribution of the sources varied substantially. E.g. the biomass burning contributions of OC were underestimated by the model by a factor of 2.2 compared to the measurements.

  18. Characterization of urban aerosol sources in Debrecen, Hungary

    International Nuclear Information System (INIS)

    Kertesz, Zs.; Szoboszlai, T.; Angyal, A.; Dobos, E.; Borbely-Kiss, I.

    2009-01-01

    Complete text of publication follows. Aerosol pollution represents significant health hazard in urban environments. Despite the fact that Debrecen has not a much stressed environment the city is highly exposed to aerosol pollution. In order to evaluate the impact of aerosol particles on health, the knowledge of the particle size distribution, chemical composition, sources, and their change in time and space is needed. This work presents a source apportionment study of fine (particles with aerodynamic diameter less than 2.5 μm) and coarse (particles with aerodynamic diameter between 2.5 and 10 μm) particulate matter in Debrecen by following the evolution of the elemental components with hourly time resolution. The variation of the elemental concentrations, their periodicity, correlation with other elements and meteorological parameters were studied on samples collected in different seasons. Aerosol sources were determined using the positive matrix factorization (PMF) method. Aerosol samples were collected in the garden of the ATOMKI with a 2-stage sequential streaker sampler manufactured by PIXE International, which collected the fine and coarse fraction separately with few hours' time resolution. Between October 2007 and January 2009 five 10-days long sampling campaigns were carried out. The elemental composition was determined by Particle Induced X-ray emission (PIXE) for Z ≥ 13, and the elemental carbon (BC) content was estimated with a smoke stain reflectometer. Source apportionment was carried out with the PMF receptor model developed for aerosol source characterization, provided by US EPA. Mass of species apportioned to factor, percentage of species apportioned to factors and average factor contributions of the campaigns, of working days and weekends and within the days were calculated. The PMF analysis resulted seven factors in the fine and seven factors in the coarse mode. The main sources of atmospheric aerosol in the city of Debrecen were traffic

  19. Sources and geographical origins of fine aerosols in Paris (France)

    International Nuclear Information System (INIS)

    Bressi, M.; Nicolas, J.B.; Sciare, J.; Feron, A.; Nonnaire, N.; Petit, J.E.

    2014-01-01

    The present study aims at identifying and apportioning fine aerosols to their major sources in Paris (France) - the second most populated - larger urban zone - in Europe - and determining their geographical origins. It is based on the daily chemical composition of PM2.5 examined over 1 year at an urban background site of Paris (Bressi et al., 2013). Positive matrix factorization (EPA PMF3.0) was used to identify and apportion fine aerosols to their sources; bootstrapping was performed to determine the adequate number of PMF factors, and statistics (root mean square error, coefficient of determination, etc.) were examined to better model PM2.5 mass and chemical components. Potential source contribution function (PSCF) and conditional probability function (CPF) allowed the geographical origins of the sources to be assessed; special attention was paid to implement suitable weighting functions. Seven factors, namely ammonium sulfate (A.S.)-rich factor, ammonium nitrate (A.N.)-rich factor, heavy oil combustion, road traffic, biomass burning, marine aerosols and metal industry, were identified; a detailed discussion of their chemical characteristics is reported. They contribute 27, 24, 17, 14, 12, 6 and 1% of PM2.5 mass (14.7 μgm -3 ) respectively on the annual average; their seasonal variability is discussed. The A.S.- and A.N.-rich factors have undergone mid- or long-range transport from continental Europe; heavy oil combustion mainly stems from northern France and the English Channel, whereas road traffic and biomass burning are primarily locally emitted. Therefore, on average more than half of PM2.5 mass measured in the city of Paris is due to mid- or long-range transport of secondary aerosols stemming from continental Europe, whereas local sources only contribute a quarter of the annual averaged mass. These results imply that fine-aerosol abatement policies conducted at the local scale may not be sufficient to notably reduce PM2.5 levels at urban background sites

  20. Modeling Secondary Organic Aerosol Formation From Emissions of Combustion Sources

    Science.gov (United States)

    Jathar, Shantanu Hemant

    Atmospheric aerosols exert a large influence on the Earth's climate and cause adverse public health effects, reduced visibility and material degradation. Secondary organic aerosol (SOA), defined as the aerosol mass arising from the oxidation products of gas-phase organic species, accounts for a significant fraction of the submicron atmospheric aerosol mass. Yet, there are large uncertainties surrounding the sources, atmospheric evolution and properties of SOA. This thesis combines laboratory experiments, extensive data analysis and global modeling to investigate the contribution of semi-volatile and intermediate volatility organic compounds (SVOC and IVOC) from combustion sources to SOA formation. The goals are to quantify the contribution of these emissions to ambient PM and to evaluate and improve models to simulate its formation. To create a database for model development and evaluation, a series of smog chamber experiments were conducted on evaporated fuel, which served as surrogates for real-world combustion emissions. Diesel formed the most SOA followed by conventional jet fuel / jet fuel derived from natural gas, gasoline and jet fuel derived from coal. The variability in SOA formation from actual combustion emissions can be partially explained by the composition of the fuel. Several models were developed and tested along with existing models using SOA data from smog chamber experiments conducted using evaporated fuel (this work, gasoline, fischertropschs, jet fuel, diesels) and published data on dilute combustion emissions (aircraft, on- and off-road gasoline, on- and off-road diesel, wood burning, biomass burning). For all of the SOA data, existing models under-predicted SOA formation if SVOC/IVOC were not included. For the evaporated fuel experiments, when SVOC/IVOC were included predictions using the existing SOA model were brought to within a factor of two of measurements with minor adjustments to model parameterizations. Further, a volatility

  1. Source apportionment of size and time resolved trace elements and organic aerosols from an urban courtyard site in Switzerland

    Science.gov (United States)

    Richard, A.; Gianini, M. F. D.; Mohr, C.; Furger, M.; Bukowiecki, N.; Minguillón, M. C.; Lienemann, P.; Flechsig, U.; Appel, K.; Decarlo, P. F.; Heringa, M. F.; Chirico, R.; Baltensperger, U.; Prévôt, A. S. H.

    2011-09-01

    Time and size resolved data of trace elements were obtained from measurements with a rotating drum impactor (RDI) and subsequent X-ray fluorescence spectrometry. Trace elements can act as indicators for the identification of sources of particulate matter Switzerland. Eight different sources were identified for the three examined size ranges (PM1-0.1, PM2.5-1 and PM10-2.5): secondary sulfate, wood combustion, fire works, road traffic, mineral dust, de-icing salt, industrial and local anthropogenic activities. The major component was secondary sulfate for the smallest size range; the road traffic factor was found in all three size ranges. This trace element analysis is complemented with data from an Aerodyne high-resolution time-of-flight aerosol mass spectrometer (AMS), assessing the PM1 fraction of organic aerosols. A separate PMF analysis revealed three factors related to three of the sources found with the RDI: oxygenated organic aerosol (OOA, related to inorganic secondary sulfate), hydrocarbon-like organic aerosol (HOA, related to road traffic) and biomass burning organic aerosol (BBOA), explaining 60 %, 22 % and 17 % of total measured organics, respectively. Since different compounds are used for the source classification, a higher percentage of the ambient PM10 mass concentration can be apportioned to sources by the combination of both methods.

  2. Chemical composition and sources of atmospheric aerosols at Djougou (Benin)

    Science.gov (United States)

    Ouafo-Leumbe, Marie-Roumy; Galy-Lacaux, Corinne; Liousse, Catherine; Pont, Veronique; Akpo, Aristide; Doumbia, Thierno; Gardrat, Eric; Zouiten, Cyril; Sigha-Nkamdjou, Luc; Ekodeck, Georges Emmanuel

    2017-06-01

    In the framework of the INDAAF (International Network to study Deposition and Atmospheric chemistry in AFrica) program, atmospheric aerosols were collected in PM2.5 and PM10 size fractions at Djougou, Benin, in the West Africa, from November, 2005 to October, 2009. Particulate carbon, ionic species, and trace metals were analyzed. Weekly PM2.5 and PM10 total mass concentrations varied between 0.7 and 47.3 µg m-3 and 1.4-148.3 µg m-3, respectively. We grouped the aerosol chemical compounds into four classes: dust, particulate organic matter (POM), elemental carbon (EC), and ions. We studied the annual variation of each class to determine their contribution in the total aerosol mass concentration and finally to investigate their potential emission sources. On an annual basis, the species presented a well-marked seasonality, with the peak of mass concentration for both sizes registered in dry season, 67 ± 2 to 86 ± 9 versus 14 ± 9 to 34 ± 5% in wet season. These values emphasized the seasonality of the emissions and the relative weak interannual standard deviation indicates the low variability of the seasonality. At the seasonal scale, major contributions to the aerosol chemistry in the dry season are: dust (26-59%), POM (30-59%), EC (5-9%), and ions (3-5%), suggesting a predominance of Sahelian and Saharan dust emissions and biomass burning source in this season. In the wet season, POM is predominant, followed by dust, EC, and ions. These results point out the contribution of surrounded biofuel combustion used for cooking and biogenic emissions during the wet season.

  3. Pollutants identification of ambient aerosols by two types of aerosol mass spectrometers over southeast coastal area, China.

    Science.gov (United States)

    Yan, Jinpei; Chen, Liqi; Lin, Qi; Zhao, Shuhui; Li, Lei

    2018-02-01

    Two different aerosol mass spectrometers, Aerodyne Aerosol Mass Spectrometer (AMS) and Single Particle Aerosol Mass Spectrometer (SPAMS) were deployed to identify the aerosol pollutants over Xiamen, representing the coastal urban area. Five obvious processes were classified during the whole observation period. Organics and sulfate were the dominant components in ambient aerosols over Xiamen. Most of the particles were in the size range of 0.2-1.0μm, accounting for over 97% of the total particles measured by both instruments. Organics, as well as sulfate, measured by AMS were in good correlation with measured by SPAMS. However, high concentration of NH 4 + was obtained by AMS, while extremely low value of NH 4 + was detected by SPAMS. Contrarily, high particle number counts of NO 3 - and Cl - were given by SPAMS while low concentrations of NO 3 - and Cl - were measured by AMS. The variations of POA and SOA obtained from SPAMS during event 1 and event 2 were in accordance with the analysis of HOA and OOA given by AMS, suggesting that both of AMS and SPAMS can well identify the organic clusters of aerosol particles. Overestimate or underestimate of the aerosol sources and acidity would be present in some circumstances when the measurement results were used to analyze the aerosol properties, because of the detection loss of some species for both instruments. Copyright © 2017. Published by Elsevier B.V.

  4. Composition and sources of carbonaceous aerosols in Northern Europe during winter

    NARCIS (Netherlands)

    Glasius, M.; Hansen, A.M.K.; Claeys, M.; Henzing, J.S.; Jedynska, A.D.; Kasper-Giebl, A.; Kistler, M.; Kristensen, K.; Martinsson, J.; Maenhaut, W.; Nøjgaard, J.K.; Spindler, G.; Stenström, K.E.; Swietlicki, E.; Szidat, S.; Simpson, D.; Yttri, K.E.

    2018-01-01

    Sources of elemental carbon (EC) and organic carbon (OC) in atmospheric aerosols (carbonaceous aerosols) were investigated by collection of weekly aerosol filter samples at six background sites in Northern Europe (Birkenes, Norway; Vavihill, Sweden; Risoe, Denmark; Cabauw and Rotterdam in The

  5. Sub-Antarctic marine aerosol: dominant contributions from biogenic sources

    Directory of Open Access Journals (Sweden)

    J. Schmale

    2013-09-01

    Full Text Available Biogenic influences on the composition and characteristics of aerosol were investigated on Bird Island (54°00' S, 38°03' W in the South Atlantic during November and December 2010. This remote marine environment is characterised by large seabird and seal colonies. The chemical composition of the submicron particles, measured by an aerosol mass spectrometer (AMS, was 21% non-sea-salt sulfate, 2% nitrate, 8% ammonium, 22% organics and 47% sea salt including sea salt sulfate. A new method to isolate the sea spray signature from the high-resolution AMS data was applied. Generally, the aerosol was found to be less acidic than in other marine environments due to the high availability of ammonia, from local fauna emissions. By positive matrix factorisation five different organic aerosol (OA profiles could be isolated: an amino acid/amine factor (AA-OA, 18% of OA mass, a methanesulfonic acid OA factor (MSA-OA, 25%, a marine oxygenated OA factor (M-OOA, 41%, a sea spray OA fraction (SS-OA, 7% and locally produced hydrocarbon-like OA (HOA, 9%. The AA-OA was dominant during the first two weeks of November and found to be related with the hatching of penguins in a nearby colony. This factor, rich in nitrogen (N : C ratio = 0.13, has implications for the biogeochemical cycling of nitrogen in the area as particulate matter is often transported over longer distances than gaseous N-rich compounds. The MSA-OA was mainly transported from more southerly latitudes where phytoplankton bloomed. The bloom was identified as one of three sources for particulate sulfate on Bird Island, next to sea salt sulfate and sulfate transported from South America. M-OOA was the dominant organic factor and found to be similar to marine OA observed at Mace Head, Ireland. An additional OA factor highly correlated with sea spray aerosol was identified (SS-OA. However, based on the available data the type of mixture, internal or external, could not be determined. Potassium was not

  6. Characteristics and sources of carbonaceous aerosols from Shanghai, China

    Science.gov (United States)

    Cao, J.-J.; Zhu, C.-S.; Tie, X.-X.; Geng, F.-H.; Xu, H.-M.; Ho, S. S. H.; Wang, G.-H.; Han, Y.-M.; Ho, K.-F.

    2013-01-01

    An intensive investigation of carbonaceous PM2.5 and TSP (total suspended particles) from Pudong (China) was conducted as part of the MIRAGE-Shanghai (Megacities Impact on Regional and Global Environment) experiment in 2009. Data for organic and elemental carbon (OC and EC), organic species, including C17 to C40 n-alkanes and 17 polycyclic aromatic hydrocarbons (PAHs), and stable carbon isotopes OC (δ13COC) and EC (δ13CEC) were used to evaluate the aerosols' temporal variations and identify presumptive sources. High OC/EC ratios indicated a large fraction of secondary organic aerosol (SOA); high char/soot ratios indicated stronger contributions to EC from motor vehicles and coal combustion than biomass burning. Diagnostic ratios of PAHs indicated that much of the SOA was produced via coal combustion. Isotope abundances (δ13COC = -24.5 ± 0.8‰ and δ13CEC = -25.1 ± 0.6‰) indicated that fossil fuels were the most important source for carbonaceous PM2.5 (particulate matter less than 2.5 micrometers in diameter), with lesser impacts from biomass burning and natural sources. An EC tracer system and isotope mass balance calculations showed that the relative contributions to total carbon from coal combustion, motor vehicle exhaust, and SOA were 41%, 21%, and 31%; other primary sources such as marine, soil and biogenic emissions contributed 7%. Combined analyses of OC and EC, n-alkanes and PAHs, and stable carbon isotopes provide a new way to apportion the sources of carbonaceous particles.

  7. Characteristics and sources of carbonaceous aerosols from Shanghai, China

    Directory of Open Access Journals (Sweden)

    J.-J. Cao

    2013-01-01

    Full Text Available An intensive investigation of carbonaceous PM2.5 and TSP (total suspended particles from Pudong (China was conducted as part of the MIRAGE-Shanghai (Megacities Impact on Regional and Global Environment experiment in 2009. Data for organic and elemental carbon (OC and EC, organic species, including C17 to C40 n-alkanes and 17 polycyclic aromatic hydrocarbons (PAHs, and stable carbon isotopes OC (δ13COC and EC (δ13CEC were used to evaluate the aerosols' temporal variations and identify presumptive sources. High OC/EC ratios indicated a large fraction of secondary organic aerosol (SOA; high char/soot ratios indicated stronger contributions to EC from motor vehicles and coal combustion than biomass burning. Diagnostic ratios of PAHs indicated that much of the SOA was produced via coal combustion. Isotope abundances (δ13COC = −24.5 ± 0.8‰ and δ13CEC = −25.1 ± 0.6‰ indicated that fossil fuels were the most important source for carbonaceous PM2.5 (particulate matter less than 2.5 micrometers in diameter, with lesser impacts from biomass burning and natural sources. An EC tracer system and isotope mass balance calculations showed that the relative contributions to total carbon from coal combustion, motor vehicle exhaust, and SOA were 41%, 21%, and 31%; other primary sources such as marine, soil and biogenic emissions contributed 7%. Combined analyses of OC and EC, n-alkanes and PAHs, and stable carbon isotopes provide a new way to apportion the sources of carbonaceous particles.

  8. Two-year study of atmospheric aerosols in Alta Floresta, Brazil: Multielemental composition and source apportionment

    International Nuclear Information System (INIS)

    Maenhaut, Willy; Fernandez-Jimenez, Maria-Teresa; Rajta, Istvan; Artaxo, Paulo

    2002-01-01

    Atmospheric aerosol samples were collected nearly continuously from August 1996 until September 1998 at Alta Floresta in a primary forest region of the Amazon basin, Brazil. The sampling device consisted of a stacked filter unit (SFU), which separates the aerosol into a coarse (2-10 μm equivalent aerodynamic diameter (EAD)) and a fine (<2 μm EAD) size fraction. The coarse and fine filters of all SFU samples (205 in total) were analysed for the particulate mass (PM), black carbon (BC), and up to 47 elements (from Na upward). The multielemental analyses were done by a combination of PIXE and instrumental neutron activation analysis. Absolute principal component analysis was used for source (source type) identification and apportionment. Five components were identified in the fine size fraction, i.e. mineral dust, a biomass burning (pyrogenic) component (with PM, BC, S, K, Zn, Br, Rb and I, having loadings in the range 0.7-0.9), a Na/Ca component, a biogenic component (with P), and an almost pure Pb component. On average 67% of the fine PM was attributed to the pyrogenic component, 14% to the mineral dust, 7% each to the biogenic and Na/Ca components, and 4% to the Pb component. The relative contribution from the pyrogenic aerosol varied substantially with season, however. It was generally between 60% and 100% during the dry season. During the wet season, on the other hand, it often became insignificant. During that season, most of the fine aerosol was attributed to the biogenic component

  9. Global source attribution of sulfate aerosol and its radiative forcing

    Science.gov (United States)

    Yang, Y.; Wang, H.; Smith, S.; Easter, R. C.; Ma, P. L.; Qian, Y.; Li, C.; Yu, H.; Rasch, P. J.

    2017-12-01

    Sulfate is an important aerosol that poses health risks and influences climate. Due to long-range atmospheric transport, local sulfate pollution could result from intercontinental influences, making domestic efforts of improving air quality inefficient. Accurate understanding of source attribution of sulfate and its radiative forcing is important for both regional air quality improvement and global climate mitigation. In this study, for the first time, a sulfur source-tagging capability is implemented in the Community Atmosphere Model (CAM5) to quantify the global source-receptor relationships of sulfate and its direct and indirect radiative forcing (DRF and IRF). Near-surface sulfate concentrations are mostly contributed by local emissions in regions with high emissions, while over regions with relatively low SO2 emissions, the near-surface sulfate is primarily attributed to non-local sources from long-range transport. The export of SO2 and sulfate from Europe contributes 20% of sulfate concentrations over North Africa, Russia and Central Asia. Sources from the Middle East account for 20% of sulfate over North Africa, Southern Africa and Central Asia in winter and autumn, and 20% over South Asia in spring. East Asia accounts for about 50% of sulfate over Southeast Asia in winter and autumn, 15% over Russia in summer, and 10% over North America in spring. South Asia contributes to 25% of sulfate over Southeast Asia in spring. Lifetime of aerosols, together with regional export, is found to determine regional air quality. The simulated global total sulfate DRF is -0.42 W m-2, with 75% contributed by anthropogenic sulfate and 25% contributed by natural sulfate. In the Southern Hemisphere tropics, dimethyl sulfide (DMS) contributes the most to the total DRF. East Asia has the largest contribution of 20-30% over the Northern Hemisphere mid- and high-latitudes. A 20% perturbation of sulfate and its precursor emissions gives a sulfate IRF of -0.44 W m-2. DMS has the

  10. Source specific risk assessment of indoor aerosol particles

    Energy Technology Data Exchange (ETDEWEB)

    Koivisto, A.J.

    2013-05-15

    In the urban environment, atmospheric aerosols consist mainly of pollutants from anthropogenic sources. The majority of these originate from traffic and other combustion processes. A fraction of these pollutants will penetrate indoors via ventilation. However, indoor air concentrations are usually predominated by indoor sources due to the small amount of dilution air. In modern societies, people spend most of their time indoors. Thus, their exposure is controlled mainly by indoor concentrations from indoor sources. During the last decades, engineering of nanosized structures has created a new field of material science. Some of these materials have been shown to be potentially toxic to human health. The greatest potential for exposure to engineered nanomaterials (ENMs) occurs in the workplace during production and handling of ENMs. In an exposure assessment, both gaseous and particulate matter pollutants need to be considered. The toxicities of the particles usually depend on the source and age. With time, particle morphology and composition changes due to their tendency to undergo coagulation, condensation and evaporation. The PM exposure risk is related to source specific emissions, and thus, in risk assessment one needs to define source specific exposures. This thesis describes methods for source specific risk assessment of airborne particulate matter. It consists of studies related to workers' ENM exposures during the synthesis of nanoparticles, packing of agglomerated TiO{sub 2} nanoparticles, and handling of nanodiamonds. Background particles were distinguished from the ENM concentrations by using different measurement techniques and indoor aerosol modelings. Risk characterization was performed by using a source specific exposure and calculated dose levels in units of particle number and mass. The exposure risk was estimated by using non-health based occupational exposure limits for ENMs. For the nanosized TiO{sub 2}, the risk was also assessed from dose

  11. Methods of analysis for complex organic aerosol mixtures from urban emission sources of particulate carbon

    International Nuclear Information System (INIS)

    Mazurek, M.A.; Hildemann, L.M.; Simoneit, B.R.T.

    1990-10-01

    Organic aerosols comprise approximately 30% by mass of the total fine particulate matter present in urban atmospheres. The chemical composition of such aerosols is complex and reflects input from multiple sources of primary emissions to the atmosphere, as well as from secondary production of carbonaceous aerosol species via photochemical reactions. To identify discrete sources of fine carbonaceous particles in urban atmospheres, analytical methods must reconcile both bulk chemical and molecular properties of the total carbonaceous aerosol fraction. This paper presents an overview of the analytical protocol developed and used in a study of the major sources of fine carbon particles emitted to an urban atmosphere. 23 refs., 1 fig., 2 tabs

  12. Sources of trace elements observed in the Arctic aerosol

    International Nuclear Information System (INIS)

    Hopke, P.K.; Cheng, M.D.; Landsberger, S.; Barrie, L.A.

    1991-01-01

    There have been many efforts made to identify the sources of the airborne particles seen in the Arctic. In this study, the Potential Source Contribution Function (PSCF), a probability function based on the air parcel trajectory data coupled with the contaminant concentrations measured in that air parcel, has been calculated for a series of week long airborne particle samples collected at Alert, N.W.T. between 1983 and 1987. These samples have been analyzed by instrumental neutron activation. Using calculated 3 level back trajectories and extended Total Potential Source Contribution methodology, the patterns of total potential source contribution probabilities can be examined for each individual species or based on the results of a principal components analysis of the elemental data to examine covarying species. Regions with high PSCF values have a higher probability of contributing pollutants to the measured concentrations at the receptor site. The implications of these results for more specific identification of source regions of the various species are discussed

  13. A large source of low-volatility secondary organic aerosol

    DEFF Research Database (Denmark)

    Ehn, Mikael; Thornton, Joel A.; Kleist, Einhard

    2014-01-01

    radiation and by acting as cloud condensation nuclei. The quantitative assessment of such climate effects remains hampered by a number of factors, including an incomplete understanding of how biogenic VOCs contribute to the formation of atmospheric secondary organic aerosol. The growth of newly formed...... particles from sizes of less than three nanometres up to the sizes of cloud condensation nuclei (about one hundred nanometres) in many continental ecosystems requires abundant, essentially non-volatile organic vapours, but the sources and compositions of such vapours remain unknown. Here we investigate...... the oxidation of VOCs, in particular the terpene α-pinene, under atmospherically relevant conditions in chamber experiments. We find that a direct pathway leads from several biogenic VOCs, such as monoterpenes, to the formation of large amounts of extremely low-volatility vapours. These vapours form...

  14. Identification of oil spill's sources

    International Nuclear Information System (INIS)

    Boniforti, R.

    1992-10-01

    Identifying the source of a marine oil spill is complicated because of the rapid modifications (weathering) undergone by oil as soon as it reaches the sea. Deciding if differences occurring between an oil sample collected after the spill and the original oil can be attributed to weathering involves not only adoption of sophisticated analytical methods but also correct sampling techniques and strict adherence to a chain-of-custody procedure. The method described in this paper, largely based on those adopted by some northern European countries, establishes the identity or non-identity of two samples by exploiting differences rather than similarities between them. It increases the efficiency of the method because it is sufficient to establish that there exists only one difference for deciding that two samples are different

  15. Identifications of Einstein Slew Survey sources

    Science.gov (United States)

    Schachter, Jonathan F.; Elvis, Martin S.; Plummer, David; Fabbiano, G.

    1992-01-01

    The status of identifications of the Einstien Slew Survey, a bright soft x-ray catalog with 550 new x-ray sources, is discussed. Possible counterparts were found for greater than 95 percent of the Slew Survey based on positional coincidences and color-color diagnostics. The survey will be fully identified via upcoming radio and optical observations.

  16. Identification of secondary aerosol precursors emitted by an aircraft turbofan

    Science.gov (United States)

    Kılıç, Doğuşhan; El Haddad, Imad; Brem, Benjamin T.; Bruns, Emily; Bozetti, Carlo; Corbin, Joel; Durdina, Lukas; Huang, Ru-Jin; Jiang, Jianhui; Klein, Felix; Lavi, Avi; Pieber, Simone M.; Rindlisbacher, Theo; Rudich, Yinon; Slowik, Jay G.; Wang, Jing; Baltensperger, Urs; Prévôt, Andre S. H.

    2018-05-01

    Oxidative processing of aircraft turbine-engine exhausts was studied using a potential aerosol mass (PAM) chamber at different engine loads corresponding to typical flight operations. Measurements were conducted at an engine test cell. Organic gases (OGs) and particle emissions pre- and post-PAM were measured. A suite of instruments, including a proton-transfer-reaction mass spectrometer (PTR-MS) for OGs, a multigas analyzer for CO, CO2, NOx, and an aerosol mass spectrometer (AMS) for nonrefractory particulate matter (NR-PM1) were used. Total aerosol mass was dominated by secondary aerosol formation, which was approximately 2 orders of magnitude higher than the primary aerosol. The chemical composition of both gaseous and particle emissions were also monitored at different engine loads and were thrust-dependent. At idling load (thrust 2.5-7 %), more than 90 % of the secondary particle mass was organic and could mostly be explained by the oxidation of gaseous aromatic species, e.g., benzene; toluene; xylenes; tri-, tetra-, and pentamethyl-benzene; and naphthalene. The oxygenated-aromatics, e.g., phenol, furans, were also included in this aromatic fraction and their oxidation could alone explain up to 25 % of the secondary organic particle mass at idling loads. The organic fraction decreased with thrust level, while the inorganic fraction increased. At an approximated cruise load sulfates comprised 85 % of the total secondary particle mass.

  17. Identification of secondary aerosol precursors emitted by an aircraft turbofan

    Directory of Open Access Journals (Sweden)

    D. Kılıç

    2018-05-01

    Full Text Available Oxidative processing of aircraft turbine-engine exhausts was studied using a potential aerosol mass (PAM chamber at different engine loads corresponding to typical flight operations. Measurements were conducted at an engine test cell. Organic gases (OGs and particle emissions pre- and post-PAM were measured. A suite of instruments, including a proton-transfer-reaction mass spectrometer (PTR-MS for OGs, a multigas analyzer for CO, CO2, NOx, and an aerosol mass spectrometer (AMS for nonrefractory particulate matter (NR-PM1 were used. Total aerosol mass was dominated by secondary aerosol formation, which was approximately 2 orders of magnitude higher than the primary aerosol. The chemical composition of both gaseous and particle emissions were also monitored at different engine loads and were thrust-dependent. At idling load (thrust 2.5–7 %, more than 90 % of the secondary particle mass was organic and could mostly be explained by the oxidation of gaseous aromatic species, e.g., benzene; toluene; xylenes; tri-, tetra-, and pentamethyl-benzene; and naphthalene. The oxygenated-aromatics, e.g., phenol, furans, were also included in this aromatic fraction and their oxidation could alone explain up to 25 % of the secondary organic particle mass at idling loads. The organic fraction decreased with thrust level, while the inorganic fraction increased. At an approximated cruise load sulfates comprised 85 % of the total secondary particle mass.

  18. Source apportionment of size and time resolved trace elements and organic aerosols from an urban courtyard site in Switzerland

    Directory of Open Access Journals (Sweden)

    A. Richard

    2011-09-01

    Full Text Available Time and size resolved data of trace elements were obtained from measurements with a rotating drum impactor (RDI and subsequent X-ray fluorescence spectrometry. Trace elements can act as indicators for the identification of sources of particulate matter <10 μm (PM10 in ambient air. Receptor modeling was performed with positive matrix factorization (PMF for trace element data from an urban background site in Zürich, Switzerland. Eight different sources were identified for the three examined size ranges (PM1−0.1, PM2.5−1 and PM10−2.5: secondary sulfate, wood combustion, fire works, road traffic, mineral dust, de-icing salt, industrial and local anthropogenic activities. The major component was secondary sulfate for the smallest size range; the road traffic factor was found in all three size ranges. This trace element analysis is complemented with data from an Aerodyne high-resolution time-of-flight aerosol mass spectrometer (AMS, assessing the PM1 fraction of organic aerosols. A separate PMF analysis revealed three factors related to three of the sources found with the RDI: oxygenated organic aerosol (OOA, related to inorganic secondary sulfate, hydrocarbon-like organic aerosol (HOA, related to road traffic and biomass burning organic aerosol (BBOA, explaining 60 %, 22 % and 17 % of total measured organics, respectively. Since different compounds are used for the source classification, a higher percentage of the ambient PM10 mass concentration can be apportioned to sources by the combination of both methods.

  19. Source apportionment of fine organic aerosols in Beijing

    Directory of Open Access Journals (Sweden)

    S. Guo

    2009-11-01

    Full Text Available Fine particles (PM2.5, i.e., particles with an aerodynamic diameter of ≤2.5 μm were collected from the air in August 2005, August–September 2006, and January–February 2007, in Beijing, China. The chemical compositions of particulate organic matter in the ambient samples were quantified by gas chromatography/mass spectrometry. The dominant compounds identified in summertime were n-alkanoic acids, followed by dicarboxylic acids and sugars, while sugars became the most abundant species in winter, followed by polycyclic aromatic hydrocarbons, n-alkanes, and n-alkanoic acids. The contributions of seven emission sources (i.e., gasoline/diesel vehicles, coal burning, wood/straw burning, cooking, and vegetative detritus to particulate organic matter in PM2.5 were estimated using a chemical mass balance receptor model. The model results present the seasonal trends of source contributions to organic aerosols. Biomass burning (straw and wood had the highest contribution in winter, followed by coal burning, vehicle exhaust, and cooking. The contribution of cooking was the highest in summer, followed by vehicle exhaust and biomass burning, while coal smoke showed only a minor contribution to ambient organic carbon.

  20. Characterization of carbonaceous aerosol emissions from selected combustion sources

    International Nuclear Information System (INIS)

    Martinez, J.P.G.; Espino, M.P.M.; Pabroa, P.C.B.; Bautista, A.T. VII

    2015-01-01

    Carbonaceous Particulates are carbon-containing solid or liquid matter which form a significant portion of the fine particulate mass (PM2.5) and these have known profound adverse effects on health, climate and visibility. This study aims to characterize carbonaceous aerosol emissions from different combustion sources to establish fingerprints for these for use in the refinement of improvement of the resolution of sources apportionment studies being done by the Philippine Nuclear Research Institute (PNRI), i.e. to resolve vehicular emission sources. Fine air particulate sample were collected in pre-baked Quartz filters using an improvised collection set-up with a Gent sampler. Concentrations of organic and elemental carbon (OC and EC, respectively) in PM2.5 were measured for the different combustion sources—vehicular emissions, tire pyrolysis, and biomass burning, using a thermal-optical method of analysis following the IMPROVE_A protocol. Measured OC ad EC concentrations are shown as percentages with respect to the total carbon (TC) and are illustrated in a 100% stacked chart. Predominance of the EC2 fraction is exhibited in both the diesel fuelled vehicle and tire pyrolysis emissions with EC2/OC2 ratio distinguishing one from the other, EC2/OC2 is 1.63 and 8.41, respectively. Predominance of either OC2 or OC3 fraction is shown in the unleaded gasoline and LPG Fuelled vehicles and in biomass burning with the OC2/OC3 ratio distinguishing one from the others. OC2/OC3 ratios are 1.33 for unleaded gasoline fuelled vehicle, 1.89 for LPG-fuelled vehicle, 0.55 for biomass burning (leaves) and 0.82 biomass burning (wood). The study has shown probable use of the EC2/OC2 and OC2/OC3 ratios to distinguish fingerprints for combustion sources covered in this study. (author)

  1. Identification of aerosol types over an urban site based on air-mass trajectory classification

    Science.gov (United States)

    Pawar, G. V.; Devara, P. C. S.; Aher, G. R.

    2015-10-01

    Columnar aerosol properties retrieved from MICROTOPS II Sun Photometer measurements during 2010-2013 over Pune (18°32‧N; 73°49‧E, 559 m amsl), a tropical urban station in India, are analyzed to identify aerosol types in the atmospheric column. Identification/classification is carried out on the basis of dominant airflow patterns, and the method of discrimination of aerosol types on the basis of relation between aerosol optical depth (AOD500 nm) and Ångström exponent (AE, α). Five potential advection pathways viz., NW/N, SW/S, N, SE/E and L have been identified over the observing site by employing the NOAA-HYSPLIT air mass back trajectory analysis. Based on AE against AOD500 nm scatter plot and advection pathways followed five major aerosol types viz., continental average (CA), marine continental average (MCA), urban/industrial and biomass burning (UB), desert dust (DD) and indeterminate or mixed type (MT) have been identified. In winter, sector SE/E, a representative of air masses traversed over Bay of Bengal and Eastern continental Indian region has relatively small AOD (τpλ = 0.43 ± 0.13) and high AE (α = 1.19 ± 0.15). These values imply the presence of accumulation/sub-micron size anthropogenic aerosols. During pre-monsoon, aerosols from the NW/N sector have high AOD (τpλ = 0.61 ± 0.21), and low AE (α = 0.54 ± 0.14) indicating an increase in the loading of coarse-mode particles over Pune. Dominance of UB type in winter season for all the years (i.e. 2010-2013) may be attributed to both local/transported aerosols. During pre-monsoon seasons, MT is the dominant aerosol type followed by UB and DD, while the background aerosols are insignificant.

  2. Characterization of distinct Arctic aerosol accumulation modes and their sources

    Science.gov (United States)

    Lange, R.; Dall'Osto, M.; Skov, H.; Nøjgaard, J. K.; Nielsen, I. E.; Beddows, D. C. S.; Simo, R.; Harrison, R. M.; Massling, A.

    2018-06-01

    In this work we use cluster analysis of long term particle size distribution data to expand an array of different shorter term atmospheric measurements, thereby gaining insights into longer term patterns and properties of Arctic aerosol. Measurements of aerosol number size distributions (9-915 nm) were conducted at Villum Research Station (VRS), Station Nord in North Greenland during a 5 year record (2012-2016). Alongside this, measurements of aerosol composition, meteorological parameters, gaseous compounds and cloud condensation nuclei (CCN) activity were performed during different shorter occasions. K-means clustering analysis of particle number size distributions on daily basis identified several clusters. Clusters of accumulation mode aerosols (main size modes > 100 nm) accounted for 56% of the total aerosol during the sampling period (89-91% during February-April, 1-3% during June-August). By association to chemical composition, cloud condensation nuclei properties, and meteorological variables, three typical accumulation mode aerosol clusters were identified: Haze (32% of the time), Bimodal (14%) and Aged (6%). In brief: (1) Haze accumulation mode aerosol shows a single mode at 150 nm, peaking in February-April, with highest loadings of sulfate and black carbon concentrations. (2) Accumulation mode Bimodal aerosol shows two modes, at 38 nm and 150 nm, peaking in June-August, with the highest ratio of organics to sulfate concentrations. (3) Aged accumulation mode aerosol shows a single mode at 213 nm, peaking in September-October and is associated with cloudy and humid weather conditions during autumn. The three aerosol clusters were considered alongside CCN concentrations. We suggest that organic compounds, that are likely marine biogenic in nature, greatly influence the Bimodal cluster and contribute significantly to its CCN activity. This stresses the importance of better characterizing the marine ecosystem and the aerosol-mediated climate effects in the

  3. Characterization of distinct Arctic aerosol accumulation modes and their sources

    DEFF Research Database (Denmark)

    Lange, R.; Dall'Osto, M.; Skov, H.

    2018-01-01

    -August). By association to chemical composition, cloud condensation nuclei properties, and meteorological variables, three typical accumulation mode aerosol clusters were identified: Haze (32% of the time), Bimodal (14%) and Aged (6%). In brief: (1) Haze accumulation mode aerosol shows a single mode at 150 nm, peaking...

  4. A Source Identification Algorithm for INTEGRAL

    Science.gov (United States)

    Scaringi, Simone; Bird, Antony J.; Clark, David J.; Dean, Anthony J.; Hill, Adam B.; McBride, Vanessa A.; Shaw, Simon E.

    2008-12-01

    We give an overview of ISINA: INTEGRAL Source Identification Network Algorithm. This machine learning algorithm, using Random Forests, is applied to the IBIS/ISGRI dataset in order to ease the production of unbiased future soft gamma-ray source catalogues. The key steps of candidate searching, filtering and feature extraction are described. Three training and testing sets are created in order to deal with the diverse timescales and diverse objects encountered when dealing with the gamma-ray sky. Three independent Random Forest are built: one dealing with faint persistent source recognition, one dealing with strong persistent sources and a final one dealing with transients. For the latter, a new transient detection technique is introduced and described: the Transient Matrix. Finally the performance of the network is assessed and discussed using the testing set and some illustrative source examples.

  5. Language identification using excitation source features

    CERN Document Server

    Rao, K Sreenivasa

    2015-01-01

    This book discusses the contribution of excitation source information in discriminating language. The authors focus on the excitation source component of speech for enhancement of language identification (LID) performance. Language specific features are extracted using two different modes: (i) Implicit processing of linear prediction (LP) residual and (ii) Explicit parameterization of linear prediction residual. The book discusses how in implicit processing approach, excitation source features are derived from LP residual, Hilbert envelope (magnitude) of LP residual and Phase of LP residual; and in explicit parameterization approach, LP residual signal is processed in spectral domain to extract the relevant language specific features. The authors further extract source features from these modes, which are combined for enhancing the performance of LID systems. The proposed excitation source features are also investigated for LID in background noisy environments. Each chapter of this book provides the motivatio...

  6. Synthesizing Scientific Progress: Outcomes from US EPA’s Carbonaceous Aerosols and Source Apportionment STAR Grants

    Science.gov (United States)

    ABSTRACTA number of studies in the past decade have transformed the way we think about atmospheric aerosols. The advances include, but are not limited to, source apportionment of organics using aerosol mass spectrometer data, the volatility basis set approach, quantifying isopre...

  7. Source term experiments project (STEP): aerosol characterization system

    International Nuclear Information System (INIS)

    Schlenger, B.J.; Dunn, P.F.

    1985-01-01

    A series of four experiments has been conducted at Argonne National Laboratory's TREAT Reactor. These experiments, which are sponsored by an international consortium organized by the Electric Power Research Institute, are designed to investigate the source term, i.e., the type, quantity and timing of release of radioactive fission products from a light water reactor to the environment in the event of a severe accident in which the core is insufficiently cooled. The STEP tests have been designed to provide some of the necessary data regarding the magnitude and release rates of volatile fission products from degraded fuel pins, their physical and chemical characteristics, and aerosol formation and transport phenomena of those fission products that condense to form particles in the cooler regions of the reactor beyond the core. These are inpile experiments, whereby the test fuels are heated in a nuclear test reactor by neutron induced fission and subsequent cladding oxidation in steam environments that simulate as closely as practical predicted severe reactor accident conditions. The test sequences cover a range of pressure and fuel heatup rate, and include the effect of Ag/In/Cd control rod material. 1 ref., 8 figs., 1 tab

  8. An attempt to determine positions of aerosol source by the PIXE analysis

    International Nuclear Information System (INIS)

    Matsuyama, S.; Tokai, Y.; Ishii, K.

    1999-01-01

    Aerosols were continuously collected for 2 or 3 hours during the periods of 4-27 August 1997 and of 23 March-2 April 1998 at a suburb of Sendai City (east 10 km from Sendai), and meteorological data such as wind directions, wind velocities, etc were measured at the same time. The collected aerosol samples were analyzed by the particle-induced X-ray emission (PIXE) method. Fourteen elements (S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Hg and Pb) were contained in these samples. The elemental concentrations increased in the daytime and decreased at night. It coincided with the time variation of people movement. The concentrations of Mn, Fe, Zn and Pb elements depended strongly on the direction of wind and their distributions for wind directions reflected to the position of aerosol sources. This result suggests that the position of aerosol source can be determined by measuring aerosols and wind directions at the many positions. (author)

  9. Source apportionment of aerosols using air parcel backward trajectories

    International Nuclear Information System (INIS)

    Lee, Jin Hong; Kim, Sung Jin; Jung, Jin Hee

    2007-02-01

    The mean concentration of the PM2.5 collected near the main road side in Daejeon was 32.1±14.1 μg/m 3 (range of 9.7 to 64.6 μg/m 3 ). The errors relative to SRM values of Al, Ca, Cu, K, Mn, Na, Sm, Ti, and V fell below 5%, while those of As, Ba, and Sb were less than 10%. The relative error of Mg was 14.0%. All RSD (relative standard deviation, %) of trace elements fell below 10% except Mg(11.1%), which means that analytical results were very precise. The range of distribution is clearly distinguished between metals with their concentrations ranging over several orders of magnitude. The concentrations of metals such as Al, Fe, K, Na, Cl, and Mg due to crustal aerosols are much higher than that of any other metal. In near the main road side in Daejeon, PM2.5 concentrations were apportioned to 7 sources by PMF; secondary sulfate (6.9±6.8 μg/m 3 , 25%), vehicle exhaust (5.4±3.3 μg/m 3 , 19%), secondary nitrate (3.9±2.8 μg/m 3 , 14%), road dust (3.8±2.5 μg/m 3 , 13%), metal smelting /incineration (2.9±2.8 μg/m 3 , 10.2%), soil dust (2.7±4.1 μg/m3, 9.5%), fossil fuel combustion(2.7±2.6 μg/m 3 , 8.8%). In order to explain the long range transport of PM2.5 in our study, we calculated the potential source contribution function based on back trajectories of air parcel with HYSPLIT. The PSCF maps show the air mass movement patterns and source regions for the PM2.5. From the PSCF maps, it is believed that much higher PM2.5 and pollution source contributions for secondary sulfate, soil dust, metal smelting/incineration, and fossil fuel combustion could be affected by long range transport process from industrial area and big city located in the China

  10. Aerosol Optical Properties Measured Onboard the Ronald H. Brown During ACE Asia as a Function of Aerosol Chemical Composition and Source Region

    Science.gov (United States)

    Quinn, P. K.; Coffman, D. J.; Bates, T. S.; Welton, E. J.; Covert, D. S.; Miller, T. L.; Johnson, J. E.; Maria, S.; Russell, L.; Arimoto, R.

    2004-01-01

    During the ACE Asia intensive field campaign conducted in the spring of 2001 aerosol properties were measured onboard the R/V Ronald H. Brown to study the effects of the Asian aerosol on atmospheric chemistry and climate in downwind regions. Aerosol properties measured in the marine boundary layer included chemical composition; number size distribution; and light scattering, hemispheric backscattering, and absorption coefficients. In addition, optical depth and vertical profiles of aerosol 180 deg backscatter were measured. Aerosol within the ACE Asia study region was found to be a complex mixture resulting from marine, pollution, volcanic, and dust sources. Presented here as a function of air mass source region are the mass fractions of the dominant aerosol chemical components, the fraction of the scattering measured at the surface due to each component, mass scattering efficiencies of the individual components, aerosol scattering and absorption coefficients, single scattering albedo, Angstrom exponents, optical depth, and vertical profiles of aerosol extinction. All results except aerosol optical depth and the vertical profiles of aerosol extinction are reported at a relative humidity of 55 +/- 5%. An over-determined data set was collected so that measured and calculated aerosol properties could be compared, internal consistency in the data set could be assessed, and sources of uncertainty could be identified. By taking into account non-sphericity of the dust aerosol, calculated and measured aerosol mass and scattering coefficients agreed within overall experimental uncertainties. Differences between measured and calculated aerosol absorption coefficients were not within reasonable uncertainty limits, however, and may indicate the inability of Mie theory and the assumption of internally mixed homogeneous spheres to predict absorption by the ACE Asia aerosol. Mass scattering efficiencies of non-sea salt sulfate aerosol, sea salt, submicron particulate organic

  11. Secondary organic aerosol formation from fossil fuel sources contribute majority of summertime organic mass at Bakersfield

    Science.gov (United States)

    Secondary organic aerosols (SOA), known to form in the atmosphere from oxidation of volatile organic compounds (VOCs) emitted by anthropogenic and biogenic sources, are a poorly understood but substantial component of atmospheric particles. In this study, we examined the chemic...

  12. Determination of the power of multielement aerosol composition emission from distant industrial sources

    International Nuclear Information System (INIS)

    Popova, S.A.; Kutsenogij, K.P.; Chankina, O.V.

    2008-01-01

    The results from the monitoring of the temporal variability of the multielement composition of atmospheric aerosols are presented. They are used to determine the emission power of a series of elements from distant sources.

  13. Characteristics and Source Apportionment of Marine Aerosols over East China Sea Using a Source-oriented Chemical Transport Model

    Science.gov (United States)

    Kang, M.; Zhang, H.; Fu, P.

    2017-12-01

    Marine aerosols exert a strong influence on global climate change and biogeochemical cycling, as oceans cover beyond 70% of the Earth's surface. However, investigations on marine aerosols are relatively limited at present due to the difficulty and inconvenience in sampling marine aerosols as well as their diverse sources. East China Sea (ECS), lying over the broad shelf of the western North Pacific, is adjacent to the Asian mainland, where continental-scale air pollution could impose a heavy load on the marine atmosphere through long-range atmospheric transport. Thus, contributions of major sources to marine aerosols need to be identified for policy makers to develop cost effective control strategies. In this work, a source-oriented version of the Community Multiscale Air Quality (CMAQ) model, which can directly track the contributions from multiple emission sources to marine aerosols, is used to investigate the contributions from power, industry, transportation, residential, biogenic and biomass burning to marine aerosols over the ECS in May and June 2014. The model simulations indicate significant spatial and temporal variations of concentrations as well as the source contributions. This study demonstrates that the Asian continent can greatly affect the marine atmosphere through long-range transport.

  14. LMFBR source term experiments in the Fuel Aerosol Simulant Test (FAST) facility

    International Nuclear Information System (INIS)

    Petrykowski, J.C.; Longest, A.W.

    1985-01-01

    The transport of uranium dioxide (UO 2 ) aerosol through liquid sodium was studied in a series of ten experiments in the Fuel Aerosol Simulant Test (FAST) facility at Oak Ridge National Laboratory (ORNL). The experiments were designed to provide a mechanistic basis for evaluating the radiological source term associated with a postulated, energetic core disruptive accident (CDA) in a liquid metal fast breeder reactor (LMFBR). Aerosol was generated by capacitor discharge vaporization of UO 2 pellets which were submerged in a sodium pool under an argon cover gas. Measurements of the pool and cover gas pressures were used to study the transport of aerosol contained by vapor bubbles within the pool. Samples of cover gas were filtered to determine the quantity of aerosol released from the pool. The depth at which the aerosol was generated was found to be the most critical parameter affecting release. The largest release was observed in the baseline experiment where the sample was vaporized above the sodium pool. In the nine ''undersodium'' experiments aerosol was generated beneath the surface of the pool at depths varying from 30 to 1060 mm. The mass of aerosol released from the pool was found to be a very small fraction of the original specimen. It appears that the bulk of aerosol was contained by bubbles which collapsed within the pool. 18 refs., 11 figs., 4 tabs

  15. Apportionment of urban aerosol sources in Cork (Ireland) by synergistic measurement techniques.

    Science.gov (United States)

    Dall'Osto, Manuel; Hellebust, Stig; Healy, Robert M; O'Connor, Ian P; Kourtchev, Ivan; Sodeau, John R; Ovadnevaite, Jurgita; Ceburnis, Darius; O'Dowd, Colin D; Wenger, John C

    2014-09-15

    The sources of ambient fine particulate matter (PM2.5) during wintertime at a background urban location in Cork city (Ireland) have been determined. Aerosol chemical analyses were performed by multiple techniques including on-line high resolution aerosol time-of-flight mass spectrometry (Aerodyne HR-ToF-AMS), on-line single particle aerosol time-of-flight mass spectrometry (TSI ATOFMS), on-line elemental carbon-organic carbon analysis (Sunset_EC-OC), and off-line gas chromatography/mass spectrometry and ion chromatography analysis of filter samples collected at 6-h resolution. Positive matrix factorization (PMF) has been carried out to better elucidate aerosol sources not clearly identified when analyzing results from individual aerosol techniques on their own. Two datasets have been considered: on-line measurements averaged over 2-h periods, and both on-line and off-line measurements averaged over 6-h periods. Five aerosol sources were identified by PMF in both datasets, with excellent agreement between the two solutions: (1) regional domestic solid fuel burning--"DSF_Regional," 24-27%; (2) local urban domestic solid fuel burning--"DSF_Urban," 22-23%; (3) road vehicle emissions--"Traffic," 15-20%; (4) secondary aerosols from regional anthropogenic sources--"SA_Regional" 9-13%; and (5) secondary aged/processed aerosols related to urban anthropogenic sources--"SA_Urban," 21-26%. The results indicate that, despite regulations for restricting the use of smoky fuels, solid fuel burning is the major source (46-50%) of PM2.5 in wintertime in Cork, and also likely other areas of Ireland. Whilst wood combustion is strongly associated with OC and EC, it was found that peat and coal combustion is linked mainly with OC and the aerosol from these latter sources appears to be more volatile than that produced by wood combustion. Ship emissions from the nearby port were found to be mixed with the SA_Regional factor. The PMF analysis allowed us to link the AMS cooking organic

  16. Sources and mixing state of summertime background aerosol in the north-western Mediterranean basin

    Science.gov (United States)

    Arndt, Jovanna; Sciare, Jean; Mallet, Marc; Roberts, Greg C.; Marchand, Nicolas; Sartelet, Karine; Sellegri, Karine; Dulac, François; Healy, Robert M.; Wenger, John C.

    2017-06-01

    An aerosol time-of-flight mass spectrometer (ATOFMS) was employed to provide real-time single particle mixing state and thereby source information for aerosols impacting the western Mediterranean basin during the ChArMEx-ADRIMED and SAF-MED campaigns in summer 2013. The ATOFMS measurements were made at a ground-based remote site on the northern tip of Corsica. Twenty-seven distinct ATOFMS particle classes were identified and subsequently grouped into eight general categories: EC-rich (elemental carbon), K-rich, Na-rich, amines, OC-rich (organic carbon), V-rich, Fe-rich and Ca-rich particles. Mass concentrations were reconstructed for the ATOFMS particle classes and found to be in good agreement with other co-located quantitative measurements (PM1, black carbon (BC), organic carbon, sulfate mass and ammonium mass). Total ATOFMS reconstructed mass (PM2. 5) accounted for 70-90 % of measured PM10 mass and was comprised of regionally transported fossil fuel (EC-rich) and biomass burning (K-rich) particles. The accumulation of these transported particles was favoured by repeated and extended periods of air mass stagnation over the western Mediterranean during the sampling campaigns. The single particle mass spectra proved to be valuable source markers, allowing the identification of fossil fuel and biomass burning combustion sources, and was therefore highly complementary to quantitative measurements made by Particle into Liquid Sampler ion chromatography (PILS-IC) and an aerosol chemical speciation monitor (ACSM), which have demonstrated that PM1 and PM10 were comprised predominantly of sulfate, ammonium and OC. Good temporal agreement was observed between ATOFMS EC-rich and K-rich particle mass concentrations and combined mass concentrations of BC, sulfate, ammonium and low volatility oxygenated organic aerosol (LV-OOA). This combined information suggests that combustion of fossil fuels and biomass produced primary EC- and OC-containing particles, which then

  17. Sources and mixing state of summertime background aerosol in the north-western Mediterranean basin

    Directory of Open Access Journals (Sweden)

    J. Arndt

    2017-06-01

    Full Text Available An aerosol time-of-flight mass spectrometer (ATOFMS was employed to provide real-time single particle mixing state and thereby source information for aerosols impacting the western Mediterranean basin during the ChArMEx-ADRIMED and SAF-MED campaigns in summer 2013. The ATOFMS measurements were made at a ground-based remote site on the northern tip of Corsica. Twenty-seven distinct ATOFMS particle classes were identified and subsequently grouped into eight general categories: EC-rich (elemental carbon, K-rich, Na-rich, amines, OC-rich (organic carbon, V-rich, Fe-rich and Ca-rich particles. Mass concentrations were reconstructed for the ATOFMS particle classes and found to be in good agreement with other co-located quantitative measurements (PM1, black carbon (BC, organic carbon, sulfate mass and ammonium mass. Total ATOFMS reconstructed mass (PM2. 5 accounted for 70–90 % of measured PM10 mass and was comprised of regionally transported fossil fuel (EC-rich and biomass burning (K-rich particles. The accumulation of these transported particles was favoured by repeated and extended periods of air mass stagnation over the western Mediterranean during the sampling campaigns. The single particle mass spectra proved to be valuable source markers, allowing the identification of fossil fuel and biomass burning combustion sources, and was therefore highly complementary to quantitative measurements made by Particle into Liquid Sampler ion chromatography (PILS-IC and an aerosol chemical speciation monitor (ACSM, which have demonstrated that PM1 and PM10 were comprised predominantly of sulfate, ammonium and OC. Good temporal agreement was observed between ATOFMS EC-rich and K-rich particle mass concentrations and combined mass concentrations of BC, sulfate, ammonium and low volatility oxygenated organic aerosol (LV-OOA. This combined information suggests that combustion of fossil fuels and biomass produced primary EC- and OC-containing particles, which

  18. ISINA: INTEGRAL Source Identification Network Algorithm

    Science.gov (United States)

    Scaringi, S.; Bird, A. J.; Clark, D. J.; Dean, A. J.; Hill, A. B.; McBride, V. A.; Shaw, S. E.

    2008-11-01

    We give an overview of ISINA: INTEGRAL Source Identification Network Algorithm. This machine learning algorithm, using random forests, is applied to the IBIS/ISGRI data set in order to ease the production of unbiased future soft gamma-ray source catalogues. First, we introduce the data set and the problems encountered when dealing with images obtained using the coded mask technique. The initial step of source candidate searching is introduced and an initial candidate list is created. A description of the feature extraction on the initial candidate list is then performed together with feature merging for these candidates. Three training and testing sets are created in order to deal with the diverse time-scales encountered when dealing with the gamma-ray sky. Three independent random forests are built: one dealing with faint persistent source recognition, one dealing with strong persistent sources and a final one dealing with transients. For the latter, a new transient detection technique is introduced and described: the transient matrix. Finally the performance of the network is assessed and discussed using the testing set and some illustrative source examples. Based on observations with INTEGRAL, an ESA project with instruments and science data centre funded by ESA member states (especially the PI countries: Denmark, France, Germany, Italy, Spain), Czech Republic and Poland, and the participation of Russia and the USA. E-mail: simo@astro.soton.ac.uk

  19. Real time measurements of submicrometer aerosols in Seoul, Korea: Sources, characteristics, and processing of organic aerosols during winter time.

    Science.gov (United States)

    Kim, H.; Zhang, Q.

    2016-12-01

    Highly time-resolved chemical characterization of non-refractory submicrometer particulate matter (NR-PM1) was conducted in Seoul, the capital of Korea, using an Aerodyne high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS). The measurements were performed during winter when persistent air quality problems associated with elevated PM concentrations were observed. The average NR-PM1 concentration was 27.5 µg m-3 and the average mass was dominated by organics (44%), followed by nitrate (24%) and sulfate (10%). Five distinct sources of organic aerosol (OA) were identified from positive matrix factorization (PMF) analysis of the AMS data: vehicle emissions represented by a hydrocarbon-like OA factor (HOA), cooking represented by a cooking OA factor (COA), wood combustion represented by a biomass burning OA factor (BBOA), and secondary aerosol formation in the atmosphere that is represented by a semi-volatile oxygenated OA factor (SVOOA) and a low volatile oxygenated OA factor (LVOOA). These factors, on average, contributed 16, 20, 23, 15 and 26% to the total OA mass, respectively, with primary organic aerosol (POA = HOA + COA + BBOA) accounting for 59% of the OA mass. On average, both primary emissions and secondary aerosol formation are important factors affecting air quality in Seoul during winter, contributing approximately equal. However, differences in the fraction of PM source and properties were observed between high and low loading PM period. For example, during stagnant period with low wind speed (WS) (0.99 ± 0.7 m/s) and high RH (71%), high PM loadings (43.6 ± 12.4 µg m-3) with enhanced fractions of nitrate (27%) and SVOOA (8%) were observed, indicating a strong influence from locally generated secondary aerosol. On the other hand, when low PM loadings (12.6 ± 7.1 µg m-3), which were commonly associated with high WS (1.8 ± 1.1 m/s) and low RH (50 %), were observed, the fraction of regional sources, such as sulfate (12%) and LVOOA (21

  20. Sources and Transport of Aerosol above the Boundary Layer over the Mediterranean Basin

    Science.gov (United States)

    Roberts, Greg; Corrigan, Craig; Ritchie, John; Pont, Veronique; Claeys, Marine; Sciare, Jean; Mallet, Marc; Dulac, François; Mihalopoulos, Nikos

    2015-04-01

    The Mediterranean Region has been identified as sensitive to changes in the hydrological cycle, which could affect the water resources for millions of people by the turn of the century. However, prior to recent observations, most climate models have not accounted for the impacts of aerosol in this region. Past airborne studies have shown that aerosol sources from Europe and Africa are often transported throughout the lower troposphere; yet, because of their complex vertical distribution, it is a challenge to capture the variability and quantify the contribution of these sources to the radiative budget and precipitation processes. The PAEROS ChArMEx Mountain Experiment (PACMEx) complemented the regional activities by collecting aerosol data from atop a mountain on the island of Corsica, France in order to assess boundary layer / free troposphere atmospheric processes. In June/July 2013, PACMEx instruments were deployed at 2000 m.asl near the center of Corsica, France to complement ground-based aerosol observations at 550 m.asl on the northern peninsula, as well as airborne measurements. Comparisons between the peninsula site and the mountain site show similar general trends in aerosol properties; yet, differences in aerosol properties reveal the myriad transport mechanisms over the Mediterranean Basin. Using aerosol physicochemical data coupled with back trajectory analysis, different sources have been identified including Saharan dust transport, residual dust mixed with sea salt, anthropogenic emissions from Western Europe, and a period of biomass burning from Eastern Europe. Each period exhibits distinct signatures in the aerosol related to transport processes above and below the boundary layer. In addition, the total aerosol concentrations at the mountain site revealed a strong diurnal cycling the between the atmospheric boundary layer and the free troposphere, which is typical of mountain-top observations. PACMEx was funded by the National Science Foundation

  1. Source apportionment of aerosol particles using polycapillary slightly focusing X-ray lens

    Energy Technology Data Exchange (ETDEWEB)

    Sun Tianxi [Key Laboratory of Beam Technology and Materials Modification of Ministry of Education, Beijing Normal University, Beijing 100875 (China) and Institute of Low Energy Nuclear Physics, Beijing Normal University, Beijing 100875 (China) and Beijing Radiation Center, Beijing 100875 (China)], E-mail: stxbeijing@163.com; Liu Zhiguo [Key Laboratory of Beam Technology and Materials Modification of Ministry of Education, Beijing Normal University, Beijing 100875 (China) and Institute of Low Energy Nuclear Physics, Beijing Normal University, Beijing 100875 (China) and Beijing Radiation Center, Beijing 100875 (China)], E-mail: liuzgbeijing@163.com; Zhu Guanghua; Liu Hui [Key Laboratory of Beam Technology and Materials Modification of Ministry of Education, Beijing Normal University, Beijing 100875 (China); Institute of Low Energy Nuclear Physics, Beijing Normal University, Beijing 100875 (China); Beijing Radiation Center, Beijing 100875 (China); Ma Yongzhong [Center for Disease Control and Prevention of Beijing, Beijing 100013 (China); Xu Qing [Institute of High Energy Physics, Chinese Academy of Science, Beijing 100039 (China); Li Yude; Wang Guangpu; Luo Ping; Pan Qiuli; Ding Xunliang [Key Laboratory of Beam Technology and Materials Modification of Ministry of Education, Beijing Normal University, Beijing 100875 (China); Institute of Low Energy Nuclear Physics, Beijing Normal University, Beijing 100875 (China); Beijing Radiation Center, Beijing 100875 (China)

    2009-06-11

    A micro-X-ray fluorescence (Micro-XRF) spectrometer based on a polycapillary slightly focusing X-ray lens (PSFXRL) and laboratory X-ray source was designed to carry out the source apportionment of aerosol particles. In the distribution curve of the X-ray intensity in the focal spot of PSFXRL, there was a plateau with a diameter of about 65 {mu}m. The uniformity of this plateau was about 3%. This was helpful in measuring the XRF spectrum of a single aerosol particle in which the element distributions are not uniform. The minimum detection limit (MDL) of this Micro-XRF spectrometer was 15 ppm for the Fe-K{sub {alpha}}. The origins of the aerosol particles at the exit of a subway station and a construction site were apportioned. This Micro-XRF spectrometer has potential applications in analysis of single aerosol particles.

  2. A study on characteristics and sources of winter time atmospheric aerosols in Kyoto and Seoul using PIXE and supplementary analysis

    International Nuclear Information System (INIS)

    Ma, C.-J.; Kasahara, M.; Tohno, S.; Yeo, H.-G.

    1999-01-01

    Atmospheric aerosols were collected using a two stages filter sampler to classify into the fine and coarse fraction in Kyoto and Seoul in winter season. Elemental concentrations of aerosols were analyzed by PIXE and EAS as well as ion concentrations by IC. Analyzed data were used to source of aerosol particles. (author)

  3. Water soluble organic aerosols in the Colorado Rocky Mountains, USA: composition, sources and optical properties

    OpenAIRE

    Xie, Mingjie; Mladenov, Natalie; Williams, Mark W.; Neff, Jason C.; Wasswa, Joseph; Hannigan, Michael P.

    2016-01-01

    Atmospheric aerosols have been shown to be an important input of organic carbon and nutrients to alpine watersheds and influence biogeochemical processes in these remote settings. For many remote, high elevation watersheds, direct evidence of the sources of water soluble organic aerosols and their chemical and optical characteristics is lacking. Here, we show that the concentration of water soluble organic carbon (WSOC) in the total suspended particulate (TSP) load at a high elevation site in...

  4. Particle generation methods applied in large-scale experiments on aerosol behaviour and source term studies

    International Nuclear Information System (INIS)

    Swiderska-Kowalczyk, M.; Gomez, F.J.; Martin, M.

    1997-01-01

    In aerosol research aerosols of known size, shape, and density are highly desirable because most aerosols properties depend strongly on particle size. However, such constant and reproducible generation of those aerosol particles whose size and concentration can be easily controlled, can be achieved only in laboratory-scale tests. In large scale experiments, different generation methods for various elements and compounds have been applied. This work presents, in a brief from, a review of applications of these methods used in large scale experiments on aerosol behaviour and source term. Description of generation method and generated aerosol transport conditions is followed by properties of obtained aerosol, aerosol instrumentation used, and the scheme of aerosol generation system-wherever it was available. An information concerning aerosol generation particular purposes and reference number(s) is given at the end of a particular case. These methods reviewed are: evaporation-condensation, using a furnace heating and using a plasma torch; atomization of liquid, using compressed air nebulizers, ultrasonic nebulizers and atomization of liquid suspension; and dispersion of powders. Among the projects included in this worked are: ACE, LACE, GE Experiments, EPRI Experiments, LACE-Spain. UKAEA Experiments, BNWL Experiments, ORNL Experiments, MARVIKEN, SPARTA and DEMONA. The aim chemical compounds studied are: Ba, Cs, CsOH, CsI, Ni, Cr, NaI, TeO 2 , UO 2 Al 2 O 3 , Al 2 SiO 5 , B 2 O 3 , Cd, CdO, Fe 2 O 3 , MnO, SiO 2 , AgO, SnO 2 , Te, U 3 O 8 , BaO, CsCl, CsNO 3 , Urania, RuO 2 , TiO 2 , Al(OH) 3 , BaSO 4 , Eu 2 O 3 and Sn. (Author)

  5. On the sources of submicron aerosol particles in savannah: implications for climate and air quality

    Energy Technology Data Exchange (ETDEWEB)

    Vakkari, V.

    2013-11-01

    Aerosol is defined as solid or liquid particles suspended in a gas lighter than the particles, which means that the atmosphere we live in is an aerosol in itself. Although aerosol particles are only a trace component of the atmosphere they affect our lives in several ways. The aerosol particles can cause adverse health effects and deteriorate visibility, but they affect also the Earth s climate directly by scattering and absorbing solar radiation and indirectly by modulating the properties of the clouds. Anthropogenic aerosol particles have a net cooling effect on the climate, but the uncertainty in the amount of cooling is presently as large as the heating effect of carbon dioxide. To reduce the uncertainty in the aerosol climate effects, spatially representative reference data of high quality are needed for the global climate models. To be able to capture the diurnal and seasonal variability the data have to be collected continuously over time periods that cover at least one full seasonal cycle. Until recently such data have been nearly non-existing for continental Africa and hence one aim of this work was to establish a permanent measurement station measuring the key aerosol particle properties in a continental location in southern Africa. In close collaboration with the North-West University in South Africa this aim has now been achieved at the Welgegund measurement station. The other aims of this work were to determine the aerosol particle concentrations including their seasonal and diurnal variation and to study the most important aerosol particle sources in continental southern Africa. In this thesis the aerosol size distribution and its seasonal and diurnal variation is reported for different environments ranging from a clean rural background to an anthropogenically heavily influenced mining region in continental southern Africa. Atmospheric regional scale new particle formation has been observed at a world record high frequency and it dominates the diurnal

  6. Aerosol sources and their contribution to the chemical composition of aerosols in the Eastern Mediterranean Sea during summertime

    Directory of Open Access Journals (Sweden)

    J. Sciare

    2003-01-01

    Full Text Available A detailed study on the temporal variability of compounds important in controlling aerosol chemical composition was performed during a one-month experiment conducted during summer 2000 at a background site on Crete, in the Eastern Mediterranean Sea. Contribution of different aerosol sources in the Eastern Mediterranean Basin could be investigated at this location since the site is influenced by a wide range of air masses originating mainly in Europe and Africa. Chemical apportionment was performed for various air mass origins and showed a strong impact of anthropogenic emissions in the Turkey and Central Europe sectors, with black carbon (BC and non-sea-salt sulfate (nss-SO4 concentrations higher than observed in the Eastern and Western Europe sectors. High levels of non-sea-salt calcium (nss-Ca were associated with air masses from Africa but also from Central Turkey. Evidence was found that BC calculation based on light absorbance during dust events was biased. This quality-controlled high temporal resolution dataset allowed to investigate in detail the source-receptor relationships responsible for the levels of BC, nss-SO4 and sulfur dioxide (SO2, observed in Crete. Among the results obtained from this model, the major contribution of Turkey and Central Europe was confirmed in terms of anthropogenic emissions. Comparisons with remote optical properties obtained from Satellite observations (SEAWIFS north of Crete indicates that our ground based aerosol characterization was suitable for describing aerosol properties in the atmospheric column for most of the time during the campaign.

  7. A new oxidation flow reactor for measuring secondary aerosol formation of rapidly changing emission sources

    Science.gov (United States)

    Simonen, Pauli; Saukko, Erkka; Karjalainen, Panu; Timonen, Hilkka; Bloss, Matthew; Aakko-Saksa, Päivi; Rönkkö, Topi; Keskinen, Jorma; Dal Maso, Miikka

    2017-04-01

    Oxidation flow reactors (OFRs) or environmental chambers can be used to estimate secondary aerosol formation potential of different emission sources. Emissions from anthropogenic sources, such as vehicles, often vary on short timescales. For example, to identify the vehicle driving conditions that lead to high potential secondary aerosol emissions, rapid oxidation of exhaust is needed. However, the residence times in environmental chambers and in most oxidation flow reactors are too long to study these transient effects ( ˜ 100 s in flow reactors and several hours in environmental chambers). Here, we present a new oxidation flow reactor, TSAR (TUT Secondary Aerosol Reactor), which has a short residence time ( ˜ 40 s) and near-laminar flow conditions. These improvements are achieved by reducing the reactor radius and volume. This allows studying, for example, the effect of vehicle driving conditions on the secondary aerosol formation potential of the exhaust. We show that the flow pattern in TSAR is nearly laminar and particle losses are negligible. The secondary organic aerosol (SOA) produced in TSAR has a similar mass spectrum to the SOA produced in the state-of-the-art reactor, PAM (potential aerosol mass). Both reactors produce the same amount of mass, but TSAR has a higher time resolution. We also show that TSAR is capable of measuring the secondary aerosol formation potential of a vehicle during a transient driving cycle and that the fast response of TSAR reveals how different driving conditions affect the amount of formed secondary aerosol. Thus, TSAR can be used to study rapidly changing emission sources, especially the vehicular emissions during transient driving.

  8. Long-term aerosol climatology over Indo-Gangetic Plain: Trend, prediction and potential source fields

    Science.gov (United States)

    Kumar, M.; Parmar, K. S.; Kumar, D. B.; Mhawish, A.; Broday, D. M.; Mall, R. K.; Banerjee, T.

    2018-05-01

    Long-term aerosol climatology is derived using Terra MODIS (Collection 6) enhanced Deep Blue (DB) AOD retrieval algorithm to investigate decadal trend (2006-2015) in columnar aerosol loading, future scenarios and potential source fields over the Indo-Gangetic Plain (IGP), South Asia. Satellite based aerosol climatology was analyzed in two contexts: for the entire IGP considering area weighted mean AOD and for nine individual stations located at upper (Karachi, Multan, Lahore), central (Delhi, Kanpur, Varanasi, Patna) and lower IGP (Kolkata, Dhaka). A comparatively high aerosol loading (AOD: 0.50 ± 0.25) was evident over IGP with a statistically insignificant increasing trend of 0.002 year-1. Analysis highlights the existing spatial and temporal gradients in aerosol loading with stations over central IGP like Varanasi (decadal mean AOD±SD; 0.67 ± 0.28) and Patna (0.65 ± 0.30) exhibit the highest AOD, followed by stations over lower IGP (Kolkata: 0.58 ± 0.21; Dhaka: 0.60 ± 0.24), with a statistically significant increasing trend (0.0174-0.0206 year-1). In contrast, stations over upper IGP reveal a comparatively low aerosol loading, having an insignificant increasing trend. Variation in AOD across IGP is found to be mainly influenced by seasonality and topography. A distinct "aerosol pool" region over eastern part of Ganges plain is identified, where meteorology, topography, and aerosol sources favor the persistence of airborne particulates. A strong seasonality in aerosol loading and types is also witnessed, with high AOD and dominance of fine particulates over central to lower IGP, especially during post-monsoon and winter. The time series analyses by autoregressive integrated moving average (ARIMA) indicate contrasting patterns in randomness of AOD over individual stations with better performance especially over central IGP. Concentration weighted trajectory analyses identify the crucial contributions of western dry regions and partial contributions from

  9. Characterization of biomass burning from olive grove areas: A major source of organic aerosol in PM10 of Southwest Europe

    Science.gov (United States)

    Sánchez de la Campa, Ana M.; Salvador, Pedro; Fernández-Camacho, Rocío; Artiñano, Begoña; Coz, Esther; Márquez, Gonzalo; Sánchez-Rodas, Daniel; de la Rosa, Jesús

    2018-01-01

    The inorganic and organic geochemistry of aerosol particulate matter (APM) was studied in a major olive grove area from Southwest Europe (Baena, Spain). The biomass consists of olive tree branches and the solid waste resulting of the olive oil production. Moreover, high PM10 levels were obtained (31.5 μg m- 3), with two days of exceedance of the daily limit of 50 μg m- 3 (2008/50/CE; EU, 2008) during the experimental period. A high mean levoglucosan concentration was obtained representing up 95% of the total mass of the isomers analysed (280 ng m- 3), while galactosan and mannosan mean concentrations were lower (8.64 ng m- 3 and 7.86 ng m- 3, respectively). The contribution of wood smoke in Baena was estimated, representing 19% of OC and 17% of OM total mass. Positive matrix factor (PMF) was applied to the organic and inorganic aerosols data, which has permitted the identification of five source categories: biomass burning, traffic, mineral dust, marine aerosol and SIC (secondary inorganic compounds). The biomass burning category reached the highest mean contribution to the PM10 mass (41%, 17.6 μg m- 3). In light of these results, the use of biomass resulting from the olive oil production for residential heating and industry must be considered the most important aerosol source during the winter months. The results of this paper can be extrapolated to other olive oil producing areas in the Mediterranean basin. Therefore, a fuller understanding of this type of biomass combustion is required in order to be able to establish appropriate polices and reduce the environmental impact on the population.

  10. Atmospheric carbonaceous aerosols from Indo-Gangetic Plain and Central Himalaya: impact of anthropogenic sources.

    Science.gov (United States)

    Ram, Kirpa; Sarin, M M

    2015-01-15

    In the present-day scenario of growing anthropogenic activities, carbonaceous aerosols contribute significantly (∼20-70%) to the total atmospheric particulate matter mass and, thus, have immense potential to influence the Earth's radiation budget and climate on a regional to global scale. In addition, formation of secondary organic aerosols is being increasingly recognized as an important process in contributing to the air-pollution and poor visibility over urban regions. It is, thus, essential to study atmospheric concentrations of carbonaceous species (EC, OC and WSOC), their mixing state and absorption properties on a regional scale. This paper presents the comprehensive data on emission sources, chemical characteristics and optical properties of carbonaceous aerosols from selected urban sites in the Indo-Gangetic Plain (IGP) and from a high-altitude location in the central Himalaya. The mass concentrations of OC, EC and WSOC exhibit large spatio-temporal variability in the IGP. This is attributed to seasonally varying emissions from post-harvest agricultural-waste burning, their source strength, boundary layer dynamics and secondary aerosol formation. The high concentrations of OC and SO4(2-), and their characteristic high mass scattering efficiency, contribute significantly to the aerosol optical depth and scattering coefficient. This has implications to the assessment of single scattering albedo and aerosol radiative forcing on a regional scale. Copyright © 2014 Elsevier Ltd. All rights reserved.

  11. Chemical compositions, sources and evolution processes of the submicron aerosols in Nanjing, China during wintertime

    Science.gov (United States)

    Wu, Y.; He, Y.; Ge, X.; Wang, J.; Yu, H.; Chen, M.

    2016-12-01

    Elevated atmospheric particulate matter pollution is one of the most significant environmental issues in the Yangtze River Delta (YRD), China. Thus it is important to unravel the characteristics, sources and evolution processes of the ambient aerosols in order to improve the air quality. In this study, we report the real-time monitoring results on submicron aerosol particles (PM1) in suburban Nanjing during wintertime of 2015, using an Aerodyne soot particle aerosol mass spectrometer (SP-AMS). This instrument allows the fast measurement of refractory black carbon simultaneously with other aerosol components. Results show that organics was on average the most abundant species of PM1 (25.9%), but other inorganic species, such as nitrate (23.7%) and sulfate (23.3%) also comprised large mass fractions. As the sampling site is heavily influenced by various sources including industrial, traffic and other anthropogenic emissions, etc., six organic aerosol (OA) factors were identified from Positive matrix factorization (PMF) analysis of the SP-AMS OA mass spectra. These factors include three primary OA factors - a hydrocarbon-like OA, an industry-related OA (IOA) and a cooking OA (COA), and three secondary OA factors, i.e., a local OOA (LSOA), a semi-volatile OOA (SV-OOA) and a low-volatility OOA (LV-OOA). Overall, the primary organic aerosol (POA) (HOA, IOA and COA) dominated the total OA mass. Behaviors and evolution processes of these OA factors will be discussed in combining with the other supporting data.

  12. Atmospheric acidification of mineral aerosols: a source of bioavailable phosphorus for the oceans

    Directory of Open Access Journals (Sweden)

    A. Nenes

    2011-07-01

    Full Text Available Primary productivity of continental and marine ecosystems is often limited or co-limited by phosphorus. Deposition of atmospheric aerosols provides the major external source of phosphorus to marine surface waters. However, only a fraction of deposited aerosol phosphorus is water soluble and available for uptake by phytoplankton. We propose that atmospheric acidification of aerosols is a prime mechanism producing soluble phosphorus from soil-derived minerals. Acid mobilization is expected to be pronounced where polluted and dust-laden air masses mix. Our hypothesis is supported by the soluble compositions and reconstructed pH values for atmospheric particulate matter samples collected over a 5-yr period at Finokalia, Crete. In addition, at least tenfold increase in soluble phosphorus was observed when Saharan soil and dust were acidified in laboratory experiments which simulate atmospheric conditions. Aerosol acidification links bioavailable phosphorus supply to anthropogenic and natural acidic gas emissions, and may be a key regulator of ocean biogeochemistry.

  13. From OLS to VIIRS, an overview of nighttime satellite aerosol retrievals using artificial light sources

    Science.gov (United States)

    Zhang, J.; Miller, S. D.; Reid, J. S.; Hyer, E. J.; McHardy, T. M.

    2015-12-01

    Compared to abundant daytime satellite-based observations of atmospheric aerosol, observations at night are relatively scarce. In particular, conventional satellite passive imaging radiometers, which offer expansive swaths of spatial coverage compared to non-scanning lidar systems, lack sensitivity to most aerosol types via the available thermal infrared bands available at night. In this talk, we make the fundamental case for the importance of nighttime aerosol information in forecast models, and the need to mitigate the existing nocturnal gap. We review early attempts at estimating nighttime aerosol optical properties using the modulation of stable artificial surface lights. Initial algorithm development using DMSP Operational Linescan System (OLS) has graduated to refined techniques based on the Suomi-NPP Visible Infrared Imaging Radiometer Suite (VIIRS) Day/Night Band (DNB). We present examples of these retrievals for selected cases and compare the results to available surface-based point-source validation data.

  14. Contributions of Organic Sources to Atmospheric Aerosol Particle Concentrations and Growth

    Science.gov (United States)

    Russell, L. M.

    2017-12-01

    Organic molecules are important contributors to aerosol particle mass and number concentrations through primary emissions as well as secondary growth in the atmosphere. New techniques for measuring organic aerosol components in atmospheric particles have improved measurements of this contribution in the last 20 years, including Scanning Transmission X-ray Microscopy Near Edge X-ray Absorption Fine Structure (STXM-NEXAFS), Fourier Transform Infrared spectroscopy (FTIR), and High-Resolution Aerosol Mass Spectrometry (AMS). STXM-NEXAFS individual aerosol particle composition illustrated the variety of morphology of organic components in marine aerosols, the inherent relationships between organic composition and shape, and the links between atmospheric aerosol composition and particles produced in smog chambers. This type of single particle microscopy has also added to size distribution measurements by providing evidence of how surface-controlled and bulk-controlled processes contribute to the growth of particles in the atmosphere. FTIR analysis of organic functional groups are sufficient to distinguish combustion, marine, and terrestrial organic particle sources and to show that each of those types of sources has a surprisingly similar organic functional group composition over four different oceans and four different continents. Augmenting the limited sampling of these off-line techniques with side-by-side inter-comparisons to online AMS provides complementary composition information and consistent quantitative attribution to sources (despite some clear method differences). Single-particle AMS techniques using light scattering and event trigger modes have now also characterized the types of particles found in urban, marine, and ship emission aerosols. Most recently, by combining with off-line techniques, single particle composition measurements have separated and quantified the contributions of organic, sulfate and salt components from ocean biogenic and sea spray

  15. Quantitative characterization of urban sources of organic aerosol by high-resolution gas chromatography

    International Nuclear Information System (INIS)

    Hildemann, L.M.; Mazurek, M.A.; Cass, G.R.; Simoneit, B.R.T.

    1991-01-01

    Fine aerosol emissions have been collected from a variety of urban combustion sources, including an industrial boiler, a fireplace, automobiles, diesel trucks, gas-fired home appliances, and meat cooking operations, by use of a dilution sampling system. Other sampling techniques have been utilized to collect fine aerosol samples of paved road dust, brake wear, tire wear, cigarette smoke, tar pot emissions, and vegetative detritus. The organic matter contained in each of these samples has been analyzed via high-resolution gas chromatography. By use of a simple computational approach, a quantitative, 50-parameter characterization of the elutable fine organic aerosol emitted from each source type has been determined. The organic mass distribution fingerprints obtained by this approach are shown to differ significantly from each other for most of the source types tested, using hierarchical cluster analysis

  16. Composition and sources of winter and summertime aerosols at Ny Alesund, Spitsbergen

    International Nuclear Information System (INIS)

    Maenhaut, W.; Cornille, P.; Pacyna, J.M.

    1991-01-01

    Filter samples of < 2.5 μm aerosol were collected in (late) winter of 1983, 1984, 1986, and 1987 and in the summer of 1984, 1986, and 1987 at Ny Alesund, Spitsbergen, and analyzed for over 40 elements by a combination of INAA and PIXE. The data sets of the various sampling campaigns and the combined winter and combined summer data were examined by receptor modeling, including absolute principal component analysis (APCA), chemical mass balance (CMB) and multiple linear regression (MLR) techniques. APCA yielded four components, both for the winter and for the summer aerosol. For the winter aerosol, the components were identified as a general pollution component, crustal dust, sea-salt, and a halogen (Br,I) component. The CMB and MLR calculations were used to obtain source (source region) apportionments for the anthropogenic trace elements and for sulfate. For the summer, about 50% of the sulfate was attributed to a marine biogenic source

  17. Source term experiments project (STEP): aerosol characterization system

    International Nuclear Information System (INIS)

    Schlenger, B.J.; Dunn, P.F.

    1985-01-01

    A series of four experiments is being conducted at Argonne National Laboratory's TREAT Reactor. They have been designed to provide some of the necessary data regarding magnitude and release rates of fission products from degraded fuel pins, physical and chemical characteristics of released fission products, and aerosol formation and transport phenomena. These are in-pile experiments, whereby the test fuel is heated by neutron induced fission and subsequent clad oxidation in steam environments that simulate as closely as practical predicted reactor accident conditions. The test sequences cover a range of pressure and fuel heatup rate, and include the effect of Ag/In/Cd control rod material

  18. Organic composition and source apportionment of fine aerosol at Monterrey, Mexico, based on organic markers

    Directory of Open Access Journals (Sweden)

    Y. Mancilla

    2016-01-01

    Full Text Available Primary emissions from anthropogenic and biogenic sources as well as secondary formation are responsible for the pollution levels of ambient air in major urban areas. These sources release fine particles into the air that negatively impact human health and the environment. Organic molecular markers, which are compounds that are unique to specific PM2.5 sources, can be utilized to identify the major emission sources in urban areas. In this study, 43 representative PM2.5 samples, for both daytime and nighttime periods, were built from individual samples collected in an urban site of the Monterrey metropolitan area (MMA during the spring and fall of 2011 and 2012. The samples were analyzed for organic carbon, elemental carbon, and organic molecular markers. Several diagnostic tools were employed for the preliminary identification of emission sources. Organic compounds for eight compound classes were quantified. The n-alkanoic acids were the most abundant, followed by n-alkanes, wood smoke markers, and levoglucosan/alkenoic acids. Polycyclic aromatic hydrocarbons (PAHs and hopanes were less abundant. The carbon preference index (0.7–2.6 for n-alkanes indicates a major contribution of anthropogenic and mixed sources during the fall and the spring, respectively. Hopanes levels confirmed the contribution from gasoline and diesel engines. In addition, the contribution of gasoline and diesel vehicle exhaust was confirmed and identified by the PAH concentrations in PM2.5. Diagnostic ratios of PAHs showed emissions from burning coal, wood, biomass, and other fossil fuels. The total PAHs and elemental carbon were correlated (r2 =  0.39–0.70 across the monitoring periods, reinforcing that motor vehicles are the major contributors of PAHs. Cholesterol levels remained constant during the spring and fall, showing evidence of the contribution of meat-cooking operations, while the isolated concentrations of levoglucosan suggested occasional biomass

  19. Single particle characterization, source apportionment, and aging effects of ambient aerosols in Southern California

    Science.gov (United States)

    Shields, Laura Grace

    Composed of a mixture of chemical species and phases and existing in a variety of shapes and sizes, atmospheric aerosols are complex and can have serious influence on human health, the environment, and climate. In order to better understand the impact of aerosols on local to global scales, detailed measurements on the physical and chemical properties of ambient particles are essential. In addition, knowing the origin or the source of the aerosols is important for policymakers to implement targeted regulations and effective control strategies to reduce air pollution in their region. One of the most ground breaking techniques in aerosol instrumentation is single particle mass spectrometry (SPMS), which can provide online chemical composition and size information on the individual particle level. The primary focus of this work is to further improve the ability of one specific SPMS technique, aerosol time-of-flight mass spectrometry (ATOFMS), for the use of identifying the specific origin of ambient aerosols, which is known as source apportionment. The ATOFMS source apportionment method utilizes a library of distinct source mass spectral signatures to match the chemical information of the single ambient particles. The unique signatures are obtained in controlled source characterization studies, such as with the exhaust emissions of heavy duty diesel vehicles (HDDV) operating on a dynamometer. The apportionment of ambient aerosols is complicated by the chemical and physical processes an individual particle can undergo as it spends time in the atmosphere, which is referred to as "aging" of the aerosol. Therefore, the performance of the source signature library technique was investigated on the ambient dataset of the highly aged environment of Riverside, California. Additionally, two specific subsets of the Riverside dataset (ultrafine particles and particles containing trace metals), which are known to cause adverse health effects, were probed in greater detail. Finally

  20. Insights into Submicron Aerosol Composition and Sources from the WINTER Aircraft Campaign Over the Eastern US.

    Science.gov (United States)

    Schroder, J. C.; Campuzano Jost, P.; Day, D. A.; Fibiger, D. L.; McDuffie, E. E.; Blake, N. J.; Hills, A. J.; Hornbrook, R. S.; Apel, E. C.; Weinheimer, A. J.; Campos, T. L.; Brown, S. S.; Jimenez, J. L.

    2015-12-01

    The WINTER aircraft campaign was a recent field experiment to probe the sources and evolution of gas pollutants and aerosols in Northeast US urban and industrial plumes during the winter. A highly customized Aerodyne aerosol mass spectrometer (AMS) was flown on the NCAR C-130 to characterize submicron aerosol composition and evolution. Thirteen research flights were conducted covering a wide range of conditions, including rural, urban, and marine environments during day and night. Organic aerosol (OA) was a large component of the submicron aerosol in the boundary layer. The fraction of OA (fOA) was smaller (35-40%) than in recent US summer campaigns (~60-70%). Biomass burning was observed to be an important source of OA in the boundary layer, which is consistent with recent wintertime studies that show a substantial contribution of residential wood burning to the OA loadings. OA oxygenation (O/C ratio) shows a broad distribution with a substantial fraction of smaller O/C ratios when compared to previous summertime campaigns. Since measurements were rarely made very close to primary sources (i.e. directly above urban areas), this is consistent with oxidative chemistry being slower during winter. SOA formation and aging in the NYC plume was observed during several flights and compared with summertime results from LA (CalNex) and Mexico City (MILAGRO). Additionally, an oxidation flow reactor (OFR) capable of oxidizing ambient air up to several equivalent days of oxidation was deployed for the first time in an aircraft platform. The aerosol outflow of the OFR was sampled with the AMS to provide real-time snapshots of the potential for aerosol formation and aging. For example, a case study of a flight through the Ohio River valley showed evidence of oxidation of SO2 to sulfate. The measured sulfate enhancements were in good agreement with our OFR chemical model. OFR results for SOA will be discussed.

  1. Aerosol characterization over the southeastern United States using high resolution aerosol mass spectrometry: spatial and seasonal variation of aerosol composition, sources, and organic nitrates

    Science.gov (United States)

    Xu, L.; Suresh, S.; Guo, H.; Weber, R. J.; Ng, N. L.

    2015-04-01

    We deployed a High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS) and an Aerosol Chemical Speciation Monitor (ACSM) to characterize the chemical composition of submicron non-refractory particles (NR-PM1) in the southeastern US. Measurements were performed in both rural and urban sites in the greater Atlanta area, GA and Centreville, AL for approximately one year, as part of Southeastern Center of Air Pollution and Epidemiology study (SCAPE) and Southern Oxidant and Aerosol Study (SOAS). Organic aerosol (OA) accounts for more than half of NR1 mass concentration regardless of sampling sites and seasons. Positive matrix factorization (PMF) analysis of HR-ToF-AMS measurements identified various OA sources, depending on location and season. Hydrocarbon-like OA (HOA) and cooking OA (COA) have important but not dominant contributions to total OA in urban sites. Biomass burning OA (BBOA) concentration shows a distinct seasonal variation with a larger enhancement in winter than summer. We find a good correlation between BBOA and brown carbon, indicating biomass burning is an important source for brown carbon, although an additional, unidentified brown carbon source is likely present at the rural Yorkville site. Isoprene-derived OA (Isoprene-OA) is only deconvolved in warmer months and contributes 18-36% of total OA. The presence of Isoprene-OA factor in urban sites is more likely from local production in the presence of NOx than transport from rural sites. More-oxidized and less-oxidized oxygenated organic aerosol (MO-OOA and LO-OOA, respectively) are dominant fractions (47-79%) of OA in all sites. MO-OOA correlates well with ozone in summer, but not in winter, indicating MO-OOA sources may vary with seasons. LO-OOA, which reaches a daily maximum at night, correlates better with estimated nitrate functionality from organic nitrates than total nitrates. Based on the HR-ToF-AMS measurements, we estimate that the nitrate functionality from organic nitrates

  2. Assessment of source-receptor relationships of aerosols: An integrated forward and backward modeling approach

    Science.gov (United States)

    Kulkarni, Sarika

    This dissertation presents a scientific framework that facilitates enhanced understanding of aerosol source -- receptor (S/R) relationships and their impact on the local, regional and global air quality by employing a complementary suite of modeling methods. The receptor -- oriented Positive Matrix Factorization (PMF) technique is combined with Potential Source Contribution Function (PSCF), a trajectory ensemble model, to characterize sources influencing the aerosols measured at Gosan, Korea during spring 2001. It is found that the episodic dust events originating from desert regions in East Asia (EA) that mix with pollution along the transit path, have a significant and pervasive impact on the air quality of Gosan. The intercontinental and hemispheric transport of aerosols is analyzed by a series of emission perturbation simulations with the Sulfur Transport and dEposition Model (STEM), a regional scale Chemical Transport Model (CTM), evaluated with observations from the 2008 NASA ARCTAS field campaign. This modeling study shows that pollution transport from regions outside North America (NA) contributed ˜ 30 and 20% to NA sulfate and BC surface concentration. This study also identifies aerosols transported from Europe, NA and EA regions as significant contributors to springtime Arctic sulfate and BC. Trajectory ensemble models are combined with source region tagged tracer model output to identify the source regions and possible instances of quasi-lagrangian sampled air masses during the 2006 NASA INTEX-B field campaign. The impact of specific emission sectors from Asia during the INTEX-B period is studied with the STEM model, identifying residential sector as potential target for emission reduction to combat global warming. The output from the STEM model constrained with satellite derived aerosol optical depth and ground based measurements of single scattering albedo via an optimal interpolation assimilation scheme is combined with the PMF technique to

  3. Aerosol composition and sources in the central Arctic Ocean during ASCOS

    Science.gov (United States)

    Chang, R. Y.-W.; Leck, C.; Graus, M.; Müller, M.; Paatero, J.; Burkhart, J. F.; Stohl, A.; Orr, L. H.; Hayden, K.; Li, S.-M.; Hansel, A.; Tjernström, M.; Leaitch, W. R.; Abbatt, J. P. D.

    2011-10-01

    Measurements of submicron aerosol chemical composition were made over the central Arctic Ocean from 5 August to 8 September 2008 as a part of the Arctic Summer Cloud Ocean Study (ASCOS) using an aerosol mass spectrometer (AMS). The median levels of sulphate and organics for the entire study were 0.051 and 0.055 μ g m-3, respectively. Positive matrix factorisation was performed on the entire mass spectral time series and this enabled marine biogenic and continental sources of particles to be separated. These factors accounted for 33% and 36% of the sampled ambient aerosol mass, respectively, and they were both predominantly composed of sulphate, with 47% of the sulphate apportioned to marine biogenic sources and 48% to continental sources, by mass. Within the marine biogenic factor, the ratio of methane sulphonate to sulphate was 0.25 ± 0.02, consistent with values reported in the literature. The organic component of the continental factor was more oxidised than that of the marine biogenic factor, suggesting that it had a longer photochemical lifetime than the organics in the marine biogenic factor. The remaining ambient aerosol mass was apportioned to an organic-rich factor that could have arisen from a combination of marine and continental sources. In particular, given that the factor does not correlate with common tracers of continental influence, we cannot rule out that the organic factor arises from a primary marine source.

  4. Fossil and non-fossil source contributions to atmospheric carbonaceous aerosols during extreme spring grassland fires in Eastern Europe

    Directory of Open Access Journals (Sweden)

    V. Ulevicius

    2016-05-01

    Full Text Available In early spring the Baltic region is frequently affected by high-pollution events due to biomass burning in that area. Here we present a comprehensive study to investigate the impact of biomass/grass burning (BB on the evolution and composition of aerosol in Preila, Lithuania, during springtime open fires. Non-refractory submicron particulate matter (NR-PM1 was measured by an Aerodyne aerosol chemical speciation monitor (ACSM and a source apportionment with the multilinear engine (ME-2 running the positive matrix factorization (PMF model was applied to the organic aerosol fraction to investigate the impact of biomass/grass burning. Satellite observations over regions of biomass burning activity supported the results and identification of air mass transport to the area of investigation. Sharp increases in biomass burning tracers, such as levoglucosan up to 683 ng m−3 and black carbon (BC up to 17 µg m−3 were observed during this period. A further separation between fossil and non-fossil primary and secondary contributions was obtained by coupling ACSM PMF results and radiocarbon (14C measurements of the elemental (EC and organic (OC carbon fractions. Non-fossil organic carbon (OCnf was the dominant fraction of PM1, with the primary (POCnf and secondary (SOCnf fractions contributing 26–44 % and 13–23 % to the total carbon (TC, respectively. 5–8 % of the TC had a primary fossil origin (POCf, whereas the contribution of fossil secondary organic carbon (SOCf was 4–13 %. Non-fossil EC (ECnf and fossil EC (ECf ranged from 13–24 and 7–13 %, respectively. Isotope ratios of stable carbon and nitrogen isotopes were used to distinguish aerosol particles associated with solid and liquid fossil fuel burning.

  5. Fossil and non-fossil source contributions to atmospheric carbonaceous aerosols during extreme spring grassland fires in Eastern Europe

    Science.gov (United States)

    Ulevicius, Vidmantas; Byčenkienė, Steigvilė; Bozzetti, Carlo; Vlachou, Athanasia; Plauškaitė, Kristina; Mordas, Genrik; Dudoitis, Vadimas; Abbaszade, Gülcin; Remeikis, Vidmantas; Garbaras, Andrius; Masalaite, Agne; Blees, Jan; Fröhlich, Roman; Dällenbach, Kaspar R.; Canonaco, Francesco; Slowik, Jay G.; Dommen, Josef; Zimmermann, Ralf; Schnelle-Kreis, Jürgen; Salazar, Gary A.; Agrios, Konstantinos; Szidat, Sönke; El Haddad, Imad; Prévôt, André S. H.

    2016-05-01

    In early spring the Baltic region is frequently affected by high-pollution events due to biomass burning in that area. Here we present a comprehensive study to investigate the impact of biomass/grass burning (BB) on the evolution and composition of aerosol in Preila, Lithuania, during springtime open fires. Non-refractory submicron particulate matter (NR-PM1) was measured by an Aerodyne aerosol chemical speciation monitor (ACSM) and a source apportionment with the multilinear engine (ME-2) running the positive matrix factorization (PMF) model was applied to the organic aerosol fraction to investigate the impact of biomass/grass burning. Satellite observations over regions of biomass burning activity supported the results and identification of air mass transport to the area of investigation. Sharp increases in biomass burning tracers, such as levoglucosan up to 683 ng m-3 and black carbon (BC) up to 17 µg m-3 were observed during this period. A further separation between fossil and non-fossil primary and secondary contributions was obtained by coupling ACSM PMF results and radiocarbon (14C) measurements of the elemental (EC) and organic (OC) carbon fractions. Non-fossil organic carbon (OCnf) was the dominant fraction of PM1, with the primary (POCnf) and secondary (SOCnf) fractions contributing 26-44 % and 13-23 % to the total carbon (TC), respectively. 5-8 % of the TC had a primary fossil origin (POCf), whereas the contribution of fossil secondary organic carbon (SOCf) was 4-13 %. Non-fossil EC (ECnf) and fossil EC (ECf) ranged from 13-24 and 7-13 %, respectively. Isotope ratios of stable carbon and nitrogen isotopes were used to distinguish aerosol particles associated with solid and liquid fossil fuel burning.

  6. Organic compounds in aerosols from selected European sites - Biogenic versus anthropogenic sources

    Science.gov (United States)

    Alves, Célia; Vicente, Ana; Pio, Casimiro; Kiss, Gyula; Hoffer, Andras; Decesari, Stefano; Prevôt, André S. H.; Minguillón, María Cruz; Querol, Xavier; Hillamo, Risto; Spindler, Gerald; Swietlicki, Erik

    2012-11-01

    Atmospheric aerosol samples from a boreal forest (Hyytiälä, April 2007), a rural site in Hungary (K-puszta, summer 2008), a polluted rural area in Italy (San Pietro Capofiume, Po Valley, April 2008), a moderately polluted rural site in Germany located on a meadow (Melpitz, May 2008), a natural park in Spain (Montseny, March 2009) and two urban background locations (Zurich, December 2008, and Barcelona, February/March 2009) were collected. Aliphatics, polycyclic aromatic hydrocarbons, carbonyls, sterols, n-alkanols, acids, phenolic compounds and anhydrosugars in aerosols were chemically characterised by gas chromatography-mass spectrometry, along with source attribution based on the carbon preference index (CPI), the ratios between the unresolved and the chromatographically resolved aliphatics, the contribution of wax n-alkanes, n-alkanols and n-alkanoic acids from plants, diagnostic ratios of individual target compounds and source-specific markers to organic carbon ratios. In spite of transboundary pollution episodes, Hyytiälä registered the lowest levels among all locations. CPI values close to 1 for the aliphatic fraction of the Montseny aerosol suggest that the anthropogenic input may be associated with the transport of aged air masses from the surrounding industrial/urban areas, which superimpose the locally originated hydrocarbons with biogenic origin. Aliphatic and aromatic hydrocarbons in samples from San Pietro Capofiume reveal that fossil fuel combustion is a major source influencing the diel pattern of concentrations. This source contributed to 25-45% of the ambient organic carbon (OC) at the Po Valley site. Aerosols from the German meadow presented variable contributions from both biogenic and anthropogenic sources. The highest levels of vegetation wax components and biogenic secondary organic aerosol (SOA) products were observed at K-puszta, while anthropogenic SOA compounds predominated in Barcelona. The primary vehicular emissions in the Spanish

  7. Modeling aerosol suspension from soils and oceans as sources of micropollutants to air.

    Science.gov (United States)

    Qureshi, Asif; MacLeod, Matthew; Hungerbühler, Konrad

    2009-10-01

    Soil and marine aerosol suspension are two physical mass transfer processes that are not usually included in models describing fate and transport of environmental pollutants. Here, we review the literature on soil and marine aerosol suspension and estimate aerosol suspension mass transfer velocities for inclusion in multimedia models, as a global average and on a 1 x 1 scale. The yearly, global average mass transfer velocity for soil aerosol suspension is estimated to be 6 x 10(-10)mh(-1), approximately an order of magnitude smaller than marine aerosol suspension, which is estimated to be 8 x 10(-9)mh(-1). Monthly averages of these velocities can be as high as 10(-7)mh(-1) and 10(-5)mh(-1) for soil and marine aerosol suspension, respectively, depending on location. We use a unit-world multimedia model to analyze the relevance of these two suspension processes as a mechanism that enhances long-range atmospheric transport of pollutants. This is done by monitoring a metric of long-range transport potential, phi-one thousand (phi1000), that denotes the fraction of modeled emissions to air, water or soil in a source region that reaches a distance of 1000 km in air. We find that when the yearly, globally averaged mass transfer velocity is used, marine aerosol suspension increases phi1000 only fractionally for both emissions to air and water. However, enrichment of substances in marine aerosols, or speciation between ionic and neutral forms in ocean water may increase the influence of this surface-to-air transfer process. Soil aerosol suspension can be the dominant process for soil-to-air transfer in an emission-to-soil scenario for certain substances that have a high affinity to soil. When a suspension mass transfer velocity near the maximum limit is used, soil suspension remains important if the emissions are made to soil, and marine aerosol suspension becomes important regardless of if emissions are made to air or water compartments. We recommend that multimedia models

  8. Nuclear microprobe analysis and source apportionment of individual atmospheric aerosol particles

    International Nuclear Information System (INIS)

    Artaxo, P.; Rabello, M.L.C.; Watt, F.; Grime, G.; Swietlicki, E.

    1993-01-01

    In atmospheric aerosol reserach, one key issue is to determine the sources of the airborne particles. Bulk PIXE analysis coupled with receptor modeling provides a useful, but limited view of the aerosol sources influencing one particular site or sample. The scanning nuclear microprobe (SNM) technique is a microanalytical technique that gives unique information on individual aerosol particles. In the SNM analyses a 1.0 μm size 2.4 MeV proton beam from the Oxford SNM was used. The trace elements with Z>11 were measured by the particle induced X-ray emission (PIXE) method with detection limits in the 1-10 ppm range. Carbon, nitrogen and oxygen are measured simultaneously using Rutherford backscattering spectrometry (RBS). Atmospheric aerosol particles were collected at the Brazilian Antarctic Station and at biomass burning sites in the Amazon basin tropical rain forest in Brazil. In the Antarctic samples, the sea-salt aerosol particles were clearly predominating, with NaCl and CaSO 4 as major compounds with several trace elements as Al, Si, P, K, Mn, Fe, Ni, Cu, Zn, Br, Sr, and Pb. Factor analysis of the elemental data showed the presence of four components: 1) Soil dust particles; 2) NaCl particles; 3) CaSO 4 with Sr; and 4) Br and Mg. Strontium, observed at 20-100 ppm levels, was always present in the CaSO 4 particles. The hierarchical cluster procedure gave results similar to the ones obtained through factor analysis. For the tropical rain forest biomass burning aerosol emissions, biogenic particles with a high organic content dominate the particle population, while K, P, Ca, Mg, Zn, and Si are the dominant elements. Zinc at 10-200 ppm is present in biogenic particles rich in P and K. The quantitative aspects and excellent detection limits make SNM analysis of individual aerosol particles a very powerful analytical tool. (orig.)

  9. Primary and secondary aerosols in Beijing in winter: sources, variations and processes

    Science.gov (United States)

    Sun, Yele; Du, Wei; Fu, Pingqing; Wang, Qingqing; Li, Jie; Ge, Xinlei; Zhang, Qi; Zhu, Chunmao; Ren, Lujie; Xu, Weiqi; Zhao, Jian; Han, Tingting; Worsnop, Douglas R.; Wang, Zifa

    2016-07-01

    Winter has the worst air pollution of the year in the megacity of Beijing. Despite extensive winter studies in recent years, our knowledge of the sources, formation mechanisms and evolution of aerosol particles is not complete. Here we have a comprehensive characterization of the sources, variations and processes of submicron aerosols that were measured by an Aerodyne high-resolution aerosol mass spectrometer from 17 December 2013 to 17 January 2014 along with offline filter analysis by gas chromatography/mass spectrometry. Our results suggest that submicron aerosols composition was generally similar across the winter of different years and was mainly composed of organics (60 %), sulfate (15 %) and nitrate (11 %). Positive matrix factorization of high- and unit-mass resolution spectra identified four primary organic aerosol (POA) factors from traffic, cooking, biomass burning (BBOA) and coal combustion (CCOA) emissions as well as two secondary OA (SOA) factors. POA dominated OA, on average accounting for 56 %, with CCOA being the largest contributor (20 %). Both CCOA and BBOA showed distinct polycyclic aromatic hydrocarbons (PAHs) spectral signatures, indicating that PAHs in winter were mainly from coal combustion (66 %) and biomass burning emissions (18 %). BBOA was highly correlated with levoglucosan, a tracer compound for biomass burning (r2 = 0.93), and made a considerable contribution to OA in winter (9 %). An aqueous-phase-processed SOA (aq-OOA) that was strongly correlated with particle liquid water content, sulfate and S-containing ions (e.g. CH2SO2+) was identified. On average aq-OOA contributed 12 % to the total OA and played a dominant role in increasing oxidation degrees of OA at high RH levels (> 50 %). Our results illustrate that aqueous-phase processing can enhance SOA production and oxidation states of OA as well in winter. Further episode analyses highlighted the significant impacts of meteorological parameters on aerosol composition, size

  10. Aerosol source apportionment from 1-year measurements at the CESAR tower in Cabauw, the Netherlands

    Directory of Open Access Journals (Sweden)

    P. Schlag

    2016-07-01

    Full Text Available Intensive measurements of submicron aerosol particles and their chemical composition were performed with an Aerosol Chemical Speciation Monitor (ACSM at the Cabauw Experimental Site for Atmospheric Research (CESAR in Cabauw, the Netherlands, sampling at 5 m height above ground. The campaign lasted nearly 1 year from July 2012 to June 2013 as part of the EU-FP7-ACTRIS project (Q-ACSM Network. Including equivalent black carbon an average particulate mass concentration of 9.50 µg m−3 was obtained during the whole campaign with dominant contributions from ammonium nitrate (45 %, organic aerosol (OA, 29 %, and ammonium sulfate (19 %. There were 12 exceedances of the World Health Organization (WHO PM2.5 daily mean limit (25 µg m−3 observed at this rural site using PM1 instrumentation only. Ammonium nitrate and OA represented the largest contributors to total particulate matter during periods of exceedance. Source apportionment of OA was performed season-wise by positive matrix factorization (PMF using the multilinear engine 2 (ME-2 controlled via the source finder (SoFi. Primary organic aerosols were attributed mainly to traffic (8–16 % contribution to total OA, averaged season-wise and biomass burning (0–23 %. Secondary organic aerosols (SOAs, 61–84 % dominated the organic fraction during the whole campaign, particularly on days with high mass loadings. A SOA factor which is attributed to humic-like substances (HULIS was identified as a highly oxidized background aerosol in Cabauw. This shows the importance of atmospheric aging processes for aerosol concentration at this rural site. Due to the large secondary fraction, the reduction of particulate mass at this rural site is challenging on a local scale.

  11. 40 CFR 62.10860 - Identification of sources.

    Science.gov (United States)

    2010-07-01

    ... (CONTINUED) APPROVAL AND PROMULGATION OF STATE PLANS FOR DESIGNATED FACILITIES AND POLLUTANTS Texas Sulfuric Acid Mist from Existing Sulfuric Acid Plants § 62.10860 Identification of sources. (a) Identification of sources. The plan includes the following sulfuric acid production plants: (1) Diamond-Shamrock...

  12. A new method to discriminate secondary organic aerosols from different sources using high-resolution aerosol mass spectra

    Science.gov (United States)

    Heringa, M. F.; Decarlo, P. F.; Chirico, R.; Tritscher, T.; Clairotte, M.; Mohr, C.; Crippa, M.; Slowik, J. G.; Pfaffenberger, L.; Dommen, J.; Weingartner, E.; Prévôt, A. S. H.; Baltensperger, U.

    2012-02-01

    Organic aerosol (OA) represents a significant and often major fraction of the non-refractory PM1 (particulate matter with an aerodynamic diameter da car and a two-stroke Euro 2 scooter were characterized with an Aerodyne high-resolution time-of-flight aerosol mass spectrometer (HR-TOF-AMS) and compared to SOA from α-pinene. The emissions were sampled from the chimney/tailpipe by a heated inlet system and filtered before injection into a smog chamber. The gas phase emissions were irradiated by xenon arc lamps to initiate photo-chemistry which led to nucleation and subsequent particle growth by SOA production. Duplicate experiments were performed for each SOA type, with the averaged organic mass spectra showing Pearson's r values >0.94 for the correlations between the four different SOA types after five hours of aging. High-resolution mass spectra (HR-MS) showed that the dominant peaks in the MS, m/z 43 and 44, are dominated by the oxygenated ions C2H3O+ and CO2+, respectively, similarly to the relatively fresh semi-volatile oxygenated OA (SV-OOA) observed in the ambient aerosol. The atomic O:C ratios were found to be in the range of 0.25-0.55 with no major increase during the first five hours of aging. On average, the diesel SOA showed the lowest O:C ratio followed by SOA from wood burning, α-pinene and the scooter emissions. Grouping the fragment ions revealed that the SOA source with the highest O:C ratio had the largest fraction of small ions. The HR data of the four sources could be clustered and separated using principal component analysis (PCA). The model showed a significant separation of the four SOA types and clustering of the duplicate experiments on the first two principal components (PCs), which explained 79% of the total variance. Projection of ambient SV-OOA spectra resolved by positive matrix factorization (PMF) showed that this approach could be useful to identify large contributions of the tested SOA sources to SV-OOA. The first results from this

  13. Aerosol-Cloud Interactions During Puijo Cloud Experiments - The effects of weather and local sources

    Science.gov (United States)

    Komppula, Mika; Portin, Harri; Leskinen, Ari; Romakkaniemi, Sami; Brus, David; Neitola, Kimmo; Hyvärinen, Antti-Pekka; Kortelainen, Aki; Hao, Liqing; Miettinen, Pasi; Jaatinen, Antti; Ahmad, Irshad; Lihavainen, Heikki; Laaksonen, Ari; Lehtinen, Kari E. J.

    2013-04-01

    The Puijo measurement station has provided continuous data on aerosol-cloud interactions since 2006. The station is located on top of the Puijo observation tower (306 m a.s.l, 224 m above the surrounding lake level) in Kuopio, Finland. The top of the tower is covered by cloud about 15 % of the time, offering perfect conditions for studying aerosol-cloud interactions. With a twin-inlet setup (total and interstitial inlets) we are able to separate the activated particles from the interstitial (non-activated) particles. The continuous twin-inlet measurements include aerosol size distribution, scattering and absorption. In addition cloud droplet number and size distribution are measured continuously with weather parameters. During the campaigns the twin-inlet system was additionally equipped with aerosol mass spectrometer (AMS) and Single Particle Soot Photometer (SP-2). This way we were able to define the differences in chemical composition of the activated and non-activated particles. Potential cloud condensation nuclei (CCN) in different supersaturations were measured with two CCN counters (CCNC). The other CCNC was operated with a Differential Mobility Analyzer (DMA) to obtain size selected CCN spectra. Other additional measurements included Hygroscopic Tandem Differential Mobility Analyzer (HTDMA) for particle hygroscopicity. Additionally the valuable vertical wind profiles (updraft velocities) are available from Halo Doppler lidar during the 2011 campaign. Cloud properties (droplet number and effective radius) from MODIS instrument onboard Terra and Aqua satellites were retrieved and compared with the measured values. This work summarizes the two latest intensive campaigns, Puijo Cloud Experiments (PuCE) 2010 & 2011. We study especially the effect of the local sources on the cloud activation behaviour of the aerosol particles. The main local sources include a paper mill, a heating plant, traffic and residential areas. The sources can be categorized and identified

  14. Variation of atmospheric aerosol components and sources during smog episodes in Debrecen, Hungary

    International Nuclear Information System (INIS)

    Angyal, A.; Kertész, Zs.; Szoboszlai, Z.; Szikszai, Z.; Ferenczi, Z.; Furu, E.; Tõrõk, Zs.

    2013-01-01

    Full text: Atmospheric particulate matter (APM) pollution is one of the leading environmental problems in densely populated urban environments. In most cities all around the world high aerosol pollution levels occurs regularly. Debrecen, an average middle-European city is no exception. Every year there are several days when the aerosol pollution level exceeds the alarm threshold value (100 μ-g/m 3 for PM10 in 24- hours average). When the PM10 pollution level remains over this limit value for days, it is called 'smog' by the authorities. In this work we studied the variation of the elemental components and sources of PM10, PM2.5 and PM coarse and their dependence on meteorological conditions in Debrecen during two smog episodes occurred in November 2011. Aerosol samples were collected with 2-hours time resolution with a PIXE International sequential streaker in an urban background site in the downtown of Debrecen. In order to get information about the size distribution of the aerosol elemental components 9-stage cascade impactors were also employed during the sampling campaigns. The elemental composition (Z ≥ 13) were determined by Particle Induced X-Ray Emission (PIXE) at the IBA Laboratory of Atomki. Concentrations of elemental carbon were measured with a smoke stain reflectometer. On this data base source apportionment was carried out by using the positive matrix factorisation (PMF) method. Four factors were identified for both size fractions, including soil dust, traffic, domestic heating, and oil combustion. The time pattern of the aerosol elemental components and PM sources exhibited strong dependence on the mixing layer thickness. We showed that domestic heating had a major contribution to the aerosol pollution. (This work was carried out in the frame of the János Bolyai Research Scholarship of the Hungarian Academy of Sciences and TÁMOP-4.2.2/B-10/1-2010-0024 project). (author)

  15. Atmospheric aerosols in Rome, Italy: sources, dynamics and spatial variations during two seasons

    Directory of Open Access Journals (Sweden)

    C. Struckmeier

    2016-12-01

    Full Text Available Investigations on atmospheric aerosols and their sources were carried out in October/November 2013 and May/June 2014 consecutively in a suburban area of Rome (Tor Vergata and in central Rome (near St Peter's Basilica. During both years a Saharan dust advection event temporarily increased PM10 concentrations at ground level by about 12–17 µg m−3. Generally, in October/November the ambient aerosol was more strongly influenced by primary emissions, whereas higher relative contributions of secondary particles (sulfate, aged organic aerosol were found in May/June. Absolute concentrations of anthropogenic emission tracers (e.g. NOx, CO2, particulate polycyclic aromatic hydrocarbons, traffic-related organic aerosol were generally higher at the urban location. Positive matrix factorization was applied to the PM1 organic aerosol (OA fraction of aerosol mass spectrometer (HR-ToF-AMS data to identify different sources of primary OA (POA: traffic, cooking, biomass burning and (local cigarette smoking. While biomass burning OA was only found at the suburban site, where it accounted for the major fraction of POA (18–24 % of total OA, traffic and cooking were more dominant sources at the urban site. A particle type associated with cigarette smoke emissions, which is associated with a potential characteristic marker peak (m∕z 84, C5H10N+, a nicotine fragment in the mass spectrum, was only found in central Rome, where it was emitted in close vicinity to the measurement location. Regarding secondary OA, in October/November, only a very aged, regionally advected oxygenated OA was found, which contributed 42–53 % to the total OA. In May/June total oxygenated OA accounted for 56–76 % of the OA. Here a fraction (18–26 % of total OA of a fresher, less oxygenated OA of more local origin was also observed. New particle formation events were identified from measured particle number concentrations and size distributions in May/June 2014 at

  16. Functional group composition of ambient and source organic aerosols determined by tandem mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Dron, J.; El Haddad, I.; Temime-Roussel, B.; Wortham, H.; Marchand, N. [Univ Aix Marseille, CNRS, Lab Chim Provence, Equipe Instrumentat and React Atmospher, UMR 6264, F-13331 Marseille 3 (France); Jaffrezo, J.L. [Univ Grenoble 1, CNRS, UMR 5183, Lab Glaciol and Geophys Environm, F-38402 St Martin Dheres (France)

    2010-07-01

    The functional group composition of various organic aerosols (OA) is investigated using a recently developed analytical approach based on atmospheric pressure chemical ionisation-tandem mass spectrometry (APCIMS/MS). The determinations of three functional groups contents are performed quantitatively by neutral loss (carboxylic and carbonyl groups, R-COOH and R-CO-R' respectively) and precursor ion (nitro groups, R-NO{sub 2}) scanning modes of a tandem mass spectrometer. Major organic aerosol sources are studied: vehicular emission and wood combustion for primary aerosol sources; and a secondary organic aerosol (SOA) produced through photooxidation of o-xylene. The results reveal significant differences in the functional group contents of these source aerosols. The laboratory generated SOA is dominated by carbonyls while carboxylics are preponderate in the wood combustion particles. On the other hand, vehicular emissions are characterised by a strong nitro content. The total amount of the three functional groups accounts for 1.7% (vehicular) to 13.5% (o-xylene photooxidation) of the organic carbon. Diagnostic functional group ratios are then used to tentatively discriminate sources of particles collected in an urban background environment located in an Alpine valley (Chamonix, France) during a strong winter pollution event. The three functional groups under study account for a total functionalization rate of 2.2 to 3.8% of the organic carbon in this ambient aerosol, which is also dominated by carboxylic moieties. In this particular case study of a deep alpine valley during winter, we show that the nitro- and carbonyl-to-carboxylic diagnostic ratios can be a useful tool to discriminate sources. In these conditions, the total OA concentrations are highly dominated by wood combustion OA. This result is confirmed by an organic markers source apportionment approach which assess a wood burning organic carbon contribution of about 60%. Finally, examples of functional

  17. Functional group composition of ambient and source organic aerosols determined by tandem mass spectrometry

    Directory of Open Access Journals (Sweden)

    J. Dron

    2010-08-01

    Full Text Available The functional group composition of various organic aerosols (OA is investigated using a recently developed analytical approach based on atmospheric pressure chemical ionisation-tandem mass spectrometry (APCI-MS/MS. The determinations of three functional groups contents are performed quantitatively by neutral loss (carboxylic and carbonyl groups, R-COOH and R-CO-R´ respectively and precursor ion (nitro groups, R-NO2 scanning modes of a tandem mass spectrometer. Major organic aerosol sources are studied: vehicular emission and wood combustion for primary aerosol sources; and a secondary organic aerosol (SOA produced through photooxidation of o-xylene. The results reveal significant differences in the functional group contents of these source aerosols. The laboratory generated SOA is dominated by carbonyls while carboxylics are preponderate in the wood combustion particles. On the other hand, vehicular emissions are characterised by a strong nitro content. The total amount of the three functional groups accounts for 1.7% (vehicular to 13.5% (o-xylene photooxidation of the organic carbon. Diagnostic functional group ratios are then used to tentatively discriminate sources of particles collected in an urban background environment located in an Alpine valley (Chamonix, France during a strong winter pollution event. The three functional groups under study account for a total functionalisation rate of 2.2 to 3.8% of the organic carbon in this ambient aerosol, which is also dominated by carboxylic moieties. In this particular case study of a deep alpine valley during winter, we show that the nitro- and carbonyl-to-carboxylic diagnostic ratios can be a useful tool to discriminate sources. In these conditions, the total OA concentrations are highly dominated by wood combustion OA. This result is confirmed by an organic markers source apportionment approach which assess a wood burning organic carbon contribution of about 60

  18. Highly controlled, reproducible measurements of aerosol emissions from combustion of a common African biofuel source

    Science.gov (United States)

    Haslett, Sophie L.; Thomas, J. Chris; Morgan, William T.; Hadden, Rory; Liu, Dantong; Allan, James D.; Williams, Paul I.; Keita, Sekou; Liousse, Cathy; Coe, Hugh

    2018-01-01

    Particulate emissions from biomass burning can both alter the atmosphere's radiative balance and cause significant harm to human health. However, due to the large effect on emissions caused by even small alterations to the way in which a fuel burns, it is difficult to study particulate production of biomass combustion mechanistically and in a repeatable manner. In order to address this gap, in this study, small wood samples sourced from Côte D'Ivoire in West Africa were burned in a highly controlled laboratory environment. The shape and mass of samples, available airflow and surrounding thermal environment were carefully regulated. Organic aerosol and refractory black carbon emissions were measured in real time using an Aerosol Mass Spectrometer and a Single Particle Soot Photometer, respectively. This methodology produced remarkably repeatable results, allowing aerosol emissions to be mapped directly onto different phases of combustion. Emissions from pyrolysis were visible as a distinct phase before flaming was established. After flaming combustion was initiated, a black-carbon-dominant flame was observed during which very little organic aerosol was produced, followed by a period that was dominated by organic-carbon-producing smouldering combustion, despite the presence of residual flaming. During pyrolysis and smouldering, the two phases producing organic aerosol, distinct mass spectral signatures that correspond to previously reported variations in biofuel emissions measured in the atmosphere are found. Organic aerosol emission factors averaged over an entire combustion event were found to be representative of the time spent in the pyrolysis and smouldering phases, rather than reflecting a coupling between emissions and the mass loss of the sample. Further exploration of aerosol yields from similarly carefully controlled fires and a careful comparison with data from macroscopic fires and real-world emissions will help to deliver greater constraints on the

  19. A new method to discriminate secondary organic aerosols from different sources using high-resolution aerosol mass spectra

    Directory of Open Access Journals (Sweden)

    M. F. Heringa

    2012-02-01

    Full Text Available Organic aerosol (OA represents a significant and often major fraction of the non-refractory PM1 (particulate matter with an aerodynamic diameter da < 1 μm mass. Secondary organic aerosol (SOA is an important contributor to the OA and can be formed from biogenic and anthropogenic precursors. Here we present results from the characterization of SOA produced from the emissions of three different anthropogenic sources. SOA from a log wood burner, a Euro 2 diesel car and a two-stroke Euro 2 scooter were characterized with an Aerodyne high-resolution time-of-flight aerosol mass spectrometer (HR-TOF-AMS and compared to SOA from α-pinene.

    The emissions were sampled from the chimney/tailpipe by a heated inlet system and filtered before injection into a smog chamber. The gas phase emissions were irradiated by xenon arc lamps to initiate photo-chemistry which led to nucleation and subsequent particle growth by SOA production.

    Duplicate experiments were performed for each SOA type, with the averaged organic mass spectra showing Pearson's r values >0.94 for the correlations between the four different SOA types after five hours of aging. High-resolution mass spectra (HR-MS showed that the dominant peaks in the MS, m/z 43 and 44, are dominated by the oxygenated ions C2H3O+ and CO2+, respectively, similarly to the relatively fresh semi-volatile oxygenated OA (SV-OOA observed in the ambient aerosol. The atomic O:C ratios were found to be in the range of 0.25–0.55 with no major increase during the first five hours of aging. On average, the diesel SOA showed the lowest O:C ratio followed by SOA from wood burning, α-pinene and the scooter emissions. Grouping the fragment ions revealed that the SOA source with the highest O:C ratio had the largest fraction of small ions.

    The HR data of the four sources could be clustered and separated using

  20. Atmospheric processing of combustion aerosols as a source of soluble iron to the open ocean

    OpenAIRE

    伊藤, 彰記; ITO, Akinori

    2015-01-01

    The majority of bioavailable iron (Fe) from the atmosphere is delivered from arid and semiarid regions to the oceans because the global deposition of iron from combustion sources is small compared with that from mineral dust. Atmospheric processing of mineral aerosols by inorganic and organic acids from anthropogenic and natural sources has been shown to increase the iron solubility of soils (initially < 0.5%) up to about 10%. On the other hand, atmospheric observations have shown that iron i...

  1. Chemical composition, sources and secondary processes of aerosols in Baoji city of northwest China

    Science.gov (United States)

    Wang, Y. C.; Huang, R.-J.; Ni, H. Y.; Chen, Y.; Wang, Q. Y.; Li, G. H.; Tie, X. X.; Shen, Z. X.; Huang, Y.; Liu, S. X.; Dong, W. M.; Xue, P.; Fröhlich, R.; Canonaco, F.; Elser, M.; Daellenbach, K. R.; Bozzetti, C.; El Haddad, I.; Prévôt, A. S. H.; Canagaratna, M. R.; Worsnop, D. R.; Cao, J. J.

    2017-06-01

    Particulate air pollution is a severe environmental problem in China, affecting visibility, air quality, climate and human health. However, previous studies focus mainly on large cities such as Beijing, Shanghai, and Guangzhou. In this study, an Aerodyne Aerosol Chemical Speciation Monitor was deployed in Baoji, a middle size inland city in northwest China from 26 February to 27 March 2014. The non-refractory submicron aerosol (NR-PM1) was dominated by organics (55%), followed by sulfate (16%), nitrate (15%), ammonium (11%) and chloride (3%). A source apportionment of the organic aerosol (OA) was performed with the Sofi (Source Finder) interface of ME-2 (Multilinear Engine), and six main sources/factors were identified and classified as hydrocarbon-like OA (HOA), cooking OA (COA), biomass burning OA (BBOA), coal combustion OA (CCOA), less oxidized oxygenated OA (LO-OOA) and more oxidized oxygenated OA (MO-OOA), which contributed 20%, 14%, 13%, 9%, 23% and 21% of total OA, respectively. The contribution of secondary components shows increasing trends from clean days to polluted days, indicating the importance of secondary aerosol formation processes in driving particulate air pollution. The formation of LO-OOA and MO-OOA is mainly driven by photochemical reactions, but significantly influenced by aqueous-phase chemistry during periods of low atmospheric oxidative capacity.

  2. Environmental radiation safety: source term modification by soil aerosols. Interim report

    International Nuclear Information System (INIS)

    Moss, O.R.; Allen, M.D.; Rossignol, E.J.; Cannon, W.C.

    1980-08-01

    The goal of this project is to provide information useful in estimating hazards related to the use of a pure refractory oxide of 238 Pu as a power source in some of the space vehicles to be launched during the next few years. Although the sources are designed and built to withstand re-entry into the earth's atmosphere, and to impact with the earth's surface without releasing any plutonium, the possibility that such an event might produce aerosols composed of soil and 238 PuO 2 cannot be absolutely excluded. This report presents the results of our most recent efforts to measure the degree to which the plutonium aerosol source term might be modified in a terrestrial environment. The five experiments described represent our best effort to use the original experimental design to study the change in the size distribution and concentration of a 238 PuO 2 aerosol due to coagulation with an aerosol of clay or sandy loam soil

  3. An Investigation of the Radiative Effects and Climate Feedbacks of Sea Ice Sources of Sea Salt Aerosol

    Science.gov (United States)

    Horowitz, H. M.; Alexander, B.; Bitz, C. M.; Jaegle, L.; Burrows, S. M.

    2017-12-01

    In polar regions, sea ice is a major source of sea salt aerosol through lofting of saline frost flowers or blowing saline snow from the sea ice surface. Under continued climate warming, an ice-free Arctic in summer with only first-year, more saline sea ice in winter is likely. Previous work has focused on climate impacts in summer from increasing open ocean sea salt aerosol emissions following complete sea ice loss in the Arctic, with conflicting results suggesting no net radiative effect or a negative climate feedback resulting from a strong first aerosol indirect effect. However, the radiative forcing from changes to the sea ice sources of sea salt aerosol in a future, warmer climate has not previously been explored. Understanding how sea ice loss affects the Arctic climate system requires investigating both open-ocean and sea ice sources of sea-salt aerosol and their potential interactions. Here, we implement a blowing snow source of sea salt aerosol into the Community Earth System Model (CESM) dynamically coupled to the latest version of the Los Alamos sea ice model (CICE5). Snow salinity is a key parameter affecting blowing snow sea salt emissions and previous work has assumed constant regional snow salinity over sea ice. We develop a parameterization for dynamic snow salinity in the sea ice model and examine how its spatial and temporal variability impacts the production of sea salt from blowing snow. We evaluate and constrain the snow salinity parameterization using available observations. Present-day coupled CESM-CICE5 simulations of sea salt aerosol concentrations including sea ice sources are evaluated against in situ and satellite (CALIOP) observations in polar regions. We then quantify the present-day radiative forcing from the addition of blowing snow sea salt aerosol with respect to aerosol-radiation and aerosol-cloud interactions. The relative contributions of sea ice vs. open ocean sources of sea salt aerosol to radiative forcing in polar regions is

  4. Geochemical, Sulfur Isotopic Characteristics and Source Contributions of Size-Aggregated Aerosols Collected in Baring Head, New Zealand.

    Science.gov (United States)

    Li, J.; Michalski, G. M.; Davy, P.; Harvey, M.; Wilkins, B. P.; Katzman, T. L.

    2017-12-01

    Sulfate aerosols are critical to the climate, human health, and the hydrological cycle in the atmosphere, yet the sources of sulfate in aerosols are not completely understood. In this work, we evaluated the sources of sulfate in size-aggregated aerosols from the Southern Pacific Ocean and the land of New Zealand using geochemical and isotopic analyses. Aerosols were collected at Baring Head, New Zealand between 6/30/15 to 8/4/16 using two collectors, one only collects Southern Pacific Ocean derived aerosols (open-ocean collector), the other collects aerosols from both the ocean and the land (all-direction collector). Each collector is equipped with two filters to sample size-aggregated aerosols (fine aerosols: NSS-SO42-, 70%), while coarse aerosols are dominated by sea-salt sulfate. However, some NSS-SO42- was also observed in coarse aerosols collected in summer, suggesting the presence of accumulation mode NSS-SO42- aerosols, which is possibly due to high summer biogenic DMS flux. The sources of sulfur in NSS-SO42- could be further determined by their d34S values. DMS emission is likely the sole sulfur source in the open-ocean collector as it shows constant DMS-like d34S signatures (15-18‰) throughout the year. Meanwhile, the d34S of NSS-SO42- in the all-direction collector display a seasonal trend: summer time d34S values are higher and DMS-like (15-18‰), indicating DMS emission is the dominant sulfur source; winter time d34S values are lower ( 6-12‰), therefore the sulfur is likely sourced from both DMS emission and terrestrial S input with low d34S values, such as volcanic activities, fossil fuel and wood burning.

  5. Atmospheric aerosol compositions and sources at two national background sites in northern and southern China

    Science.gov (United States)

    Zhu, Qiao; He, Ling-Yan; Huang, Xiao-Feng; Cao, Li-Ming; Gong, Zhao-Heng; Wang, Chuan; Zhuang, Xin; Hu, Min

    2016-08-01

    Although China's severe air pollution has become a focus in the field of atmospheric chemistry and the mechanisms of urban air pollution there have been researched extensively, few field sampling campaigns have been conducted at remote background sites in China, where air pollution characteristics on a larger scale are highlighted. In this study, an Aerodyne high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS), together with an Aethalometer, was deployed at two of China's national background sites in northern (Lake Hongze site; 33.23° N, 118.33° E; altitude 21 m) and southern (Mount Wuzhi site; 18.84° N, 109.49° E; altitude 958 m) China in the spring seasons in 2011 and 2015, respectively, in order to characterize submicron aerosol composition and sources. The campaign-average PM1 concentration was 36.8 ± 19.8 µg m-3 at the northern China background (NCB) site, which was far higher than that at the southern China background (SCB) site (10.9 ± 7.8 µg m-3). Organic aerosol (OA) (27.2 %), nitrate (26.7 %), and sulfate (22.0 %) contributed the most to the PM1 mass at NCB, while OA (43.5 %) and sulfate (30.5 %) were the most abundant components of the PM1 mass at SCB, where nitrate only constituted a small fraction (4.7 %) and might have contained a significant amount of organic nitrates (5-11 %). The aerosol size distributions and organic aerosol elemental compositions all indicated very aged aerosol particles at both sites. The OA at SCB was more oxidized with a higher average oxygen to carbon (O / C) ratio (0.98) than that at NCB (0.67). Positive matrix factorization (PMF) analysis was used to classify OA into three components, including a hydrocarbon-like component (HOA, attributed to fossil fuel combustion) and two oxygenated components (OOA1 and OOA2, attributed to secondary organic aerosols from different source areas) at NCB. PMF analysis at SCB identified a semi-volatile oxygenated component (SV-OOA) and a low-volatility oxygenated

  6. Sulfate Aerosol in the Arctic: Source Attribution and Radiative Forcing

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Yang [Atmospheric Science and Global Change Division, Pacific Northwest National Laboratory, Richland WA USA; Wang, Hailong [Atmospheric Science and Global Change Division, Pacific Northwest National Laboratory, Richland WA USA; Smith, Steven J. [Joint Global Change Research Institute, Pacific Northwest National Laboratory, College Park MD USA; Easter, Richard C. [Atmospheric Science and Global Change Division, Pacific Northwest National Laboratory, Richland WA USA; Rasch, Philip J. [Atmospheric Science and Global Change Division, Pacific Northwest National Laboratory, Richland WA USA

    2018-02-08

    Source attributions of Arctic sulfate and its direct radiative effect for 2010–2014 are quantified in this study using the Community Earth System Model (CESM) equipped with an explicit sulfur source-tagging technique. Regions that have high emissions and/or are near/within the Arctic present relatively large contributions to Arctic sulfate burden, with the largest contribution from sources in East Asia (27%). East Asia and South Asia together have the largest contributions to Arctic sulfate concentrations at 9–12 km, whereas sources within or near the Arctic account largely below 2 km. For remote sources with strong emissions, their contributions to Arctic sulfate burden are primarily driven by meteorology, while contributions of sources within or near the Arctic are dominated by their emission strength. The sulfate direct radiative effect (DRE) is –0.080 W m-2 at the Arctic surface, offsetting the net warming effect from the combination of in-snow heating and DRE cooling from black carbon. East Asia, Arctic local and Russia/Belarus/Ukraine sources contribute –0.017, –0.016 and –0.014 W m-2, respectively, to Arctic sulfate DRE. A 20% reduction in anthropogenic SO2 emissions leads to a net increase of +0.013 W m-2 forcing at the Arctic surface. These results indicate that a joint reduction in BC emissions could prevent possible Arctic warming from future reductions in SO2 emissions. Sulfate DRE efficiency calculations suggest that short transport pathways together with meteorology favoring long sulfate lifetimes make certain sources more efficient in influencing the Arctic sulfate DRE.

  7. Water-soluble Organic Components in Aerosols Associated with Savanna Fires in Southern Africa: Identification, Evolution and Distribution

    Science.gov (United States)

    Gao, Song; Hegg, Dean A.; Hobbs, Peter V.; Kirchstetter, Thomas W.; Magi, Brian I.; Sadilek, Martin

    2003-01-01

    During the SAFARI 2000 field campaign, both smoke aerosols from savanna fires and haze aerosols in the boundary layer and in the free troposphere were collected from an aircraft in southern Africa. These aerosol samples were analyzed for their water-soluble chemical components, particularly the organic species. A novel technique, electrospray ionization-ion trap mass spectrometry, was used concurrently with an ion chromatography system to analyze for carbohydrate species. Seven carbohydrates, seven organic acids, five metallic elements, and three inorganic anions were identified and quantified. On the average, these 22 species comprised 36% and 27% of the total aerosol mass in haze and smoke aerosols, respectively. For the smoke aerosols, levoglucosan was the most abundant carbohydrate species, while gluconic acid was tentatively identified as the most abundant organic acid. The mass abundance and possible source of each class of identified species are discussed, along with their possible formation pathways. The combustion phase of a fire had an impact on the chemical composition of the emitted aerosols. Secondary formation of sulfate, nitrate, levoglucosan, and several organic acids occurred during the initial aging of smoke aerosols. It is likely that under certain conditions, some carbohydrate species in smoke aerosols, such as levoglucosan, were converted to organic acids during upward transport.

  8. Equipment for the continuous measurement and identification of gamma radioactivity on aerosols

    Energy Technology Data Exchange (ETDEWEB)

    De Blas, Alfredo; Tapia, Carlos; Riego, Albert; Garcia, Roger; Dies, Javier; Diaz, Pedro [Nuclear Engineering Research Group, Departament of Physics and Nuclear Engineering, Technical University of Catalonia, Barcelona (Spain); Toral, Juan [Raditel Serveis. Tarragona (Spain); Batalla, Enric [Radiological Activities Corrdination Service - SCAR, Generalitat de Catalunya, Barcelona (Spain)

    2015-07-01

    Presentation the Equipment for the Continuous Measurement and Identification of Gamma Radioactivity on Aerosols developed by the Nuclear Engineering Research Group (NERG) from the Technical University of Catalonia (UPC) and the Raditel Company. The device is based on a fixed filter of glass fiber (100% borosilicate), this allows determine the concentration of activity of gamma emitters on aerosols in air. A specifically developed Spectrometry Analysis System has been developed. The analysis of the spectra allows the identification of the emitters and determine the concentration of activity. Nowadays four Stations with this equipment are operating on the Environmental Radiological Surveillance Network of the Catalonian Generalitat (Spain): two near the Asco and Vandellos Nuclear Power Plants in the province of Tarragona and one in the city of Barcelona. Soon a fourth monitor will be incorporated at Roses (province of Girona) and a fifth in Puigcerda (province of Barcelona). We present measurements and analysis of the evolution of the emitters identified on different stations of the Network. (authors)

  9. Organic aerosols

    International Nuclear Information System (INIS)

    Penner, J.E.

    1994-01-01

    Organic aerosols scatter solar radiation. They may also either enhance or decrease concentrations of cloud condensation nuclei. This paper summarizes observed concentrations of aerosols in remote continental and marine locations and provides estimates for the sources of organic aerosol matter. The anthropogenic sources of organic aerosols may be as large as the anthropogenic sources of sulfate aerosols, implying a similar magnitude of direct forcing of climate. The source estimates are highly uncertain and subject to revision in the future. A slow secondary source of organic aerosols of unknown origin may contribute to the observed oceanic concentrations. The role of organic aerosols acting as cloud condensation nuclei (CCN) is described and it is concluded that they may either enhance or decrease the ability of anthropogenic sulfate aerosols to act as CCN

  10. Size-segregated aerosol in a hot-spot pollution urban area: Chemical composition and three-way source apportionment.

    Science.gov (United States)

    Bernardoni, V; Elser, M; Valli, G; Valentini, S; Bigi, A; Fermo, P; Piazzalunga, A; Vecchi, R

    2017-12-01

    In this work, a comprehensive characterisation and source apportionment of size-segregated aerosol collected using a multistage cascade impactor was performed. The samples were collected during wintertime in Milan (Italy), which is located in the Po Valley, one of the main pollution hot-spot areas in Europe. For every sampling, size-segregated mass concentration, elemental and ionic composition, and levoglucosan concentration were determined. Size-segregated data were inverted using the program MICRON to identify and quantify modal contributions of all the measured components. The detailed chemical characterisation allowed the application of a three-way (3-D) receptor model (implemented using Multilinear Engine) for size-segregated source apportionment and chemical profiles identification. It is noteworthy that - as far as we know - this is the first time that three-way source apportionment is attempted using data of aerosol collected by traditional cascade impactors. Seven factors were identified: wood burning, industry, resuspended dust, regional aerosol, construction works, traffic 1, and traffic 2. Further insights into size-segregated factor profiles suggested that the traffic 1 factor can be associated to diesel vehicles and traffic 2 to gasoline vehicles. The regional aerosol factor resulted to be the main contributor (nearly 50%) to the droplet mode (accumulation sub-mode with modal diameter in the range 0.5-1 μm), whereas the overall contribution from the two factors related to traffic was the most important one in the other size modes (34-41%). The results showed that applying a 3-D receptor model to size-segregated samples allows identifying factors of local and regional origin while receptor modelling on integrated PM fractions usually singles out factors characterised by primary (e.g. industry, traffic, soil dust) and secondary (e.g. ammonium sulphate and nitrate) origin. Furthermore, the results suggested that the information on size

  11. Aerosol composition and its sources at the King Sejong Station, Antarctic peninsula

    Science.gov (United States)

    Mishra, Vinit K.; Kim, Ki-Hyun; Hong, Sungmin; Lee, Khanghyun

    The annual cycles of major metals and ions in suspended particulate matters (SPM) have been investigated at a costal site of the Antarctic Peninsula in order to elucidate temporal variations as well as major source processes responsible for their formation. The measurements had been performed from January 2000 to December 2001 at the Korean Antarctic research station, 'King Sejong' (62°13' S, 58°47' W). The observed time series of important aerosol components showed clear seasonal variation patterns, while the mean elemental concentrations (e.g., 1875 (Al), 10.3 (Ba), 0.3 (Bi), 1.3 (Cd), 1.7 pg m -3 (Co)) were generally compatible with those reported previously. The presence of high EF values with respect to both mean crustal and seawater composition (such as Bi, Cd, Cr, Cu, Ni, V, and Zn), however, suggests a possibly important role of anthropogenic processes in this remote site. In contrast, the concentrations of ionic species were not clearly distinguishable from those of other Antarctic sites; but the consideration of ionic mass balance between cations and anions pointed out the uniqueness of their source/sink processes in the study area. The major source processes of those aerosol components were also investigated using a series of statistical analyses. The overall results of our study indicated the dominance of several processes (or sources) such as sea-salt emission, secondary aerosol formation, and anthropogenic pollution from both local and distant sources.

  12. Online Chemical Characterization of Food-Cooking Organic Aerosols: Implications for Source Apportionment.

    Science.gov (United States)

    Reyes-Villegas, Ernesto; Bannan, Thomas; Le Breton, Michael; Mehra, Archit; Priestley, Michael; Percival, Carl; Coe, Hugh; Allan, James D

    2018-04-11

    Food-cooking organic aerosols (COA) are one of the primary sources of submicron particulate matter in urban environments. However, there are still many questions surrounding source apportionment related to instrumentation as well as semivolatile partitioning because COA evolve rapidly in the ambient air, making source apportionment more complex. Online measurements of emissions from cooking different types of food were performed in a laboratory to characterize particles and gases. Aerosol mass spectrometer (AMS) measurements showed that the relative ionization efficiency for OA was higher (1.56-3.06) relative to a typical value of 1.4, concluding that AMS is over-estimating COA and suggesting that previous studies likely over-estimated COA concentrations. Food-cooking mass spectra were generated using AMS, and gas and particle food markers were identified with filter inlets for gases and aerosols-chemical ionization mass spectrometer (CIMS) measurements to be used in future food cooking-source apportionment studies. However, there is a considerable variability in both gas and particle markers, and dilution plays an important role in the particle mass budget, showing the importance of using these markers with caution during receptor modeling. These findings can be used to better understand the chemical composition of COA, and they provides useful information to be used in future source-apportionment studies.

  13. Source apportionment of the summer time carbonaceous aerosol at Nordic rural background sites

    Directory of Open Access Journals (Sweden)

    K. E. Yttri

    2011-12-01

    Full Text Available In the present study, natural and anthropogenic sources of particulate organic carbon (OCp and elemental carbon (EC have been quantified based on weekly filter samples of PM10 (particles with aerodynamic diameter <10 μm collected at four Nordic rural background sites [Birkenes (Norway, Hyytiälä (Finland, Vavihill (Sweden, Lille Valby, (Denmark] during late summer (5 August–2 September 2009. Levels of source specific tracers, i.e. cellulose, levoglucosan, mannitol and the 14C/12C ratio of total carbon (TC, have been used as input for source apportionment of the carbonaceous aerosol, whereas Latin Hypercube Sampling (LHS was used to statistically treat the multitude of possible combinations resulting from this approach. The carbonaceous aerosol (here: TCp; i.e. particulate TC was totally dominated by natural sources (69–86%, with biogenic secondary organic aerosol (BSOA being the single most important source (48–57%. Interestingly, primary biological aerosol particles (PBAP were the second most important source (20–32%. The anthropogenic contribution was mainly attributed to fossil fuel sources (OCff and ECff (10–24%, whereas no more than 3–7% was explained by combustion of biomass (OCbb and ECbb in this late summer campaign i.e. emissions from residential wood burning and/or wild/agricultural fires. Fossil fuel sources totally dominated the ambient EC loading, which accounted for 4–12% of TCp, whereas <1.5% of EC was attributed to combustion of biomass. The carbonaceous aerosol source apportionment showed only minor variation between the four selected sites. However, Hyytiälä and Birkenes showed greater resemblance to each other, as did Lille Valby and Vavihill, the two latter being somewhat more influenced by anthropogenic sources. Ambient levels of organosulphates and nitrooxy-organosulphates in the Nordic rural

  14. Isotopic evidence for enhanced fossil fuel sources of aerosol ammonium in the urban atmosphere.

    Science.gov (United States)

    Pan, Yuepeng; Tian, Shili; Liu, Dongwei; Fang, Yunting; Zhu, Xiaying; Gao, Meng; Gao, Jian; Michalski, Greg; Wang, Yuesi

    2018-04-20

    The sources of aerosol ammonium (NH 4 + ) are of interest because of the potential of NH 4 + to impact the Earth's radiative balance, as well as human health and biological diversity. Isotopic source apportionment of aerosol NH 4 + is challenging in the urban atmosphere, which has excess ammonia (NH 3 ) and where nitrogen isotopic fractionation commonly occurs. Based on year-round isotopic measurements in urban Beijing, we show the source dependence of the isotopic abundance of aerosol NH 4 + , with isotopically light (-33.8‰) and heavy (0 to +12.0‰) NH 4 + associated with strong northerly winds and sustained southerly winds, respectively. On an annual basis, 37-52% of the initial NH 3 concentrations in urban Beijing arises from fossil fuel emissions, which are episodically enhanced by air mass stagnation preceding the passage of cold fronts. These results provide strong evidence for the contribution of non-agricultural sources to NH 3 in urban regions and suggest that priority should be given to controlling these emissions for haze regulation. This study presents a carefully executed application of existing stable nitrogen isotope measurement and mass-balance techniques to a very important problem: understanding source contributions to atmospheric NH 3 in Beijing. This question is crucial to informing environmental policy on reducing particulate matter concentrations, which are some of the highest in the world. However, the isotopic source attribution results presented here still involve a number of uncertain assumptions and they are limited by the incomplete set of chemical and isotopic measurements of gas NH 3 and aerosol NH 4 + . Further field work and lab experiments are required to adequately characterize endmember isotopic signatures and the subsequent isotopic fractionation process under different air pollution and meteorological conditions. Copyright © 2018 Elsevier Ltd. All rights reserved.

  15. Potential sea salt aerosol sources from frost flowers in the pan-Arctic region

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Li [Scripps Institution of Oceanography, University of California, San Diego, La Jolla California USA; Now at Department of Earth System Science, University of California, Irvine California USA; Russell, Lynn M. [Scripps Institution of Oceanography, University of California, San Diego, La Jolla California USA; Burrows, Susannah M. [Atmospheric Science and Global Change Division, Pacific Northwest National Laboratory, Richland Washington USA

    2016-09-23

    In order to better represent observed wintertime aerosol concentrations at Barrow, Alaska, we implemented an observationally-based parameterization for estimating sea salt production from frost flowers in the Community Earth System Model (CESM). In this work, we evaluate the potential influence of this sea salt source on the pan-Arctic (60ºN-90ºN) climate. Results show that frost flower salt emissions substantially increase the modeled surface sea salt aerosol concentration in the winter months when new sea ice and frost flowers are present. The parameterization reproduces both the magnitude and seasonal variation of the observed submicron sea salt aerosol concentration at surface in Barrow during winter much better than the standard CESM simulation without a frost-flower salt particle source. Adding these frost flower salt particle emissions increases aerosol optical depth by 10% and results in a small cooling at surface. The increase in salt particle mass concentrations of a factor of 8 provides nearly two times the cloud condensation nuclei concentration, as well as 10% increases in cloud droplet number and 40% increases in liquid water content near coastal regions adjacent to continents. These cloud changes reduce longwave cloud forcing by 3% and cause a small surface warming, increasing the downward longwave flux at the surface by 2 W m-2 in the pan-Arctic under the present-day climate.

  16. Characteristics, sources and evolution of fine aerosol (PM1) at urban, coastal and forest background sites in Lithuania

    NARCIS (Netherlands)

    Masalaite, A.; Holzinger, R.; Remeikis, V.; Roeckmann, Thomas; Dusek, U.

    The chemical and isotopic composition of organic aerosol (OA) samples collected on PM1 filters was determined as a function of desorption temperature to investigate the main sources of organic carbon and the effects of photochemical processing on atmospheric aerosol. The filter samples were

  17. Global combustion sources of organic aerosols: model comparison with 84 AMS factor-analysis data sets

    Science.gov (United States)

    Tsimpidi, Alexandra P.; Karydis, Vlassis A.; Pandis, Spyros N.; Lelieveld, Jos

    2016-07-01

    Emissions of organic compounds from biomass, biofuel, and fossil fuel combustion strongly influence the global atmospheric aerosol load. Some of the organics are directly released as primary organic aerosol (POA). Most are emitted in the gas phase and undergo chemical transformations (i.e., oxidation by hydroxyl radical) and form secondary organic aerosol (SOA). In this work we use the global chemistry climate model ECHAM/MESSy Atmospheric Chemistry (EMAC) with a computationally efficient module for the description of organic aerosol (OA) composition and evolution in the atmosphere (ORACLE). The tropospheric burden of open biomass and anthropogenic (fossil and biofuel) combustion particles is estimated to be 0.59 and 0.63 Tg, respectively, accounting for about 30 and 32 % of the total tropospheric OA load. About 30 % of the open biomass burning and 10 % of the anthropogenic combustion aerosols originate from direct particle emissions, whereas the rest is formed in the atmosphere. A comprehensive data set of aerosol mass spectrometer (AMS) measurements along with factor-analysis results from 84 field campaigns across the Northern Hemisphere are used to evaluate the model results. Both the AMS observations and the model results suggest that over urban areas both POA (25-40 %) and SOA (60-75 %) contribute substantially to the overall OA mass, whereas further downwind and in rural areas the POA concentrations decrease substantially and SOA dominates (80-85 %). EMAC does a reasonable job in reproducing POA and SOA levels during most of the year. However, it tends to underpredict POA and SOA concentrations during winter indicating that the model misses wintertime sources of OA (e.g., residential biofuel use) and SOA formation pathways (e.g., multiphase oxidation).

  18. Dust Aerosols at the Source Region During ACE-ASIA: A Surface/Satellite Perspective

    Science.gov (United States)

    Tsay, Si-Chee; Lau, William K. M. (Technical Monitor)

    2001-01-01

    ACE (Aerosol Characterization Experiment)-Asia is designed to study the compelling variability in spatial and temporal scale of both pollution-derived and naturally occurring aerosols, which often exist in high concentrations over eastern Asia and along the rim of the western Pacific. The phase-I of ACE-Asia was conducted from March-May 2001 in the vicinity of the Gobi desert, East Coast of China, Yellow Sea, Korea, and Japan, along the pathway of Kosa (severe events that blanket East Asia with yellow desert dust, peaked in the Spring season). Asian dust typically originates in desert areas far from polluted urban regions. During transport, dust layers can interact with anthropogenic sulfate and soot aerosols from heavily polluted urban areas. Added to the complex effects of clouds and natural marine aerosols, dust particles reaching the marine environment can have drastically different properties than those from the source. Thus, understanding the unique temporal and spatial variations of Asian dust is of special importance in regional-to-global climate issues such as radiative forcing, the hydrological cycle, and primary biological productivity in the mid-Pacific Ocean. During ACE-Asia we have measured continuously aerosol physical/optical/radiative properties, column precipitable water amount, and surface reflectivity over homogeneous areas from surface. The inclusion of flux measurements permits the determination of dust aerosol radiative flux in addition to measurements of loading and optical thickness. At the time of the Terra/MODIS, SeaWiFS, TOMS and other satellite overpasses, these ground-based observations can provide valuable data to compare with satellite retrievals over land. Preliminary results will be presented and discussed their implications in regional climatic effects.

  19. Source Region Identification Using Kernel Smoothing

    Science.gov (United States)

    As described in this paper, Nonparametric Wind Regression is a source-to-receptor source apportionment model that can be used to identify and quantify the impact of possible source regions of pollutants as defined by wind direction sectors. It is described in detail with an exam...

  20. Interannual Variations in Aerosol Sources and Their Impact on Orographic Precipitation over California's Central Sierra Nevada

    Science.gov (United States)

    Creamean, J.; Ault, A. P.; White, A. B.; Neiman, P. J.; Minnis, P.; Prather, K. A.

    2014-12-01

    Aerosols that serve as cloud condensation nuclei (CCN) and ice nuclei (IN) have the potential to profoundly influence precipitation processes. Furthermore, changes in orographic precipitation have broad implications for reservoir storage and flood risks. As part of the CalWater I field campaign (2009-2011), the impacts of aerosol sources on precipitation were investigated in the California Sierra Nevada Mountains. In 2009, the precipitation collected on the ground was influenced by both local biomass burning and long-range transported dust and biological particles, while in 2010, by mostly local sources of biomass burning and pollution, and in 2011 by mostly long-range transport of dust and biological particles from distant sources. Although vast differences in the sources of residues were observed from year-to-year, dust and biological residues were omnipresent (on average, 55% of the total residues combined) and were associated with storms consisting of deep convective cloud systems and larger quantities of precipitation initiated in the ice phase. Further, biological residues were dominant during storms with relatively warm cloud temperatures (up to -15°C), suggesting biological components were more efficient IN than mineral dust. On the other hand, when precipitation quantities were lower, local biomass burning and pollution residues were observed (on average 31% and 9%, respectively), suggesting these residues potentially served as CCN at the base of shallow cloud systems and that lower level polluted clouds of storm systems produced less precipitation than non-polluted (i.e., marine) clouds. The direct connection of the sources of aerosols within clouds and precipitation type and quantity can be used in models to better assess how local emissions versus long-range transported dust and biological aerosols play a role in impacting regional weather and climate, ultimately with the goal of more accurate predictive weather forecast models and water resource

  1. Chemical composition and source apportionment of aerosol over the Klang valley

    International Nuclear Information System (INIS)

    Shamsiah Abdul Rahman; Mohd Suhaimi Hamzah; Abdul Khalik Wood; Nazaratul Ashifa Abdullah Salim; Mohd Suhaimi Elias; Eswiza Sanuri

    2009-01-01

    This paper reports the study of aerosol chemical composition of fine particles (PM 2.5) and possible sources of air pollution over the Klang Valley, Kuala Lumpur, based on the samples collected for a period of 6 years from July 2000 to Jun 2006. Samples collected were measured for mass, black carbon and elemental content of Na, Mg, Al, Si, P, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, As, Br and Pb. The fine aerosol mass concentration ranged from 11 - 110 ?g/m3. Black carbon is the major component of the fine aerosol with the weight fraction of 20%, whilst S is the major elemental content with the weight fraction about 5% as relative to the fine particle mass. The factor analysis method, positive matrix factorization (PMF) was then used to confirm the possible sources. The result of PMF analysis produced five-factor sources that contribute to the fine particles in the Klang Valley area. The five factors represent sea spray, industry, motor vehicles, smoke and soil. Motor vehicle is the main source of particulates in the area, with an average contribution of 51% of the fine mass concentration, followed by industry, smoke, sea spray and soil, with average contribution of 28%, 14%, 3.6% and 2.1%, respectively. (Author)

  2. Aerosol composition, chemistry, and source characterization during the 2008 VOCALS Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Y.; Springston, S.; Jayne, J.; Wang, J.; Senum, G.; Hubbe, J.; Alexander, L.; Brioude, J.; Spak, S.; Mena-Carrasco, M.; Kleinman, L.; Daum, P.

    2010-03-15

    Chemical composition of fine aerosol particles over the northern Chilean coastal waters was determined onboard the U.S. DOE G-1 aircraft during the VOCALS (VAMOS Ocean-Cloud-Atmosphere-Land Study) field campaign between October 16 and November 15, 2008. SO42-, NO3-, NH4+, and total organics (Org) were determined using an Aerodyne Aerosol Mass Spectrometer, and SO42-, NO3-, NH4+, Na+, Cl-, CH3SO3-, Mg2+, Ca2+, and K+ were determined using a particle-into-liquid sampler-ion chromatography technique. The results show the marine boundary layer (MBL) aerosol mass was dominated by non- sea-salt SO42- followed by Na+, Cl-, Org, NO3-, and NH4+, in decreasing importance; CH3SO3-, Ca2+, and K+ rarely exceeded their respective limits of detection. The SO42- aerosols were strongly acidic as the equivalent NH4+ to SO42- ratio was only {approx}0.25 on average. NaCl particles, presumably of sea-salt origin, showed chloride deficits but retained Cl- typically more than half the equivalency of Na+, and are externally mixed with the acidic sulfate aerosols. Nitrate was observed only on sea-salt particles, consistent with adsorption of HNO3 on sea-salt aerosols, responsible for the Cl- deficit. Dust particles appeared to play a minor role, judging from the small volume differences between that derived from the observed mass concentrations and that calculated based on particle size distributions. Because SO42- concentrations were substantial ({approx}0.5 - {approx}3 {micro}g/m3) with a strong gradient (highest near the shore), and the ocean-emitted dimethylsulfide and its unique oxidation product, CH3SO3-, were very low (i.e., {le} 40 parts per trillion and <0.05 {micro}g/m3, respectively), the observed SO42- aerosols are believed to be primarily of terrestrial origin. Back trajectory calculations indicate sulfur emissions from smelters and power plants along coastal regions of Peru and Chile are the main sources of these SO4- aerosols. However, compared to observations, model

  3. Analysis of internal radiation and radiotoxicity source base on aerosol distribution in RMI

    International Nuclear Information System (INIS)

    Yuwono, I.

    2000-01-01

    Destructive testing of nuclear fuel element during post irradiation examination in radio metallurgy installation may cause air contamination in the working area in the form of radioactive aerosol. Inhalation of the radioactive aerosol by worker will to become internal radiation source. Potential hazard of radioactive particle in the body also depends on the particle size. Analysis of internal radiation source and radiotoxicity showed that in the normal operation only natural radioactive materials are found with high radiotoxicity, i.e. Pb-212 and Ac-228. High deposit in the alveolar instersial (Ai) is 95 % and lower in the bronchial area (BB) is 1 % for particle size 11.7 nm and 350 nm respectively. (author)

  4. Sources of reactive nitrogen in marine aerosol over the Northwest Pacific Ocean in spring

    Science.gov (United States)

    Luo, Li; Kao, Shuh-Ji; Bao, Hongyan; Xiao, Huayun; Xiao, Hongwei; Yao, Xiaohong; Gao, Huiwang; Li, Jiawei; Lu, Yangyang

    2018-05-01

    Atmospheric deposition of long-range transport of anthropogenic reactive nitrogen (Nr, mainly comprised of NHx, NOy and water-soluble organic nitrogen, WSON) from continents may have profound impact on marine biogeochemistry. In addition, surface ocean dissolved organic nitrogen (DON) may also contribute to aerosol WSON in the overlying atmosphere. Despite the importance of off-continent dispersion and Nr interactions at the atmosphere-ocean boundary, our knowledge of the sources of various nitrogen species in the atmosphere over the open ocean remains limited due to insufficient observations. We conducted two cruises in the spring of 2014 and 2015 from the coast of China through the East China seas (ECSs, i.e. the Yellow Sea and East China Sea) to the open ocean (i.e. the Northwest Pacific Ocean, NWPO). Concentrations of water-soluble total nitrogen (WSTN), NO3- and NH4+, as well as the δ15N of WSTN and NO3- in marine aerosol, were measured during both cruises. In the spring of 2015, we also analysed the concentrations and δ15N of NO3- and the DON of surface seawater (SSW; at a depth of 5 m) along the cruise track. Aerosol NO3-, NH4+ and WSON decreased logarithmically (1-2 orders of magnitude) with distance from the shore, reflecting strong anthropogenic emission sources of NO3-, NH4+ and WSON in China. Average aerosol NO3- and NH4+ concentrations were significantly higher in 2014 (even in the remote NWOP) than in 2015 due to the stronger wind field in 2014, underscoring the role of the Asian winter monsoon in the seaward transport of anthropogenic NO3- and NH4+. However, the background aerosol WSON over the NWPO in 2015 (13.3 ± 8.5 nmol m-3) was similar to that in 2014 (12.2 ± 6.3 nmol m-3), suggesting an additional non-anthropogenic WSON source in the open ocean. Obviously, marine DON emissions should be considered in model and field assessments of net atmospheric WSON deposition in the open ocean. This study contributes information on parallel isotopic

  5. Sources of reactive nitrogen in marine aerosol over the Northwest Pacific Ocean in spring

    Directory of Open Access Journals (Sweden)

    L. Luo

    2018-05-01

    Full Text Available Atmospheric deposition of long-range transport of anthropogenic reactive nitrogen (Nr, mainly comprised of NHx, NOy and water-soluble organic nitrogen, WSON from continents may have profound impact on marine biogeochemistry. In addition, surface ocean dissolved organic nitrogen (DON may also contribute to aerosol WSON in the overlying atmosphere. Despite the importance of off-continent dispersion and Nr interactions at the atmosphere–ocean boundary, our knowledge of the sources of various nitrogen species in the atmosphere over the open ocean remains limited due to insufficient observations. We conducted two cruises in the spring of 2014 and 2015 from the coast of China through the East China seas (ECSs, i.e. the Yellow Sea and East China Sea to the open ocean (i.e. the Northwest Pacific Ocean, NWPO. Concentrations of water-soluble total nitrogen (WSTN, NO3− and NH4+, as well as the δ15N of WSTN and NO3− in marine aerosol, were measured during both cruises. In the spring of 2015, we also analysed the concentrations and δ15N of NO3− and the DON of surface seawater (SSW; at a depth of 5 m along the cruise track. Aerosol NO3−, NH4+ and WSON decreased logarithmically (1–2 orders of magnitude with distance from the shore, reflecting strong anthropogenic emission sources of NO3−, NH4+ and WSON in China. Average aerosol NO3− and NH4+ concentrations were significantly higher in 2014 (even in the remote NWOP than in 2015 due to the stronger wind field in 2014, underscoring the role of the Asian winter monsoon in the seaward transport of anthropogenic NO3− and NH4+. However, the background aerosol WSON over the NWPO in 2015 (13.3 ± 8.5 nmol m−3 was similar to that in 2014 (12.2 ± 6.3 nmol m−3, suggesting an additional non-anthropogenic WSON source in the open ocean. Obviously, marine DON emissions should be considered in model and field assessments of net atmospheric WSON deposition in the open ocean. This

  6. Effects of continental anthropogenic sources on organic aerosols in the coastal atmosphere of East China

    International Nuclear Information System (INIS)

    Shang, Dongjie; Hu, Min; Guo, Qingfeng; Zou, Qi; Zheng, Jing; Guo, Song

    2017-01-01

    source data and meteorological parameters. - Highlights: • Molecular and spatial characteristics of particulate organic compounds in coastal atmosphere of East China are reported. • Terrestrial fossil fuels and biomass burning have significant influences on aerosols in coastal atmosphere of East China. • Continental influences are highly dependent on the air mass origins. • Proportion of compounds from photochemical oxidation increased during the long range transport. - Capsule: Influences of continental anthropogenic sources on the composition of organic aerosols in the coastal atmosphere of East China were found to be significant and dependent on the origins of the air masses.

  7. Primary and secondary aerosols in Beijing in winter: sources, variations and processes

    Directory of Open Access Journals (Sweden)

    Y. Sun

    2016-07-01

    Full Text Available Winter has the worst air pollution of the year in the megacity of Beijing. Despite extensive winter studies in recent years, our knowledge of the sources, formation mechanisms and evolution of aerosol particles is not complete. Here we have a comprehensive characterization of the sources, variations and processes of submicron aerosols that were measured by an Aerodyne high-resolution aerosol mass spectrometer from 17 December 2013 to 17 January 2014 along with offline filter analysis by gas chromatography/mass spectrometry. Our results suggest that submicron aerosols composition was generally similar across the winter of different years and was mainly composed of organics (60 %, sulfate (15 % and nitrate (11 %. Positive matrix factorization of high- and unit-mass resolution spectra identified four primary organic aerosol (POA factors from traffic, cooking, biomass burning (BBOA and coal combustion (CCOA emissions as well as two secondary OA (SOA factors. POA dominated OA, on average accounting for 56 %, with CCOA being the largest contributor (20 %. Both CCOA and BBOA showed distinct polycyclic aromatic hydrocarbons (PAHs spectral signatures, indicating that PAHs in winter were mainly from coal combustion (66 % and biomass burning emissions (18 %. BBOA was highly correlated with levoglucosan, a tracer compound for biomass burning (r2 = 0.93, and made a considerable contribution to OA in winter (9 %. An aqueous-phase-processed SOA (aq-OOA that was strongly correlated with particle liquid water content, sulfate and S-containing ions (e.g. CH2SO2+ was identified. On average aq-OOA contributed 12 % to the total OA and played a dominant role in increasing oxidation degrees of OA at high RH levels (> 50 %. Our results illustrate that aqueous-phase processing can enhance SOA production and oxidation states of OA as well in winter. Further episode analyses highlighted the significant impacts of meteorological parameters on

  8. Improved identification of primary biological aerosol particles using single-particle mass spectrometry

    Directory of Open Access Journals (Sweden)

    M. A. Zawadowicz

    2017-06-01

    Full Text Available Measurements of primary biological aerosol particles (PBAP, especially at altitudes relevant to cloud formation, are scarce. Single-particle mass spectrometry (SPMS has been used to probe aerosol chemical composition from ground and aircraft for over 20 years. Here we develop a method for identifying bioaerosols (PBAP and particles containing fragments of PBAP as part of an internal mixture using SPMS. We show that identification of bioaerosol using SPMS is complicated because phosphorus-bearing mineral dust and phosphorus-rich combustion by-products such as fly ash produce mass spectra with peaks similar to those typically used as markers for bioaerosol. We have developed a methodology to differentiate and identify bioaerosol using machine learning statistical techniques applied to mass spectra of known particle types. This improved method provides far fewer false positives compared to approaches reported in the literature. The new method was then applied to two sets of ambient data collected at Storm Peak Laboratory and a forested site in Central Valley, California to show that 0.04–2 % of particles in the 200–3000 nm aerodynamic diameter range were identified as bioaerosol. In addition, 36–56 % of particles identified as biological also contained spectral features consistent with mineral dust, suggesting internal dust–biological mixtures.

  9. Phase identification of individual crystalline particles by combining EDX and EBSD: application to workplace aerosols.

    Science.gov (United States)

    Ervik, Torunn Kringlen; Benker, Nathalie; Weinbruch, Stephan; Skogstad, Asbjørn; Thomassen, Yngvar; Ellingsen, Dag G; Berlinger, Balázs

    2018-04-01

    This paper discusses the combined use of electron backscatter diffraction (EBSD) and energy dispersive X-ray microanalysis (EDX) to identify unknown phases in particulate matter from different workplace aerosols. Particles of α-silicon carbide (α-SiC), manganese oxide (MnO) and α-quartz (α-SiO 2 ) were used to test the method. Phase identification of spherical manganese oxide particles from ferromanganese production, with diameter less than 200 nm, was unambiguous, and phases of both MnO and Mn 3 O 4 were identified in the same agglomerate. The same phases were identified by selected area electron diffraction (SAED) in transmission electron microscopy (TEM). The method was also used to identify the phases of different SiC fibres, and both β-SiC and α-SiC fibres were found. Our results clearly demonstrate that EBSD combined with EDX can be successfully applied to the characterisation of workplace aerosols. Graphical abstract Secondary electron image of an agglomerate of manganese oxide particles collected at a ferromanganese smelter (a). EDX spectrum of the particle highlighted by an arrow (b). Indexed patterns after dynamic background subtraction from three particles shown with numbers in a (c).

  10. Isotope source apportionment of carbonaceous aerosol as a function of particle size and thermal refractiveness

    Science.gov (United States)

    Masalaite, Agne; Holzinger, Rupert; Remeikis, Vidmantas; Röckmann, Thomas; Dusek, Ulrike

    2016-04-01

    The stable carbon isotopes can be used to get information about sources and processing of carbonaceous aerosol. We will present results from source apportionment of carbonaceous aerosol as a function of particle size thermal refractiveness. Separate source apportionment for particles smaller than 200 nm and for different carbon volatility classes are rarely reported and give new insights into aerosol sources in the urban environment. Stable carbon isotope ratios were measured for the organic carbon (OC) fraction and total carbon (TC) of MOUDI impactor samples that were collected on a coastal site (Lithuania) during the winter 2012 and in the city of Vilnius (Lithuania) during the winter of 2009. The 11 impactor stages spanned a size range from 0.056 to 18 μm, but only the 6 stages in the submicron range were analysed. The δ13C values of bulk total carbon (δ13CTC) were determined with an elemental analyser (Flash EA 1112) coupled with an isotope ratio mass spectrometer (Thermo Finnigan Delta Plus Advantage) (EA - IRMS). Meanwhile δ13COC was measured using thermal-desorption isotope ratio mass spectrometry (IRMS) system. This allows a rough separation of the more volatile OC fraction (desorbed in the oven of IRMS up to 250 0C) from the more refractory fraction (desorbed up to 400 0C). In this study we investigated the composition of organic aerosol desorbed from filter samples at different temperatures using the thermal-desorption proton-transfer-reaction mass spectrometry (TD-PTR-MS) technique. During winter-time in Lithuania we expect photochemistry and biogenic emissions to be of minor importance. The main sources of aerosol carbon should be fossil fuel and biomass combustion. In both sites, the coastal and the urban site, δ13C measurements give a clear indication that the source contributions differ for small and large particles. Small particles < 200 nm are depleted in 13C with respect to larger particles by 1 - 2 ‰Ṫhis shows that OC in small particle

  11. Chemical characterisation of atmospheric aerosols during a 2007 summer field campaign at Brasschaat, Belgium: sources and source processes of biogenic secondary organic aerosol

    Directory of Open Access Journals (Sweden)

    Y. Gómez-González

    2012-01-01

    Full Text Available Measurements of organic marker compounds and inorganic species were performed on PM2.5 aerosols from a Belgian forest site that is severely impacted by urban pollution ("De Inslag", Brasschaat, Belgium during a 2007 summer period within the framework of the "Formation mechanisms, marker compounds, and source apportionment for biogenic atmospheric aerosols (BIOSOL" project. The measured organic species included (i low-molecular weight (MW dicarboxylic acids (LMW DCAs, (ii methanesulfonate (MSA, (iii terpenoic acids originating from the oxidation of α-pinene, β-pinene, d-limonene and Δ3-carene, and (iv organosulfates related to secondary organic aerosol from the oxidation of isoprene and α-pinene. The organic tracers explained, on average, 5.3 % of the organic carbon (OC, of which 0.7 % was due to MSA, 3.4 % to LMW DCAs, 0.6 % to organosulfates, and 0.6 % to terpenoic acids. The highest atmospheric concentrations of most species were observed during the first five days of the campaign, which were characterised by maximum day-time temperatures >22 °C. Most of the terpenoic acids and the organosulfates peaked during day-time, consistent with their local photochemical origin. High concentrations of 3-methyl-1,2,3-butanetricarboxylic acid (MBTCA and low concentrations of cis-pinonic acid were noted during the first five days of the campaign, indicative of an aged biogenic aerosol. Several correlations between organic species were very high (r>0.85, high (0.7<r<0.85, or substantial (0.5<r<0.7, suggesting that they are generated through similar formation pathways. Substantial correlations with temperature were found for OC, water-soluble OC, MBTCA, and several other organic species. MBTCA and terebic acid were highly correlated with the temperature (r>0.7 and showed an Arrhenius-type relationship, consistent with their formation through OH radical chemistry.

  12. Tracing of aerosol sources in an urban environment using chemical, Sr isotope, and mineralogical characterization.

    Science.gov (United States)

    Duarte, Regina M B O; Matos, João T V; Paula, Andreia S; Lopes, Sónia P; Ribeiro, Sara; Santos, José Francisco; Patinha, Carla; da Silva, Eduardo Ferreira; Soares, Rosário; Duarte, Armando C

    2017-04-01

    In the framework of two national research projects (ORGANOSOL and CN-linkAIR), fine particulate matter (PM 2.5 ) was sampled for 17 months at an urban location in the Western European Coast. The PM 2.5 samples were analyzed for organic carbon (OC), water-soluble organic carbon (WSOC), elemental carbon (EC), major water-soluble inorganic ions, mineralogical, and for the first time in this region, strontium isotope ( 87 Sr/ 86 Sr) composition. Organic matter dominates the identifiable urban PM 2.5 mass, followed by secondary inorganic aerosols. The acquired data resulted also in a seasonal overview of the carbonaceous and inorganic aerosol composition, with an important contribution from primary biomass burning and secondary formation processes in colder and warmer periods, respectively. The fossil-related primary EC seems to be continually present throughout the sampling period. The 87 Sr/ 86 Sr ratios were measured on both the labile and residual PM 2.5 fractions as well as on the bulk PM 2.5 samples. Regardless of the air mass origin, the residual fractions are more radiogenic (representative of a natural crustal dust source) than the labile fractions, whose 87 Sr/ 86 Sr ratios are comparable to that of seawater. The 87 Sr/ 86 Sr ratios and the mineralogical composition data further suggest that sea salt and mineral dust are important primary natural sources of fine aerosols throughout the sampling period.

  13. COLLABORATIVE RESEARCH: Study of Aerosol Sources and Processing at the GVAX Pantnagar Supersite

    Energy Technology Data Exchange (ETDEWEB)

    Thornton, Joel A. [Univ. of Washington, Seattle, WA (United States); Worsnop, Douglas [Aerodyne Research, Billerica, MA (United States)

    2016-09-22

    This project was part of a collaborative campaign, including the participation of scientists from seven research groups as part of the Winter Intensive Operating Period (January-February 2012) of the Clean Air for London (ClearfLo) campaign at a rural site in Detling, UK, 45 km southeast of central London to study wintertime sources of urban particulate matter. The UW contribution by PI Thornton’s group was to make the first deployment of a chemical ionization mass spectrometer instrument (MOVI-CI-ToFMS) to measure both particle and gas phase organic acids. The new instrument ran nearly continuously during the ClearfLo WINTER IOP at the Detling site, producing a first-ever data set of molecular composition information that can be used for source apportionment and process studies. The UW group published a paper in Environmental Science and Technology and contributed to another (Bohnenstengel et al BAMS 2015) detailing a direct molecular connection between biomass/biofuel burning particles and aerosol light absorption. The ES&T paper (Mohr, et al ES&T 2013) has received 42 citations in just 3 years indicative of its significant impact on the field. These measurements of urban and rural aerosol properties will contribute to improved modeling of regional aerosol emissions, and of atmospheric aging and removal.

  14. [Regional atmospheric environment risk source identification and assessment].

    Science.gov (United States)

    Zhang, Xiao-Chun; Chen, Wei-Ping; Ma, Chun; Zhan, Shui-Fen; Jiao, Wen-Tao

    2012-12-01

    Identification and assessment for atmospheric environment risk source plays an important role in regional atmospheric risk assessment and regional atmospheric pollution prevention and control. The likelihood exposure and consequence assessment method (LEC method) and the Delphi method were employed to build a fast and effective method for identification and assessment of regional atmospheric environment risk sources. This method was applied to the case study of a large coal transportation port in North China. The assessment results showed that the risk characteristics and the harm degree of regional atmospheric environment risk source were in line with the actual situation. Fast and effective identification and assessment of risk source has laid an important foundation for the regional atmospheric environmental risk assessment and regional atmospheric pollution prevention and control.

  15. Carbonaceous aerosols and pollutants over Delhi urban environment: Temporal evolution, source apportionment and radiative forcing

    Energy Technology Data Exchange (ETDEWEB)

    Bisht, D.S. [Indian Institute of Tropical Meteorology, New Delhi (India); Dumka, U.C., E-mail: dumka@aries.res.in [Aryabhatta Research Institute of Observational Sciences, Nainital (India); Kaskaoutis, D.G. [School of Natural Sciences, Shiv Nadar University, Tehsil Dadri (India); Pipal, A.S. [Department of Chemistry, Savitribai Phule Pune University, Pune (India); Srivastava, A.K. [Indian Institute of Tropical Meteorology, New Delhi (India); Soni, V.K.; Attri, S.D.; Sateesh, M. [India Meteorology Department, Lodhi Road, New Delhi (India); Tiwari, S. [Indian Institute of Tropical Meteorology, New Delhi (India)

    2015-07-15

    Particulate matter (PM{sub 2.5}) samples were collected over Delhi, India during January to December 2012 and analysed for carbonaceous aerosols and inorganic ions (SO{sub 4}{sup 2−} and NO{sub 3}{sup −}) in order to examine variations in atmospheric chemistry, combustion sources and influence of long-range transport. The PM{sub 2.5} samples are measured (offline) via medium volume air samplers and analysed gravimetrically for carbonaceous (organic carbon, OC; elemental carbon, EC) aerosols and inorganic ions (SO{sub 4}{sup 2−} and NO{sub 3}{sup −}). Furthermore, continuous (online) measurements of PM{sub 2.5} (via Beta-attenuation analyser), black carbon (BC) mass concentration (via Magee scientific Aethalometer) and carbon monoxide (via CO-analyser) are carried out. PM{sub 2.5} (online) range from 18.2 to 500.6 μg m{sup −3} (annual mean of 124.6 ± 87.9 μg m{sup −3}) exhibiting higher night-time (129.4 μg m{sup −3}) than daytime (103.8 μg m{sup −3}) concentrations. The online concentrations are 38% and 28% lower than the offline during night and day, respectively. In general, larger night-time concentrations are found for the BC, OC, NO{sub 3}{sup −}and SO{sub 4}{sup 2−}, which are seasonally dependent with larger differences during late post-monsoon and winter. The high correlation (R{sup 2} = 0.74) between OC and EC along with the OC/EC of 7.09 (day time) and 4.55 (night-time), suggest significant influence of biomass-burning emissions (burning of wood and agricultural waste) as well as secondary organic aerosol formation during daytime. Concentrated weighted trajectory (CWT) analysis reveals that the potential sources for the carbonaceous aerosols and pollutants are local emissions within the urban environment and transported smoke from agricultural burning in northwest India during post-monsoon. BC radiative forcing estimates result in very high atmospheric heating rates (~ 1.8–2.0 K day{sup −1}) due to agricultural burning effects

  16. Carbonaceous aerosols and pollutants over Delhi urban environment: Temporal evolution, source apportionment and radiative forcing

    International Nuclear Information System (INIS)

    Bisht, D.S.; Dumka, U.C.; Kaskaoutis, D.G.; Pipal, A.S.; Srivastava, A.K.; Soni, V.K.; Attri, S.D.; Sateesh, M.; Tiwari, S.

    2015-01-01

    Particulate matter (PM 2.5 ) samples were collected over Delhi, India during January to December 2012 and analysed for carbonaceous aerosols and inorganic ions (SO 4 2− and NO 3 − ) in order to examine variations in atmospheric chemistry, combustion sources and influence of long-range transport. The PM 2.5 samples are measured (offline) via medium volume air samplers and analysed gravimetrically for carbonaceous (organic carbon, OC; elemental carbon, EC) aerosols and inorganic ions (SO 4 2− and NO 3 − ). Furthermore, continuous (online) measurements of PM 2.5 (via Beta-attenuation analyser), black carbon (BC) mass concentration (via Magee scientific Aethalometer) and carbon monoxide (via CO-analyser) are carried out. PM 2.5 (online) range from 18.2 to 500.6 μg m −3 (annual mean of 124.6 ± 87.9 μg m −3 ) exhibiting higher night-time (129.4 μg m −3 ) than daytime (103.8 μg m −3 ) concentrations. The online concentrations are 38% and 28% lower than the offline during night and day, respectively. In general, larger night-time concentrations are found for the BC, OC, NO 3 − and SO 4 2− , which are seasonally dependent with larger differences during late post-monsoon and winter. The high correlation (R 2 = 0.74) between OC and EC along with the OC/EC of 7.09 (day time) and 4.55 (night-time), suggest significant influence of biomass-burning emissions (burning of wood and agricultural waste) as well as secondary organic aerosol formation during daytime. Concentrated weighted trajectory (CWT) analysis reveals that the potential sources for the carbonaceous aerosols and pollutants are local emissions within the urban environment and transported smoke from agricultural burning in northwest India during post-monsoon. BC radiative forcing estimates result in very high atmospheric heating rates (~ 1.8–2.0 K day −1 ) due to agricultural burning effects during the 2012 post-monsoon season. - Highlights: • Very high PM 2.5 (> 200 µg m −3 ) levels

  17. Sources of anions in aerosols in northeast Greenland during late winter

    Directory of Open Access Journals (Sweden)

    M. Fenger

    2013-02-01

    Full Text Available The knowledge of climate effects of atmospheric aerosols is associated with large uncertainty, and a better understanding of their physical and chemical properties is needed, especially in the Arctic environment. The objective of the present study is to improve our understanding of the processes affecting the composition of aerosols in the high Arctic. Therefore size-segregated aerosols were sampled at a high Arctic site, Station Nord (Northeast Greenland, in March 2009 using a Micro Orifice Uniform Deposit Impactor. The aerosol samples were extracted in order to analyse three water-soluble anions: chloride, nitrate and sulphate. The results are discussed based on possible chemical and physical transformations as well as transport patterns.

    The total concentrations of the ions at Station Nord were 53–507 ng m−3, 2–298 ng m−3 and 535–1087 ng m−3 for chloride (Cl, nitrate (NO3 and sulphate (SO42−, respectively. The aerosols in late winter/early spring, after polar sunrise, are found to be a mixture of long-range transported and regional to local originating aerosols. Fine particles, smaller than 1 μm, containing SO42−, Cl and NO3, are hypothesized to originate from long-range transport, where SO42− is by far the dominating anion accounting for 50–85% of the analyzed mass. The analysis suggests that Cl and NO3 in coarser particles (> 1.5 μm originate from local/regional sources. Under conditions where the air mass is transported over sea ice at high wind speeds, very coarse particles (> 18 μm are observed, and it is hypothesized that frost flowers on the sea ice are a source of the very coarse nitrate particles.

  18. Connecting Organic Aerosol Climate-Relevant Properties to Chemical Mechanisms of Sources and Processing

    Energy Technology Data Exchange (ETDEWEB)

    Thornton, Joel [Univ. of Washington, Seattle, WA (United States)

    2015-01-26

    The research conducted on this project aimed to improve our understanding of secondary organic aerosol (SOA) formation in the atmosphere, and how the properties of the SOA impact climate through its size, phase state, and optical properties. The goal of this project was to demonstrate that the use of molecular composition information to mechanistically connect source apportionment and climate properties can improve the physical basis for simulation of SOA formation and properties in climate models. The research involved developing and improving methods to provide online measurements of the molecular composition of SOA under atmospherically relevant conditions and to apply this technology to controlled simulation chamber experiments and field measurements. The science we have completed with the methodology will impact the simulation of aerosol particles in climate models.

  19. Levels, chemical composition and sources of fine aerosol particles (PM1) in an area of the Mediterranean basin

    International Nuclear Information System (INIS)

    Caggiano, Rosa; Macchiato, Maria; Trippetta, Serena

    2010-01-01

    Daily samples of fine aerosol particles (i.e., PM1, aerosol particles with an aerodynamic diameter less than 1.0 μm) were collected in Tito Scalo - Southern Italy - from April 2006 to March 2007. Measurements were performed by means of a low-volume gravimetric sampler, and each PM1 sample was analyzed by means of Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES) or Atomic Absorption Spectrometry (GFAAS and FAAS) techniques in order to determine its content in fourteen trace elements (Al, Ca, Cd, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, Pb, Ti and Zn). During the period examined, PM1 daily concentrations ranged between 0.3 μg m -3 and 55 μg m -3 with a mean value of 8 μg m -3 , a standard deviation of 7 μg m -3 and a median value of 6 μg m -3 . As far as PM1 chemical composition is concerned, the mean values of the trace element concentrations decreased in the following order: Ca > Fe > Al > Na > K > Cr > Mg > Pb > Ni ∼ Ti ∼ Zn > Cd ∼ Cu > Mn. Principal Component Analysis (PCA) allowed the identification of three probable PM1 sources: industrial emissions, traffic and re-suspension of soil dust. Moreover, the results of a procedure applied to study the potential long-range transport contribution to PM1 chemical composition, showed that trace element concentrations do not seem to be affected by air mass origin and path. This was probably due to the strong impact of the local emission sources and the lack of the concentration measurements of some important elements and compounds that could better reveal the long-range transport influence on PM1 measurements at ground level.

  20. Levels, chemical composition and sources of fine aerosol particles (PM1) in an area of the Mediterranean basin.

    Science.gov (United States)

    Caggiano, Rosa; Macchiato, Maria; Trippetta, Serena

    2010-01-15

    Daily samples of fine aerosol particles (i.e., PM1, aerosol particles with an aerodynamic diameter less than 1.0mum) were collected in Tito Scalo - Southern Italy - from April 2006 to March 2007. Measurements were performed by means of a low-volume gravimetric sampler, and each PM1 sample was analyzed by means of Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES) or Atomic Absorption Spectrometry (GFAAS and FAAS) techniques in order to determine its content in fourteen trace elements (Al, Ca, Cd, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, Pb, Ti and Zn). During the period examined, PM1 daily concentrations ranged between 0.3microgm(-3) and 55microgm(-3) with a mean value of 8 microg m(-3), a standard deviation of 7microgm(-3) and a median value of 6microgm(-3). As far as PM1 chemical composition is concerned, the mean values of the trace element concentrations decreased in the following order: Ca>Fe>Al>Na>K>Cr>Mg>Pb>Ni approximately Ti approximately Zn>Cd approximately Cu>Mn. Principal Component Analysis (PCA) allowed the identification of three probable PM1 sources: industrial emissions, traffic and re-suspension of soil dust. Moreover, the results of a procedure applied to study the potential long-range transport contribution to PM1 chemical composition, showed that trace element concentrations do not seem to be affected by air mass origin and path. This was probably due to the strong impact of the local emission sources and the lack of the concentration measurements of some important elements and compounds that could better reveal the long-range transport influence on PM1 measurements at ground level. Copyright 2009 Elsevier B.V. All rights reserved.

  1. Coupling aerosol-cloud-radiative processes in the WRF-Chem model: Investigating the radiative impact of elevated point sources

    Directory of Open Access Journals (Sweden)

    E. G. Chapman

    2009-02-01

    Full Text Available The local and regional influence of elevated point sources on summertime aerosol forcing and cloud-aerosol interactions in northeastern North America was investigated using the WRF-Chem community model. The direct effects of aerosols on incoming solar radiation were simulated using existing modules to relate aerosol sizes and chemical composition to aerosol optical properties. Indirect effects were simulated by adding a prognostic treatment of cloud droplet number and adding modules that activate aerosol particles to form cloud droplets, simulate aqueous-phase chemistry, and tie a two-moment treatment of cloud water (cloud water mass and cloud droplet number to precipitation and an existing radiation scheme. Fully interactive feedbacks thus were created within the modified model, with aerosols affecting cloud droplet number and cloud radiative properties, and clouds altering aerosol size and composition via aqueous processes, wet scavenging, and gas-phase-related photolytic processes. Comparisons of a baseline simulation with observations show that the model captured the general temporal cycle of aerosol optical depths (AODs and produced clouds of comparable thickness to observations at approximately the proper times and places. The model overpredicted SO2 mixing ratios and PM2.5 mass, but reproduced the range of observed SO2 to sulfate aerosol ratios, suggesting that atmospheric oxidation processes leading to aerosol sulfate formation are captured in the model. The baseline simulation was compared to a sensitivity simulation in which all emissions at model levels above the surface layer were set to zero, thus removing stack emissions. Instantaneous, site-specific differences for aerosol and cloud related properties between the two simulations could be quite large, as removing above-surface emission sources influenced when and where clouds formed within the modeling domain. When summed spatially over the finest

  2. Primary and secondary organic aerosol origin by combined gas-particle phase source apportionment

    Directory of Open Access Journals (Sweden)

    M. Crippa

    2013-08-01

    Full Text Available Secondary organic aerosol (SOA, a prominent fraction of particulate organic mass (OA, remains poorly constrained. Its formation involves several unknown precursors, formation and evolution pathways and multiple natural and anthropogenic sources. Here a combined gas-particle phase source apportionment is applied to wintertime and summertime data collected in the megacity of Paris in order to investigate SOA origin during both seasons. This was possible by combining the information provided by an aerosol mass spectrometer (AMS and a proton transfer reaction mass spectrometer (PTR-MS. A better constrained apportionment of primary OA (POA sources is also achieved using this methodology, making use of gas-phase tracers. These tracers made possible the discrimination between biogenic and continental/anthropogenic sources of SOA. We found that continental SOA was dominant during both seasons (24–50% of total OA, while contributions from photochemistry-driven SOA (9% of total OA and marine emissions (13% of total OA were also observed during summertime. A semi-volatile nighttime component was also identified (up to 18% of total OA during wintertime. This approach was successfully applied here and implemented in a new source apportionment toolkit.

  3. Sources of light-absorbing aerosol in arctic snow and their seasonal variation

    Directory of Open Access Journals (Sweden)

    Dean A. Hegg

    2010-11-01

    Full Text Available Two data sets consisting of measurements of light absorbing aerosols (LAA in arctic snow together with suites of other corresponding chemical constituents are presented; the first from Siberia, Greenland and near the North Pole obtained in 2008, and the second from the Canadian arctic obtained in 2009. A preliminary differentiation of the LAA into black carbon (BC and non-BC LAA is done. Source attribution of the light absorbing aerosols was done using a positive matrix factorization (PMF model. Four sources were found for each data set (crop and grass burning, boreal biomass burning, pollution and marine. For both data sets, the crops and grass biomass burning was the main source of both LAA species, suggesting the non-BC LAA was brown carbon. Depth profiles at most of the sites allowed assessment of the seasonal variation in the source strengths. The biomass burning sources dominated in the spring but pollution played a more significant (though rarely dominant role in the fall, winter and, for Greenland, summer. The PMF analysis is consistent with trajectory analysis and satellite fire maps.

  4. Radioactive aerosols of the object 'Ukryttya' (a review). Part 4.2. Sources and generation of radioactive aerosols during technogenic activities in 1987 - 2005

    International Nuclear Information System (INIS)

    Ogorodnikov, B.I.; Pazukhin, Eh.M.

    2006-01-01

    The sources of radioactive aerosol formation were considered at operation. It is shown that concentrations, radionuclide composition, size distribution, transfer and transformation in environment depended on physical and chemical processes proceeding within reactor breakdown, man-caused activity into premises of the object 'Shelter' and near ChNPP. 34 refs.; 7 figs.; 11 tab

  5. Characterization of polar organic compounds and source analysis of fine organic aerosols in Hong Kong

    Science.gov (United States)

    Li, Yunchun

    Organic aerosols, as an important fraction of airborne particulate mass, significantly affect the environment, climate, and human health. Compared with inorganic species, characterization of individual organic compounds is much less complete and comprehensive because they number in thousands or more and are diverse in chemical structures. The source contributions of organic aerosols are far from being well understood because they can be emitted from a variety of sources as well as formed from photochemical reactions of numerous precursors. This thesis work aims to improve the characterization of polar organic compounds and source apportionment analysis of fine organic carbon (OC) in Hong Kong, which consists of two parts: (1) An improved analytical method to determine monocarboxylic acids, dicarboxylic acids, ketocarboxylic acids, and dicarbonyls collected on filter substrates has been established. These oxygenated compounds were determined as their butyl ester or butyl acetal derivatives using gas chromatography-mass spectrometry. The new method made improvements over the original Kawamura method by eliminating the water extraction and evaporation steps. Aerosol materials were directly mixed with the BF 3/BuOH derivatization agent and the extracting solvent hexane. This modification improves recoveries for both the more volatile and the less water-soluble compounds. This improved method was applied to study the abundances and sources of these oxygenated compounds in PM2.5 aerosol samples collected in Hong Kong under different synoptic conditions during 2003-2005. These compounds account for on average 5.2% of OC (range: 1.4%-13.6%) on a carbon basis. Oxalic acid was the most abundant species. Six C2 and C3 oxygenated compounds, namely oxalic, malonic, glyoxylic, pyruvic acids, glyoxal, and methylglyoxal, dominated this suite of oxygenated compounds. More efforts are therefore suggested to focus on these small compounds in understanding the role of oxygenated

  6. Carbonaceous aerosol characteristics over Delhi in Northern India: Seasonal variability and possible sources

    Science.gov (United States)

    Srivastava, Atul Kumar; Bisht, Ds; Tiwari, S.

    Carbonaceous aerosols have been the focus of extensive studies during the last decade due to its significant impacts on human health, visibility and climate change. As per Asian regions are concerned, aerosols in south-Asia are gaining considerable importance because of their potential impacts on regional climate, yet their possible sources are poorly understood. Semi-continuous measurements of organic carbon (OC) and elemental carbon (EC) and continuous measurements of black carbon (BC) aerosols were conducted simultaneously at Delhi during the period from January 2011 to May 2012. Delhi is the capital city of India and one of the densely populated and industrialized urban megacities in Asia, located at the Ganga basin in the northern part of India. Being highly polluted region, mass concentrations of OC, EC and BC over Delhi were found to vary from about 6-92 mug m (-3) (mean: 23±16 mug m (-3) ), 3-38 mug m (-3) (mean: 11±7 mug m (-3) ) and 1-24 mug m (-3) (mean: 7±5 mug m (-3) ), respectively during the entire measurement period, with about two times higher concentration during winter as compared to summer. A significant correlation between OC and EC (R=0.95, n=232) and relatively lower OC/EC ratio (range: 1.0-3.6; mean: 2.2±0.5) suggest fossil fuel emission as a dominant source of carbonaceous aerosols over the station. The average mass concentration of EC was found about 38% higher than BC during the study period, which is interestingly different as reported at other locations over Ganga basin. We also determined the associated optical properties of carbonaceous species (e.g. absorption coefficient and mass absorption efficiency) over the station. Significant loading of carbonaceous species over such regions emphasize an urgent need to focus on air quality management and proper impact assessment on health perspective.

  7. Submicron organic aerosol in Tijuana, Mexico, from local and Southern California sources during the CalMex campaign

    Science.gov (United States)

    Takahama, S.; Johnson, A.; Guzman Morales, J.; Russell, L. M.; Duran, R.; Rodriguez, G.; Zheng, J.; Zhang, R.; Toom-Sauntry, D.; Leaitch, W. R.

    2013-05-01

    The CalMex campaign was conducted from May 15 to June 30 of 2010 to study the properties and sources of air pollution in Tijuana, Mexico. In this study, submicron organic aerosol mass (OM) composition measured by Fourier Transform Infrared Spectroscopy (FTIR), Aerosol Chemical Speciation Monitor (ACSM), and X-ray spectromicroscopy are combined with statistical analysis and measurements of other atmospheric constituents. The average (±one standard deviation) OM concentration was 3.3 ± 1.7 μg m-3. A large source of submicron aerosol mass at this location was determined to be vehicular sources, which contributed approximately 40% to the submicron OM; largely during weekday mornings. The O/C ratio estimated from ACSM measurements was 0.64 ± 0.19; diurnal variations in this value and the more oxygenated fraction of OM as determined from Positive Matrix Factorization and classification analyses suggest the high degree of oxygenation originates from aged OM, rather than locally-produced secondary organic aerosol. A large contribution of this oxygenated aerosol to Tijuana from various source classes was observed; some fraction of this aerosol mass may be associated with non-refractory components, such as dust or BC. Backtrajectory simulations using the HYSPLIT model suggest that the mean wind vector consistently originated from the northwest region, over the Pacific Ocean and near the Southern California coast, which suggests that the origin of much of the oxygenated organic aerosol observed in Tijuana (as much as 60% of OM) may have been the Southern California Air Basin. The marine aerosol contribution to OM during the period was on average 23 ± 24%, though its contribution varied over synoptic rather than diurnal timescales. BB aerosol contributed 20 ± 20% of the OM during the campaign period, with notable BB events occurring during several weekend evenings.

  8. Composition and sources of carbonaceous aerosols in Northern Europe during winter

    Science.gov (United States)

    Glasius, M.; Hansen, A. M. K.; Claeys, M.; Henzing, J. S.; Jedynska, A. D.; Kasper-Giebl, A.; Kistler, M.; Kristensen, K.; Martinsson, J.; Maenhaut, W.; Nøjgaard, J. K.; Spindler, G.; Stenström, K. E.; Swietlicki, E.; Szidat, S.; Simpson, D.; Yttri, K. E.

    2018-01-01

    Sources of elemental carbon (EC) and organic carbon (OC) in atmospheric aerosols (carbonaceous aerosols) were investigated by collection of weekly aerosol filter samples at six background sites in Northern Europe (Birkenes, Norway; Vavihill, Sweden; Risoe, Denmark; Cabauw and Rotterdam in The Netherlands; Melpitz, Germany) during winter 2013. Analysis of 14C and a set of molecular tracers were used to constrain the sources of EC and OC. During the four-week campaign, most sites (in particular those in Germany and The Netherlands) were affected by an episode during the first two weeks with high concentrations of aerosol, as continental air masses were transported westward. The analysis results showed a clear, increasing north to south gradient for most molecular tracers. Total carbon (TC = OC + EC) at Birkenes showed an average concentration of 0.5 ± 0.3 μg C m-3, whereas the average concentration at Melpitz was 6.0 ± 4.3 μg C m-3. One weekly mean TC concentration as high as 11 μg C m-3 was observed at Melpitz. Average levoglucosan concentrations varied by an order of magnitude from 25 ± 13 ng m-3 (Birkenes) to 249 ± 13 ng m-3 (Melpitz), while concentrations of tracers of fungal spores (arabitol and mannitol) and vegetative debris (cellulose) were very low, showing a minor influence of primary biological aerosol particles during the North European winter. The fraction of modern carbon generally varied from 0.57 (Melpitz) to 0.91 (Birkenes), showing an opposite trend compared to the molecular tracers and TC. Total concentrations of 10 biogenic and anthropogenic carboxylic acids, mainly of secondary origin, were 4-53 ng m-3, with the lowest concentrations observed at Birkenes and the highest at Melpitz. However, the highest relative concentrations of carboxylic acids (normalized to TC) were observed at the most northern sites. Levels of organosulphates and nitrooxy organosulphates varied more than two orders of magnitude, from 2 to 414 ng m-3, between

  9. Principal sources of EMI identification and fixes

    International Nuclear Information System (INIS)

    Nason, W.D.

    1993-01-01

    The sources of disruptive energy involved in an EMI episode all fall in one or the other of two types: intentional emitters or incidental emitters. Intentional emitters, such as communications transmitters, radars, walkie talkies etc., depend on emitting energy to satisfy the functional role assigned to the. Incidental emitters are those devices that emit energy unintentionally and are not dependent on those emissions to fulfill the assigned function. Power line conducted emissions typically fall in this latter category. The corrective action to be taken in controlling a problem that is present in a system is quite different if an incidental emitter is involved from that which is proper if an intentional emitter is present. Some of the methods that can be used to identify the emission sources which are contributing to a problem are presented in this paper along with some of the possible corrective actions that can be applied. 7 figs

  10. Atmospheric aerosol compositions and sources at two national background sites in northern and southern China

    Directory of Open Access Journals (Sweden)

    Q. Zhu

    2016-08-01

    Full Text Available Although China's severe air pollution has become a focus in the field of atmospheric chemistry and the mechanisms of urban air pollution there have been researched extensively, few field sampling campaigns have been conducted at remote background sites in China, where air pollution characteristics on a larger scale are highlighted. In this study, an Aerodyne high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS, together with an Aethalometer, was deployed at two of China's national background sites in northern (Lake Hongze site; 33.23° N, 118.33° E; altitude 21 m and southern (Mount Wuzhi site; 18.84° N, 109.49° E; altitude 958 m China in the spring seasons in 2011 and 2015, respectively, in order to characterize submicron aerosol composition and sources. The campaign-average PM1 concentration was 36.8 ± 19.8 µg m−3 at the northern China background (NCB site, which was far higher than that at the southern China background (SCB site (10.9 ± 7.8 µg m−3. Organic aerosol (OA (27.2 %, nitrate (26.7 %, and sulfate (22.0 % contributed the most to the PM1 mass at NCB, while OA (43.5 % and sulfate (30.5 % were the most abundant components of the PM1 mass at SCB, where nitrate only constituted a small fraction (4.7 % and might have contained a significant amount of organic nitrates (5–11 %. The aerosol size distributions and organic aerosol elemental compositions all indicated very aged aerosol particles at both sites. The OA at SCB was more oxidized with a higher average oxygen to carbon (O ∕ C ratio (0.98 than that at NCB (0.67. Positive matrix factorization (PMF analysis was used to classify OA into three components, including a hydrocarbon-like component (HOA, attributed to fossil fuel combustion and two oxygenated components (OOA1 and OOA2, attributed to secondary organic aerosols from different source areas at NCB. PMF analysis at SCB identified a semi-volatile oxygenated

  11. Noise source identification for ducted fan systems

    OpenAIRE

    BENNETT, GARETH; FITZPATRICK, JOHN AIDAN

    2008-01-01

    PUBLISHED Coherence based source analysis techniques can be used to identify the contribution of combustion noise in the exhaust of a jet engine and hence enable the design of noise reduction devices. However, when the combustion noise propagates in a non-linear fashion the identified contribution using ordinary coherence methods will be inaccurate. In this paper, an analysis technique to enable the contribution of linear and non-linear mechanisms to the propagated sound ...

  12. Water soluble ions in aerosols (TSP) : Characteristics, sources and seasonal variation over the central Himalayas, Nepal

    Science.gov (United States)

    Tripathee, Lekhendra; Kang, Shichang; Zhang, Qianggong; Rupakheti, Dipesh

    2016-04-01

    Atmspheric pollutants transported from South Asia could have adverse impact on the Himalayan ecosystems. Investigation of aerosol chemistry in the Himalayan region in Nepal has been limited on a temporal and spatial scale to date. Therefore, the water-soluble ionic composition of aerosol using TSP sampler was investigated for a year period from April 2013 to March 2014 at four sites Bode, Dhunche, Lumbini and Jomsom characterized as an urban, rural, semi-urban and remote sites in Nepal. During the study period, the highest concentration of major cation was Ca2+ with an average concentration of 8.91, 2.17, 7.85 and 6.42 μg m-3 and the highest concentration of major anion was SO42- with an average of 10.96, 4.06, 6.85 and 3.30 μg m-3 at Bode, Dhunche, Lumbini and Jomsom respectively. The soluble ions showed the decrease in concentrations from urban to the rural site. Correlations and PCA analysis suggested that that SO42-, NO3- and NH4+ were derived from the anthropogenic sources where as the Ca2+ and Mg2+ were from crustal sources. Our results also suggest that the largest acid neutralizing agent at our sampling sites in the central Himalayas are Ca2+ followed by NH4+. Seasonal variations of soluble ions in aerosols showed higher concentrations during pre-monsoon and winter (dry-periods) due to limited precipitation amount and lower concentrations during the monsoon which can be explained by the dilution effect, higher the precipitation lower the concentration. K+ which is regarded as the tracer of biomss burning had a significant peaks during pre-monsoon season when the forest fires are active around the regions. In general, the results of this study suggests that the atmospheric chemistry is influenced by natural and anthropogenic sources. Thus, soluble ionic concentrations in aerosols from central Himalayas, Nepal can provide a useful database to assess atmospheric environment and its impacts on human health and ecosystem in the southern side of central

  13. Characteristics, sources, and transport of aerosols measured in spring 2008 during the aerosol, radiation, and cloud processes affecting Arctic Climate (ARCPAC Project

    Directory of Open Access Journals (Sweden)

    C. A. Brock

    2011-03-01

    Full Text Available We present an overview of the background, scientific goals, and execution of the Aerosol, Radiation, and Cloud Processes affecting Arctic Climate (ARCPAC project of April 2008. We then summarize airborne measurements, made in the troposphere of the Alaskan Arctic, of aerosol particle size distributions, composition, and optical properties and discuss the sources and transport of the aerosols. The aerosol data were grouped into four categories based on gas-phase composition. First, the background troposphere contained a relatively diffuse, sulfate-rich aerosol extending from the top of the sea-ice inversion layer to 7.4 km altitude. Second, a region of depleted (relative to the background aerosol was present within the surface inversion layer over sea-ice. Third, layers of dense, organic-rich smoke from open biomass fires in southern Russia and southeastern Siberia were frequently encountered at all altitudes from the top of the inversion layer to 7.1 km. Finally, some aerosol layers were dominated by components originating from fossil fuel combustion.

    Of these four categories measured during ARCPAC, the diffuse background aerosol was most similar to the average springtime aerosol properties observed at a long-term monitoring site at Barrow, Alaska. The biomass burning (BB and fossil fuel layers were present above the sea-ice inversion layer and did not reach the sea-ice surface during the course of the ARCPAC measurements. The BB aerosol layers were highly scattering and were moderately hygroscopic. On average, the layers produced a noontime net heating of ~0.1 K day−1 between 3 and 7 km and a slight cooling at the surface. The ratios of particle mass to carbon monoxide (CO in the BB plumes, which had been transported over distances >5000 km, were comparable to the high end of literature values derived from previous measurements in wildfire smoke. These ratios suggest minimal precipitation scavenging and removal of the BB

  14. Positive matrix factorization and trajectory modelling for source identification: A new look at Indian Ocean Experiment ship observations

    Science.gov (United States)

    Bhanuprasad, S. G.; Venkataraman, Chandra; Bhushan, Mani

    The sources of aerosols on a regional scale over India have only recently received attention in studies using back trajectory analysis and chemical transport modelling. Receptor modelling approaches such as positive matrix factorization (PMF) and the potential source contribution function (PSCF) are effective tools in source identification of urban and regional-scale pollution. In this work, PMF and PSCF analysis is applied to identify categories and locations of sources that influenced surface concentrations of aerosols in the Indian Ocean Experiment (INDOEX) domain measured on-board the research vessel Ron Brown [Quinn, P.K., Coffman, D.J., Bates, T.S., Miller, T.L., Johnson, J.E., Welton, E.J., et al., 2002. Aerosol optical properties during INDOEX 1999: means, variability, and controlling factors. Journal of Geophysical Research 107, 8020, doi:10.1029/2000JD000037]. Emissions inventory information is used to identify sources co-located with probable source regions from PSCF. PMF analysis identified six factors influencing PM concentrations during the INDOEX cruise of the Ron Brown including a biomass combustion factor (35-40%), three industrial emissions factors (35-40%), primarily secondary sulphate-nitrate, balance trace elements and Zn, and two dust factors (20-30%) of Si- and Ca-dust. The identified factors effectively predict the measured submicron PM concentrations (slope of regression line=0.90±0.20; R2=0.76). Probable source regions shifted based on changes in surface and elevated flows during different times in the ship cruise. They were in India in the early part of the cruise, but in west Asia, south-east Asia and Africa, during later parts of the cruise. Co-located sources include coal-fired electric utilities, cement, metals and petroleum production in India and west Asia, biofuel combustion for energy and crop residue burning in India, woodland/forest burning in north sub-Saharan Africa and forest burning in south-east Asia. Significant findings

  15. Data sources avalaibility to dangers identification

    International Nuclear Information System (INIS)

    Carrillo, M.

    2013-01-01

    The power point presentation is about epidemiological studies, animals in vivo studies, in vitro studies, activity and structure, key data to consider for risk characterization, stimation and dose, exposicition limits,NOEL, data sources more important to exposition evaluation, consumption Data, concentration data, population data studies, chemical concentration in food, maximum levels(LMs) maximum limits of wastes LMRs, monitoring data and sanitary surveillance, diet studies, (EDTs), data base GEMS/Food, data report and use, consumption data base, risk determination strategy in health produced by food contaminant intake

  16. Quantitative evaluation of emission controls on primary and secondary organic aerosol sources during Beijing 2008 Olympics

    Directory of Open Access Journals (Sweden)

    S. Guo

    2013-08-01

    Full Text Available To assess the primary and secondary sources of fine organic aerosols after the aggressive implementation of air pollution controls during the 2008 Beijing Olympic Games, 12 h PM2.5 values were measured at an urban site at Peking University (PKU and an upwind rural site at Yufa during the CAREBEIJING-2008 (Campaigns of Air quality REsearch in BEIJING and surrounding region summer field campaign. The average PM2.5 concentrations were 72.5 ± 43.6 μg m−3 and 64.3 ± 36.2 μg m−3 (average ± standard deviation, below as the same at PKU and Yufa, respectively, showing the lowest concentrations in recent years. Combining the results from a CMB (chemical mass balance model and secondary organic aerosol (SOA tracer-yield model, five primary and four secondary fine organic aerosol sources were compared with the results from previous studies in Beijing. The relative contribution of mobile sources to PM2.5 concentrations was increased in 2008, with diesel engines contributing 16.2 ± 5.9% and 14.5 ± 4.1% and gasoline vehicles contributing 10.3 ± 8.7% and 7.9 ± 6.2% to organic carbon (OC at PKU and Yufa, respectively. Due to the implementation of emission controls, the absolute OC concentrations from primary sources were reduced during the Olympics, and the contributions from secondary formation of OC represented a larger relative source of fine organic aerosols. Compared with the non-controlled period prior to the Olympics, primary vehicle contributions were reduced by 30% at the urban site and 24% at the rural site. The reductions in coal combustion contributions were 57% at PKU and 7% at Yufa. Our results demonstrate that the emission control measures implemented in 2008 significantly alleviated the primary organic particle pollution in and around Beijing. However, additional studies are needed to provide a more comprehensive assessment of the emission control effectiveness on SOA formation.

  17. Sources of anions in aerosols in northeast Greenland during late winter

    DEFF Research Database (Denmark)

    Lauridsen, Marlene Fenger; Sørensen, Lise Lotte; Kristensen, Kasper

    2013-01-01

    −4 is by far the dominating anion accounting for 50–85% of the analyzed mass. The analysis suggests that Cl− and NO−3 in coarser particles (> 1.5 μm) originate from local/regional sources. Under conditions where the air mass is transported over sea ice at high wind speeds, very coarse particles (> 18 μm...... ), respectively. The aerosols in late winter/early spring, after polar sunrise, are found to be a mixture of long-range transported and regional to local originating aerosols. Fine particles, smaller than 1 μm, containing SO2−4 , Cl− and NO− 3 , are hypothesized to originate from long-range transport, where SO2......The knowledge of climate effects of atmospheric aerosols is associated with large uncertainty, and a better understanding of their physical and chemical properties is needed, especially in the Arctic environment. The objective of the present study is to improve our understanding of the processes...

  18. Global-scale combustion sources of organic aerosols: sensitivity to formation and removal mechanisms

    Science.gov (United States)

    Tsimpidi, Alexandra P.; Karydis, Vlassis A.; Pandis, Spyros N.; Lelieveld, Jos

    2017-06-01

    Organic compounds from combustion sources such as biomass burning and fossil fuel use are major contributors to the global atmospheric load of aerosols. We analyzed the sensitivity of model-predicted global-scale organic aerosols (OA) to parameters that control primary emissions, photochemical aging, and the scavenging efficiency of organic vapors. We used a computationally efficient module for the description of OA composition and evolution in the atmosphere (ORACLE) of the global chemistry-climate model EMAC (ECHAM/MESSy Atmospheric Chemistry). A global dataset of aerosol mass spectrometer (AMS) measurements was used to evaluate simulated primary (POA) and secondary (SOA) OA concentrations. Model results are sensitive to the emission rates of intermediate-volatility organic compounds (IVOCs) and POA. Assuming enhanced reactivity of semi-volatile organic compounds (SVOCs) and IVOCs with OH substantially improved the model performance for SOA. The use of a hybrid approach for the parameterization of the aging of IVOCs had a small effect on predicted SOA levels. The model performance improved by assuming that freshly emitted organic compounds are relatively hydrophobic and become increasingly hygroscopic due to oxidation.

  19. Point source identification in nonlinear advection–diffusion–reaction systems

    International Nuclear Information System (INIS)

    Mamonov, A V; Tsai, Y-H R

    2013-01-01

    We consider a problem of identification of point sources in time-dependent advection–diffusion systems with a nonlinear reaction term. The linear counterpart of the problem in question can be reduced to solving a system of nonlinear algebraic equations via the use of adjoint equations. We extend this approach by constructing an algorithm that solves the problem iteratively to account for the nonlinearity of the reaction term. We study the question of improving the quality of source identification by adding more measurements adaptively using the solution obtained previously with a smaller number of measurements. (paper)

  20. Sources and atmospheric processing of organic aerosol in the Mediterranean: insights from aerosol mass spectrometer factor analysis

    Directory of Open Access Journals (Sweden)

    L. Hildebrandt

    2011-12-01

    Full Text Available Atmospheric particles were measured in the late winter (25 February–26 March 2009 at a remote coastal site on the island of Crete, Greece during the Finokalia Aerosol Measurement Experiment-2009. A quadrupole aerosol mass spectrometer (Q-AMS was employed to quantify the size-resolved chemical composition of non-refractory submicron aerosol, and a thermodenuder was used to analyze the organic aerosol (OA volatility. Complementary measurements included particle size distributions from a scanning mobility particle sizer, inorganic and organic particle composition from filter analysis, air ion concentrations, O3, NOx and NOy concentrations, and meteorological measurements. Factor analysis was performed on the OA mass spectra, and the variability in OA composition could best be explained with three OA components. The oxygenated organic aerosol (OOA was similar in composition and volatility to the summertime OA previously measured at this site and may represent an effective endpoint in particle-phase oxidation of organics. The two other OA components, one associated with amines (Amine-OA and the other probably associated with the burning of olive branches (OB-OA, had very low volatility but were less oxygenated. Hydrocarbon-like organic aerosol (HOA was not detected. The absence of OB-OA and Amine-OA in the summer data may be due to lower emissions and/or photochemical conversion of these components to OOA.

  1. Airborne measurements of aerosol optical properties related to early spring transport of mid-latitude sources into the Arctic

    Directory of Open Access Journals (Sweden)

    R. A. de Villiers

    2010-06-01

    Full Text Available Airborne lidar and in-situ measurements of the aerosol properties were conducted between Svalbard Island and Scandinavia in April 2008. Evidence of aerosol transport from Europe and Asia is given. The analysis of the aerosol optical properties based on a multiwavelength lidar (355, 532, 1064 nm including volume depolarization at 355 nm aims at distinguishing the role of the different aerosol sources (Siberian wild fires, Eastern Asia and European anthropogenic emissions. Combining, first aircraft measurements, second FLEXPART simulations with a calculation of the PBL air fraction originating from the three different mid-latitude source regions, and third level-2 CALIPSO data products (i.e. backscatter coefficient 532 nm,volume depolarization and color ratio between 1064 and 532 nm in aerosol layers along the transport pathways, appears a valuable approach to identify the role of the different aerosol sources even after a transport time larger than 4 days. Optical depth of the aerosol layers are always rather small (<4% while transported over the Arctic and ratio of the total attenuated backscatter (i.e. including molecular contribution provide more stable result than conventional aerosol backscatter ratio. Above Asia, CALIPSO data indicate more depolarization (up to 15% and largest color ratio (>0.5 for the northeastern Asia emissions (i.e. an expected mixture of Asian pollution and dust, while low depolarization together with smaller and quasi constant color ratio (≈0.3 are observed for the Siberian biomass burning emissions. A similar difference is visible between two layers observed by the aircraft above Scandinavia. The analysis of the time evolution of the aerosol optical properties revealed by CALIPSO between Asia and Scandinavia shows a gradual decrease of the aerosol backscatter, depolarization ratio and color ratio which suggests the removal of the largest particles in the accumulation mode. A similar study conducted for a European

  2. Spatial and Temporal Variations of EC and OC Aerosol Combustion Sources in a Polluted Metropolitan Area

    Science.gov (United States)

    Mouteva, G.; Randerson, J. T.; Fahrni, S.; Santos, G.; Bush, S. E.; Ehleringer, J. R.; Czimczik, C. I.

    2015-12-01

    Anthropogenic emissions of carbonaceous aerosols are a major component of fine air particulate matter (PM2.5) in polluted metropolitan areas and in the global atmosphere. Elemental (EC) and organic carbon (OC) aerosols influence Earth's energy balance by means of direct and indirect pathways and EC has been suggested as a better indicator of public health impacts from combustion-related sources than PM mass. Quantifying the contribution of fossil fuel and biomass combustion to the EC and OC emissions and their temporal and spatial variations is critical for developing efficient legislative air pollution control measures and successful climate mitigation strategies. In this study, we used radiocarbon (14C) to separate and quantify fossil and biomass contributions to a time series of EC and OC collected at 3 locations in Salt Lake City (SLC). Aerosol samples were collected on quartz fiber filters and a modified OC/EC analyzer was used with the Swiss_4S protocol to isolate and trap the EC fraction. Together with the total carbon (TC) content of the samples, the EC was analyzed for its 14C content with accelerator mass spectrometry. The 14C of OC was derived as a mass balance difference between TC and EC. EC had an annual average fraction modern of 0.13±0.06 and did not vary significantly across seasons. OC had an annual average FM of 0.49±0.13, with the winter mean (0.43±0.11) lower than the summer mean (0.64±0.13) at the 5% significance level. While the 3 stations were chosen to represent a variety of environmental conditions within SLC, no major differences in this source partitioning were observed between stations. During winter, the major sources of air pollutants in SLC are motor vehicles and wood stove combustion and determining their relative contributions has been the subject of debate. Our results indicated that fossil fuels were the dominant source of carbonaceous aerosols during winter, contributing 87% or more of the total EC mass and 40-75% of the OC

  3. Relation between aerosol sources and meteorological parameters for inhalable atmospheric particles in Sao Paulo City, Brazil

    Science.gov (United States)

    Andrade, Fatima; Orsini, Celso; Maenhaut, Willy

    Stacked filter units were used to collect atmospheric particles in separate coarse and fine fractions at the Sao Paulo University Campus during the winter of 1989. The samples were analysed by particle-induced X-ray emission (PIXE) and the data were subjected to an absolute principal component analysis (APCA). Five sources were identified for the fine particles: industrial emissions, which accounted for 13% of the fine mass; emissions from residual oil and diesel, explaining 41%; resuspended soil dust, with 28%; and emissions of Cu and of Mg, together with 18%. For the coarse particles, four sources were identified: soil dust, accounting for 59% of the coarse mass; industrial emissions, with 19%; oil burning, with 8%; and sea salt aerosol, with 14% of the coarse mass. A data set with various meteorological parameters was also subjected to APCA, and a correlation analysis was performed between the meteorological "absolute principal component scores" (APCS) and the APCS from the fine and coarse particle data sets. The soil dust sources for the fine and coarse aerosol were highly correlated with each other and were anticorrelated with the sea breeze component. The industrial components in the fine and coarse size fractions were also highly positively correlated. Furthermore, the industrial component was related with the northeasterly wind direction and, to a lesser extent, with the sea breeze component.

  4. Source identification of hydrocarbons following environmental releases

    Energy Technology Data Exchange (ETDEWEB)

    Birkholz, D.A. [ALS Environmental, Edmonton, AB (Canada)

    2010-07-01

    Methods of identifying the sources of hydrocarbon contaminations were discussed in this PowerPoint presentation. Laboratories analyze for total petroleum hydrocarbons (TPH) by obtaining chromatograms of observed products. However, many petroleum products provide similar chromatograms. Several independent lines of evidence are needed for the purposes of accurate determination in legal applications. A case study of a lube oil plant spill was used to demonstrate the inconclusiveness of chromatograms and the need to determine petroleum biomarkers. Terpane, sterane, triaromatic sterane, isoprenoid, and alkylcyclohexane analyses were conducted to differentiate between the hydrocarbon samples. The analysis methods are being used with various soil, water, and crab species samples from the BP oil spill. Oil found at the different sites must be directly related to the spill. However, there are 3858 oil and gas platforms currently operating in the Gulf of Mexico. Ratios of biomarkers and polycyclic aromatic hydrocarbons (PAHs) are being developed to generate weight of evidence. A critical difference analysis was also presented. tabs., figs.

  5. Attribution of aerosol radiative forcing over India during the winter monsoon to emissions from source categories and geographical regions

    Science.gov (United States)

    Verma, S.; Venkataraman, C.; Boucher, O.

    2011-08-01

    We examine the aerosol radiative effects due to aerosols emitted from different emission sectors (anthropogenic and natural) and originating from different geographical regions within and outside India during the northeast (NE) Indian winter monsoon (January-March). These studies are carried out through aerosol transport simulations in the general circulation (GCM) model of the Laboratoire de Météorologie Dynamique (LMD). The model estimates of aerosol single scattering albedo (SSA) show lower values (0.86-0.92) over the region north to 10°N comprising of the Indian subcontinent, Bay of Bengal, and parts of the Arabian Sea compared to the region south to 10°N where the estimated SSA values lie in the range 0.94-0.98. The model estimated SSA is consistent with the SSA values inferred through measurements on various platforms. Aerosols of anthropogenic origin reduce the incoming solar radiation at the surface by a factor of 10-20 times the reduction due to natural aerosols. At the top-of-atmosphere (TOA), aerosols from biofuel use cause positive forcing compared to the negative forcing from fossil fuel and natural sources in correspondence with the distribution of SSA which is estimated to be the lowest (0.7-0.78) from biofuel combustion emissions. Aerosols originating from India and Africa-west Asia lead to the reduction in surface radiation (-3 to -8 W m -2) by 40-60% of the total reduction in surface radiation due to all aerosols over the Indian subcontinent and adjoining ocean. Aerosols originating from India and Africa-west Asia also lead to positive radiative effects at TOA over the Arabian Sea, central India (CNI), with the highest positive radiative effects over the Bay of Bengal and cause either negative or positive effects over the Indo-Gangetic plain (IGP).

  6. Identification of amines in wintertime ambient particulate material using high resolution aerosol mass spectrometry

    Science.gov (United States)

    Bottenus, Courtney L. H.; Massoli, Paola; Sueper, Donna; Canagaratna, Manjula R.; VanderSchelden, Graham; Jobson, B. Thomas; VanReken, Timothy M.

    2018-05-01

    Significant amounts of amines were detected in fine particulate matter (PM) during ambient wintertime conditions in Yakima, WA, using a high resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS). Positive matrix factorization (PMF) of the organic aerosol (OA) signal resulted in a six-factor solution that included two previously unreported amine OA factors. The contributions of the amine factors were strongly episodic, but the concentration of the combined amine factors was as high as 10-15 μg m-3 (2-min average) during those episodes. In one occasion, the Amine-II component was 45% of total OA signal. The Amine-I factor was dominated by spectral peaks at m/z 86 (C5H12N+) and m/z 100 (C6H14N+), while the Amine-II factor was dominated by spectral peaks at m/z 58 (C3H8N+ and C2H6N2+) and m/z 72 (C4H10N+ and C3H8N2+). The ions dominating each amine factor showed distinct time traces, suggesting different sources or formation processes. Investigation into the chemistry of the amine factors suggests a correlation with inorganic anions for Amine-I, but no evidence that the Amine-II was being neutralized by the same inorganic ions. We also excluded the presence of organonitrates (ON) in the OA. The presence of C2H4O2+ at m/z 60 (a levoglucosan fragment) in the Amine-I spectrum suggests some influence of biomass burning emissions (more specifically residential wood combustion) in this PMF factor, but wind direction suggested that the most likely sources of these amines were agricultural activities and feedlots to the S-SW of the site.

  7. 40 CFR 62.1101 - Identification of sources.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 8 2010-07-01 2010-07-01 false Identification of sources. 62.1101 Section 62.1101 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS... Company in San Joaquin County. (b) Simplot Company in Kings County. (c) Valley Nitrogen Products, Inc., in...

  8. 40 CFR 62.5103 - Identification of sources.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 8 2010-07-01 2010-07-01 false Identification of sources. 62.5103 Section 62.5103 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS..., Frederick, Maryland. [50 FR 9628, Mar. 11, 1985] Metals, Acid Gases, Organic Compounds and Nitrogen Oxide...

  9. 40 CFR 62.9140 - Identification of source.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 8 2010-07-01 2010-07-01 false Identification of source. 62.9140 Section 62.9140 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS...] Metals, Acid Gases, Organic Compounds and Nitrogen Oxide Emissions From Existing Municipal Waste...

  10. Aerosol composition, oxidation properties, and sources in Beijing: results from the 2014 Asia-Pacific Economic Cooperation summit study

    Science.gov (United States)

    Xu, W. Q.; Sun, Y. L.; Chen, C.; Du, W.; Han, T. T.; Wang, Q. Q.; Fu, P. Q.; Wang, Z. F.; Zhao, X. J.; Zhou, L. B.; Ji, D. S.; Wang, P. C.; Worsnop, D. R.

    2015-12-01

    The mitigation of air pollution in megacities remains a great challenge because of the complex sources and formation mechanisms of aerosol particles. The 2014 Asia-Pacific Economic Cooperation (APEC) summit in Beijing serves as a unique experiment to study the impacts of emission controls on aerosol composition, size distributions, and oxidation properties. Herein, a high-resolution time-of-flight aerosol mass spectrometer was deployed in urban Beijing for real-time measurements of size-resolved non-refractory submicron aerosol (NR-PM1) species from 14 October to 12 November 2014, along with a range of collocated measurements. The average (±σ) PM1 was 41.6 (±38.9) μg m-3 during APEC, which was decreased by 53 % compared with that before APEC. The aerosol composition showed substantial changes owing to emission controls during APEC. Secondary inorganic aerosol (SIA: sulfate + nitrate + ammonium) showed significant reductions of 62-69 %, whereas organics presented much smaller decreases (35 %). The results from the positive matrix factorization of organic aerosol (OA) indicated that highly oxidized secondary organic aerosol (SOA) showed decreases similar to those of SIA during APEC. However, primary organic aerosol (POA) from cooking, traffic, and biomass-burning sources were comparable to those before APEC, indicating the presence of strong local source emissions. The oxidation properties showed corresponding changes in response to OA composition. The average oxygen-to-carbon level during APEC was 0.36 (±0.10), which is lower than the 0.43 (±0.13) measured before APEC, demonstrating a decrease in the OA oxidation degree. The changes in size distributions of primary and secondary species varied during APEC. SIA and SOA showed significant reductions in large accumulation modes with peak diameters shifting from ~ 650 to 400 nm during APEC, whereas those of POA remained relatively unchanged. The changes in aerosol composition, size distributions, and oxidation

  11. Effects of continental anthropogenic sources on organic aerosols in the coastal atmosphere of East China.

    Science.gov (United States)

    Shang, Dongjie; Hu, Min; Guo, Qingfeng; Zou, Qi; Zheng, Jing; Guo, Song

    2017-10-01

    Although organic compounds in marine atmospheric aerosols have significant effects on climate and marine ecosystems, they have rarely been studied, especially in the coastal regions of East China. To assess the origins of the organic aerosols in the East China coastal atmosphere, PM 2.5 samples were collected from the atmospheres of the Yellow Sea, the East China Sea, and Changdao Island during the CAPTAIN (Campaign of Air PolluTion At INshore Areas of Eastern China) field campaign in the spring of 2011. The marine atmospheric aerosol samples that were collected were grouped based on the backward trajectories of their air masses. The organic carbon concentrations in the PM 2.5 samples from the marine and Changdao Island atmospheres were 5.5 ± 3.1 μgC/m 3 and 6.9 ± 2.4 μgC/m 3 , respectively, which is higher than in other coastal water atmospheres. The concentration of polycyclic aromatic hydrocarbons (PAHs) in the marine atmospheric PM 2.5 samples was 17.0 ± 20.2 ng/m 3 , indicating significant continental anthropogenic influences. The influences of fossil fuels and biomass burning on the composition of organic aerosols in the coastal atmosphere of East China were found to be highly dependent on the origins of the air masses. Diesel combustion had a strong impact on air masses from the Yangtze River Delta (YRD), and gasoline emissions had a more significant impact on the "North China" marine atmospheric samples. The "Northeast China" marine atmospheric samples were most impacted by biomass burning. Coal combustion contributed significantly to the compositions of all of the atmospheric samples. The proportions of secondary compounds increased as samples aged in the marine atmosphere indicating that photochemical oxidation occured during transport. Our results quantified ecosystem effects on marine atmospheric aerosols and highlighted the uncertainties that arise when modeling marine atmospheric PM 2.5 without considering high spatial resolution source

  12. Local source impacts on primary and secondary aerosols in the Midwestern United States

    Science.gov (United States)

    Jayarathne, Thilina; Rathnayake, Chathurika M.; Stone, Elizabeth A.

    2016-04-01

    Atmospheric particulate matter (PM) exhibits heterogeneity in composition across urban areas, leading to poor representation of outdoor air pollutants in human exposure assessments. To examine heterogeneity in PM composition and sources across an urban area, fine particulate matter samples (PM2.5) were chemically profiled in Iowa City, IA from 25 August to 10 November 2011 at two monitoring stations. The urban site is the federal reference monitoring (FRM) station in the city center and the peri-urban site is located 8.0 km to the west on the city edge. Measurements of PM2.5 carbonaceous aerosol, inorganic ions, molecular markers for primary sources, and secondary organic aerosol (SOA) tracers were used to assess statistical differences in composition and sources across the two sites. PM2.5 mass ranged from 3 to 26 μg m-3 during this period, averaging 11.2 ± 4.9 μg m-3 (n = 71). Major components of PM2.5 at the urban site included organic carbon (OC; 22%), ammonium (14%), sulfate (13%), nitrate (7%), calcium (2.9%), and elemental carbon (EC; 2.2%). Periods of elevated PM were driven by increases in ammonium, sulfate, and SOA tracers that coincided with hot and dry conditions and southerly winds. Chemical mass balance (CMB) modeling was used to apportion OC to primary sources; biomass burning, vegetative detritus, diesel engines, and gasoline engines accounted for 28% of OC at the urban site and 24% of OC at the peri-urban site. Secondary organic carbon from isoprene and monoterpene SOA accounted for an additional 13% and 6% of OC at the urban and peri-urban sites, respectively. Differences in biogenic SOA across the two sites were associated with enhanced combustion activities in the urban area and higher aerosol acidity at the urban site. Major PM constituents (e.g., OC, ammonium, sulfate) were generally well-represented by a single monitoring station, indicating a regional source influence. Meanwhile, nitrate, biomass burning, food cooking, suspended dust, and

  13. Light absorption of biomass burning and vehicle emission-sourced carbonaceous aerosols of the Tibetan Plateau.

    Science.gov (United States)

    Hu, Zhaofu; Kang, Shichang; Li, Chaoliu; Yan, Fangping; Chen, Pengfei; Gao, Shaopeng; Wang, Zhiyong; Zhang, Yulan; Sillanpää, Mika

    2017-06-01

    Carbonaceous aerosols over the Tibetan Plateau originate primarily from biomass burning and vehicle emissions (BB and VEs, respectively). The light absorption characteristics of these carbonaceous aerosols are closely correlated with the burning conditions and represent key factors that influence climate forcing. In this study, the light absorption characteristics of elemental carbon (EC) and water-soluble organic carbon (WSOC) in PM 2.5 (fine particulate matter smaller than 2.5 μm) generated from BB and VEs were investigated over the Tibetan Plateau (TP). The results showed that the organic carbon (OC)/EC ratios from BB- and VE-sourced PM 2.5 were 17.62 ± 10.19 and 1.19 ± 0.36, respectively. These values were higher than the ratios in other regions, which was primarily because of the diminished amount of oxygen over the TP. The mass absorption cross section of EC (MAC EC ) at 632 nm for the BB-sourced PM 2.5 (6.10 ± 1.21 m 2 .g -1 ) was lower than that of the VE-sourced PM 2.5 (8.10 ± 0.98 m 2 .g -1 ), indicating that the EC content of the BB-sourced PM 2.5 was overestimated because of the high OC/EC ratio. The respective absorption per mass (α/ρ) values at 365 nm for the VE- and BB-sourced PM 2.5 were 0.71 ± 0.17 m 2 .g -1 and 0.91 ± 0.18 m 2 .g -1 . The α/ρ value of the VEs was loaded between that of gasoline and diesel emissions, indicating that the VE-sourced PM 2.5 originated from both types of emissions. Because OC and WSOC accounts for most of the carbonaceous aerosols at remote area of the TP, the radiative forcing contributed by the WSOC should be high, and requires further investigation.

  14. Detection of aerosol pollution sources during sandstorms in Northwestern China using remote sensed and model simulated data

    Science.gov (United States)

    Filonchyk, Mikalai; Yan, Haowen; Yang, Shuwen; Lu, Xiaomin

    2018-02-01

    The present paper has used a comprehensive approach to study atmosphere pollution sources including the study of vertical distribution characteristics, the epicenters of occurrence and transport of atmospheric aerosol in North-West China under intensive dust storm registered in all cities of the region in April 2014. To achieve this goal, the remote sensing data using Moderate Resolution Imaging Spectroradiometer satellite (MODIS) as well as model-simulated data, were used, which facilitate tracking the sources, routes, and spatial extent of dust storms. The results of the study have shown strong territory pollution with aerosol during sandstorm. According to ground-based air quality monitoring stations data, concentrations of PM10 and PM2.5 exceeded 400 μg/m3 and 150 μg/m3, respectively, the ratio PM2.5/PM10 being within the range of 0.123-0.661. According to MODIS/Terra Collection 6 Level-2 aerosol products data and the Deep Blue algorithm data, the aerosol optical depth (AOD) at 550 nm in the pollution epicenter was within 0.75-1. The vertical distribution of aerosols indicates that the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) 532 nm total attenuates backscatter coefficient ranges from 0.01 to 0.0001 km-1 × sr-1 with the distribution of the main types of aerosols in the troposphere of the region within 0-12.5 km, where the most severe aerosol contamination is observed in the lower troposphere (at 3-6 km). According to satellite sounding and model-simulated data, the sources of pollution are the deserted regions of Northern and Northwestern China.

  15. Sources of atmospheric aerosol from long-term measurements (5 years) of chemical composition in Athens, Greece.

    Science.gov (United States)

    Paraskevopoulou, D; Liakakou, E; Gerasopoulos, E; Mihalopoulos, N

    2015-09-15

    To identify the sources of aerosols in Greater Athens Area (GAA), a total of 1510 daily samples of fine (PM 2.5) and coarse (PM 10-2,5) aerosols were collected at a suburban site (Penteli), during a five year period (May 2008-April 2013) corresponding to the period before and during the financial crisis. In addition, aerosol sampling was also conducted in parallel at an urban site (Thissio), during specific, short-term campaigns during all seasons. In all these samples mass and chemical composition measurements were performed, the latest only at the fine fraction. Particulate organic matter (POM) and ionic masses (IM) are the main contributors of aerosol mass, equally contributing by accounting for about 24% of the fine aerosol mass. In the IM, nss-SO4(-2) is the prevailing specie followed by NO3(-) and NH4(+) and shows a decreasing trend during the 2008-2013 period similar to that observed for PM masses. The contribution of water in fine aerosol is equally significant (21 ± 2%), while during dust transport, the contribution of dust increases from 7 ± 2% to 31 ± 9%. Source apportionment (PCA and PMF) and mass closure exercises identified the presence of six sources of fine aerosols: secondary photochemistry, primary combustion, soil, biomass burning, sea salt and traffic. Finally, from winter 2012 to winter 2013 the contribution of POM to the urban aerosol mass is increased by almost 30%, reflecting the impact of wood combustion (dominant fuel for domestic heating) to air quality in Athens, which massively started in winter 2013. Copyright © 2015 Elsevier B.V. All rights reserved.

  16. Chemical composition, sources, and aging process of submicron aerosols in Beijing: Contrast between summer and winter

    Science.gov (United States)

    Hu, Weiwei; Hu, Min; Hu, Wei; Jimenez, Jose L.; Yuan, Bin; Chen, Wentai; Wang, Ming; Wu, Yusheng; Chen, Chen; Wang, Zhibin; Peng, Jianfei; Zeng, Limin; Shao, Min

    2016-02-01

    To investigate the seasonal characteristics of submicron aerosol (PM1) in Beijing urban areas, a high-resolution time-of-flight aerosol-mass-spectrometer (HR-ToF-AMS) was utilized at an urban site in summer (August to September 2011) and winter (November to December 2010), coupled with multiple state of the art online instruments. The average mass concentrations of PM1 (60-84 µg m-3) and its chemical compositions in different campaigns of Beijing were relatively consistent in recent years. In summer, the daily variations of PM1 mass concentrations were stable and repeatable. Eighty-two percent of the PM1 mass concentration on average was composed of secondary species, where 62% is secondary inorganic aerosol and 20% secondary organic aerosol (SOA). In winter, PM1 mass concentrations changed dramatically because of the different meteorological conditions. The high average fraction (58%) of primary species in PM1 including primary organic aerosol (POA), black carbon, and chloride indicates primary emissions usually played a more important role in the winter. However, aqueous chemistry resulting in efficient secondary formation during occasional periods with high relative humidity may also contribute substantially to haze in winter. Results of past OA source apportionment studies in Beijing show 45-67% of OA in summer and 22-50% of OA in winter can be composed of SOA. Based on the source apportionment results, we found 45% POA in winter and 61% POA in summer are from nonfossil sources, contributed by cooking OA in both seasons and biomass burning OA (BBOA) in winter. Cooking OA, accounting for 13-24% of OA, is an important nonfossil carbon source in all years of Beijing and should not be neglected. The fossil sources of POA include hydrocarbon-like OA from vehicle emissions in both seasons and coal combustion OA (CCOA) in winter. The CCOA and BBOA were the two main contributors (57% of OA) for the highest OA concentrations (>100 µg m-3) in winter. The POA

  17. Global dust sources detection using MODIS Deep Blue Collection 6 aerosol products

    Science.gov (United States)

    Pérez García-Pando, C.; Ginoux, P. A.

    2015-12-01

    Our understanding of the global dust cycle is limited by a dearth of information about dust sources, especially small-scale features which could account for a large fraction of global emissions. Remote sensing sensors are the most useful tool to locate dust sources. These sensors include microwaves, visible channels, and lidar. On the global scale, major dust source regions have been identified using polar orbiting satellite instruments. The MODIS Deep Blue algorithm has been particularly useful to detect small-scale sources such as floodplains, alluvial fans, rivers, and wadis , as well as to identify anthropogenic sources from agriculture. The recent release of Collection 6 MODIS aerosol products allows to extend dust source detection to the entire land surfaces, which is quite useful to identify mid to high latitude dust sources and detect not only dust from agriculture but fugitive dust from transport and industrial activities. This presentation will overview the advantages and drawbacks of using MODIS Deep Blue for dust detection, compare to other instruments (polar orbiting and geostationary). The results of Collection 6 with a new dust screening will be compared against AERONET. Applications to long range transport of anthropogenic dust will be presented.

  18. Review on recent progress in observations, source identifications and countermeasures of PM2.5.

    Science.gov (United States)

    Liang, Chun-Sheng; Duan, Feng-Kui; He, Ke-Bin; Ma, Yong-Liang

    2016-01-01

    Recently, PM2.5 (atmospheric fine particulate matter with aerodynamic diameter ≤ 2.5 μm) have received so much attention that the observations, source appointment and countermeasures of it have been widely studied due to its harmful impacts on visibility, mood (mental health), physical health, traffic safety, construction, economy and nature, as well as its complex interaction with climate. A review on the PM2.5 related research is necessary. We start with summary of chemical composition and characteristics of PM2.5 that contains both macro and micro observation results and analysis, wherein the temporal variability of concentrations of PM2.5 and major components in many recent reports is embraced. This is closely followed by an overview of source appointment, including the composition and sources of PM2.5 in different countries in the six inhabitable continents based on the best available results. Besides summarizing PM2.5 pollution countermeasures by policy, planning, technology and ideology, the World Air Day is proposed to be established to inspire and promote the crucial social action in energy-saving and emission-reduction. Some updated knowledge of the important topics (such as formation and evolution mechanisms of hazes, secondary aerosols, aerosol mass spectrometer, organic tracers, radiocarbon, emissions, solutions for air pollution problems, etc.) is also included in the present review by logically synthesizing the studies. In addition, the key research challenges and future directions are put forward. Despite our efforts, our understanding of the recent reported observations, source identifications and countermeasures of PM2.5 is limited, and subsequent efforts both of the authors and readers are needed. Copyright © 2015 Elsevier Ltd. All rights reserved.

  19. Identifiability and Identification of Trace Continuous Pollutant Source

    Directory of Open Access Journals (Sweden)

    Hongquan Qu

    2014-01-01

    Full Text Available Accidental pollution events often threaten people’s health and lives, and a pollutant source is very necessary so that prompt remedial actions can be taken. In this paper, a trace continuous pollutant source identification method is developed to identify a sudden continuous emission pollutant source in an enclosed space. The location probability model is set up firstly, and then the identification method is realized by searching a global optimal objective value of the location probability. In order to discuss the identifiability performance of the presented method, a conception of a synergy degree of velocity fields is presented in order to quantitatively analyze the impact of velocity field on the identification performance. Based on this conception, some simulation cases were conducted. The application conditions of this method are obtained according to the simulation studies. In order to verify the presented method, we designed an experiment and identified an unknown source appearing in the experimental space. The result showed that the method can identify a sudden trace continuous source when the studied situation satisfies the application conditions.

  20. Identification of Cu’s sources in Jiaozhou Bay

    Science.gov (United States)

    Yang, Dongfang; Li, Haixia; Ding, Jun; Zhang, Longlei; Li, Jiangmin

    2017-12-01

    Many marine bays have been polluted by Cu along with the rapid development of industry, economy and population size, and identification the sources of Cu is essential to environmental protection. This paper identified the sources of Cu in according to the horizontal distribution in Jiaozhou Bay during 1982-1986. Results showed that there were five Cu sources during study years including marine current, stream flow, island top, overland runoff and marine traffic, respectively. These findings were helpful information in decision-making of pollution control and environmental remediation practice.

  1. Understanding sources of organic aerosol during CalNex-2010 using the CMAQ-VBS

    Directory of Open Access Journals (Sweden)

    M. C. Woody

    2016-03-01

    Full Text Available Community Multiscale Air Quality (CMAQ model simulations utilizing the traditional organic aerosol (OA treatment (CMAQ-AE6 and a volatility basis set (VBS treatment for OA (CMAQ-VBS were evaluated against measurements collected at routine monitoring networks (Chemical Speciation Network (CSN and Interagency Monitoring of Protected Visual Environments (IMPROVE and those collected during the 2010 California at the Nexus of Air Quality and Climate Change (CalNex field campaign to examine important sources of OA in southern California. Traditionally, CMAQ treats primary organic aerosol (POA as nonvolatile and uses a two-product framework to represent secondary organic aerosol (SOA formation. CMAQ-VBS instead treats POA as semivolatile and lumps OA using volatility bins spaced an order of magnitude apart. The CMAQ-VBS approach underpredicted organic carbon (OC at IMPROVE and CSN sites to a greater degree than CMAQ-AE6 due to the semivolatile POA treatment. However, comparisons to aerosol mass spectrometer (AMS measurements collected at Pasadena, CA, indicated that CMAQ-VBS better represented the diurnal profile and primary/secondary split of OA. CMAQ-VBS SOA underpredicted the average measured AMS oxygenated organic aerosol (OOA, a surrogate for SOA concentration by a factor of 5.2, representing a considerable improvement to CMAQ-AE6 SOA predictions (factor of 24 lower than AMS. We use two new methods, one based on species ratios (SOA/ΔCO and SOA/Ox and another on a simplified SOA parameterization, to apportion the SOA underprediction for CMAQ-VBS to slow photochemical oxidation (estimated as 1.5 ×  lower than observed at Pasadena using −log(NOx : NOy, low intrinsic SOA formation efficiency (low by 1.6 to 2 ×  for Pasadena, and low emissions or excessive dispersion for the Pasadena site (estimated to be 1.6 to 2.3 ×  too low/excessive. The first and third factors are common to CMAQ-AE6, while the intrinsic SOA formation efficiency

  2. Source characterization of ambient fine aerosol in Singapore during a haze episode in 2015

    Science.gov (United States)

    Hapsari Budisulistiorini, Sri; Riva, Matthieu; Williams, Michael; Miyakawa, Takuma; Komazaki, Yuichi; Chen, Jing; Surratt, Jason; Kuwata, Mikinori

    2017-04-01

    Recurring transboundary haze from Indonesia peatland fires in the previous decades has significantly elevated particulate matter (PM) concentration in Southeast Asia, particularly during the 2015 El Niño event. Previous studies have investigated chemical composition of particles emitted during haze episodes; however, they were limited to time-integrated samples and the number of identified compounds. Low time-resolution measurement results in co-variance of PM sources; therefore, higher time-resolution measurement is important in PM source apportionment. Between October 10-31, 2015, Aerodyne Time-of-Flight Aerosol Chemical Speciation Monitor (ToF-ACSM) was deployed for real-time chemical characterization of ambient submicron PM (NR-PM1) in Singapore. Simultaneously, PM2.5 filter samples were collected for molecular-level organic aerosol (OA) constituents, organic carbon (OC), elemental carbon (EC) and water-soluble OC (WSOC) analyses. OA constituents were quantified by gas chromatography interfaced to electron ionization mass spectrometry (GC/EI-MS) and ultra-performance liquid chromatography interfaced to electrospray ionization high-resolution quadrupole time-of-flight mass spectrometer operated in the negative ion mode (UPLC/(-)ESI-HR-Q-TOFMS). OA and SO42- are dominant components of the haze particles, accounting for ˜77% and ˜12% of the total NR-PM1 mass, respectively. OC/EC ratio of 4.8 might indicate formation of secondary OA (SOA) and aerosols from biomass burning, including those from peat burning. OA fraction from ToF-ACSM measurements was analyzed for source apportionment using a bilinear model through multi-linear engine algorithm (ME-2) in graphical user interface SoFi (Source Finder). Five OA factors were identified: hydrocarbon-like OA (HOA), biomass burning OA (BBOA), peat burning OA (PBOA), low-volatility oxygenated OA (LV-OOA), and semi-volatile oxygenated OA (SV-OOA). The HOA factor shows a distinct diurnal profile peaking in the morning and

  3. Chemical characterization and source apportionment of submicron aerosols measured in Senegal during the 2015 SHADOW campaign

    Science.gov (United States)

    Rivellini, Laura-Hélèna; Chiapello, Isabelle; Tison, Emmanuel; Fourmentin, Marc; Féron, Anaïs; Diallo, Aboubacry; N'Diaye, Thierno; Goloub, Philippe; Canonaco, Francesco; Prévôt, André Stephan Henry; Riffault, Véronique

    2017-09-01

    The present study offers the first chemical characterization of the submicron (PM1) fraction in western Africa at a high time resolution, thanks to collocated measurements of nonrefractory (NR) species with an Aerosol Chemical Speciation Monitor (ACSM), black carbon and iron concentrations derived from absorption coefficient measurements with a 7-wavelength Aethalometer, and total PM1 determined by a TEOM-FDMS (tapered element oscillating microbalance-filtered dynamic measurement system) for mass closure. The field campaign was carried out over 3 months (March to June 2015) as part of the SHADOW (SaHAran Dust Over West Africa) project at a coastal site located in the outskirts of the city of Mbour, Senegal. With an averaged mass concentration of 5.4 µg m-3, levels of NR PM1 in Mbour were 3 to 10 times lower than those generally measured in urban and suburban polluted environments. Nonetheless the first half of the observation period was marked by intense but short pollution events (NR PM1 concentrations higher than 15 µg m-3), sea breeze phenomena and Saharan desert dust outbreaks (PM10 up to 900 µg m-3). During the second half of the campaign, the sampling site was mainly under the influence of marine air masses. The air masses on days under continental and sea breeze influences were dominated by organics (36-40 %), whereas sulfate particles were predominant (40 %) for days under oceanic influence. Overall, measurements showed that about three-quarters of the total PM1 were explained by NR PM1, BC (black carbon) and Fe (a proxy for dust) concentrations, leaving approximately one-quarter for other refractory species. A mean value of 4.6 % for the Fe / PM1 ratio was obtained. Source apportionment of the organic fraction, using positive matrix factorization (PMF), highlighted the impact of local combustion sources, such as traffic and residential activities, which contribute on average to 52 % of the total organic fraction. A new organic aerosol (OA) source

  4. Geographical Distribution and Sources of Nutrients in Atmospheric Aerosol Over the Pacific Ocean

    Science.gov (United States)

    Uematsu, M.

    2016-12-01

    The Pacific Ocean, the world's largest (occupying about 30% of the Earth's total surface area) has several distinguishing biogeochemical features. In the western Pacific, dust particles originating from arid and semi-arid regions in Asia and Australia are transported to the north and south, respectively. Biomass burning emissions from Southeast Asia are exported to the tropical Pacific, and anthropogenic substances flowing out of Asia and Eurasia spread both regionally and globally. Over high primary productive areas such as the subarctic North Pacific, the equatorial Pacific and the Southern Ocean, biogenic gasses are released to the atmosphere and transported to other areas. These processes may affect cloud and rainfall patterns, air quality, and the radiative balance of downwind regions. The deposition of atmospheric aerosols containing iron and other essential nutrients is important for biogeochemical cycles in the oceans because this source of nutrients helps sustain primary production and affects food-web structure; these effects in turn influence the chemical properties of marine atmosphere. From an atmospheric chemistry standpoint, sea-salt aerosols produced by strong winds and marine biogenic gases emitted from highly productive waters affect the physicochemical characteristics of marine aerosols. As phytoplankton populations are patchy and atmospheric processes sporadic, the interactions between atmospheric chemical constituents and marine biota vary for different regions as well as seasonally and over longer timescales. To address these and other emerging issues, and more generally to better understand the important biogeochemical processes and interactions occurring over the open oceans, more long-term recurrent research cruises with standardized atmospheric shipboard measurements will be needed in the future.

  5. Identification of emission sources of umbral flashes using phase congruency

    International Nuclear Information System (INIS)

    Feng Song; Yang Yun-Fei; Ji Kai-Fan; Yu Lan

    2014-01-01

    The emission sources of umbral flashes (UFs) are believed to be closely related to running umbral and penumbral waves, and are concluded to be associated with umbral dots in the solar photosphere. Accurate identification of emission sources of UFs is crucial for investigating these physical phenomena and their inherent relationships. A relatively novel model of shape perception, namely phase congruency (PC), uses phase information in the Fourier domain to identify the geometrical shape of the region of interest in different intensity levels, rather than intensity or gradient. Previous studies indicate that the model is suitable for identifying features with low contrast and low luminance. In the present paper, we applied the PC model to identify the emission sources of UFs and to locate their positions. For illustrating the high performance of our proposed method, two time sequences of Ca II H images derived from the Hinode/SOT on 2010 August 10 and 2013 August 20 were used. Furthermore, we also compared these results with the analysis results that are identified by the traditional/classical identification methods, including the gray-scale adjusted technique and the running difference technique. The result of our analysis demonstrates that our proposed method is more accurate and effective than the traditional identification methods when applied to identifying the emission sources of UFs and to locating their positions. (research papers)

  6. Sources and atmospheric processing of winter aerosols in Seoul, Korea: insights from real-time measurements using a high-resolution aerosol mass spectrometer

    Science.gov (United States)

    Kim, Hwajin; Zhang, Qi; Bae, Gwi-Nam; Kim, Jin Young; Bok Lee, Seung

    2017-02-01

    Highly time-resolved chemical characterization of nonrefractory submicrometer particulate matter (NR-PM1) was conducted in Seoul, the capital and largest metropolis of Korea, using an Aerodyne high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS). The measurements were performed during winter, when elevated particulate matter (PM) pollution events are often observed. This is the first time that detailed real-time aerosol measurement results have been reported from Seoul, Korea, and they reveal valuable insights into the sources and atmospheric processes that contribute to PM pollution in this region. The average concentration of submicron aerosol (PM1 = NR-PM1+ black carbon (BC)) was 27.5 µg m-3, and the total mass was dominated by organics (44 %), followed by nitrate (24 %) and sulfate (10 %). The average atomic ratios of oxygen to carbon (O / C), hydrogen to carbon (H / C), and nitrogen to carbon (N / C) of organic aerosols (OA) were 0.37, 1.79, and 0.018, respectively, which result in an average organic mass-to-carbon (OM / OC) ratio of 1.67. The concentrations (2.6-90.7 µg m-3) and composition of PM1 varied dynamically during the measurement period due to the influences of different meteorological conditions, emission sources, and air mass origins. Five distinct sources of OA were identified via positive matrix factorization (PMF) analysis of the HR-ToF-AMS data: vehicle emissions represented by a hydrocarbon-like OA factor (HOA, O / C = 0.06), cooking activities represented by a cooking OA factor (COA, O / C = 0.14), wood combustion represented by a biomass burning OA factor (BBOA, O / C = 0.34), and secondary organic aerosol (SOA) represented by a semivolatile oxygenated OA factor (SV-OOA, O / C = 0.56) and a low-volatility oxygenated OA factor (LV-OOA, O / C = 0.68). On average, primary OA (POA = HOA + COA + BBOA) accounted for 59 % the OA mass, whereas SV-OOA and LV-OOA contributed 15 and 26 %, respectively. Our results indicate that air

  7. Predicting the Mineral Composition of Dust Aerosols. Part 2; Model Evaluation and Identification of Key Processes with Observations

    Science.gov (United States)

    Perlwitz, J. P.; Garcia-Pando, C. Perez; Miller, R. L.

    2015-01-01

    A global compilation of nearly sixty measurement studies is used to evaluate two methods of simulating the mineral composition of dust aerosols in an Earth system model. Both methods are based upon a Mean Mineralogical Table (MMT) that relates the soil mineral fractions to a global atlas of arid soil type. The Soil Mineral Fraction (SMF) method assumes that the aerosol mineral fractions match the fractions of the soil. The MMT is based upon soil measurements after wet sieving, a process that destroys aggregates of soil particles that would have been emitted from the original, undisturbed soil. The second method approximately reconstructs the emitted aggregates. This model is referred to as the Aerosol Mineral Fraction (AMF) method because the mineral fractions of the aerosols differ from those of the wet-sieved parent soil, partly due to reaggregation. The AMF method remedies some of the deficiencies of the SMF method in comparison to observations. Only the AMF method exhibits phyllosilicate mass at silt sizes, where they are abundant according to observations. In addition, the AMF quartz fraction of silt particles is in better agreement with measured values, in contrast to the overestimated SMF fraction. Measurements at distinct clay and silt particle sizes are shown to be more useful for evaluation of the models, in contrast to the sum over all particles sizes that is susceptible to compensating errors, as illustrated by the SMF experiment. Model errors suggest that allocation of the emitted silt fraction of each mineral into the corresponding transported size categories is an important remaining source of uncertainty. Evaluation of both models and the MMT is hindered by the limited number of size-resolved measurements of mineral content that sparsely sample aerosols from the major dust sources. The importance of climate processes dependent upon aerosol mineral composition shows the need for global and routine mineral measurements.

  8. The Denver Aerosol Sources and Health (DASH) study: Overview and early findings

    Science.gov (United States)

    Vedal, S.; Hannigan, M. P.; Dutton, S. J.; Miller, S. L.; Milford, J. B.; Rabinovitch, N.; Kim, S.-Y.; Sheppard, L.

    Improved understanding of the sources of air pollution that are most harmful could aid in developing more effective measures for protecting human health. The Denver Aerosol Sources and Health (DASH) study was designed to identify the sources of ambient fine particulate matter (PM 2.5) that are most responsible for the adverse health effects of short-term exposure to PM 2.5. Daily 24-h PM 2.5 sampling began in July 2002 at a residential monitoring site in Denver, Colorado, using both Teflon and quartz filter samplers. Sampling is planned to continue through 2008. Chemical speciation is being carried out for mass, inorganic ionic compounds (sulfate, nitrate and ammonium), and carbonaceous components, including elemental carbon, organic carbon, temperature-resolved organic carbon fractions and a large array of organic compounds. In addition, water-soluble metals were measured daily for 12 months in 2003. A receptor-based source apportionment approach utilizing positive matrix factorization (PMF) will be used to identify PM 2.5 source contributions for each 24-h period. Based on a preliminary assessment using synthetic data, the proposed source apportionment should be able to identify many important sources on a daily basis, including secondary ammonium nitrate and ammonium sulfate, diesel vehicle exhaust, road dust, wood combustion and vegetative debris. Meat cooking, gasoline vehicle exhaust and natural gas combustion were more challenging for PMF to accurately identify due to high detection limits for certain organic molecular marker compounds. Measurements of these compounds are being improved and supplemented with additional organic molecular marker compounds. The health study will investigate associations between daily source contributions and an array of health endpoints, including daily mortality and hospitalizations and measures of asthma control in asthmatic children. Findings from the DASH study, in addition to being of interest to policymakers, by

  9. Atmospheric Aerosol Source-Receptor Relationships: The Role of Coal-Fired Power Plants

    Energy Technology Data Exchange (ETDEWEB)

    Allen L. Robinson; Spyros N. Pandis; Cliff I. Davidson

    2005-12-01

    This report describes the technical progress made on the Pittsburgh Air Quality Study (PAQS) during the period of March 2005 through August 2005. Significant progress was made this project period on the source characterization, source apportionment, and deterministic modeling activities. This report highlights new data on road dust, vegetative detritus and motor vehicle emissions. For example, the results show significant differences in the composition in urban and rural road dust. A comparison of the organic of the fine particulate matter in the tunnel with the ambient provides clear evidence of the significant contribution of vehicle emissions to ambient PM. The source profiles developed from this work are being used by the source-receptor modeling activities. The report presents results on the spatial distribution of PMF-factors. The results can be grouped into three different categories: regional sources, local sources, or potentially both regional and local sources. Examples of the regional sources are the sulfate and selenium PMF-factors which most likely-represent coal fired power plants. Examples of local sources are the specialty steel and lead factors. There is reasonable correspondence between these apportionments and data from the EPA TRI and AIRS emission inventories. Detailed comparisons between PMCAMx predictions and measurements by the STN and IMPROVE measurements in the Eastern US are presented. Comparisons were made for the major aerosol components and PM{sub 2.5} mass in July 2001, October 2001, January 2002, and April 2002. The results are encouraging with average fraction biases for most species less than 0.25. The improvement of the model performance during the last two years was mainly due to the comparison of the model predictions with the continuous measurements in the Pittsburgh Supersite. Major improvements have included the descriptions: of ammonia emissions (CMU inventory), night time nitrate chemistry, EC emissions and their diurnal

  10. Chromatographic fingerprint similarity analysis for pollutant source identification

    International Nuclear Information System (INIS)

    Xie, Juan-Ping; Ni, Hong-Gang

    2015-01-01

    In the present study, a similarity analysis method was proposed to evaluate the source-sink relationships among environmental media for polybrominated diphenyl ethers (PBDEs), which were taken as the representative contaminants. Chromatographic fingerprint analysis has been widely used in the fields of natural products chemistry and forensic chemistry, but its application to environmental science has been limited. We established a library of various sources of media containing contaminants (e.g., plastics), recognizing that the establishment of a more comprehensive library allows for a better understanding of the sources of contamination. We then compared an environmental complex mixture (e.g., sediment, soil) with the profiles in the library. These comparisons could be used as the first step in source tracking. The cosine similarities between plastic and soil or sediment ranged from 0.53 to 0.68, suggesting that plastic in electronic waste is an important source of PBDEs in the environment, but it is not the only source. A similarity analysis between soil and sediment indicated that they have a source-sink relationship. Generally, the similarity analysis method can encompass more relevant information of complex mixtures in the environment than a profile-based approach that only focuses on target pollutants. There is an inherent advantage to creating a data matrix containing all peaks and their relative levels after matching the peaks based on retention times and peak areas. This data matrix can be used for source identification via a similarity analysis without quantitative or qualitative analysis of all chemicals in a sample. - Highlights: • Chromatographic fingerprint analysis can be used as the first step in source tracking. • Similarity analysis method can encompass more relevant information of pollution. • The fingerprints strongly depend on the chromatographic conditions. • A more effective and robust method for identifying similarities is required

  11. Molecular marker analysis as a guide to the sources of fine organic aerosols

    International Nuclear Information System (INIS)

    Rogge, W.F.; Cass, G.R.; Hildemann, L.M.; Simoneit, B.R.T.

    1992-07-01

    The molecular composition of fine particulate (D p ≥ 2 μm) organic aerosol emissions from the most important sources in the Los Angeles area has been determined. Likewise, ambient concentration patterns for more than 80 single organic compounds have been measured at four urban sites (West Los Angeles, Downtown Los Angeles, Pasadena, and Rubidoux) and at one remote offshore site (San Nicolas Island). It has been found that cholesterol serves as a marker compound for emissions from charbroilers and other meat cooking operations. Vehicular exhaust being emitted from diesel and gasoline powered engines can be traced in the Los Angeles atmosphere using fossil petroleum marker compounds such as steranes and pentacyclic triterpanes (e.g., hopanes). Biogenic fine particle emission sources such as plant fragments abraded from leaf surfaces by wind and weather can be traced in the urban atmosphere. Using distinct and specific source organic tracers or assemblages of organic compounds characteristic for the sources considered it is possible to estimate the influence of different source types at any urban site where atmospheric data are available

  12. Exploring sources of biogenic secondary organic aerosol compounds using chemical analysis and the FLEXPART model

    Directory of Open Access Journals (Sweden)

    J. Martinsson

    2017-09-01

    Full Text Available Molecular tracers in secondary organic aerosols (SOAs can provide information on origin of SOA, as well as regional scale processes involved in their formation. In this study 9 carboxylic acids, 11 organosulfates (OSs and 2 nitrooxy organosulfates (NOSs were determined in daily aerosol particle filter samples from Vavihill measurement station in southern Sweden during June and July 2012. Several of the observed compounds are photo-oxidation products from biogenic volatile organic compounds (BVOCs. Highest average mass concentrations were observed for carboxylic acids derived from fatty acids and monoterpenes (12. 3 ± 15. 6 and 13. 8 ± 11. 6 ng m−3, respectively. The FLEXPART model was used to link nine specific surface types to single measured compounds. It was found that the surface category sea and ocean was dominating the air mass exposure (56 % but contributed to low mass concentration of observed chemical compounds. A principal component (PC analysis identified four components, where the one with highest explanatory power (49 % displayed clear impact of coniferous forest on measured mass concentration of a majority of the compounds. The three remaining PCs were more difficult to interpret, although azelaic, suberic, and pimelic acid were closely related to each other but not to any clear surface category. Hence, future studies should aim to deduce the biogenic sources and surface category of these compounds. This study bridges micro-level chemical speciation to air mass surface exposure at the macro level.

  13. Source apportionment of submicron organic aerosol collected from Atlanta, Georgia, during 2014-2015 using the aerosol chemical speciation monitor (ACSM)

    Science.gov (United States)

    Rattanavaraha, Weruka; Canagaratna, Manjula R.; Budisulistiorini, Sri Hapsari; Croteau, Philip L.; Baumann, Karsten; Canonaco, Francesco; Prevot, Andre S. H.; Edgerton, Eric S.; Zhang, Zhenfa; Jayne, John T.; Worsnop, Douglas R.; Gold, Avram; Shaw, Stephanie L.; Surratt, Jason D.

    2017-10-01

    The Aerodyne Aerosol Chemical Speciation Monitor (ACSM) was redeployed at the Jefferson Street (JST) site in downtown Atlanta, Georgia (GA) for 1 year (March 20, 2014-February 08, 2015) to chemically characterize non-refractory submicron particulate matter (NR-PM1) in near real-time and to assess whether organic aerosol (OA) types and amounts change from year-to-year. Submicron organic aerosol (OA) mass spectra were analyzed by season using multilinear engine (ME-2) to apportion OA subtypes to potential sources and chemical processes. A suite of real-time collocated measurements from the Southeastern Aerosol Research and Characterization (SEARCH) network was compared with ME-2 factor solutions to aid in the interpretation of OA subtypes during each season. OA tracers measured from high-volume filter samples using gas chromatography interfaced with electron ionization-mass spectrometry (GC/EI-MS) also aided in identifying OA sources. The initial application of ME-2 to the yearlong ACSM dataset revealed that OA source apportionment by season was required to better resolve sporadic OA types. Spring and fall OA mass spectral datasets were separated into finer periods to capture potential OA sources resulting from non-homogeneous emissions during transitioning periods. NR-PM1 was highest in summer (16.7 ± 8.4 μg m-3) and lowest in winter (8.0 ± 5.7 μg m-3), consistent with prior studies. OA dominated NR-PM1 mass (56-74% on average) in all seasons. Hydrocarbon-like OA (HOA) from primary emissions was observed in all seasons, averaging 5-22% of total OA mass. Strong correlations of HOA with carbon monoxide (CO) (R = 0.71-0.88) and oxides of nitrogen (NOx) (R = 0.55-0.79) indicated that vehicular traffic was the likely source. Biomass burning OA (BBOA) was observed in all seasons, with lower contributions (2%) in summer and higher in colder seasons (averaging 8-20% of total OA mass). BBOA correlated strongly with levoglucosan (R = 0.78-0.95) during colder seasons

  14. Organic aerosol source apportionment by offline-AMS over a full year in Marseille

    Science.gov (United States)

    Bozzetti, Carlo; El Haddad, Imad; Salameh, Dalia; Daellenbach, Kaspar Rudolf; Fermo, Paola; Gonzalez, Raquel; Cruz Minguillón, María; Iinuma, Yoshiteru; Poulain, Laurent; Elser, Miriam; Müller, Emanuel; Gates Slowik, Jay; Jaffrezo, Jean-Luc; Baltensperger, Urs; Marchand, Nicolas; Prévôt, André Stephan Henry

    2017-07-01

    We investigated the seasonal trends of OA sources affecting the air quality of Marseille (France), which is the largest harbor of the Mediterranean Sea. This was achieved by measurements of nebulized filter extracts using an aerosol mass spectrometer (offline-AMS). In total 216 PM2. 5 (particulate matter with an aerodynamic diameter water-soluble ions, metals, elemental and organic carbon (EC / OC), and organic markers, including n-alkanes, hopanes, polycyclic aromatic hydrocarbons (PAHs), lignin and cellulose pyrolysis products, and nitrocatechols. The application of positive matrix factorization (PMF) to the water-soluble AMS spectra enabled the extraction of five factors, related to hydrocarbon-like OA (HOA), cooking OA (COA), biomass burning OA (BBOA), oxygenated OA (OOA), and an industry-related OA (INDOA). Seasonal trends and relative contributions of OA sources were compared with the source apportionment of OA spectra collected from the AMS field deployment at the same station but in different years and for shorter monitoring periods (February 2011 and July 2008). Online- and offline-AMS source apportionment revealed comparable seasonal contribution of the different OA sources. Results revealed that BBOA was the dominant source during winter, representing on average 48 % of the OA, while during summer the main OA component was OOA (63 % of OA mass on average). HOA related to traffic emissions contributed on a yearly average 17 % to the OA mass, while COA was a minor source contributing 4 %. The contribution of INDOA was enhanced during winter (17 % during winter and 11 % during summer), consistent with an increased contribution from light alkanes, light PAHs (fluoranthene, pyrene, phenanthrene), and selenium, which is commonly considered as a unique coal combustion and coke production marker. Online- and offline-AMS source apportionments revealed evolving levoglucosan : BBOA ratios, which were higher during late autumn and March. A similar seasonality was

  15. Retrieval of Aerosol Optical Depth Over Land by Inverse Modeling of Multi-Source Satellite Data

    NARCIS (Netherlands)

    Wu, Y.

    2018-01-01

    The Aerosol Optical Depth (AOD), a measure of the scattering and absorption of light by aerosols, has been extensively used for scientific research such as monitoring air quality near the surface due to fine particles aggregated, aerosol radiative forcing (cooling effect against the warming effect

  16. Aerosol composition, oxidative properties, and sources in Beijing: results from the 2014 Asia-Pacific Economic Cooperation Summit study

    Science.gov (United States)

    Xu, W. Q.; Sun, Y. L.; Chen, C.; Du, W.; Han, T. T.; Wang, Q. Q.; Fu, P. Q.; Wang, Z. F.; Zhao, X. J.; Zhou, L. B.; Ji, D. S.; Wang, P. C.; Worsnop, D. R.

    2015-08-01

    The mitigation of air pollution in megacities remains a great challenge because of the complex sources and formation mechanisms of aerosol particles. The 2014 Asia- Pacific Economic Cooperation (APEC) summit in Beijing serves as a unique experiment to study the impacts of emission controls on aerosol composition, size distributions, and oxidative properties. Herein, a high-resolution time-of-flight aerosol mass spectrometer was deployed in urban Beijing for real-time measurements of size-resolved non-refractory submicron aerosol (NR-PM1) species from 14 October to 12 November 2014, along with a range of collocated measurements. The average (±σ) PM1 was 41.6 (±38.9) μg m-3 during APEC, which was decreased by 53 % compared with that before APEC. The aerosol composition showed substantial changes owing to emission controls during APEC. Secondary inorganic aerosols (SIA = sulfate + nitrate + ammonium) showed significant reductions of 62-69 %, whereas organics presented much smaller decreases (35 %). The results from the positive matrix factorization of organic aerosols (OA) indicated that highly oxidized secondary OA (SOA) showed decreases similar to those of SIA during APEC. However, primary OA (POA) from cooking, traffic, and biomass burning sources were comparable to those before APEC, indicating the presence of strong local source emissions. The oxidation properties showed corresponding changes in response to OA composition. The average oxygen-to-carbon level during APEC was 0.36 (±0.10), which is lower than the 0.43 (±0.13) measured before APEC, demonstrating a decrease in the OA oxidation degree. The changes in size distributions of primary and secondary species varied during APEC. SIA and SOA showed significant reductions in large accumulation modes with peak diameters shifting from ~ 650 to 400 nm during APEC, whereas those of POA remained relatively unchanged. The changes in aerosol composition, size distributions, and oxidation degrees during the aging

  17. Source apportionment of fine organic aerosol in Mexico City during the MILAGRO experiment 2006

    Directory of Open Access Journals (Sweden)

    E. A. Stone

    2008-03-01

    Full Text Available Organic carbon (OC comprises a large fraction of fine particulate matter (PM2.5 in Mexico City. Daily and select 12-h PM2.5 samples were collected in urban and peripheral sites in Mexico City from 17–30 March 2006. Samples were analyzed for OC and elemental carbon (EC using thermal-optical filter-based methods. Real-time water-soluble organic carbon (WSOC was collected at the peripheral site. Organic compounds, particularly molecular markers, were quantified by soxhlet extraction with methanol and dichloromethane, derivitization, and gas chromatography with mass spectrometric detection (GCMS. A chemical mass balance model (CMB based on molecular marker species was used to determine the relative contribution of major sources to ambient OC. Motor vehicles, including diesel and gasoline, consistently accounted for 49% of OC in the urban area and 32% on the periphery. The daily contribution of biomass burning to OC was highly variable, and ranged from 5–26% at the urban site and 7–39% at the peripheral site. The remaining OC unapportioned to primary sources showed a strong correlation with WSOC and was considered to be secondary in nature. Comparison of temporally resolved OC showed that contributions from primary aerosol sources during daylight hours were not significantly different from nighttime. This study provides quantitative understanding of the important sources of OC during the MILAGRO 2006 field campaign.

  18. Groundwater Pollution Source Identification using Linked ANN-Optimization Model

    Science.gov (United States)

    Ayaz, Md; Srivastava, Rajesh; Jain, Ashu

    2014-05-01

    Groundwater is the principal source of drinking water in several parts of the world. Contamination of groundwater has become a serious health and environmental problem today. Human activities including industrial and agricultural activities are generally responsible for this contamination. Identification of groundwater pollution source is a major step in groundwater pollution remediation. Complete knowledge of pollution source in terms of its source characteristics is essential to adopt an effective remediation strategy. Groundwater pollution source is said to be identified completely when the source characteristics - location, strength and release period - are known. Identification of unknown groundwater pollution source is an ill-posed inverse problem. It becomes more difficult for real field conditions, when the lag time between the first reading at observation well and the time at which the source becomes active is not known. We developed a linked ANN-Optimization model for complete identification of an unknown groundwater pollution source. The model comprises two parts- an optimization model and an ANN model. Decision variables of linked ANN-Optimization model contain source location and release period of pollution source. An objective function is formulated using the spatial and temporal data of observed and simulated concentrations, and then minimized to identify the pollution source parameters. In the formulation of the objective function, we require the lag time which is not known. An ANN model with one hidden layer is trained using Levenberg-Marquardt algorithm to find the lag time. Different combinations of source locations and release periods are used as inputs and lag time is obtained as the output. Performance of the proposed model is evaluated for two and three dimensional case with error-free and erroneous data. Erroneous data was generated by adding uniformly distributed random error (error level 0-10%) to the analytically computed concentration

  19. Aqueous organic chemistry in the atmosphere: sources and chemical processing of organic aerosols.

    Science.gov (United States)

    McNeill, V Faye

    2015-02-03

    Over the past decade, it has become clear that aqueous chemical processes occurring in cloud droplets and wet atmospheric particles are an important source of organic atmospheric particulate matter. Reactions of water-soluble volatile (or semivolatile) organic gases (VOCs or SVOCs) in these aqueous media lead to the formation of highly oxidized organic particulate matter (secondary organic aerosol; SOA) and key tracer species, such as organosulfates. These processes are often driven by a combination of anthropogenic and biogenic emissions, and therefore their accurate representation in models is important for effective air quality management. Despite considerable progress, mechanistic understanding of some key aqueous processes is still lacking, and these pathways are incompletely represented in 3D atmospheric chemistry and air quality models. In this article, the concepts, historical context, and current state of the science of aqueous pathways of SOA formation are discussed.

  20. Disentangling the major source areas for an intense aerosol advection in the Central Mediterranean on the basis of Potential Source Contribution Function modeling of chemical and size distribution measurements

    Science.gov (United States)

    Petroselli, Chiara; Crocchianti, Stefano; Moroni, Beatrice; Castellini, Silvia; Selvaggi, Roberta; Nava, Silvia; Calzolai, Giulia; Lucarelli, Franco; Cappelletti, David

    2018-05-01

    In this paper, we combined a Potential Source Contribution Function (PSCF) analysis of daily chemical aerosol composition data with hourly aerosol size distributions with the aim to disentangle the major source areas during a complex and fast modulating advection event impacting on Central Italy in 2013. Chemical data include an ample set of metals obtained by Proton Induced X-ray Emission (PIXE), main soluble ions from ionic chromatography and elemental and organic carbon (EC, OC) obtained by thermo-optical measurements. Size distributions have been recorded with an optical particle counter for eight calibrated size classes in the 0.27-10 μm range. We demonstrated the usefulness of the approach by the positive identification of two very different source areas impacting during the transport event. In particular, biomass burning from Eastern Europe and desert dust from Sahara sources have been discriminated based on both chemistry and size distribution time evolution. Hourly BT provided the best results in comparison to 6 h or 24 h based calculations.

  1. Sources and composition of submicron organic mass in marine aerosol particles

    Science.gov (United States)

    Frossard, Amanda A.; Russell, Lynn M.; Burrows, Susannah M.; Elliott, Scott M.; Bates, Timothy S.; Quinn, Patricia K.

    2014-11-01

    The sources and composition of atmospheric marine aerosol particles (aMA) have been investigated with a range of physical and chemical measurements from open-ocean research cruises. This study uses the characteristic functional group composition (from Fourier transform infrared spectroscopy) of aMA from five ocean regions to show the following: (i) The organic functional group composition of aMA that can be identified as mainly atmospheric primary marine (ocean derived) aerosol particles (aPMA) is 65 ± 12% hydroxyl, 21 ± 9% alkane, 6 ± 6% amine, and 7 ± 8% carboxylic acid functional groups. Contributions from photochemical reactions add carboxylic acid groups (15%-25%), shipping effluent in seawater and ship emissions add additional alkane groups (up to 70%), and coastal or continental emissions mix in alkane and carboxylic acid groups. (ii) The organic composition of aPMA is nearly identical to model-generated primary marine aerosol particles from bubbled seawater (gPMA, which has 55 ± 14% hydroxyl, 32 ± 14% alkane, and 13 ± 3% amine functional groups), indicating that its overall functional group composition is the direct consequence of the organic constituents of the seawater source. (iii) While the seawater organic functional group composition was nearly invariant across all three ocean regions studied and the ratio of organic carbon to sodium (OC/Na+) in the gPMA remained nearly constant over a broad range of chlorophyll a concentrations, the gPMA alkane group fraction appeared to increase with chlorophyll a concentrations (r = 0.66). gPMA from productive seawater had a larger fraction of alkane functional groups (42 ± 9%) compared to gPMA from nonproductive seawater (22 ± 10%), perhaps due to the presence of surfactants in productive seawater that stabilize the bubble film and lead to preferential drainage of the more soluble (lower alkane group fraction) organic components. gPMA has a hydroxyl group absorption peak location characteristic of

  2. A51F-0123: Model Analysis of Tropospheric Aerosol Variability and Sources over the North Atlantic During NAAMES 2015-2016

    Science.gov (United States)

    Liu, Hongyu; Moore, Richard; Hostetler, Chris A.; Ferrare, Richard Anthony; Fairlie, Thomas Duncan; Hu, Youngxiang; Chen, Gao; Hair, Johnathan W.; Johnson, Matthew S.

    2016-01-01

    The North Atlantic Aerosols and Marine Ecosystems Study (NAAMES) is a five-year Earth-Venture Suborbital-2 Mission to characterize the plankton ecosystems and their influences on remote marine aerosols, boundary layer clouds, and their implications for climate in the North Atlantic. While marine-sourced aerosols have been shown to make important contributions to surface aerosol loading, cloud condensation nuclei and ice nuclei concentrations over remote marine and coastal regions, it is still a challenge to differentiate the marine biogenic aerosol signal from the strong influence of continental pollution outflow. We examine here the spatiotemporal variability and quantify the sources of tropospheric aerosols over the North Atlantic during the first two phases (November 2015 and May-June 2016) of NAAMES using a state-of-the-art chemical transport model (GEOS-Chem). The model is driven by the Modern-Era Retrospective analysis for Research and Applications, Version 2 (MERRA-2) from the NASA Global Modeling and Assimilation Office (GMAO). It includes sulfate-nitrate-ammonium aerosol thermodynamics coupled to ozone-NOx-hydrocarbon-aerosol chemistry, mineral dust, sea salt, elemental and organic carbon aerosols, and especially a recently implemented parameterization for the marine primary organic aerosol emission. The simulated aerosols over the North Atlantic are evaluated with available satellite (e.g., MODIS) observations of aerosol optical depths (AOD), and aircraft and ship aerosol measurements. We diagnose transport pathways for continental pollution outflow over the North Atlantic using carbon monoxide, an excellent tracer for anthropogenic pollution transport. We also conduct model perturbation experiments to quantify the relative contributions of terrestrial and oceanic sources to the aerosol loading, AOD, and their variability over the North Atlantic.

  3. Case studies using the United States Coast Guard's Oil Identification System for petroleum spill source identification

    International Nuclear Information System (INIS)

    Grosser, P.W.; Castellano, F.P.

    1993-01-01

    The Oil Identification System (OIS) was developed in the 1970's at the Coast Guard Research and Development Center, to determine the unique, intrinsic properties which would allow the matching of a spilled oil with its correct source. The Central Oil Identification Laboratory (COIL) was established in 1978 as the operating facility to implement the OIS. The OIS encompasses four analytical methods; thin layer chromatography, fluorescence spectroscopy, infrared spectroscopy and gas chromatography. A sample can be studied according to each individual method or multi-methods approach can be chosen if no single technique gives unequivocal results. Combined these methods are greater than 99% effective. The authors recently utilized the OIS and the COIL for three petroleum spill investigations in New York. As part of the investigation to determine the source(s) of several different petroleum product spills, OIS was conducted along with a review of groundwater sample chromatograms

  4. High summertime aerosol organic functional group concentrations from marine and seabird sources at Ross Island, Antarctica, during AWARE

    Directory of Open Access Journals (Sweden)

    J. Liu

    2018-06-01

    Full Text Available Observations of the organic components of the natural aerosol are scarce in Antarctica, which limits our understanding of natural aerosols and their connection to seasonal and spatial patterns of cloud albedo in the region. From November 2015 to December 2016, the ARM West Antarctic Radiation Experiment (AWARE measured submicron aerosol properties near McMurdo Station at the southern tip of Ross Island. Submicron organic mass (OM, particle number, and cloud condensation nuclei concentrations were higher in summer than other seasons. The measurements included a range of compositions and concentrations that likely reflected both local anthropogenic emissions and natural background sources. We isolated the natural organic components by separating a natural factor and a local combustion factor. The natural OM was 150 times higher in summer than in winter. The local anthropogenic emissions were not hygroscopic and had little contribution to the CCN concentrations. Natural sources that included marine sea spray and seabird emissions contributed 56 % OM in summer but only 3 % in winter. The natural OM had high hydroxyl group fraction (55 %, 6 % alkane, and 6 % amine group mass, consistent with marine organic composition. In addition, the Fourier transform infrared (FTIR spectra showed the natural sources of organic aerosol were characterized by amide group absorption, which may be from seabird populations. Carboxylic acid group contributions were high in summer and associated with natural sources, likely forming by secondary reactions.

  5. Detailed Source-Specific Molecular Composition of Ambient Aerosol Organic Matter Using Ultrahigh Resolution Mass Spectrometry and 1H NMR

    Directory of Open Access Journals (Sweden)

    Amanda S. Willoughby

    2016-06-01

    Full Text Available Organic aerosols (OA are universally regarded as an important component of the atmosphere that have far-ranging impacts on climate forcing and human health. Many of these impacts are related to OA molecular characteristics. Despite the acknowledged importance, current uncertainties related to the source apportionment of molecular properties and environmental impacts make it difficult to confidently predict the net impacts of OA. Here we evaluate the specific molecular compounds as well as bulk structural properties of total suspended particulates in ambient OA collected from key emission sources (marine, biomass burning, and urban using ultrahigh resolution mass spectrometry (UHR-MS and proton nuclear magnetic resonance spectroscopy (1H NMR. UHR-MS and 1H NMR show that OA within each source is structurally diverse, and the molecular characteristics are described in detail. Principal component analysis (PCA revealed that (1 aromatic nitrogen species are distinguishing components for these biomass burning aerosols; (2 these urban aerosols are distinguished by having formulas with high O/C ratios and lesser aromatic and condensed aromatic formulas; and (3 these marine aerosols are distinguished by lipid-like compounds of likely marine biological origin. This study provides a unique qualitative approach for enhancing the chemical characterization of OA necessary for molecular source apportionment.

  6. Contaminant source identification using semi-supervised machine learning

    International Nuclear Information System (INIS)

    Vesselinov, Velimir Valentinov; Alexandrov, Boian S.; O’Malley, Dan

    2017-01-01

    Identification of the original groundwater types present in geochemical mixtures observed in an aquifer is a challenging but very important task. Frequently, some of the groundwater types are related to different infiltration and/or contamination sources associated with various geochemical signatures and origins. The characterization of groundwater mixing processes typically requires solving complex inverse models representing groundwater flow and geochemical transport in the aquifer, where the inverse analysis accounts for available site data. Usually, the model is calibrated against the available data characterizing the spatial and temporal distribution of the observed geochemical types. Numerous different geochemical constituents and processes may need to be simulated in these models which further complicates the analyses. In this paper, we propose a new contaminant source identification approach that performs decomposition of the observation mixtures based on Non-negative Matrix Factorization (NMF) method for Blind Source Separation (BSS), coupled with a custom semi-supervised clustering algorithm. Our methodology, called NMFk, is capable of identifying (a) the unknown number of groundwater types and (b) the original geochemical concentration of the contaminant sources from measured geochemical mixtures with unknown mixing ratios without any additional site information. NMFk is tested on synthetic and real-world site data. Finally, the NMFk algorithm works with geochemical data represented in the form of concentrations, ratios (of two constituents; for example, isotope ratios), and delta notations (standard normalized stable isotope ratios).

  7. Primary sources of PM2.5 organic aerosol in an industrial Mediterranean city, Marseille

    Science.gov (United States)

    El Haddad, I.; Marchand, N.; Wortham, H.; Piot, C.; Besombes, J.-L.; Cozic, J.; Chauvel, C.; Armengaud, A.; Robin, D.; Jaffrezo, J.-L.

    2011-03-01

    Marseille, the most important port of the Mediterranean Sea, represents a challenging case study for source apportionment exercises, combining an active photochemistry and multiple emission sources, including fugitive emissions from industrial sources and shipping. This paper presents a Chemical Mass Balance (CMB) approach based on organic markers and metals to apportion the primary sources of organic aerosol in Marseille, with a special focus on industrial emissions. Overall, the CMB model accounts for the major primary anthropogenic sources including motor vehicles, biomass burning and the aggregate emissions from three industrial processes (heavy fuel oil combustion/shipping, coke production and steel manufacturing) as well as some primary biogenic emissions. This source apportionment exercise is well corroborated by 14C measurements. Primary OC estimated by the CMB accounts on average for 22% of total OC and is dominated by the vehicular emissions that contribute on average for 17% of OC mass concentration (vehicular PM contributes for 17% of PM2.5). Even though industrial emissions contribute only 2.3% of the total OC (7% of PM2.5), they are associated with ultrafine particles (Dpheavy metals such as Pb, Ni and V. On one hand, given that industrial emissions governed key primary markers, their omission would lead to substantial uncertainties in the CMB analysis performed in areas heavily impacted by such sources, hindering accurate estimation of non-industrial primary sources and secondary sources. On the other hand, being associated with bursts of submicron particles and carcinogenic and mutagenic components such as PAH, these emissions are most likely related with acute ill-health outcomes and should be regulated despite their small contributions to OC. Another important result is the fact that 78% of OC mass cannot be attributed to the major primary sources and, thus, remains un-apportioned. We have consequently critically investigated the uncertainties

  8. An open source toolkit for medical imaging de-identification

    International Nuclear Information System (INIS)

    Rodriguez Gonzalez, David; Carpenter, Trevor; Wardlaw, Joanna; Hemert, Jano I. van

    2010-01-01

    Medical imaging acquired for clinical purposes can have several legitimate secondary uses in research projects and teaching libraries. No commonly accepted solution for anonymising these images exists because the amount of personal data that should be preserved varies case by case. Our objective is to provide a flexible mechanism for anonymising Digital Imaging and Communications in Medicine (DICOM) data that meets the requirements for deployment in multicentre trials. We reviewed our current de-identification practices and defined the relevant use cases to extract the requirements for the de-identification process. We then used these requirements in the design and implementation of the toolkit. Finally, we tested the toolkit taking as a reference those requirements, including a multicentre deployment. The toolkit successfully anonymised DICOM data from various sources. Furthermore, it was shown that it could forward anonymous data to remote destinations, remove burned-in annotations, and add tracking information to the header. The toolkit also implements the DICOM standard confidentiality mechanism. A DICOM de-identification toolkit that facilitates the enforcement of privacy policies was developed. It is highly extensible, provides the necessary flexibility to account for different de-identification requirements and has a low adoption barrier for new users. (orig.)

  9. Long-term dust aerosol production from natural sources in Iceland.

    Science.gov (United States)

    Dagsson-Waldhauserova, Pavla; Arnalds, Olafur; Olafsson, Haraldur

    2017-02-01

    Iceland is a volcanic island in the North Atlantic Ocean with maritime climate. In spite of moist climate, large areas are with limited vegetation cover where >40% of Iceland is classified with considerable to very severe erosion and 21% of Iceland is volcanic sandy deserts. Not only do natural emissions from these sources influenced by strong winds affect regional air quality in Iceland ("Reykjavik haze"), but dust particles are transported over the Atlantic ocean and Arctic Ocean >1000 km at times. The aim of this paper is to place Icelandic dust production area into international perspective, present long-term frequency of dust storm events in northeast Iceland, and estimate dust aerosol concentrations during reported dust events. Meteorological observations with dust presence codes and related visibility were used to identify the frequency and the long-term changes in dust production in northeast Iceland. There were annually 16.4 days on average with reported dust observations on weather stations within the northeastern erosion area, indicating extreme dust plume activity and erosion within the northeastern deserts, even though the area is covered with snow during the major part of winter. During the 2000s the highest occurrence of dust events in six decades was reported. We have measured saltation and Aeolian transport during dust/volcanic ash storms in Iceland, which give some of the most intense wind erosion events ever measured. Icelandic dust affects the ecosystems over much of Iceland and causes regional haze. It is likely to affect the ecosystems of the oceans around Iceland, and it brings dust that lowers the albedo of the Icelandic glaciers, increasing melt-off due to global warming. The study indicates that Icelandic dust may contribute to the Arctic air pollution. Long-term records of meteorological dust observations from Northeast Iceland indicate the frequency of dust events from Icelandic deserts. The research involves a 60-year period and

  10. Impact of anthropogenic aerosols from global, East Asian, and non-East Asian sources on East Asian summer monsoon system

    Science.gov (United States)

    Wang, Qiuyan; Wang, Zhili; Zhang, Hua

    2017-01-01

    The impact of the total effects due to anthropogenic aerosols from global, East Asian, and non-East Asian sources on East Asian summer monsoon (EASM) system is studied using an aerosol-climate online model BCC_AGCM2.0.1_CUACE/Aero. The results show that the summer mean net all-sky shortwave fluxes averaged over East Asian monsoon region (EAMR) at the top of the atmosphere (TOA) and surface reduce by 4.8 and 5.0 W m- 2, respectively, due to the increases of global aerosol emissions in 2000 relative to 1850. Changes in radiations and their resulting changes in heat and water transport and cloud fraction contribute together to the surface cooling over EAMR in summer. The increases in global anthropogenic aerosols lead to a decrease of 2.1 K in summer mean surface temperature and an increase of 0.4 hPa in summer mean surface pressure averaged over EAMR, respectively. It is shown that the changes in surface temperature and pressure are significantly larger over land than ocean, thus decreasing the contrast of land-sea surface temperature and pressure. This results in the marked anomalies of north and northeast winds over eastern and southern China and the surrounding oceans in summer, thereby weakening the EASM. The summer mean precipitation averaged over the EAMR reduces by 12%. The changes in non-East Asian aerosol emissions play a more important role in inducing the changes of local temperature and pressure, and thus significantly exacerbate the weakness of the EASM circulation due to local aerosol changes. The weakening of circulation due to both is comparable, and even the effect of non-local aerosols is larger in individual regions. The changes of local and non-local aerosols contribute comparably to the reductions in precipitation over oceans, whereas cause opposite changes over eastern China. Our results highlight the importance of aerosol changes outside East Asia in the impact of the changes of anthropogenic aerosols on EASM.

  11. Identification of long-range transport of aerosols over Austria using EARLINET lidar measurements

    Science.gov (United States)

    Camelia, Talianu

    2018-04-01

    The aims of the study is to identify the paths of the long-range transported aerosols over Austria and their potential origin, and to estimate their properties, using lidar measurements from EARLINET stations closest to Austria from Germany and Romania and aerosol transport models. As of now, there is no lidar station in Austria. The study is part of a project to estimate the usefulness of a lidar station located in Vienna, Austria.

  12. Organic aerosols over Indo-Gangetic Plain: Sources, distributions and climatic implications

    Science.gov (United States)

    Singh, Nandita; Mhawish, Alaa; Deboudt, Karine; Singh, R. S.; Banerjee, Tirthankar

    2017-05-01

    Organic aerosol (OA) constitutes a dominant fraction of airborne particulates over Indo-Gangetic Plain (IGP) especially during post-monsoon and winter. Its exposure has been associated with adverse health effects while there are evidences of its interference with Earth's radiation balance and cloud condensation (CC), resulting possible alteration of hydrological cycle. Therefore, presence and effects of OA directly link it with food security and thereby, sustainability issues. In these contexts, atmospheric chemistry involving formation, volatility and aging of primary OA (POA) and secondary OA (SOA) have been reviewed with specific reference to IGP. Systematic reviews on science of OA sources, evolution and climate perturbations are presented with databases collected from 82 publications available throughout IGP till 2016. Both gaseous and aqueous phase chemical reactions were studied in terms of their potential to form SOA. Efforts were made to recognize the regional variation of OA, its chemical constituents and sources throughout IGP and inferences were made on its possible impacts on regional air quality. Mass fractions of OA to airborne particulate showed spatial variation likewise in Lahore (37 and 44% in fine and coarse fractions, respectively), Patiala (28 and 37%), Delhi (25 and 38%), Kanpur (24 and 30%), Kolkata (11 and 21%) and Dhaka. Source apportionment studies indicate biomass burning, coal combustion and vehicular emissions as predominant OA sources. However, sources represent considerable seasonal variations with dominance of gasoline and diesel emissions during summer and coal and biomass based emissions during winter and post-monsoon. Crop residue burning over upper-IGP was also frequently held responsible for massive OA emission, mostly characterized by its hygroscopic nature, thus having potential to act as CC nuclei. Conclusively, climatic implication of particulate bound OA has been discussed in terms of its interaction with radiation balance.

  13. Highly controlled, reproducible measurements of aerosol emissions from combustion of a common African biofuel source

    Directory of Open Access Journals (Sweden)

    S. L. Haslett

    2018-01-01

    Full Text Available Particulate emissions from biomass burning can both alter the atmosphere's radiative balance and cause significant harm to human health. However, due to the large effect on emissions caused by even small alterations to the way in which a fuel burns, it is difficult to study particulate production of biomass combustion mechanistically and in a repeatable manner. In order to address this gap, in this study, small wood samples sourced from Côte D'Ivoire in West Africa were burned in a highly controlled laboratory environment. The shape and mass of samples, available airflow and surrounding thermal environment were carefully regulated. Organic aerosol and refractory black carbon emissions were measured in real time using an Aerosol Mass Spectrometer and a Single Particle Soot Photometer, respectively. This methodology produced remarkably repeatable results, allowing aerosol emissions to be mapped directly onto different phases of combustion. Emissions from pyrolysis were visible as a distinct phase before flaming was established. After flaming combustion was initiated, a black-carbon-dominant flame was observed during which very little organic aerosol was produced, followed by a period that was dominated by organic-carbon-producing smouldering combustion, despite the presence of residual flaming. During pyrolysis and smouldering, the two phases producing organic aerosol, distinct mass spectral signatures that correspond to previously reported variations in biofuel emissions measured in the atmosphere are found. Organic aerosol emission factors averaged over an entire combustion event were found to be representative of the time spent in the pyrolysis and smouldering phases, rather than reflecting a coupling between emissions and the mass loss of the sample. Further exploration of aerosol yields from similarly carefully controlled fires and a careful comparison with data from macroscopic fires and real-world emissions will help to deliver

  14. Characteristics, sources and evolution of fine aerosol (PM1) at urban, coastal and forest background sites in Lithuania

    Science.gov (United States)

    Masalaite, A.; Holzinger, R.; Remeikis, V.; Röckmann, T.; Dusek, U.

    2017-01-01

    The chemical and isotopic composition of organic aerosol (OA) samples collected on PM1 filters was determined as a function of desorption temperature to investigate the main sources of organic carbon and the effects of photochemical processing on atmospheric aerosol. The filter samples were collected at an urban (54°38‧ N, 25°18‧ E), coastal (55°55‧ N, 21°00‧ E) and forest (55°27‧ N, 26°00' E) site in Lithuania in March 2013. They can be interpreted as winter-time samples because the monthly averaged temperature was -4 °C. The detailed chemical composition of organic compounds was analysed with a thermal desorption PTR-MS. The mass concentration of organic aerosol at the forest site was roughly by a factor of 30 lower than at the urban and coastal site. This fact could be an indication that in this cold month the biogenic secondary organic aerosol (SOA) formation was very low. Moreover, the organic aerosol collected at the forest site was more refractory and contained a larger fraction of heavy molecules with m/z > 200. The isotopic composition of the aerosol was used to differentiate the two main sources of organic aerosol in winter, i.e. biomass burning (BB) and fossil fuel (FF) combustion. Organic aerosol from biomass burning is enriched in 13C compared to OA from fossil fuel emissions. δ13COC values of the OA samples showed a positive correlation with the mass fraction of several individual organic compounds. Most of these organic compounds contained nitrogen indicating that organic nitrogen compounds formed during the combustion of biomass may be indicative of BB. Other compounds that showed negative correlations with δ13COC were possibly indicative of FF. These compounds included heavy hydrocarbons and were on the average less oxidized than the bulk organic carbon. The correlation of δ13COC and the O/C ratio was positive at low but negative at high desorption temperatures at the forest site. We propose that this might be due to

  15. Wintertime aerosol chemical composition and source apportionment of the organic fraction in the metropolitan area of Paris

    Directory of Open Access Journals (Sweden)

    M. Crippa

    2013-01-01

    Full Text Available The effect of a post-industrial megacity on local and regional air quality was assessed via a month-long field measurement campaign in the Paris metropolitan area during winter 2010. Here we present source apportionment results from three aerosol mass spectrometers and two aethalometers deployed at three measurement stations within the Paris region. Submicron aerosol composition is dominated by the organic fraction (30–36% and nitrate (28–29%, with lower contributions from sulfate (14–16%, ammonium (12–14% and black carbon (7–13%.

    Organic source apportionment was performed using positive matrix factorization, resulting in a set of organic factors corresponding both to primary emission sources and secondary production. The dominant primary sources are traffic (11–15% of organic mass, biomass burning (13–15% and cooking (up to 35% during meal hours. Secondary organic aerosol contributes more than 50% to the total organic mass and includes a highly oxidized factor from indeterminate and/or diverse sources and a less oxidized factor related to wood burning emissions. Black carbon was apportioned to traffic and wood burning sources using a model based on wavelength-dependent light absorption of these two combustion sources. The time series of organic and black carbon factors from related sources were strongly correlated. The similarities in aerosol composition, total mass and temporal variation between the three sites suggest that particulate pollution in Paris is dominated by regional factors, and that the emissions from Paris itself have a relatively low impact on its surroundings.

  16. COLLABORATIVE RESEARCH: Study of Aerosol Sources and Processing at the GVAX Pantnagar Supersite

    Energy Technology Data Exchange (ETDEWEB)

    Worsnop, Douglas R. [Principal Investigator

    2014-07-28

    This project funded the participation of scientists from seven research groups, running more than thirty instruments, in the Winter Intensive Operating Period (January-February 2012) of the Clean Air for London (ClearfLo) campaign at a rural site in Detling, UK, 45 km southeast of central London. The primary science questions for the ClearfLo Winter IOP were, 1) what is the urban increment of particulate matter (PM) and other pollutants in the greater London area, and, 2) what is the contribution of solid fuel use for home heating to wintertime PM? An additional motivation for the Detling measurements was the question of whether coatings on black carbon particles enhance absorption. The following four key accomplishments have been identified so far: 1) Chemical, physical and optical characterization of PM from local and regional sources (Figures 2, 4, 5 and 6). 2) Measurement of urban increment in particulate matter and gases in London (Figure 3). 3) Measurement of optical properties and chemical composition of coatings on black carbon containing particles indicates absorption enhancement. 4) First deployment of chemical ionization instrument (MOVI-CI-TOFMS) to measure both particle-phase and gas-phase organic acids. (See final report from Joel Thornton, University of Washington, for details.) Analysis of the large dataset acquired in Detling is ongoing and will yield further key accomplishments. These measurements of urban and rural aerosol properties will contribute to improved modeling of regional aerosol emissions, and of atmospheric aging and removal. The measurement of absorption enhancement by coatings on black carbon will contribute to improved modeling of the direct radiative properties of PM.

  17. Wintertime aerosol chemical composition and source apportionment of the organic fraction across Ireland

    Science.gov (United States)

    Ovadnevaite, J.; Lin, C.; Ceburnis, D.; Huang, R. J. J.; O'Dowd, C. D. D.

    2017-12-01

    A national wide characterization of PM1 was studied for the first time using a high-time resolution Aerosol Chemical Speciation Monitor (ACSM) and Aethalometer in Ireland during the heating season. Dublin, the capital of Ireland, is the most polluted area with an average PM1 of 7.6 μg/m3, with frequent occurrence of peak concentration over 200 μg/m3 primarily due to solid fuels burning, while Mace Head, in the west coast, is least polluted with an average PM1 of 0.8 μg/m3 due to the distance from the emission sources. The organic aerosol is the most dominant species across Ireland, contributing 65%, 58%, 32%, 33% to total PM1 mass in Dublin, Birr, Carnsore Point, and Mace Head, respectively. Birr, a small town in the midland of Ireland, has comparable PM1 levels (4.8 μg/m3) and similar chemical compositions with that in Dublin. Carnsore Point, on the southeast coast, has similar composition with that at Mace Head, but nearly 3 times the levels of PM1 mass due to its relative closeness to other European countries. Positive matrix factorization (PMF) with the multi-linear engine (ME-2) was performed on the organic matrix to quantify the contribution of factor candidates. Peat burning was found to be the dominant factor across Ireland, contributing more than 40% of the total organic mass in Dublin and Birr while OOA is dominant at rural Carnsore Point and Mace Head. Possible geographic origins of PM1 species and organic factors using polar plots were explored. The findings of solid fuels burning (primarily peat burning) driving the pollution episodes suggest an elimination or controlled emission of solid fuels burning would reduce PM1 by at least 50%.

  18. Chemically-resolved volatility measurements of organic aerosol fom different sources.

    Science.gov (United States)

    Huffman, J A; Docherty, K S; Mohr, C; Cubison, M J; Ulbrich, I M; Ziemann, P J; Onasch, T B; Jimenez, J L

    2009-07-15

    A newly modified fast temperature-stepping thermodenuder (TD) was coupled to a High Resolution Time-of-Flight Aerosol Mass Spectrometer for rapid determination of chemically resolved volatility of organic aerosols (OA) emitted from individual sources. The TD-AMS system was used to characterize primary OA (POA) from biomass burning, trash burning surrogates (paper and plastic), and meat cooking as well as chamber-generated secondary OA (SOA) from alpha-pinene and gasoline vapor. Almost all atmospheric models represent POA as nonvolatile, with no allowance for evaporation upon heating or dilution, or condensation upon cooling. Our results indicate that all OAs observed show semivolatile behavior and that most POAs characterized here were at least as volatile as SOA measured in urban environments. Biomass-burning OA (BBOA) exhibited a wide range of volatilities, but more often showed volatility similar to urban OA. Paper-burning resembles some types of BBOA because of its relatively high volatility and intermediate atomic oxygen-to-carbon (O/C) ratio, while meat-cooking OAs (MCOA) have consistently lower volatility than ambient OA. Chamber-generated SOA under the relatively high concentrations used intraditional experiments was significantly more volatile than urban SOA, challenging extrapolation of traditional laboratory volatility measurements to the atmosphere. Most OAs sampled show increasing O/C ratio and decreasing H/C (hydrogen-to-carbon) ratio with temperature, further indicating that more oxygenated OA components are typically less volatile. Future experiments should systematically explore a wider range of mass concentrations to more fully characterize the volatility distributions of these OAs.

  19. Onshore Wind Speed Modulates Microbial Aerosols along an Urban Waterfront

    Directory of Open Access Journals (Sweden)

    M. Elias Dueker

    2017-11-01

    Full Text Available Wind blowing over aquatic and terrestrial surfaces produces aerosols, which include microbial aerosols. We studied the effect of onshore wind speeds on aerosol concentrations as well as total and culturable microbial aerosols (bacterial and viral at an urban waterfront (New York, NY, United States of America. We used two distinct methods to characterize microbial aerosol responses to wind speed: A culture-based exposure-plate method measuring viable bacterial deposition near-shore (CFU accumulation rate; and a culture-independent aerosol sampler-based method measuring total bacterial and viral aerosols (cells m−3 air. While ambient coarse (>2 µm and fine (0.3–2 µm aerosol particle number concentrations (regulated indicators of air quality decreased with increasing onshore wind speeds, total and depositing culturable bacterial aerosols and total viral aerosols increased. Taxonomic identification of the 16S rDNA of bacterial aerosol isolates suggested both terrestrial and aquatic sources. Wind appears to increase microbial aerosol number concentrations in the near-shore environment by onshore transport at low wind speeds (<4 m s−1, and increased local production and transport of new microbial aerosols from adjacent water surfaces at higher wind speeds (>4 m s−1. This study demonstrates a wind-modulated microbial connection between water and air in the coastal urban environment, with implications for public health management and urban microbial ecology.

  20. The generation of diesel exhaust particle aerosols from a bulk source in an aerodynamic size range similar to atmospheric particles

    Directory of Open Access Journals (Sweden)

    Daniel J Cooney

    2008-08-01

    Full Text Available Daniel J Cooney1, Anthony J Hickey21Department of Biomedical Engineering; 2School of Pharmacy, University of North Carolina, Chapel Hill, NC, USAAbstract: The influence of diesel exhaust particles (DEP on the lungs and heart is currently a topic of great interest in inhalation toxicology. Epidemiological data and animal studies have implicated airborne particulate matter and DEP in increased morbidity and mortality due to a number of cardiopulmonary diseases including asthma, chronic obstructive pulmonary disorder, and lung cancer. The pathogeneses of these diseases are being studied using animal models and cell culture techniques. Real-time exposures to freshly combusted diesel fuel are complex and require significant infrastructure including engine operations, dilution air, and monitoring and control of gases. A method of generating DEP aerosols from a bulk source in an aerodynamic size range similar to atmospheric DEP would be a desirable and useful alternative. Metered dose inhaler technology was adopted to generate aerosols from suspensions of DEP in the propellant hydrofluoroalkane 134a. Inertial impaction data indicated that the particle size distributions of the generated aerosols were trimodal, with count median aerodynamic diameters less than 100 nm. Scanning electron microscopy of deposited particles showed tightly aggregated particles, as would be expected from an evaporative process. Chemical analysis indicated that there were no major changes in the mass proportion of 2 specific aromatic hydrocarbons (benzo[a]pyrene and benzo[k]fluoranthene in the particles resulting from the aerosolization process.Keywords: diesel exhaust particles, aerosol, inhalation toxicology

  1. Chemical composition and sources of organic aerosols over London from the ClearfLo 2012 campaigns

    Science.gov (United States)

    Finessi, Emanuela; Holmes, Rachel; Hopkins, James; Lee, James; Harrison, Roy; Hamilton, Jacqueline

    2014-05-01

    Air quality in urban areas represents a major public health issue with around one third of the European population concentrated in cities and numbers expected to increase at global scale, particularly in developing countries. Particulate matter (PM) represents a primary threat for human health as numerous studies have confirmed the association between increased levels of cardiovascular and respiratory diseases with the exposure to PM. Despite considerable efforts made in improving air quality and progressively stricter emissions regulations, the PM concentrations have not changed much over the past decades for reasons that remain unclear, and highlight that studies on PM source apportionment are required for the formulation of effective policy. We investigated the chemical composition of organic aerosol (OA) collected during two intensive field campaigns held in winter and summer 2012 in the frame of the project Clean air for London (http://www.clearflo.ac.uk/). PM samples were collected both at a city background site (North Kensington) and at a rural site 50 km southeast of London (Detling) with 8 to 24 hours sampling schedule and analysed using off-line methods. Thermal-optical analysis was used to quantify OC-EC components while a suite of soft ionization mass spectrometric techniques was deployed for detailed chemical characterization. Liquid chromatography mass Spectrometry (LC-MSn) was mostly used for the simultaneous detection and quantification of various tracers for both primary and secondary OA sources. Well-established markers for wood burning primary OA like levoglucosan and azelaic acid were quantified together with various classes of nitroaromatics including methyl-nitrocatechols that are potential tracers for wood burning secondary OA. In addition, oxidation products of biogenic VOCs such as isoprene and monoterpenes were also quantified for both seasons and sites. A non-negligible contribution from biogenic SOA to urban OA was found in summertime

  2. Chemical composition, sources and evolution processes of aerosol at an urban site in Yangtze River Delta, China during wintertime

    Science.gov (United States)

    Zhang, Yunjiang; Tang, Lili; Yu, Hongxia; Wang, Zhuang; Sun, Yele; Qin, Wei; Chen, Wentai; Chen, Changhong; Ding, Aijun; Wu, Jing; Ge, Shun; Chen, Cheng; Zhou, Hong-cang

    2015-12-01

    To investigate the composition, sources and evolution processes of submicron aerosol during wintertime, a field experiment was conducted during December 1-31, 2013 in urban Nanjing, a megacity in Yangtze River Delta of China. Non-refractory submicron aerosol (NR-PM1) species were measured with an Aerodyne Aerosol Chemical Speciation Monitor. NR-PM1 is dominated by secondary inorganic aerosol (55%) and organic aerosol (OA, 42%) during haze periods. Six OA components were identified by positive matrix factorization of the OA mass spectra. The hydrocarbon-like OA and cooking-related OA represent the local traffic and cooking sources, respectively. A highly oxidized factor related to biomass burning OA accounted for 15% of the total OA mass during haze periods. Three types of oxygenated OA (OOA), i.e., a less-oxidized OOA (LO-OOA), a more-oxidized OOA (MO-OOA), and a low-volatility OOA (LV-OOA), were identified. LO-OOA is likely associated with fresh urban secondary OA. MO-OOA likely represents photochemical products showing a similar diurnal cycle to nitrate with a pronounced noon peak. LV-OOA appears to be a more oxidized factor with a pronounced noon peak. The OA composition is dominated by secondary species, especially during haze events. LO-OOA, MO-OOA and LV-OOA on average account for 11%, (18%), 24% (21%) and 23% (18%) of the total OA mass for the haze (clean) periods respectively. Analysis of meteorological influence suggested that regional transport from the northern and southeastern areas of the city is responsible for large secondary and low-volatility aerosol formation.

  3. Organic aerosol source apportionment by offline-AMS over a full year in Marseille

    Directory of Open Access Journals (Sweden)

    C. Bozzetti

    2017-07-01

    Full Text Available We investigated the seasonal trends of OA sources affecting the air quality of Marseille (France, which is the largest harbor of the Mediterranean Sea. This was achieved by measurements of nebulized filter extracts using an aerosol mass spectrometer (offline-AMS. In total 216 PM2. 5 (particulate matter with an aerodynamic diameter  <  2.5 µm filter samples were collected over 1 year from August 2011 to July 2012. These filters were used to create 54 composite samples which were analyzed by offline-AMS. The same samples were also analyzed for major water-soluble ions, metals, elemental and organic carbon (EC ∕ OC, and organic markers, including n-alkanes, hopanes, polycyclic aromatic hydrocarbons (PAHs, lignin and cellulose pyrolysis products, and nitrocatechols. The application of positive matrix factorization (PMF to the water-soluble AMS spectra enabled the extraction of five factors, related to hydrocarbon-like OA (HOA, cooking OA (COA, biomass burning OA (BBOA, oxygenated OA (OOA, and an industry-related OA (INDOA. Seasonal trends and relative contributions of OA sources were compared with the source apportionment of OA spectra collected from the AMS field deployment at the same station but in different years and for shorter monitoring periods (February 2011 and July 2008. Online- and offline-AMS source apportionment revealed comparable seasonal contribution of the different OA sources. Results revealed that BBOA was the dominant source during winter, representing on average 48 % of the OA, while during summer the main OA component was OOA (63 % of OA mass on average. HOA related to traffic emissions contributed on a yearly average 17 % to the OA mass, while COA was a minor source contributing 4 %. The contribution of INDOA was enhanced during winter (17 % during winter and 11 % during summer, consistent with an increased contribution from light alkanes, light PAHs (fluoranthene, pyrene, phenanthrene, and

  4. Characterization of emissions from South Asian biofuels and application to source apportionment of carbonaceous aerosol in the Himalayas

    Science.gov (United States)

    Stone, Elizabeth A.; Schauer, James J.; Pradhan, Bidya Banmali; Dangol, Pradeep Man; Habib, Gazala; Venkataraman, Chandra; Ramanathan, V.

    2010-03-01

    This study focuses on improving source apportionment of carbonaceous aerosol in South Asia and consists of three parts: (1) development of novel molecular marker-based profiles for real-world biofuel combustion, (2) application of these profiles to a year-long data set, and (3) evaluation of profiles by an in-depth sensitivity analysis. Emissions profiles for biomass fuels were developed through source testing of a residential stove commonly used in South Asia. Wood fuels were combusted at high and low rates, which corresponded to source profiles high in organic carbon (OC) or high in elemental carbon (EC), respectively. Crop wastes common to the region, including rice straw, mustard stalk, jute stalk, soybean stalk, and animal residue burnings, were also characterized. Biofuel profiles were used in a source apportionment study of OC and EC in Godavari, Nepal. This site is located in the foothills of the Himalayas and was selected for its well-mixed and regionally impacted air masses. At Godavari, daily samples of fine particulate matter (PM2.5) were collected throughout the year of 2006, and the annual trends in particulate mass, OC, and EC followed the occurrence of a regional haze in South Asia. Maximum concentrations occurred during the dry winter season and minimum concentrations occurred during the summer monsoon season. Specific organic compounds unique to aerosol sources, molecular markers, were measured in monthly composite samples. These markers implicated motor vehicles, coal combustion, biomass burning, cow dung burning, vegetative detritus, and secondary organic aerosol as sources of carbonaceous aerosol. A molecular marker-based chemical mass balance (CMB) model provided a quantitative assessment of primary source contributions to carbonaceous aerosol. The new profiles were compared to widely used biomass burning profiles from the literature in a sensitivity analysis. This analysis indicated a high degree of stability in estimates of source

  5. A study of photochemical againg of ambient air using Potential Aerosol Mass (PAM) chamber under the different sources and types of emissions

    Science.gov (United States)

    Lee, T.; Son, J.; Kim, J.; Kim, S.; Sung, K.; Park, G.; Link, M.; Park, T.; Kim, K.; Kang, S.; Ban, J.; Kim, D. S.

    2016-12-01

    Recent research proposed that Secondary Aerosol (SA) is important class of predicting future climate change scenarios, health effect, and a general air quality. However, there has been lack of studies to investigate SA formation all over the world. This study tried to focus on understanding potential secondary aerosol formation and its local impact by the photochemical aging of inorganic and organic aerosols in the ambient air using the Potential Aerosol Mass (PAM) chamber under the different sources and types of emissions. PAM chamber manufactured by Aerodyne make an oxidizing environment that simulates oxidation processes on timescales of 12-15 hrs in the atmosphere. Chemical compositions of ambient aerosol and aerosol that was aged in the PAM chamber were alternately measured every 2-minutes using the High Resolution-Time of Flight-Aerosol Mass Spectrometer (HR-ToF-AMS). HR-ToF-AMS provides non-refractory aerosol mass concentrations including nitrate, sulfate, hydrocarbon-like and oxygenated organic aerosol in real time. This study includes a residence area of mixture of sources, a forest site of dominant source of biogenic VOCs, an underground parking lot of dominant vehicle emission, and laboratory experiment of vehicle emissions under different fuels and speeds using the chassis dynamometer. As a result, it was revealed that gasoline and LPG vehicle relatively made more potential SA than diesel vehicle.

  6. Historical evolution of sources identification by means of Receptor Modeling in the Metropolitan Area of São Paulo, Brazil.

    Science.gov (United States)

    Miranda, R. M.; Andrade, M. D. F.; Marien, Y., Sr.

    2017-12-01

    The atmospheric aerosols sources have been identified in Sao Paulo since the 80´s with the use of receptor models. The Metropolitan Area of São Paulo (MASP) is a megacity with a population of 21 million, corresponding to more than 11% of the total population of Brazil. The first results for the identification of sources of particles were obtained with the application of Absolute Principal Component Analysis, Factor Analysis and Chemical Mass Balance. More recently the Positive Matrix Factorization has been used in combination with the other receptor models. With the improvement of the aerosol composition analytical determination (more elements and better resolution) the source identification has became more accurate. But, in spite of that, the main sources are the same for fine particles: vehicular emission, secondary formation and biomass burning. The large amount of biofuels used in the MASP makes this region an important example of the atmospheric chemistry of fossil fuel and biofuel emissions. The 7 million vehicles can run on gasohol, ethanol (95% ethanol + 5% gasoline) and biodiesel (mostly for trucks and buses). We have considered the Black Carbon as the tracer for diesel engines and biomass burning, being this last source associated not only with burning of sugar cane plantation and forest fires, but also with wood and charcoal used in restaurant and domestic cooking and residues burning. The responsibility of the vehicular emission to the fine particles has been maintained in approximately 50% of the mass. The soil resuspension was associated with 8% of the fine particles origin. We are presenting the data obtained from experiments performed from 1983 to 2014, not continuously and mainly performed in the winter time. It is a long period of data that is going to be considered. The previous results obtained with the application of PCA were compared to that obtained with PMF applied to the historical data collected at MASP, showing the evolution of the

  7. Lead isotopic characterization of respirable urban aerosols and related sources, Santiago-Chile

    International Nuclear Information System (INIS)

    Diaz, M; Kawashita, K; Antinao, J.L

    2001-01-01

    Santiago de Chile is located in a poorly ventilated valley at 33 o 30' latitude south at an altitude of 550m. Local climate is semi-arid with mean annual rainfall below 350mm. The atmospheric particles constitute one of the main factors of urban air pollution in the city. Morphological characterization of airborne particles of Santiago done by Scanning Electron Microscopy showed the presence of three groups of particles: crystalline. spherical and agglomerate particles. The crystalline shapes originated in geologic sources have perfectly defined crystallographic parameters. The agglomerated shapes are formed by organic material and submicrometrical mineral particles derived from combustion of fossil fuel and the spherical shapes are products of metallurgical activities. Some of them could been associated with the wear of motorcars. Samples of aerosols. sediments and leaded petrol of different distributors were collected. Aerosols were sampled in two sites of Santiago: the Movil monitoring station, at east of the city, and Parque O'Higgins monitoring station in downtown. These two monitoring stations belong to the MACAM network. Sediments of Mapocho, Maipo, San Francisco and Zanjon de la Aguada rivers and two samples from Disputada and Merceditas ores were studied. All the samples have been measured for their 206 Pb/ 204 Pb, 207 Pb/ 204 Pb and 208 Pb/ 204 Pb ratios. The experimental chemical procedures of sample dissolution and Pb separation by anion exchange chromatography were developed in the Sernageomin clean laboratory of Santiago de Chile. The isotopic measurements were made using a VG-Sector isotope ratio mass spectrometer fitted with a thermal ion source, multi Faraday collector and Daly collector of the Isotopic Geology Laboratory in the Universidade Federal de Rio Grande do Sul, Brazil. The measurements were corrected using NBS 981 and 982 standards. Isotopic results plotted in a 208 Pb/ 204 Pb versus 206 Pb/ 204 Pb diagram and in a 207 Pb/ 204 Pb versus

  8. Aerosol optical properties in the mega-cities Beijing and Guangzhou: Measurements and implications for regional air pollution, aerosol sources and remote sensing

    Science.gov (United States)

    Garland, R. M.; Yang, H.; Schmid, O.; Rose, D.; Gunthe, S. S.

    2009-04-01

    Aerosol optical properties were measured in two mega-city regions in China. The first site (Backgarden) was in a rural area approximately 60 km northwest of the mega-city Guangzhou in south China and was part of the "Program of Regional Integrated Experiments of Air Quality over the Pearl River Delta" intensive campaign in July 2006 (PRIDE-PRD2006). The second site (Yufa) was in a suburban area approximately 40 km south of Beijing and was part of "Campaigns of Air Quality Research in Beijing" (CAREBeijing-2006) in August 2006. Both sites were designed to measure the regional pollution of the mega-cities. The optical parameters determined with a nephelometer and photoacoustic spectrometer include absorption and scattering coefficients, single scattering albedos and Angstrom exponents at multiple wavelengths (450-700 nm). In both measurement campaigns, we observed pronounced diurnal cycles in absorption and scattering coefficients and single scattering albedo, which can be explained by boundary layer mixing effects and enhanced light absorbing carbon emissions from traffic activity during the nighttime and early morning, respectively (diesel soot from regulated truck traffic). In Beijing both the extensive and the intensive properties were highly dependent upon the origin of the air mass, which indicates that not only does the aerosol concentration change with air mass origin, but so do the chemical composition and sources. When the measured air masses originated in the north and passed over Beijing, the single scattering albedo was generally low (transported into the city from the south. The scattering and absorption coefficients measured in the outflow of the Guangzhou area during PRIDE-PRD2006 were ~2 times smaller than the southerly inflow into Beijing during CARBeijing-2006, which indicates that the sources of particulate pollution south of Beijing are even stronger than those in the Pearl River Delta. In both mega-city regions the Angstrom exponent exhibited a

  9. Identification and chemical characterization of industrial particulate matter sources in southwest Spain.

    Science.gov (United States)

    Alastuey, Andrés; Querol, Xavier; Plana, Feliciano; Viana, Mar; Ruiz, Carmen R; Sánchez de la Campa, Ana; de la Rosa, Jesús; Mantilla, Enrique; García dos Santos, Saul

    2006-07-01

    A detailed physical and chemical characterization of coarse particulate matter (PM10) and fine particulate matter (PM2.5) in the city of Huelva (in Southwestern Spain) was carried out during 2001 and 2002. To identify the major emission sources with a significant influence on PM10 and PM2.5, a methodology was developed based on the combination of: (1) real-time measurements of levels of PM10, PM2.5, and very fine particulate matter (PM1); (2) chemical characterization and source apportionment analysis of PM10 and PM2.5; and (3) intensive measurements in field campaigns to characterize the emission plumes of several point sources. Annual means of 37, 19, and 16 microg/m3 were obtained for the study period for PM10, PM2.5, and PM1, respectively. High PM episodes, characterized by a very fine grain size distribution, are frequently detected in Huelva mainly in the winter as the result of the impact of the industrial emission plumes on the city. Chemical analysis showed that PM at Huelva is characterized by high PO4(3-) and As levels, as expected from the industrial activities. Source apportionment analyses identified a crustal source (36% of PM10 and 31% of PM2.5); a traffic-related source (33% of PM10 and 29% of PM2.5), and a marine aerosol contribution (only in PM10, 4%). In addition, two industrial emission sources were identified in PM10 and PM2.5: (1) a petrochemical source, 13% in PM10 and 8% in PM2.5; and (2) a mixed metallurgical-phosphate source, which accounts for 11-12% of PM10 and PM2.5. In PM2.5 a secondary source has been also identified, which contributed to 17% of the mass. A complete characterization of industrial emission plumes during their impact on the ground allowed for the identification of tracer species for specific point sources, such as petrochemical, metallurgic, and fertilizer and phosphate production industries.

  10. Evaluation of the health impact of aerosols emitted from different combustion sources: Comprehensive characterization of the aerosol physicochemical properties as well as the molecular biological and toxicological effects of the aerosols on human lung cells and macrophages.

    Science.gov (United States)

    Zimmermann, R.; Dittmar, G.; Kanashova, T.; Buters, J.; Öder, S.; Paur, H. R.; Mülhopt, S.; Dilger, M.; Weiss, C.; Harndorf, H.; Stengel, B.; Hirvonen, M. R.; Jokiniemi, J.; Hiller, K.; Sapcariu, S.; Sippula, O.; Streibel, T.; Karg, E.; Weggler, B.; Schnelle-Kreis, J.; Lintelmann, J.; Sklorz, M.; Orasche, J.; Müller, L.; Passig, J.; Gröger, T.; Jalava, P. I.; Happo, M.; Uski, O.

    2017-12-01

    . Detailed analyses suggest a large difference in relative toxicity for different combustion sources. Recently the cell experiments were successively evaluated and verified by animal exposure tests. This is important to develop a reliable animal-test free-monitoring method for aerosol-induced health effects.

  11. Expanding Single Particle Mass Spectrometer Analyses for the Identification of Microbe Signatures in Sea Spray Aerosol.

    Science.gov (United States)

    Sultana, Camille M; Al-Mashat, Hashim; Prather, Kimberly A

    2017-10-03

    Ocean-derived microbes in sea spray aersosol (SSA) have the potential to influence climate and weather by acting as ice nucleating particles in clouds. Single particle mass spectrometers (SPMSs), which generate in situ single particle composition data, are excellent tools for characterizing aerosols under changing environmental conditions as they can provide high temporal resolution and require no sample preparation. While SPMSs have proven capable of detecting microbes, these instruments have never been utilized to definitively identify aerosolized microbes in ambient sea spray aersosol. In this study, an aerosol time-of-flight mass spectrometer was used to analyze laboratory generated SSA produced from natural seawater in a marine aerosol reference tank. We present the first description of a population of biological SSA mass spectra (BioSS), which closely match the ion signatures observed in previous terrestrial microbe studies. The fraction of BioSS dramatically increased in the largest supermicron particles, consistent with field and laboratory measurements of microbes ejected by bubble bursting, further supporting the assignment of BioSS mass spectra as microbes. Finally, as supported by analysis of inorganic ion signals, we propose that dry BioSS particles have heterogeneous structures, with microbes adhered to sodium chloride nodules surrounded by magnesium-enriched coatings. Consistent with this structure, chlorine-containing ion markers were ubiquitous in BioSS spectra and identified as possible tracers for distinguishing recently aerosolized marine from terrestrial microbes.

  12. Sources of PM2.5 carbonaceous aerosol in Riyadh, Saudi Arabia

    Science.gov (United States)

    Bian, Qijing; Alharbi, Badr; Shareef, Mohammed M.; Husain, Tahir; Pasha, Mohammad J.; Atwood, Samuel A.; Kreidenweis, Sonia M.

    2018-03-01

    Knowledge of the sources of carbonaceous aerosol affecting air quality in Riyadh, Saudi Arabia, is limited but needed for the development of pollution control strategies. We conducted sampling of PM2.5 from April to September 2012 at various sites in the city and used a thermo-optical semi-continuous method to quantify the organic carbon (OC) and elemental carbon (EC) concentrations. The average OC and EC concentrations were 4.7 ± 4.4 and 2.1 ± 2.5 µg m-3, respectively, during this period. Both OC and EC concentrations had strong diurnal variations, with peaks at 06:00-08:00 LT and 20:00-22:00 LT, attributed to the combined effect of increased vehicle emissions during rush hour and the shallow boundary layer in the early morning and at night. This finding suggested a significant influence of local vehicular emissions on OC and EC. The OC / EC ratio in primary emissions was estimated to be 1.01, close to documented values for diesel emissions. Estimated primary organic carbon (POC) and secondary organic carbon (SOC) concentrations were comparable, with average concentrations of 2.0 ± 2.4 and 2.8 ± 3.4 µg m-3, respectively.We also collected 24 h samples of PM10 onto quartz microfiber filters and analyzed these for an array of metals by inductively coupled plasma atomic emission spectroscopy (ICP-AES). Total OC was correlated with Ca (R2 of 0.63), suggesting that OC precursors and Ca may have similar sources, and the possibility that they underwent similar atmospheric processing. In addition to a ubiquitous dust source, Ca is emitted during desalting processes in the numerous refineries in the region and from cement kilns, suggesting these sources may also contribute to observed OC concentrations in Riyadh. Concentration weighted trajectory (CWT) analysis showed that high OC and EC concentrations were associated with air masses arriving from the Persian Gulf and the region around Baghdad, locations with high densities of oil fields and refineries as well as a

  13. Efficient Bayesian experimental design for contaminant source identification

    Science.gov (United States)

    Zhang, Jiangjiang; Zeng, Lingzao; Chen, Cheng; Chen, Dingjiang; Wu, Laosheng

    2015-01-01

    In this study, an efficient full Bayesian approach is developed for the optimal sampling well location design and source parameters identification of groundwater contaminants. An information measure, i.e., the relative entropy, is employed to quantify the information gain from concentration measurements in identifying unknown parameters. In this approach, the sampling locations that give the maximum expected relative entropy are selected as the optimal design. After the sampling locations are determined, a Bayesian approach based on Markov Chain Monte Carlo (MCMC) is used to estimate unknown parameters. In both the design and estimation, the contaminant transport equation is required to be solved many times to evaluate the likelihood. To reduce the computational burden, an interpolation method based on the adaptive sparse grid is utilized to construct a surrogate for the contaminant transport equation. The approximated likelihood can be evaluated directly from the surrogate, which greatly accelerates the design and estimation process. The accuracy and efficiency of our approach are demonstrated through numerical case studies. It is shown that the methods can be used to assist in both single sampling location and monitoring network design for contaminant source identifications in groundwater.

  14. Calibration experiments of neutron source identification and detection in soil

    International Nuclear Information System (INIS)

    Gorin, N. V.; Lipilina, E. N.; Rukavishnikov, G. V.; Shmakov, D. V.; Ulyanov, A. I.

    2007-01-01

    In the course of detection of fissile materials in soil, series of calibration experiments were carried out on in laboratory conditions on an experimental installation, presenting a mock-up of an endless soil with various heterogeneous bodies in it, fissile material, measuring boreholes. A design of detecting device, methods of neutrons detection are described. Conditions of neutron background measuring are given. Soil density, humidity, chemical composition of soil was measured. Sensitivity of methods of fissile materials detection and identification in soil was estimated in the calibration experiments. Minimal detectable activity and the distance at which it can be detected were defined. Characteristics of neutron radiation in a borehole mock-up were measured; dependences of method sensitivities from water content in soil, source-detector distance and presence of heterogeneous bodies were examined. Possibility of direction detection to a fissile material as neutron source from a borehole using a collimator is shown. Identification of fissile material was carried out by measuring the gamma-spectrum. Mathematical modeling was carried out using the PRIZMA code (Developed in RFNC-VNIITF) and MCNP code (Developed in LANL). Good correlation of calculational and experimental values was shown. The methodic were shown to be applicable in the field conditions

  15. Seasonal characterization of submicron aerosol chemical composition and organic aerosol sources in the southeastern United States: Atlanta, Georgia,and Look Rock, Tennessee

    Directory of Open Access Journals (Sweden)

    S. H. Budisulistiorini

    2016-04-01

    Full Text Available A year-long near-real-time characterization of non-refractory submicron aerosol (NR-PM1 was conducted at an urban (Atlanta, Georgia, in 2012 and rural (Look Rock, Tennessee, in 2013 site in the southeastern US using the Aerodyne Aerosol Chemical Speciation Monitor (ACSM collocated with established air-monitoring network measurements. Seasonal variations in organic aerosol (OA and inorganic aerosol species are attributed to meteorological conditions as well as anthropogenic and biogenic emissions in this region. The highest concentrations of NR-PM1 were observed during winter and fall seasons at the urban site and during spring and summer at the rural site. Across all seasons and at both sites, NR-PM1 was composed largely of OA (up to 76 % and sulfate (up to 31 %. Six distinct OA sources were resolved by positive matrix factorization applied to the ACSM organic mass spectral data collected from the two sites over the 1 year of near-continuous measurements at each site: hydrocarbon-like OA (HOA, biomass burning OA (BBOA, semi-volatile oxygenated OA (SV-OOA, low-volatility oxygenated OA (LV-OOA, isoprene-derived epoxydiols (IEPOX OA (IEPOX-OA and 91Fac (a factor dominated by a distinct ion at m∕z 91 fragment ion previously observed in biogenic influenced areas. LV-OOA was observed throughout the year at both sites and contributed up to 66 % of total OA mass. HOA was observed during the entire year only at the urban site (on average 21 % of OA mass. BBOA (15–33 % of OA mass was observed during winter and fall, likely dominated by local residential wood burning emission. Although SV-OOA contributes quite significantly ( ∼  27 %, it was observed only at the urban site during colder seasons. IEPOX-OA was a major component (27–41 % of OA at both sites, particularly in spring and summer. An ion fragment at m∕z 75 is well correlated with the m∕z 82 ion associated with the aerosol mass spectrum of IEPOX

  16. Optical properties and source analysis of aerosols over a desert area in Dunhuang, Northwest china

    Science.gov (United States)

    Ma, Yongjing; Xin, Jinyuan; Ma, Yining; Kong, Lingbin; Zhang, Kequan; Zhang, Wenyu; Wang, Yuesi; Wang, Xiuqin; Zhu, Yongfeng

    2017-08-01

    Aerosol observational data for 2012 obtained from Dunhuang Station of CARE-China (Campaign on Atmospheric Aerosol Research Network of China) were analyzed to achieve in-depth knowledge of aerosol optical properties over Dunhuang region. The results showed that the annual average aerosol optical depth (AOD) at 500 nm was 0.32±0.06, and the Ångström exponent ( α) was 0.73 ± 0.27. Aerosol optical properties revealed significant seasonal characteristics. Frequent sandstorms in MAM (March-April-May) resulted in the seasonal maximum AOD, 0.41 ± 0.04, and a relatively smaller α value, 0.44±0.04. The tourism seasons, JJA (June-July-August) and SON (September-October-November) coincide with serious emissions of small anthropogenic aerosols. While in DJF (December-January-February), the composition of the atmosphere was a mixture of dust particles and polluted aerosols released by domestic heating; the average AOD and α were 0.29 ± 0.02 and 0.66 ± 0.17, respectively. Different air masses exhibited different degrees of influence on the aerosol concentration over Dunhuang in different seasons. During MAM, ranges of AOD (0.11-1.18) and α (0.06-0.82) were the largest under the dust influence of northwest-short-distance air mass in the four trajectories. Urban aerosols transported by northwest-short-distance air mass accounted for a very large proportion in JJA and the mixed aerosols observed in SON were mainly conveyed by air masses from the west. In DJF, the similar ranges of AOD and α under the three air mass demonstrated the analogous diffusion effects on regional pollutants over Dunhuang.

  17. Characterization and source apportionment of organic aerosol at 260 m on a meteorological tower in Beijing, China

    Science.gov (United States)

    Zhou, Wei; Wang, Qingqing; Zhao, Xiujuan; Xu, Weiqi; Chen, Chen; Du, Wei; Zhao, Jian; Canonaco, Francesco; Prévôt, André S. H.; Fu, Pingqing; Wang, Zifa; Worsnop, Douglas R.; Sun, Yele

    2018-03-01

    Despite extensive efforts toward the characterization of submicron aerosols at ground level in the megacity of Beijing, our understanding of aerosol sources and processes at high altitudes remains low. Here we conducted a 3-month real-time measurement of non-refractory submicron aerosol (NR-PM1) species at a height of 260 m from 10 October 2014 to 18 January 2015 using an aerosol chemical speciation monitor. Our results showed a significant change in aerosol composition from the non-heating period (NHP) to the heating period (HP). Organics and chloride showed clear increases during HP due to coal combustion emissions, while nitrate showed substantial decreases from 28 to 15-18 %. We also found that NR-PM1 species in the heating season can have average mass differences of 30-44 % under similar emission sources yet different meteorological conditions. Multi-linear engine 2 (ME-2) using three primary organic aerosol (OA) factors as constraints, i.e., fossil-fuel-related OA (FFOA) dominantly from coal combustion emissions, cooking OA (COA), and biomass burning OA (BBOA) resolved from ground high-resolution aerosol mass spectrometer measurements, was applied to OA mass spectra of ACSM. Two types of secondary OA (SOA) that were well correlated with nitrate and chloride-CO, respectively, were identified. SOA played a dominant role in OA during all periods at 260 m although the contributions were decreased from 72 % during NHP to 58-64 % during HP. The SOA composition also changed significantly from NHP to HP. While the contribution of oxygenated OA (OOA) was decreased from 56-63 to 32-40 %, less oxidized OOA (LO-OOA) showed a large increase from 9-16 to 24-26 %. COA contributed a considerable fraction of OA at high altitude, and the contribution was relatively similar across different periods (10-13 %). In contrast, FFOA showed a large increase during HP due to the influences of coal combustion emissions. We also observed very different OA composition between ground level

  18. Distribution and Source Identification of Pb Contamination in industrial soil

    Science.gov (United States)

    Ko, M. S.

    2017-12-01

    INTRODUCTION Lead (Pb) is toxic element that induce neurotoxic effect to human, because competition of Pb and Ca in nerve system. Lead is classified as a chalophile element and galena (PbS) is the major mineral. Although the Pb is not an abundant element in nature, various anthropogenic source has been enhanced Pb enrichment in the environment after the Industrial Revolution. The representative anthropogenic sources are batteries, paint, mining, smelting, and combustion of fossil fuel. Isotope analysis widely used to identify the Pb contamination source. The Pb has four stable isotopes that are 208Pb, 207Pb, 206Pb, and 204Pb in natural. The Pb is stable isotope and the ratios maintain during physical and chemical fractionation. Therefore, variations of Pb isotope abundance and relative ratios could imply the certain Pb contamination source. In this study, distributions and isotope ratios of Pb in industrial soil were used to identify the Pb contamination source and dispersion pathways. MATERIALS AND METHODS Soil samples were collected at depth 0­-6 m from an industrial area in Korea. The collected soil samples were dried and sieved under 2 mm. Soil pH, aqua-regia digestion and TCLP carried out using sieved soil sample. The isotope analysis was carried out to determine the abundance of Pb isotope. RESULTS AND DISCUSSION The study area was developed land for promotion of industrial facilities. The study area was forest in 1980, and the satellite image show the alterations of land use with time. The variations of land use imply the possibilities of bringing in external contaminated soil. The Pb concentrations in core samples revealed higher in lower soil compare with top soil. Especially, 4 m soil sample show highest Pb concentrations that are approximately 1500 mg/kg. This result indicated that certain Pb source existed at 4 m depth. CONCLUSIONS This study investigated the distribution and source identification of Pb in industrial soil. The land use and Pb

  19. Observation of optical properties and sources of aerosols at Buddha's birthplace, Lumbini, Nepal: environmental implications.

    Science.gov (United States)

    Rupakheti, Dipesh; Kang, Shichang; Rupakheti, Maheswar; Cong, Zhiyuan; Tripathee, Lekhendra; Panday, Arnico K; Holben, Brent N

    2018-03-15

    For the first time, aerosol optical properties are measured over Lumbini, Nepal, with CIMEL sunphotometer of the Aerosol Robotic Network (AERONET) program. Lumbini is a sacred place as the birthplace of Lord Buddha, and thus a UNESCO world heritage site, located near the northern edge of the central Indo-Gangetic Plains (IGP) and before the Himalayan foothills (and Himalayas) to its north. Average aerosol optical depth (AOD) is found to be 0.64 ± 0.38 (0.06-3.28) over the sampling period (January 2013-December 2014), with the highest seasonal AOD during the post-monsoon season (0.72 ± 0.44). More than 80% of the daily averaged AOD values, during the monitoring period, are above 0.3, indicating polluted conditions in the region. The levels of aerosol load observed over Lumbini are comparable to those observed at several heavily polluted sites in the IGP. Based on the relationship between AOD and Ångstrom exponent (α), anthropogenic, biomass burning, and mixed aerosols are found to be the most prevalent aerosol types. The aerosol volume-size distribution is bi-modal during all four seasons with modes centered at 0.1-0.3 and 3-4 μm. For both fine and coarse modes, the highest volumetric concentration of ~ 0.08 μm -3  μm -2 is observed during the post-monsoon and pre-monsoon seasons. As revealed by the single-scattering albedo (SSA), asymmetry parameter (AP), and refractive index (RI) analyses, aerosol loading over Lumbini is dominated by absorbing, urban-industrial, and biomass burning aerosols.

  20. Advanced source apportionment of carbonaceous aerosols by coupling offline AMS and radiocarbon size-segregated measurements over a nearly 2-year period

    Science.gov (United States)

    Vlachou, Athanasia; Daellenbach, Kaspar R.; Bozzetti, Carlo; Chazeau, Benjamin; Salazar, Gary A.; Szidat, Soenke; Jaffrezo, Jean-Luc; Hueglin, Christoph; Baltensperger, Urs; El Haddad, Imad; Prévôt, André S. H.

    2018-05-01

    Carbonaceous aerosols are related to adverse human health effects. Therefore, identification of their sources and analysis of their chemical composition is important. The offline AMS (aerosol mass spectrometer) technique offers quantitative separation of organic aerosol (OA) factors which can be related to major OA sources, either primary or secondary. While primary OA can be more clearly separated into sources, secondary (SOA) source apportionment is more challenging because different sources - anthropogenic or natural, fossil or non-fossil - can yield similar highly oxygenated mass spectra. Radiocarbon measurements provide unequivocal separation between fossil and non-fossil sources of carbon. Here we coupled these two offline methods and analysed the OA and organic carbon (OC) of different size fractions (particulate matter below 10 and 2.5 µm - PM10 and PM2.5, respectively) from the Alpine valley of Magadino (Switzerland) during the years 2013 and 2014 (219 samples). The combination of the techniques gave further insight into the characteristics of secondary OC (SOC) which was rather based on the type of SOC precursor and not on the volatility or the oxidation state of OC, as typically considered. Out of the primary sources separated in this study, biomass burning OC was the dominant one in winter, with average concentrations of 5.36 ± 2.64 µg m-3 for PM10 and 3.83 ± 1.81 µg m-3 for PM2.5, indicating that wood combustion particles were predominantly generated in the fine mode. The additional information from the size-segregated measurements revealed a primary sulfur-containing factor, mainly fossil, detected in the coarse size fraction and related to non-exhaust traffic emissions with a yearly average PM10 (PM2.5) concentration of 0.20 ± 0.24 µg m-3 (0.05 ± 0.04 µg m-3). A primary biological OC (PBOC) was also detected in the coarse mode peaking in spring and summer with a yearly average PM10 (PM2.5) concentration of 0.79 ± 0.31 µg m-3 (0.24 ± 0

  1. The online measured black carbon aerosol and source orientations in the Nam Co region, Tibet.

    Science.gov (United States)

    Zhang, Xin; Ming, Jing; Li, Zhongqin; Wang, Feiteng; Zhang, Guoshuai

    2017-11-01

    Equivalent black carbon (eBC) mass concentrations were measured by an aethalometer (AE-31) in the Nam Co, central Tibet from 2010 to 2014. Different from previous filter-sampling studies (Ming et al., J Environ Sci 22(11):1748-1756, 2010; Zhao et al., Environ Sci Pollut Res 20:5827-5838, 2013), the first high-resolution online eBC measurement conducted in central Tibet is reported here, allowing to discuss the diurnal variations as well as seasonal variabilities of eBC. Average daily eBC concentration was 74 ± 50 ng/m 3 , reflecting a global background level. Meteorological conditions influenced eBC concentrations largely at seasonal scale, which are higher in February-May but lower in June-January. The highest eBC concentrations (greater than 210 ng/m 3 ) were more associated with the W and WSW winds smaller than 6 m/s. The diurnal variations of eBC showed plateaus from 10:00 to 15:00 with seasonal variations, associated with local anthropogenic activities, such as indigenous Tibetan burning animal waste and tourism traffic. The PBLHs showed a co-variance with eBC concentrations, implicating close sources. The aerosol optical depths derived from the MODIS data over the Nam Co Observatory Station (NCOS)-included sub-area (30° N-40° N, 90° E-100° E) showed significant relationship with eBC concentrations. This suggests that nearby or short-distance sources other than long-distance transported pollutants could be important contributors to eBC concentrations at the NCOS, different from the conclusions suggested by previous studies.

  2. Aqueous Oxidation of Green Leaf Volatiles as a Source of Secondary Organic Aerosol

    Science.gov (United States)

    Richards-Henderson, N. K.; Hansel, A.; Pham, A. T.; Vempati, H. S.; Valsaraj, K. T.; Anastasio, C.

    2013-12-01

    Vegetation emits volatile oxygenated hydrocarbons - the green leaf volatiles (GLVs) - which are formed from the biochemical conversion of linoleic and linolenic acids within plant cells. Stress or damage to vegetation can significantly elevate emission fluxes of these compounds, some of which are fairly water soluble. Aqueous-phase reactions of the GLVs with photochemically generated oxidants - such as hydroxyl radical (OH), singlet oxygen (1O2) and excited triplet states of organic compounds (3C*) _ might then form low-volatility products that can act as secondary organic aerosol (SOA). In order to determine if GLVs can be a significant source of secondary organic carbon in fogwater, studies of GLVs in laboratory solutions are needed to elucidate the oxidation kinetics and the corresponding SOA mass yields. In this study we are determining the second-order rate constants, and SOA mass yields, for five GLVs (cis-3-hexen-1-ol, cis-3-hexenylacetate, methyl salicylate, methyl jasmonate, and 2-methyl-3-butene-2-ol) reacting with OH,1O2 and 3C*. Experiments are performed at relevant fog water pHs, temperatures, and oxidant concentrations. Rate constants are determined using a relative rate approach in which the decay of GLVs and reference compounds are monitored as function of time by HPLC. The capacity of GLVs to form aqueous SOA was determined by following the formation of their decomposition products with HPLC-UV/DAD and HPLC-ESI/MS. SOA mass yields are measured gravimetrically from laboratory solutions containing atmospherically relevant concentrations of photooxidants and GLVs, and irradiated with simulated sunlight. We will use our results to assess the potential contribution of aqueous GLV reactions as a source of SOA in cloudy or foggy atmospheres.

  3. Black Carbon and Sulfate Aerosols in the Arctic: Long-term Trends, Radiative Impacts, and Source Attributions

    Science.gov (United States)

    Wang, H.; Zhang, R.; Yang, Y.; Smith, S.; Rasch, P. J.

    2017-12-01

    The Arctic has warmed dramatically in recent decades. As one of the important short-lived climate forcers, aerosols affect the Arctic radiative budget directly by interfering radiation and indirectly by modifying clouds. Light-absorbing particles (e.g., black carbon) in snow/ice can reduce the surface albedo. The direct radiative impact of aerosols on the Arctic climate can be either warming or cooling, depending on their composition and location, which can further alter the poleward heat transport. Anthropogenic emissions, especially, BC and SO2, have changed drastically in low/mid-latitude source regions in the past few decades. Arctic surface observations at some locations show that BC and sulfate aerosols had a decreasing trend in the recent decades. In order to understand the impact of long-term emission changes on aerosols and their radiative effects, we use the Community Earth System Model (CESM) equipped with an explicit BC and sulfur source-tagging technique to quantify the source-receptor relationships and decadal trends of Arctic sulfate and BC and to identify variations in their atmospheric transport pathways from lower latitudes. The simulation was conducted for 36 years (1979-2014) with prescribed sea surface temperatures and sea ice concentrations. To minimize potential biases in modeled large-scale circulations, wind fields in the simulation are nudged toward an atmospheric reanalysis dataset, while atmospheric constituents including water vapor, clouds, and aerosols are allowed to evolve according to the model physics. Both anthropogenic and open fire emissions came from the newly released CMIP6 datasets, which show strong regional trends in BC and SO2 emissions during the simulation time period. Results show that emissions from East Asia and South Asia together have the largest contributions to Arctic sulfate and BC concentrations in the upper troposphere, which have an increasing trend. The strong decrease in emissions from Europe, Russia and

  4. Aerosol composition and source apportionment in the Mexico City Metropolitan Area with PIXE/PESA/STIM and multivariate analysis

    OpenAIRE

    K. S. Johnson; B. de Foy; B. de Foy; B. Zuberi; B. Zuberi; L. T. Molina; L. T. Molina; M. J. Molina; M. J. Molina; Y. Xie; A. Laskin; V. Shutthanandan

    2006-01-01

    Aerosols play an important role in the atmosphere but are poorly characterized, particularly in urban areas like the Mexico City Metropolitan Area (MCMA). The chemical composition of urban particles must be known to assess their effects on the environment, and specific particulate emissions sources should be identified to establish effective pollution control standards. For these reasons, samples of particulate matter ≤2.5 μm (PM2.5) were collected during the MCMA-2003 Field Campaign f...

  5. Aerosol composition and source apportionment in the Mexico City Metropolitan Area with PIXE/PESA/STIM and multivariate analysis

    OpenAIRE

    Johnson , K. S.; De Foy , B.; Zuberi , B.; Molina , L. T.; Molina , M. J.; Xie , Y.; Laskin , A.; Shutthanandan , V.

    2006-01-01

    Aerosols play an important role in the atmosphere but are poorly characterized, particularly in urban areas like the Mexico City Metropolitan Area (MCMA). The chemical composition of urban particles must be known to assess their effects on the environment, and specific particulate emissions sources should be identified to establish effective pollution control standards. For these reasons, samples of particulate matter ≤2.5 μm (PM2.5) were collected dur...

  6. Religious Burning as a Major Source of Atmospheric Fine Aerosols in Lhasa city in the Tibetan Plateau

    Science.gov (United States)

    Liu, S.; Cui, Y.; Zhixuan, B.; Bian, J.; McKeen, S. A.; Watts, L. A.; Ciciora, S. J.; Gao, R. S.

    2017-12-01

    Measurements of aerosols in the Tibetan Plateau are scant due to the high altitude and harsh climate. To bridge this gap, we carried out the first field measurements of aerosol size distributions in Lhasa, a major city in the Tibetan Plateau that has been experiencing fast urbanization and reduced air quality. Aerosol number size distribution was continuously measured using an optical particle size spectrometer near the center of Lhasa city during the Asian summer monsoon season in 2016. The mass concentration of fine particles was modulated by boundary layer dynamics, with an average of 11 µg m-3 and the high values exceeding 50 µg m-3 during religious holidays. Daytime high concentration coincided with the religious burning of biomass and incense in the temples during morning hours, which produced heavy smoke. Factor analysis revealed a factor that is likely induced by religious burning. The factor contributed 34% of the campaign-average fine particle mass and the contribution reached up to 80% during religious holidays. The mass size distribution of aerosols produced from religious burnings peaked at 500 nm, indicating that these particles could efficiently decrease visibility and promote health risk. Because of its significance, our results suggest that more attention should be paid to religious burning, a currently under-studied source, in the Tibetan Plateau and in other regions of the world where religious burnings are frequently practiced.

  7. Global modelling of direct and indirect effects of sea spray aerosol using a source function encapsulating wave state

    Directory of Open Access Journals (Sweden)

    A.-I. Partanen

    2014-11-01

    Full Text Available Recently developed parameterizations for the sea spray aerosol source flux, encapsulating wave state, and its organic fraction were incorporated into the aerosol–climate model ECHAM-HAMMOZ to investigate the direct and indirect radiative effects of sea spray aerosol particles. Our simulated global sea salt emission of 805 Tg yr−1 (uncertainty range 378–1233 Tg yr−1 was much lower than typically found in previous studies. Modelled sea salt and sodium ion concentrations agreed relatively well with measurements in the smaller size ranges at Mace Head (annual normalized mean model bias −13% for particles with vacuum aerodynamic diameter Dva Da Da Da −2, in contrast to previous studies. This positive effect was ascribed to the tendency of sea salt aerosol to suppress both the in-cloud supersaturation and the formation of cloud condensation nuclei from sulfate. These effects can be accounted for only in models with sufficiently detailed aerosol microphysics and physics-based parameterizations of cloud activation. However, due to a strong negative direct effect, the simulated effective radiative forcing (total radiative effect was −0.2 W m−2. The simulated radiative effects of the primary marine organic emissions were small, with a direct effect of 0.03 W m−2 and an indirect effect of −0.07 W m−2.

  8. Decentralized modal identification using sparse blind source separation

    International Nuclear Information System (INIS)

    Sadhu, A; Hazra, B; Narasimhan, S; Pandey, M D

    2011-01-01

    Popular ambient vibration-based system identification methods process information collected from a dense array of sensors centrally to yield the modal properties. In such methods, the need for a centralized processing unit capable of satisfying large memory and processing demands is unavoidable. With the advent of wireless smart sensor networks, it is now possible to process information locally at the sensor level, instead. The information at the individual sensor level can then be concatenated to obtain the global structure characteristics. A novel decentralized algorithm based on wavelet transforms to infer global structure mode information using measurements obtained using a small group of sensors at a time is proposed in this paper. The focus of the paper is on algorithmic development, while the actual hardware and software implementation is not pursued here. The problem of identification is cast within the framework of under-determined blind source separation invoking transformations of measurements to the time–frequency domain resulting in a sparse representation. The partial mode shape coefficients so identified are then combined to yield complete modal information. The transformations are undertaken using stationary wavelet packet transform (SWPT), yielding a sparse representation in the wavelet domain. Principal component analysis (PCA) is then performed on the resulting wavelet coefficients, yielding the partial mixing matrix coefficients from a few measurement channels at a time. This process is repeated using measurements obtained from multiple sensor groups, and the results so obtained from each group are concatenated to obtain the global modal characteristics of the structure

  9. Decentralized modal identification using sparse blind source separation

    Science.gov (United States)

    Sadhu, A.; Hazra, B.; Narasimhan, S.; Pandey, M. D.

    2011-12-01

    Popular ambient vibration-based system identification methods process information collected from a dense array of sensors centrally to yield the modal properties. In such methods, the need for a centralized processing unit capable of satisfying large memory and processing demands is unavoidable. With the advent of wireless smart sensor networks, it is now possible to process information locally at the sensor level, instead. The information at the individual sensor level can then be concatenated to obtain the global structure characteristics. A novel decentralized algorithm based on wavelet transforms to infer global structure mode information using measurements obtained using a small group of sensors at a time is proposed in this paper. The focus of the paper is on algorithmic development, while the actual hardware and software implementation is not pursued here. The problem of identification is cast within the framework of under-determined blind source separation invoking transformations of measurements to the time-frequency domain resulting in a sparse representation. The partial mode shape coefficients so identified are then combined to yield complete modal information. The transformations are undertaken using stationary wavelet packet transform (SWPT), yielding a sparse representation in the wavelet domain. Principal component analysis (PCA) is then performed on the resulting wavelet coefficients, yielding the partial mixing matrix coefficients from a few measurement channels at a time. This process is repeated using measurements obtained from multiple sensor groups, and the results so obtained from each group are concatenated to obtain the global modal characteristics of the structure.

  10. Evaluating the impact of improvements to the FLAMBE smoke source model on forecasts of aerosol distribution from NAAPS

    Science.gov (United States)

    Hyer, E. J.; Reid, J. S.

    2006-12-01

    As more forecast models aim to include aerosol and chemical species, there is a need for source functions for biomass burning emissions that are accurate, robust, and operable in real-time. NAAPS is a global aerosol forecast model running every six hours and forecasting distributions of biomass burning, industrial sulfate, dust, and sea salt aerosols. This model is run operationally by the U.S. Navy as an aid to planning. The smoke emissions used as input to the model are calculated from the data collected by the FLAMBE system, driven by near-real-time active fire data from GOES WF_ABBA and MODIS Rapid Response. The smoke source function uses land cover data to predict properties of detected fires based on literature data from experimental burns. This scheme is very sensitive to the choice of land cover data sets. In areas of rapid land cover change, the use of static land cover data can produce artifactual changes in emissions unrelated to real changes in fire patterns. In South America, this change may be as large as 40% over five years. We demonstrate the impact of a modified land cover scheme on FLAMBE emissions and NAAPS forecasts, including a fire size algorithm developed using MODIS burned area data. We also describe the effects of corrections to emissions estimates for cloud and satellite coverage. We outline areas where existing data sources are incomplete and improvements are required to achieve accurate modeling of biomass burning emissions in real time.

  11. Comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry in the identification of organic compounds in atmospheric aerosols from coniferous forest

    NARCIS (Netherlands)

    Kallio, M.; Jussila, M.; Rissanen, T.; Anttila, P.; Hartonen, K.; Reissell, A.; Vreuls, R.J.J.; Adahchour, M.; Hyotylainen, T.

    2006-01-01

    Comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry (GC × GC-TOF-MS) was applied in the identification of organic compounds in atmospheric aerosols from coniferous forest. The samples were collected at Hyytiälä, Finland, as part of the QUEST campaign, in

  12. Enhanced UV Absorption in Carbonaceous Aerosols during MILAGRO and Identification of Potential Organic Contributors.

    Science.gov (United States)

    Mangu, A.; Kelley, K. L.; Marchany-Rivera, A.; Kilaparty, S.; Gunawan, G.; Gaffney, J. S.; Marley, N. A.

    2007-12-01

    Measurements of aerosol absorption were obtained as part of the MAX-Mex component of the MILAGRO field campaign at site T0 (Instituto Mexicano de Petroleo in Mexico City) during the month of March, 2006 by using a 7- channel aethalometer (Thermo-Anderson). These measurements, obtained at 370, 470, 520, 590, 660, 880, and 950 nm at a 5 minute time resolution, showed an enhanced absorption in the UV over that expected from carbon soot alone. Samples of fine atmospheric aerosols (less than 0.1micron) were also collected at site T0 and T1 (Universidad Technologica de Tecamac, State of Mexico) from 5 am to 5 pm (day) and from 5 pm to 5 am (night) during the month of March 2006. The samples were collected on quartz fiber filters with high volume impactor samplers. The samples have been characterized for total carbon content (stable isotope ratio mass spectroscopy) and natural radionuclide tracers (210Pb, 210Po, 210Bi, 7Be, 13C, 14C, 40K, 15N). Continuous absorption spectra of these aerosol samples have been obtained in the laboratory from 280 to 900nm with the use of an integrating sphere coupled to a UV-visible spectrometer (Beckman DU with a Labsphere accessory). The integrating sphere allows the detector to collect and spatially integrate the total radiant flux reflected from the sample and therefore allows for the measurement of absorption on highly reflective or diffusely scattering samples (1). The continuous spectra also show an enhanced UV absorption over that expected from carbon soot and the general profiles are quite similar to those observed for humic and fulvic acids found as colloidal materials in surface and groundwaters (2), indicating the presence of humic-like substances (HULIS) in the fine aerosols. The spectra also show evidence of narrow band absorbers below 400 nm typical of polycyclic aromatics (PAH) and nitrated aromatic compounds. Spectra were also obtained on NIST standard diesel soot (SRM 2975), NIST standard air particulate matter (SRM 8785

  13. Submicron aerosol source apportionment of wintertime pollution in Paris, France by double positive matrix factorization (PMF2) using an aerosol chemical speciation monitor (ACSM) and a multi-wavelength Aethalometer

    International Nuclear Information System (INIS)

    Petit, J.E.; Favez, O.; Leoz-Garziandia, E.; Sciare, J.

    2014-01-01

    Online non-refractory submicron aerosol mass spectrometer (AMS) measurements in urban areas have successfully allowed the apportionment of specific sources and/or physical and chemical properties of the organic fraction. However, in order to be fully representative of PM pollution, a comprehensive source apportionment analysis is needed by taking into account all major components of submicron aerosols, creating strengthened bonds between the organic components and pollution sources. We present here a novel two-step methodology to perform such an analysis, by taking advantage of high time resolution of monitoring instruments: the aerosol chemical speciation monitor (ACSM) and the multi-wavelength absorption measurements (Aethalometer AE31) in Paris, France. As a first step, organic aerosols (OA) were de-convolved to hydrocarbon-like OA (HOA), biomass burning OA (BBOA) and oxygenated OA (OOA) with positive matrix factorization (PMF), and black carbon was de-convolved into its wood burning and fossil fuel combustion fractions. A second PMF analysis was then carried out with organic factors, BC fractions and inorganic species (nitrate, sulfate, ammonium, chloride), leading to a four-factor solution allowing highly time-resolved characterization of the major sources of PM1. Outputs of this PMF2 include two dominant combustion sources (wood burning and traffic) as well as semi-volatile and low-volatile secondary aerosols. While HOA is found to be emitted by both wood burning and traffic, the latter sources occurred to significantly contribute also to OOA. (authors)

  14. Stratospheric aerosols

    International Nuclear Information System (INIS)

    Rosen, J.; Ivanov, V.A.

    1993-01-01

    Stratospheric aerosol measurements can provide both spatial and temporal data of sufficient resolution to be of use in climate models. Relatively recent results from a wide range of instrument techniques for measuring stratospheric aerosol parameters are described. Such techniques include impactor sampling, lidar system sensing, filter sampling, photoelectric particle counting, satellite extinction-sensing using the sun as a source, and optical depth probing, at sites mainly removed from tropospheric aerosol sources. Some of these techniques have also had correlative and intercomparison studies. The main methods for determining the vertical profiles of stratospheric aerosols are outlined: lidar extinction measurements from satellites; impactor measurements from balloons and aircraft; and photoelectric particle counter measurements from balloons, aircraft, and rockets. The conversion of the lidar backscatter to stratospheric aerosol mass loading is referred to. Absolute measurements of total solar extinction from satellite orbits can be used to extract the aerosol extinction, and several examples of vertical profiles of extinction obtained with the SAGE satellite are given. Stratospheric mass loading can be inferred from extinction using approximate linear relationships but under restrictive conditions. Impactor sampling is essentially the only method in which the physical nature of the stratospheric aerosol is observed visually. Vertical profiles of stratospheric aerosol number concentration using impactor data are presented. Typical profiles using a dual-size-range photoelectric dustsonde particle counter are given for volcanically disturbed and inactive periods. Some measurements of the global distribution of stratospheric aerosols are also presented. Volatility measurements are described, indicating that stratospheric aerosols are composed primarily of about 75% sulfuric acid and 25% water

  15. Sources of PM2.5 carbonaceous aerosol in Riyadh, Saudi Arabia

    Directory of Open Access Journals (Sweden)

    Q. Bian

    2018-03-01

    Full Text Available Knowledge of the sources of carbonaceous aerosol affecting air quality in Riyadh, Saudi Arabia, is limited but needed for the development of pollution control strategies. We conducted sampling of PM2.5 from April to September 2012 at various sites in the city and used a thermo-optical semi-continuous method to quantify the organic carbon (OC and elemental carbon (EC concentrations. The average OC and EC concentrations were 4.7 ± 4.4 and 2.1 ± 2.5 µg m−3, respectively, during this period. Both OC and EC concentrations had strong diurnal variations, with peaks at 06:00–08:00 LT and 20:00–22:00 LT, attributed to the combined effect of increased vehicle emissions during rush hour and the shallow boundary layer in the early morning and at night. This finding suggested a significant influence of local vehicular emissions on OC and EC. The OC ∕ EC ratio in primary emissions was estimated to be 1.01, close to documented values for diesel emissions. Estimated primary organic carbon (POC and secondary organic carbon (SOC concentrations were comparable, with average concentrations of 2.0 ± 2.4 and 2.8 ± 3.4 µg m−3, respectively.We also collected 24 h samples of PM10 onto quartz microfiber filters and analyzed these for an array of metals by inductively coupled plasma atomic emission spectroscopy (ICP-AES. Total OC was correlated with Ca (R2 of 0.63, suggesting that OC precursors and Ca may have similar sources, and the possibility that they underwent similar atmospheric processing. In addition to a ubiquitous dust source, Ca is emitted during desalting processes in the numerous refineries in the region and from cement kilns, suggesting these sources may also contribute to observed OC concentrations in Riyadh. Concentration weighted trajectory (CWT analysis showed that high OC and EC concentrations were associated with air masses arriving from the Persian Gulf and the region around Baghdad, locations with

  16. Characterization and sources assignation of PM2.5 organic aerosol in a rural area of Spain

    Science.gov (United States)

    Pindado, Oscar; Pérez, Rosa M. a.; García, Susana; Sánchez, Miguel; Galán, Pilar; Fernández, Marta

    The results from a year-long study of the organic composition of PM2.5 aerosol collected in a rural area influenced by a highway of Spain are reported. The lack of prior information related to the organic composition of PM2.5 aerosol in Spain, concretely in rural areas, led definition of the goals of this study. As a result, this work has been able to characterize the main organic components of atmospheric aerosols, including several compounds of SOA, and has conducted a multivariate analysis in order to assign sources of particulate matter. A total of 89 samples were taken between April 2004 and April 2005 using a high-volume sampler. Features and abundance of n-alkanes, polycyclic aromatic hydrocarbons (PAHs), alcohols and acids were separately determined using gas chromatography/mass spectrometry and high performance liquid chromatography analysis. The Σ n-alkane and ΣPAHs ranged from 3 to 81 ng m -3 and 0.1 to 6 ng m -3 respectively, with higher concentrations during colder months. Ambient concentrations of Σalcohols and Σacids ranged from 21 to 184 ng m -3 and 39 to 733 ng m -3, respectively. Also, several components of secondary organic aerosol have been quantified, confirming the biogenic contribution to ambient aerosol. In addition, factor analysis was used to reveal origin of organic compounds associated to particulate matter. Eight factors were extracted accounting more than 83% of the variability in the original data. These factors were assigned to a typical high pollution episode by anthropogenic particles, crustal material, plant waxes, fossil fuel combustion, temperature, microbiological emissions, SOA and dispersion of pollutants by wind action. Finally, a cluster analysis was used to compare the organic composition between the four seasons.

  17. Influences of emission sources and meteorology on aerosol chemistry in a polluted urban environment: results from DISCOVER-AQ California

    Directory of Open Access Journals (Sweden)

    D. E. Young

    2016-05-01

    Full Text Available The San Joaquin Valley (SJV in California experiences persistent air-quality problems associated with elevated particulate matter (PM concentrations due to anthropogenic emissions, topography, and meteorological conditions. Thus it is important to unravel the various sources and processes that affect the physicochemical properties of PM in order to better inform pollution abatement strategies and improve parameterizations in air-quality models. During January and February 2013, a ground supersite was installed at the Fresno–Garland California Air Resources Board (CARB monitoring station, where comprehensive, real-time measurements of PM and trace gases were performed using instruments including an Aerodyne high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS and an Ionicon proton transfer reaction time-of-flight mass spectrometer (PTR-TOF-MS as part of the NASA Deriving Information on Surface Conditions from Column and Vertically Resolved Observations Relevant to Air Quality (DISCOVER-AQ campaign. The average submicron aerosol (PM1 concentration was 31.0 µg m−3 and the total mass was dominated by organic aerosols (OA, 55 %, followed by ammonium nitrate (35 %. High PM pollution events were commonly associated with elevated OA concentrations, mostly from primary sources. Organic aerosols had average atomic oxygen-to-carbon (O / C, hydrogen-to-carbon (H / C, and nitrogen-to-carbon (N / C ratios of 0.42, 1.70, and 0.017, respectively. Six distinct sources of organic aerosol were identified from positive matrix factorization (PMF analysis of the AMS data: hydrocarbon-like OA (HOA; 9 % of total OA, O / C  =  0.09 associated with local traffic, cooking OA (COA; 18 % of total OA, O / C  =  0.19 associated with food cooking activities, two biomass burning OA (BBOA1: 13 % of total OA, O / C  =  0.33; BBOA2: 20 % of total OA, O / C  =  0.60 most likely

  18. Variation in Microbial Identification System Accuracy for Yeast Identification Depending on Commercial Source of Sabouraud Dextrose Agar

    OpenAIRE

    Kellogg, James A.; Bankert, David A.; Chaturvedi, Vishnu

    1999-01-01

    The accuracy of the Microbial Identification System (MIS; MIDI, Inc.) for identification of yeasts to the species level was compared by using 438 isolates grown on prepoured BBL Sabouraud dextrose agar (SDA) and prepoured Remel SDA. Correct identification was observed for 326 (74%) of the yeasts cultured on BBL SDA versus only 214 (49%) of yeasts grown on Remel SDA (P < 0.001). The commercial source of the SDA used in the MIS procedure significantly influences the system’s accuracy.

  19. Variation in Microbial Identification System accuracy for yeast identification depending on commercial source of Sabouraud dextrose agar.

    Science.gov (United States)

    Kellogg, J A; Bankert, D A; Chaturvedi, V

    1999-06-01

    The accuracy of the Microbial Identification System (MIS; MIDI, Inc. ) for identification of yeasts to the species level was compared by using 438 isolates grown on prepoured BBL Sabouraud dextrose agar (SDA) and prepoured Remel SDA. Correct identification was observed for 326 (74%) of the yeasts cultured on BBL SDA versus only 214 (49%) of yeasts grown on Remel SDA (P < 0.001). The commercial source of the SDA used in the MIS procedure significantly influences the system's accuracy.

  20. [Research on source profile of aerosol organic compounds in leather plant].

    Science.gov (United States)

    Wang, Bo-Guang; Zhou, Yan; Feng, Zhi-Cheng; Liu, Hui-Xuan

    2009-04-15

    Through investigating current air pollution condition for PM10 in every factories of different style leather plants in Pearl River Delta, characteristic profile of semi-volatile organic compounds in PM10 emitted from leather factories and their contents were researched by using ultrasonic and gas chromatography and mass spectrum technology. The 6 types of organic compounds containing 46 species in total were found in the collected samples, including phenyl compounds, alcohols, PAHs, acids, esters and amides. The concentrations of PM10 in leather tanning plant, leather dying plant and man-made leather plant were 678.5, 454.5, 498.6 microgm x m(-3) respectively, and concentration of organic compounds in PM10 were 10.04, 6.89, 14.21 microg x m(-3) in sequence. The more important type of pollutants in each leather plants had higher contribution to total organic mass as follows, esters and amides in tanning plants profile account for 43.47% and 36.51% respectively; esters and alcohols in dying plants profiles account for 52.52% and 16.16% respectively; esters and amide in man-made leather plant have the highest content and account for 57.07% and 24.17% respectively. In the aerosol organic source profiles of tested leather plants, 9-octadecenamide was the abundant important species with the weight of 26.15% in tanning plant, and Bis(2-ethylhexyl) phthalate was up to 44.19% in the dying plant, and Bis(2-ethylhexyl) maleate and 1-hydroxy-piperidine had obviously higher weight in man-made plant than the other two plants.

  1. Sources and Characterization of Submicron Aerosols in a Rural Forest During the PROPHET-AMOS 2016 Campaign

    Science.gov (United States)

    Bui, A. T.; Wallace, H. W., IV; Alvarez, S. L.; Erickson, M.; Alwe, H. D.; May, N.; Cook, R.; Connor, M.; Slade, J. H., Jr.; Shi, Q.; Kavassalis, S.; Tyndall, G. S.; Shepson, P. B.; Pratt, K.; Ault, A. P.; Millet, D. B.; Murphy, J. G.; Usenko, S.; Sheesley, R. J.; Flynn, J. H., III; Griffin, R. J.; Wang, W.

    2017-12-01

    Forests are a rich source of biogenic volatile organic compounds (BVOCs). Oxidation of BVOCs can result in the formation of secondary organic aerosol (SOA) and in the presence of NOx (NO+NO2) produce organic nitrate-containing particles. However, the distribution of both BVOCs and oxidants can be dramatically altered by the physical barriers provided by a forest canopy. Global models currently neglect the effect of these canopies on SOA formation in forested regions. In this work, we characterize non-refractory submicron aerosol (NR-PM1) using a high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) during the 2016 Program on Oxidants: Photochemistry, Emissions, and Transport-Atmospheric Measurements of Oxidants in Summer (PROPHET-AMOS) campaign. This site is located in a rural forest in northern Michigan and features a tower that allowed for both above and below canopy measurements. Our results indicate that organic aerosols (OA) account for a substantial portion of the NR-PM1 measured at this site. Organic nitrate aerosol can contribute up to 18% of the total OA and an average of 75% of the total measured nitrate aerosol. Episodes of above- and below-canopy NR-PM1 concentration differences indicate that above-canopy OA concentrations can be up to 40% greater than below-canopy, which represents an increase of up to 1.5 µg/m3. Organic fragment ions such as CxHy, CxHyOz, and CxHyO1 contribute to enhanced above-canopy OA concentrations. Positive matrix factorization analysis of the high-resolution OA mass spectra identified three SOA factors: low volatility oxygenated OA (LVOOA), isoprene-derived OOA (ISOOA), and oxygenated organic aerosol. Analysis of air mass backward trajectories and correlations with external data indicate that LVOOA correlates well with sulfate and aged, urban-influenced air masses, whereas ISOOA correlates well with isoprene SOA tracers and air masses originating from semi-remote areas. Our results indicate that the OA at this

  2. Evaluation of New and Proposed Organic Aerosol Sources and Mechanisms using the Aerosol Modeling Testbed. MILAGRO, CARES, CalNex, BEACHON, and GVAX

    Energy Technology Data Exchange (ETDEWEB)

    Hodzic, Alma [National Center for Atmospheric Research (NCAR), Boulder, CO (United States); Jimenez, Jose L. [Univ. of Colorado, Boulder, CO (United States)

    2015-04-09

    This work investigated the formation and evolution of organic aerosols (OA) arising from anthropogenic and biogenic sources in a framework that combined state-of-the-science process and regional modeling, and their evaluation against advanced and emerging field measurements. Although OA are the dominant constituents of submicron particles, our understanding of their atmospheric lifecycle is limited, and current models fail to describe the observed amounts and properties of chemically formed secondary organic aerosols (SOA), leaving large uncertainties on the effects of SOA on climate. Our work has provided novel modeling constraints on sources, formation, aging and removal of SOA by investigating in particular (i) the contribution of trash burning emissions to OA levels in a megacity, (ii) the contribution of glyoxal to SOA formation in aqueous particles in California during CARES/CalNex and over the continental U.S., (iii) SOA formation and regional growth over a pine forest in Colorado and its sensitivity to anthropogenic NOx levels during BEACHON, and the sensitivity of SOA to (iv) the sunlight exposure during its atmospheric lifetime, and to (v) changes in solubility and removal of organic vapors in the urban plume (MILAGRO, Mexico City), and over the continental U.S.. We have also developed a parameterization of water solubility for condensable organic gases produced from major anthropogenic and biogenic precursors based on explicit chemical modeling, and made it available to the wider community. This work used for the first time constraints from the explicit model GECKO-A to improve SOA representation in 3D regional models such as WRF-Chem.

  3. Improved source apportionment of organic aerosols in complex urban air pollution using the multilinear engine (ME-2)

    Science.gov (United States)

    Zhu, Qiao; Huang, Xiao-Feng; Cao, Li-Ming; Wei, Lin-Tong; Zhang, Bin; He, Ling-Yan; Elser, Miriam; Canonaco, Francesco; Slowik, Jay G.; Bozzetti, Carlo; El-Haddad, Imad; Prévôt, André S. H.

    2018-02-01

    Organic aerosols (OAs), which consist of thousands of complex compounds emitted from various sources, constitute one of the major components of fine particulate matter. The traditional positive matrix factorization (PMF) method often apportions aerosol mass spectrometer (AMS) organic datasets into less meaningful or mixed factors, especially in complex urban cases. In this study, an improved source apportionment method using a bilinear model of the multilinear engine (ME-2) was applied to OAs collected during the heavily polluted season from two Chinese megacities located in the north and south with an Aerodyne high-resolution aerosol mass spectrometer (HR-ToF-AMS). We applied a rather novel procedure for utilization of prior information and selecting optimal solutions, which does not necessarily depend on other studies. Ultimately, six reasonable factors were clearly resolved and quantified for both sites by constraining one or more factors: hydrocarbon-like OA (HOA), cooking-related OA (COA), biomass burning OA (BBOA), coal combustion (CCOA), less-oxidized oxygenated OA (LO-OOA) and more-oxidized oxygenated OA (MO-OOA). In comparison, the traditional PMF method could not effectively resolve the appropriate factors, e.g., BBOA and CCOA, in the solutions. Moreover, coal combustion and traffic emissions were determined to be primarily responsible for the concentrations of PAHs and BC, respectively, through the regression analyses of the ME-2 results.

  4. Insights on nitrate sources at Dome C (East Antarctic Plateau from multi-year aerosol and snow records

    Directory of Open Access Journals (Sweden)

    Rita Traversi

    2014-06-01

    Full Text Available Here we present the first multi-year record of nitrate in the atmospheric aerosol (2005–2008 and surface snow (2006–08 from central Antarctica. PM10 and size-segregated aerosol, together with superficial snow, have been collected all year-round at high resolution (daily for all the snow samples and for most of aerosol samples at Dome C since the 2004/05 field season and analysed for main and trace ionic markers. The suitability of the sampling location in terms of possible contamination from the base is shown in detail. In spite of the relevance of nitrate in Antarctic atmosphere, both for better understanding the chemistry of N cycle in the plateau boundary layer and for improving the interpretation of long-term nitrate records from deep ice core records, nitrate sources in Antarctica are not well constrained yet, neither in extent nor in timing. A recurring seasonal pattern was pointed out in both aerosol and snow records, showing summer maxima and winter minima, although aerosol maxima lead the snow ones of 1–2 months, possibly due to a higher acidity in the atmosphere in mid-summer, favouring the repartition of nitrate as nitric acid and thus its uptake by the surface snow layers. On the basis of a meteorological analysis of one major nitrate event, of data related to PSC I extent and of irradiance values, we propose that the high nitrate summer levels in aerosol and snow are likely due to a synergy of enhanced source of nitrate and/or its precursors (such as the stratospheric inputs, higher solar irradiance and higher oxidation rates in this season. Moreover, we show here a further evidence of the substantial contribution of HNO3/NOx re-emission from the snowpack, already shown in previous works, and which can explain a significant fraction of atmospheric nitrate, maintaining the same seasonal pattern in the snow. As concerning snow specifically, the presented data suggest that nitrate is likely to be controlled mainly by atmospheric

  5. Characterization of the sources and processes of organic and inorganic aerosols in New York city with a high-resolution time-of-flight aerosol mass apectrometer

    Directory of Open Access Journals (Sweden)

    Y.-L. Sun

    2011-02-01

    Full Text Available Submicron aerosol particles (PM1 were measured in-situ using a High-Resolution Time-of-Flight Aerosol Mass Spectrometer during the summer 2009 Field Intensive Study at Queens College in New York, NY. Organic aerosol (OA and sulfate are the two dominant species, accounting for 54% and 24%, respectively, of the total PM1 mass. The average mass-based size distribution of OA presents a small mode peaking at ~150 nm (Dva and an accumulation mode (~550 nm that is internally mixed with sulfate, nitrate, and ammonium. The diurnal cycles of both sulfate and OA peak between 01:00–02:00 p.m. EST due to photochemical production. The average (±σ oxygen-to-carbon (O/C, hydrogen-to-carbon (H/C, and nitrogen-to-carbon (N/C ratios of OA in NYC are 0.36 (±0.09, 1.49 (±0.08, and 0.012 (±0.005, respectively, corresponding to an average organic mass-to-carbon (OM/OC ratio of 1.62 (±0.11. Positive matrix factorization (PMF of the high resolution mass spectra identified two primary OA (POA sources, traffic and cooking, and three secondary OA (SOA components including a highly oxidized, regional low-volatility oxygenated OA (LV-OOA; O/C = 0.63, a less oxidized, semi-volatile SV-OOA (O/C = 0.38 and a unique nitrogen-enriched OA (NOA; N/C = 0.053 characterized with prominent CxH2x + 2N+ peaks likely from amino compounds. Our results indicate that cooking and traffic are two distinct and mass-equivalent POA sources in NYC, together contributing ~30% of the total OA mass during this study. The OA composition is dominated by secondary species, especially during high PM events. SV-OOA and LV-OOA on average account for 34% and 30%, respectively, of the total OA mass. The chemical evolution of SOA in NYC appears to progress with a continuous oxidation from SV-OOA to LV-OOA, which is further supported by a gradual increase of O/C ratio and a simultaneous decrease of H/C ratio in total OOA. Detailed

  6. Microfluidic Air Sampler for Highly Efficient Bacterial Aerosol Collection and Identification.

    Science.gov (United States)

    Bian, Xiaojun; Lan, Ying; Wang, Bing; Zhang, Yu Shrike; Liu, Baohong; Yang, Pengyuan; Zhang, Weijia; Qiao, Liang

    2016-12-06

    The early warning capability of the presence of biological aerosol threats is an urgent demand in ensuing civilian and military safety. Efficient and rapid air sample collection in relevant indoor or outdoor environment is a key step for subsequent analysis of airborne microorganisms. Herein, we report a portable battery-powered sampler that is capable of highly efficient bioaerosol collection. The essential module of the sampler is a polydimethylsiloxane (PDMS) microfluidic chip, which consisted of a 3-loop double-spiral microchannel featuring embedded herringbone and sawtooth wave-shaped structures. Vibrio parahemolyticus (V. parahemolyticus) as a model microorganism, was initially employed to validate the bioaerosol collection performance of the device. Results showed that the sampling efficacy reached as high as >99.9%. The microfluidic sampler showed greatly improved capturing efficiency compared with traditional plate sedimentation methods. The high performance of our device was attributed to the horizontal inertial centrifugal force and the vertical turbulence applied to airflow during sampling. The centrifugation field and turbulence were generated by the specially designed herringbone structures when air circulated in the double-spiral microchannel. The sawtooth wave-shaped microstructure created larger specific surface area for accommodating more aerosols. Furthermore, a mixture of bacterial aerosols formed by V. parahemolyticus, Listeria monocytogenes, and Escherichia coli was extracted by the microfluidic sampler. Subsequent integration with mass spectrometry conveniently identified the multiple bacterial species captured by the sampler. Our developed stand-alone and cable-free sampler shows clear advantages comparing with conventional strategies, including portability, easy-to-use, and low cost, indicating great potential in future field applications.

  7. Impact of aerosol particle sources on optical properties in urban, regional and remote areas in the north-western Mediterranean

    Science.gov (United States)

    Ealo, Marina; Alastuey, Andrés; Pérez, Noemí; Ripoll, Anna; Querol, Xavier; Pandolfi, Marco

    2018-01-01

    Further research is needed to reduce the existing uncertainties on the effect that specific aerosol particle sources have on light extinction and consequently on climate. This study presents a new approach that aims to quantify the mass scattering and absorption efficiencies (MSEs and MAEs) of different aerosol sources at urban (Barcelona - BCN), regional (Montseny - MSY) and remote (Montsec - MSA) background sites in the north-western (NW) Mediterranean. An analysis of source apportionment to the measured multi-wavelength light scattering (σsp) and absorption (σap) coefficients was performed by means of a multilinear regression (MLR) model for the periods 2009-2014, 2010-2014 and 2011-2014 at BCN, MSY and MSA respectively. The source contributions to PM10 mass concentration, identified by means of the positive matrix factorization (PMF) model, were used as dependent variables in the MLR model. With this approach we addressed both the effect that aerosol sources have on air quality and their potential effect on light extinction through the determination of their MSEs and MAEs. An advantage of the presented approach is that the calculated MSEs and MAEs take into account the internal mixing of atmospheric particles. Seven aerosol sources were identified at MSA and MSY, and eight sources at BCN. Mineral, aged marine, secondary sulfate, secondary nitrate and V-Ni bearing sources were common at the three sites. Traffic, industrial/metallurgy and road dust resuspension sources were isolated at BCN, whereas mixed industrial/traffic and aged organics sources were identified at MSY and MSA. The highest MSEs were observed for secondary sulfate (4.5 and 10.7 m2 g-1, at MSY and MSA), secondary nitrate (8.8 and 7.8 m2 g-1) and V-Ni bearing source (8 and 3.5 m2 g-1). These sources dominated the scattering throughout the year with marked seasonal trends. The V-Ni bearing source, originating mainly from shipping in the area under study, simultaneously contributed to both

  8. Sources and characteristics of carbonaceous aerosol in two largest cities in Pearl River Delta Region, China

    Science.gov (United States)

    Duan, Jingchun; Tan, Jihua; Cheng, Dingxi; Bi, Xinhui; Deng, Wenjing; Sheng, Guoying; Fu, Jiamo; Wong, M. H.

    PM 2.5 samples were collected at five sites in Guangzhou and Hong Kong, Pearl River Delta Region (PRDR), China in both summer and winter during 2004-2005. Elemental carbon (EC) and organic carbon (OC) in these samples were measured. The OC and EC concentrations ranked in the order of urban Guangzhou > urban Hong Kong > background Hong Kong. Total carbonaceous aerosol (TCA) contributed less to PM 2.5 in urban Guangzhou (32-35%) than that in urban Hong Kong (43-57%). The reason may be that, as an major industrial city in South China, Guangzhou would receive large amount of inorganic aerosol from all kinds of industries, however, as a trade center and seaport, urban Hong Kong would mainly receive organic aerosol and EC from container vessels and heavy-duty diesel trucks. At Hong Kong background site Hok Tsui, relatively lower contribution of TCA to PM 2.5 may result from contributions of marine inorganic aerosol and inland China pollutant. Strong correlation ( R2=0.76-0.83) between OC and EC indicates minor fluctuation of emission and the secondary organic aerosol (SOA) formation in urban Guangzhou. Weak correlation between OC and EC in Hong Kong can be related to the impact of the long-range transported aerosol from inland China. Averagely, secondary OC (SOC) concentrations were 3.8-5.9 and 10.2-12.8 μg m -3, respectively, accounting for 21-32% and 36-42% of OC in summer and winter in Guangzhou. The average values of 4.2-6.8% for SOA/ PM 2.5 indicate that SOA was minor component in PM 2.5 in Guangzhou.

  9. IDENTIFICATIONS OF FIVE INTEGRAL SOURCES VIA OPTICAL SPECTROSCOPY

    International Nuclear Information System (INIS)

    Butler, Suzanne C.; Tomsick, John A.; Chaty, Sylvain; Heras, Juan A. Zurita; Rodriguez, Jerome; Walter, Roland; Kaaret, Philip; Kalemci, Emrah; Oezbey, Mehtap

    2009-01-01

    The International Gamma-Ray Astrophysics Laboratory (INTEGRAL) is discovering hundreds of new hard X-ray sources, many of which remain unidentified. We report on optical spectroscopy of five such sources for which X-ray observations at lower energies (∼0.5-10 keV) and higher angular resolutions than INTEGRAL have allowed for unique optical counterparts to be located. We find that INTEGRAL Gamma-Ray (IGR) J16426+6536 and IGR J22292+6647 are Type 1 Seyfert active galactic nuclei (with IGR J16426+6536 further classified as a Seyfert 1.5) which have redshifts of z = 0.323 and z = 0.113, respectively. IGR J18308-1232 is identified as a cataclysmic variable (CV), and we confirm a previous identification of IGR J19267+1325 as a magnetic CV. IGR J18214-1318 is identified as an obscured high-mass X-ray binary (HMXB), which are systems thought to have a compact object embedded in the stellar wind of a massive star. We combine Chandra fluxes with distances based on the optical observations to calculate X-ray luminosities of the HMXB and CVs, finding L 0.3-10keV = 5 x 10 36 erg s -1 for IGR J18214-1318, L 0.3-10keV = 1.3 x 10 32 erg s -1 for IGR J18308-1232, and L 0.3-10keV = 6.7 x 10 32 erg s -1 for IGR J19267+1325.

  10. Quantitative Real-Time PCR Fecal Source Identification in the ...

    Science.gov (United States)

    Rivers in the Tillamook Basin play a vital role in supporting a thriving dairy and cheese-making industry, as well as providing a safe water resource for local human and wildlife populations. Historical concentrations of fecal bacteria in these waters are at times too high to allow for safe use leading to economic loss, endangerment of local wildlife, and poor conditions for recreational use. In this study, we employ host-associated qPCR methods for human (HF183/BacR287 and HumM2), ruminant (Rum2Bac), cattle (CowM2 and CowM3), canine (DG3 and DG37), and avian (GFD) fecal pollution combined with high-resolution geographic information system (GIS) land use data and general indicator bacteria measurements to elucidatewater quality spatial and temporal trends. Water samples (n=584) were collected over a 1-year period at 29 sites along the Trask, Kilchis, and Tillamook rivers and tributaries (Tillamook Basin, OR). A total of 16.6% of samples (n=97) yielded E. coli levels considered impaired based on Oregon Department of Environmental Quality bacteria criteria (406 MPN/100mL). Hostassociated genetic indicators were detected at frequencies of 39.2% (HF183/BacR287), 16.3% (HumM2), 74.6% (Rum2Bac), 13.0% (CowM2), 26.7% (CowM3), 19.8% (DG3), 3.2% (DG37), and 53.4% (GFD) across all water samples (n=584). Seasonal trends in avian, cattle, and human fecal pollution sources were evident over the study area. On a sample site basis, quantitative fecal source identification and

  11. Identification of sources of heavy metals in the Dutch atmosphere using air filter and lichen analysis

    International Nuclear Information System (INIS)

    de Bruin, M.; Wolterbeek, H.T.

    1984-01-01

    Aerosol samples collected in an industrialized region were analyzed by instrumental neutron activation analysis. Correlation with wind direction and factor analysis were applied to the concentration data to obtain information on the nature and position of the sources. Epiphytic lichens were sampled over the country and analyzed for heavy metals (As, Cd, Sc, Zn, Sb). The data were interpreted by geographically plotting element concentrations and enrichment factors, and by factor analysis. Some pitfalls are discussed which are associated with the use of aerosol and lichen data in studies of heavy metal air pollution. 14 references, 8 figures, 3 tables

  12. Characterization of urban aerosol using aerosol mass spectrometry and proton nuclear magnetic resonance spectroscopy

    Science.gov (United States)

    Cleveland, M. J.; Ziemba, L. D.; Griffin, R. J.; Dibb, J. E.; Anderson, C. H.; Lefer, B.; Rappenglück, B.

    2012-07-01

    Particulate matter was measured during August and September of 2006 in Houston as part of the Texas Air Quality Study II Radical and Aerosol Measurement Project. Aerosol size and composition were determined using an Aerodyne quadrupole aerosol mass spectrometer. Aerosol was dominated by sulfate (4.1 ± 2.6 μg m-3) and organic material (5.5 ± 4.0 μg m-3), with contributions of organic material from both primary (˜32%) and secondary (˜68%) sources. Secondary organic aerosol appears to be formed locally. In addition, 29 aerosol filter samples were analyzed using proton nuclear magnetic resonance (1H NMR) spectroscopy to determine relative concentrations of organic functional groups. Houston aerosols are less oxidized than those observed elsewhere, with smaller relative contributions of carbon-oxygen double bonds. These particles do not fit 1H NMR source apportionment fingerprints for identification of secondary, marine, and biomass burning organic aerosol, suggesting that a new fingerprint for highly urbanized and industrially influenced locations be established.

  13. Chemical characterization of PM1.0 aerosol in Delhi and source apportionment using positive matrix factorization.

    Science.gov (United States)

    Jaiprakash; Singhai, Amrita; Habib, Gazala; Raman, Ramya Sunder; Gupta, Tarun

    2017-01-01

    Fine aerosol fraction (particulate matter with aerodynamic diameter <= 1.0 μm (PM) 1.0 ) over the Indian Institute of Technology Delhi campus was monitored day and night (10 h each) at 30 m height from November 2009 to March 2010. The samples were analyzed for 5 ions (NH 4 + , NO 3 - , SO 4 2- , F - , and Cl - ) and 12 trace elements (Na, K, Mg, Ca, Pb, Zn, Fe, Mn, Cu, Cd, Cr, and Ni). Importantly, secondary aerosol (sulfate and nitrate) formation was observed during dense foggy events, supporting the fog-smog-fog cycle. A total of 76 samples were used for source apportionment of PM mass. Six factors were resolved by PMF analyses and were identified as secondary aerosol, secondary chloride, biomass burning, soil dust, iron-rich source, and vehicular emission. The geographical location of the sources and/or preferred transport pathways was identified by conditional probability function (for local sources) and potential source contribution function (for regional sources) analyses. Medium- and small-scale metal processing (e.g. steel sheet rolling) industries in Haryana and National Capital Region (NCR) Delhi, coke and petroleum refining in Punjab, and thermal power plants in Pakistan, Punjab, and NCR Delhi were likely contributors to secondary sulfate, nitrate, and secondary chloride at the receptor site. The agricultural residue burning after harvesting season (Sept-Dec and Feb-Apr) in Punjab, and Haryana contributed to potassium at receptor site during November-December and March 2010. The soil dust from North and East Pakistan, and Rajasthan, North-East Punjab, and Haryana along with the local dust contributed to soil dust at the receptor site, during February and March 2010. A combination of temporal behavior and air parcel trajectory ensemble analyses indicated that the iron-rich source was most likely a local source attributed to emissions from metal processing facilities. Further, as expected, the vehicular emissions source did not show any seasonality and

  14. Religious burning as a potential major source of atmospheric fine aerosols in summertime Lhasa on the Tibetan Plateau

    Science.gov (United States)

    Cui, Yu Yan; Liu, Shang; Bai, Zhixuan; Bian, Jianchun; Li, Dan; Fan, Kaiyu; McKeen, Stuart A.; Watts, Laurel A.; Ciciora, Steven J.; Gao, Ru-Shan

    2018-05-01

    We carried out field measurements of aerosols in Lhasa, a major city in the Tibetan Plateau that has been experiencing fast urbanization and industrialization. Aerosol number size distribution was continuously measured using an optical particle size spectrometer near the center of Lhasa city during the Asian summer monsoon season in 2016. The mass concentration of fine particles was modulated by boundary layer dynamics, with an average of 11 μg m-3 and the high values exceeding 50 μg m-3 during religious holidays. Daytime high concentration coincided with the religious burning of biomass and incense in the temples during morning hours, which produced heavy smoke. Factor analysis revealed a factor that likely represented religious burning. The factor contributed 34% of the campaign-average fine particle mass and the contribution reached up to 80% during religious holidays. The mass size distribution of aerosols produced from religious burnings peaked at ∼500 nm, indicating that these particles could efficiently decrease visibility and promote health risk. Because of its significance, our results suggest that further studies of religious burning, a currently under-studied source, are needed in the Tibetan Plateau and in other regions of the world where religious burnings are frequently practiced.

  15. [Size distributions and source apportionment of soluble ions in aerosol in Nanjing].

    Science.gov (United States)

    Xue, Guo-Qiang; Zhu, Bin; Wang, Hong-Lei

    2014-05-01

    To explore the seasonal variation and source apportionment of soluble ions in PM10, PM2.1 and PM1.1, the aerosol mass. concentration and soluble ion concentration were investigated during a one-year observation in the urban-district and north suburb. As the results showed, (1)The concentrations of PM10, PM2.1, PM1.1 were in the order of winter > spring > autumn > summer. In spring, summer and autumn, the concentrations of PM10, PM2.1, PM1.1 in the north suburb were higher than in the urban, while the situation, was opposite in winter. (2) SO(2-)(4), NO(-)(3), Ca2+, NH(+)(4), Cl-, K+, Na+, F-, NO;, Mg2+ were measured, and their total concentration in PM10 was 46 microg.m -3 in urban sites and 39.6 microg m in north suburbs. Mass fraction percentage o f water soluble ion in PM2.1-10, PM1 1-2.1, PM1.1 in the urban district increased from 20.4% to 49.5% and 56% , and the value in the north suburb increased from 18.3% to 37. 9% and 42.5%. (3) Major ions, SO(2-)(4), NO(-)(3) , NH(+)(4) , second components and Ca2+ , had significant seasonal variation. In the urban district, the highest concentrations were observed in winter, and the lowest in summer, while in the. north suburb, the highest concentrations were observed in spring, and the lowest in summer. The seasonal changing climate in Nanjing and different anthropogenic influences with land surface in urban-suburb may be the major factors for the ions' seasonal variation. (4) NH(+)(4) , SO(2-)(4) , NO(-)(3) came from secondary chemical reactions of NH3, SO2, NO,, and these precursors mostly came from automobile exhaust in Summer while equally came from automobile exhaust and fossil fuel in winter. Cl- came from biomass burning in Winter . while transported from sea salt with Na+ in Summer. Ca2+ and Mg2+ came from ground dust and construction dust. K+, F- , NO(-)(2) may come from biomass burning and industrial emissions.

  16. 2007 California Aerosol Study: Evaluation of δ15N as a Tracer Of NOx Sources and Chemsitry

    Science.gov (United States)

    Katzman, T. L.

    2017-12-01

    Although stable isotopes of N are commonly used as a source tracer, how this tracer is applied is a point of contention. The "source" hypothesis argues that the δ15N value of NO3- reflects the δ15N value of NOx source inputs into the environment, and any observed variation is solely the result of differences in source contributions. Conversely, the "chemistry" hypothesis argues that N isotopes are influenced by chemical reactions, atmospheric or biologic processing, and post-depositional effects. Previous studies often apply the source hypothesis, writing off the chemistry hypothesis as "minor," but others have noted the impact chemistry should has on δ15N values. Given the known complications, this work seeks to assess the use of stable isotopes as tracers, specifically, the assumption that the δ15N value is a tracer of source alone without significant influence from chemical reactions. If the "source" hypothesis is correct, source emission data, known source δ15N values, and isotope mass balance should be able to approximate measured δ15NNO3 values and determine the δ15N value associated with wildfire derived NOx, which is currently unknown. Significant deviations from observed values would support the significance of equilibrium and kinetic isotope effects associated with chemical reactions and processing in the atmosphere. Aerosols collected in during 2007, emission data, and isotopic analysis were utilized to determine the utility of δ15N as tracer of NOx sources. San Diego, California is a coastal urban area influenced by sea salt aerosols, anthropogenic combustion emissions, and seasonal wildfires. Wildfires also have a significant influence on local atmospheric chemistry and 2007 was notable for being one of the worst fire seasons in the San Diego region on record. Isotopic analysis of collected NO3- has suggested that source δ15N values are likely not conserved as NOx is oxidized into NO3-. Given known source contributions and known δ15N values

  17. Aerosol Health Impact Source Attribution Studies with the CMAQ Adjoint Air Quality Model

    Science.gov (United States)

    Turner, M. D.

    , reductions in emissions from large industrial combustion sources that are not classified as EGUs (i.e., non-EGU) are estimated to have up to triple the benefits per unit emission of reductions to onroad diesel sectors, and provide similar benefits per unit of reduced emission to that of onroad gasoline emissions in the region. While a majority of vehicle emission controls that regulate PM focus on diesel emissions, our analysis shows the most efficient target for stricter controls is actually onroad gasoline emissions. From an analysis of the health impacts of BC emissions on specific demographic populations, we find that emissions in the southern half of the US tend to disproportionally affect persons with a below high school education and persons below 50% of the poverty level. Analysis of national risk (independent of population and mortality rates) shows that the largest risks are associated with drier climates, due to the increased atmospheric lifetime resulting from less wet removal of aerosols. Lastly, analysis of the impacts of BC emissions on maximum individual risk shows that contributions to maximum individual risk are weakly to strongly correlated with emissions (R2 ranging from 0.23 in the San Joaquin Valley to 0.93 in the Dallas region). Overall, this thesis shows the value of high-resolution, adjoint-based source attribution studies for determining the locations, seasons, and sectors that have the greatest estimated impact on human health in air quality models.

  18. Organic Aerosol Composition and Sources in Pasadena, California during the 2010 CalNex Campaign

    Science.gov (United States)

    Organic aerosols (OA) in Pasadena are characterized using multiple measurements from the California Research at the Nexus of Air Quality and Climate Change (CalNex) campaign. Five OA components are identified using positive matrix factorization including hydrocarbon-like OA (HOA) ...

  19. Heavy Ion Formation in Titan's Ionosphere: Magnetospheric Introduction of Free Oxygen and a Source of Titan's Aerosols?

    Science.gov (United States)

    Sittler, E. C., Jr.; Ali, A.; Cooper, J. F.; Hartle, R. E.; Johnson, R. E.; Coates, A. J.; Young, D. T.

    2009-01-01

    Discovery by Cassini's plasma instrument of heavy positive and negative ions within Titan's upper atmosphere and ionosphere has advanced our understanding of ion neutral chemistry within Titan's upper atmosphere, primarily composed of molecular nitrogen, with approx.2.5% methane. The external energy flux transforms Titan's upper atmosphere and ionosphere into a medium rich in complex hydrocarbons, nitriles and haze particles extending from the surface to 1200 km altitudes. The energy sources are solar UV, solar X-rays, Saturn's magnetospheric ions and electrons, solar wind and shocked magnetosheath ions and electrons, galactic cosmic rays (CCR) and the ablation of incident meteoritic dust from Enceladus' E-ring and interplanetary medium. Here it is proposed that the heavy atmospheric ions detected in situ by Cassini for heights >950 km, are the likely seed particles for aerosols detected by the Huygens probe for altitudes <100km. These seed particles may be in the form of polycyclic aromatic hydrocarbons (PAH) containing both carbon and hydrogen atoms CnHx. There could also be hollow shells of carbon atoms, such as C60, called fullerenes which contain no hydrogen. The fullerenes may compose a significant fraction of the seed particles with PAHs contributing the rest. As shown by Cassini, the upper atmosphere is bombarded by magnetospheric plasma composed of protons, H(2+) and water group ions. The latter provide keV oxygen, hydroxyl and water ions to Titan's upper atmosphere and can become trapped within the fullerene molecules and ions. Pickup keV N(2+), N(+) and CH(4+) can also be implanted inside of fullerenes. Attachment of oxygen ions to PAH molecules is uncertain, but following thermalization O(+) can interact with abundant CH4 contributing to the CO and CO2 observed in Titan's atmosphere. If an exogenic keV O(+) ion is implanted into the haze particles, it could become free oxygen within those aerosols that eventually fall onto Titan's surface. The process

  20. Carbonaceous and inorganic aerosols over a sub-urban site in peninsular India: Temporal variability and source characteristics

    Science.gov (United States)

    Aswini, A. R.; Hegde, Prashant; Nair, Prabha R.

    2018-01-01

    PM10 aerosol samples collected from a sub-urban site in Coimbatore during pre-monsoon, monsoon, post-monsoon and winter from 2014 to 2016 showed a large variability from 7.6 to 89 μg m- 3 with an annual average of 41 ± 21 μg m- 3 (N = 69). High abundance of PM10 and other components were recorded during winter and lowest during monsoon period. Total carbonaceous aerosols and water soluble ionic species contributed to 31% and 45% of PM10 mass respectively. SO42 - was the most abundant species (average 9.8 ± 4.8 μg m- 3) and constituted for 24% of total mass. Organic Carbon (OC) was the next most abundant species ranging from 1 to 16 μg m- 3 with an average of 7 ± 3.6 μg m- 3 accounting for 17% of PM10 mass concentration. POC (primary organic carbon) and SOC (secondary organic carbon) accounted for 56% and 44% of OC respectively. A major portion of OC ( 60%) was found to be water soluble. The correlation between OC and EC (elemental carbon) was found to be higher for night-time compared to daytime suggesting their origin from common sources during night-time. K+ was found to be strongly correlated with OC during night-time. WSOC showed good correlation with POC and K+ which was high especially during night-time. WSON (water soluble organic nitrogen) accounted for 34% of water soluble total nitrogen (WSTN). HCO3- exhibited significant positive correlation with Ca2 + during daytime indicating their crustal origin. The observations suggest that the region is influenced by biomass burning sources, however during day-time, secondary production and terrestrial sources (due to high temperature and wind) significantly influence the atmospheric aerosols over this region.

  1. Organic aerosol source apportionment in London 2013 with ME-2: exploring the solution space with annual and seasonal analysis

    Directory of Open Access Journals (Sweden)

    E. Reyes-Villegas

    2016-12-01

    Full Text Available The multilinear engine (ME-2 factorization tool is being widely used following the recent development of the Source Finder (SoFi interface at the Paul Scherrer Institute. However, the success of this tool, when using the a value approach, largely depends on the inputs (i.e. target profiles applied as well as the experience of the user. A strategy to explore the solution space is proposed, in which the solution that best describes the organic aerosol (OA sources is determined according to the systematic application of predefined statistical tests. This includes trilinear regression, which proves to be a useful tool for comparing different ME-2 solutions. Aerosol Chemical Speciation Monitor (ACSM measurements were carried out at the urban background site of North Kensington, London from March to December 2013, where for the first time the behaviour of OA sources and their possible environmental implications were studied using an ACSM. Five OA sources were identified: biomass burning OA (BBOA, hydrocarbon-like OA (HOA, cooking OA (COA, semivolatile oxygenated OA (SVOOA and low-volatility oxygenated OA (LVOOA. ME-2 analysis of the seasonal data sets (spring, summer and autumn showed a higher variability in the OA sources that was not detected in the combined March–December data set; this variability was explored with the triangle plots f44 : f43 f44 : f60, in which a high variation of SVOOA relative to LVOOA was observed in the f44 : f43 analysis. Hence, it was possible to conclude that, when performing source apportionment to long-term measurements, important information may be lost and this analysis should be done to short periods of time, such as seasonally. Further analysis on the atmospheric implications of these OA sources was carried out, identifying evidence of the possible contribution of heavy-duty diesel vehicles to air pollution during weekdays compared to those fuelled by petrol.

  2. Aerosol characterization over the southeastern United States using high-resolution aerosol mass spectrometry: spatial and seasonal variation of aerosol composition and sources with a focus on organic nitrates

    Science.gov (United States)

    Xu, L.; Suresh, S.; Guo, H.; Weber, R. J.; Ng, N. L.

    2015-07-01

    We deployed a High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS) and an Aerosol Chemical Speciation Monitor (ACSM) to characterize the chemical composition of submicron non-refractory particulate matter (NR-PM1) in the southeastern USA. Measurements were performed in both rural and urban sites in the greater Atlanta area, Georgia (GA), and Centreville, Alabama (AL), for approximately 1 year as part of Southeastern Center for Air Pollution and Epidemiology study (SCAPE) and Southern Oxidant and Aerosol Study (SOAS). Organic aerosol (OA) accounts for more than half of NR-PM1 mass concentration regardless of sampling sites and seasons. Positive matrix factorization (PMF) analysis of HR-ToF-AMS measurements identified various OA sources, depending on location and season. Hydrocarbon-like OA (HOA) and cooking OA (COA) have important, but not dominant, contributions to total OA in urban sites (i.e., 21-38 % of total OA depending on site and season). Biomass burning OA (BBOA) concentration shows a distinct seasonal variation with a larger enhancement in winter than summer. We find a good correlation between BBOA and brown carbon, indicating biomass burning is an important source for brown carbon, although an additional, unidentified brown carbon source is likely present at the rural Yorkville site. Isoprene-derived OA factor (isoprene-OA) is only deconvolved in warmer months and contributes 18-36 % of total OA. The presence of isoprene-OA factor in urban sites is more likely from local production in the presence of NOx than transport from rural sites. More-oxidized and less-oxidized oxygenated organic aerosol (MO-OOA and LO-OOA, respectively) are dominant fractions (47-79 %) of OA in all sites. MO-OOA correlates well with ozone in summer but not in winter, indicating MO-OOA sources may vary with seasons. LO-OOA, which reaches a daily maximum at night, correlates better with estimated nitrate functionality from organic nitrates than total nitrates. Based

  3. Secondary inorganic aerosols in Europe: sources and the significant influence of biogenic VOC emissions, especially on ammonium nitrate

    Science.gov (United States)

    Aksoyoglu, Sebnem; Ciarelli, Giancarlo; El-Haddad, Imad; Baltensperger, Urs; Prévôt, André S. H.

    2017-06-01

    Contributions of various anthropogenic sources to the secondary inorganic aerosol (SIA) in Europe as well as the role of biogenic emissions on SIA formation were investigated using the three-dimensional regional model CAMx (comprehensive air quality model with extensions). Simulations were carried out for two periods of EMEP field campaigns, February-March 2009 and June 2006, which are representative of cold and warm seasons, respectively. Biogenic volatile organic compounds (BVOCs) are known mainly as precursors of ozone and secondary organic aerosol (SOA), but their role on inorganic aerosol formation has not attracted much attention so far. In this study, we showed the importance of the chemical reactions of BVOCs and how they affect the oxidant concentrations, leading to significant changes, especially in the formation of ammonium nitrate. A sensitivity test with doubled BVOC emissions in Europe during the warm season showed a large increase in secondary organic aerosol (SOA) concentrations (by about a factor of two), while particulate inorganic nitrate concentrations decreased by up to 35 %, leading to a better agreement between the model results and measurements. Sulfate concentrations decreased as well; the change, however, was smaller. The changes in inorganic nitrate and sulfate concentrations occurred at different locations in Europe, indicating the importance of precursor gases and biogenic emission types for the negative correlation between BVOCs and SIA. Further analysis of the data suggested that reactions of the additional terpenes with nitrate radicals at night were responsible for the decline in inorganic nitrate formation, whereas oxidation of BVOCs with OH radicals led to a decrease in sulfate. Source apportionment results suggest that the main anthropogenic source of precursors leading to formation of particulate inorganic nitrate is road transport (SNAP7; see Table 1 for a description of the categories), whereas combustion in energy and

  4. Aerosol composition and source apportionment in the Mexico City Metropolitan Area with PIXE/PESA/STIM and multivariate analysis

    Directory of Open Access Journals (Sweden)

    K. S. Johnson

    2006-01-01

    Full Text Available Aerosols play an important role in the atmosphere but are poorly characterized, particularly in urban areas like the Mexico City Metropolitan Area (MCMA. The chemical composition of urban particles must be known to assess their effects on the environment, and specific particulate emissions sources should be identified to establish effective pollution control standards. For these reasons, samples of particulate matter ≤2.5 μm (PM2.5 were collected during the MCMA-2003 Field Campaign for elemental and multivariate analyses. Proton-Induced X-ray Emission (PIXE, Proton-Elastic Scattering Analysis (PESA and Scanning Transmission Ion Microscopy (STIM measurements were done to determine concentrations of 19 elements from Na to Pb, hydrogen, and total mass, respectively. The most abundant elements from PIXE analysis were S, Si, K, Fe, Ca, and Al, while the major emissions sources associated with these elements were industry, wind-blown soil, and biomass burning. Wind trajectories suggest that metals associated with industrial emissions came from northern areas of the city whereas soil aerosols came from the southwest and increased in concentration during dry conditions. Elemental markers for fuel oil combustion, V and Ni, correlated with a large SO2 plume to suggest an anthropogenic, rather than volcanic, emissions source. By subtracting major components of soil and sulfates determined by PIXE analysis from STIM total mass measurements, we estimate that approximately 50% of non-volatile PM2.5 consisted of carbonaceous material.

  5. Long-term trends in California mobile source emissions and ambient concentrations of black carbon and organic aerosol.

    Science.gov (United States)

    McDonald, Brian C; Goldstein, Allen H; Harley, Robert A

    2015-04-21

    A fuel-based approach is used to assess long-term trends (1970-2010) in mobile source emissions of black carbon (BC) and organic aerosol (OA, including both primary emissions and secondary formation). The main focus of this analysis is the Los Angeles Basin, where a long record of measurements is available to infer trends in ambient concentrations of BC and organic carbon (OC), with OC used here as a proxy for OA. Mobile source emissions and ambient concentrations have decreased similarly, reflecting the importance of on- and off-road engines as sources of BC and OA in urban areas. In 1970, the on-road sector accounted for ∼90% of total mobile source emissions of BC and OA (primary + secondary). Over time, as on-road engine emissions have been controlled, the relative importance of off-road sources has grown. By 2010, off-road engines were estimated to account for 37 ± 20% and 45 ± 16% of total mobile source contributions to BC and OA, respectively, in the Los Angeles area. This study highlights both the success of efforts to control on-road emission sources, and the importance of considering off-road engine and other VOC source contributions when assessing long-term emission and ambient air quality trends.

  6. Long-range transport and mixing of aerosol sources during the 2013 North American biomass burning episode: analysis of multiple lidar observations in the western Mediterranean basin

    Directory of Open Access Journals (Sweden)

    G. Ancellet

    2016-04-01

    Full Text Available Long-range transport of biomass burning (BB aerosols between North America and the Mediterranean region took place in June 2013. A large number of ground-based and airborne lidar measurements were deployed in the western Mediterranean during the Chemistry-AeRosol Mediterranean EXperiment (ChArMEx intensive observation period. A detailed analysis of the potential North American aerosol sources is conducted including the assessment of their transport to Europe using forward simulations of the FLEXPART Lagrangian particle dispersion model initialized using satellite observations by MODIS and CALIOP. The three-dimensional structure of the aerosol distribution in the ChArMEx domain observed by the ground-based lidars (Minorca, Barcelona and Lampedusa, a Falcon-20 aircraft flight and three CALIOP tracks, agrees very well with the model simulation of the three major sources considered in this work: Canadian and Colorado fires, a dust storm from western US and the contribution of Saharan dust streamers advected from the North Atlantic trade wind region into the westerlies region. Four aerosol types were identified using the optical properties of the observed aerosol layers (aerosol depolarization ratio, lidar ratio and the transport model analysis of the contribution of each aerosol source: (i pure BB layer, (ii weakly dusty BB, (iii significant mixture of BB and dust transported from the trade wind region, and (iv the outflow of Saharan dust by the subtropical jet and not mixed with BB aerosol. The contribution of the Canadian fires is the major aerosol source during this episode while mixing of dust and BB is only significant at an altitude above 5 km. The mixing corresponds to a 20–30 % dust contribution in the total aerosol backscatter. The comparison with the MODIS aerosol optical depth horizontal distribution during this episode over the western Mediterranean Sea shows that the Canadian fire contributions were as large as the direct

  7. Broadband optical properties of biomass-burning aerosol and identification of brown carbon chromophores: OPTICAL AND CHEMICAL PROPERTIES OF BROWN CARBON AEROSOLS

    Energy Technology Data Exchange (ETDEWEB)

    Bluvshtein, Nir [Department of Earth and Planetary Sciences, Weizmann Institute of Science, Rehovot Israel; Lin, Peng [Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland Washington USA; Flores, J. Michel [Department of Earth and Planetary Sciences, Weizmann Institute of Science, Rehovot Israel; Segev, Lior [Department of Earth and Planetary Sciences, Weizmann Institute of Science, Rehovot Israel; Mazar, Yinon [Department of Earth and Planetary Sciences, Weizmann Institute of Science, Rehovot Israel; Tas, Eran [The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot Israel; Snider, Graydon [Department of Physics and Atmospheric Science, Dalhousie University, Halifax Nova Scotia Canada; Weagle, Crystal [Department of Chemistry, Dalhousie University, Halifax Nova Scotia Canada; Brown, Steven S. [Cooperative Institute for Research in Environmental Sciences, University of Colorado Boulder, Boulder Colorado USA; Chemical Sciences Division, Earth System Research Laboratory, National Oceanic and Atmospheric Administration, Boulder Colorado USA; Laskin, Alexander [Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland Washington USA; Rudich, Yinon [Department of Earth and Planetary Sciences, Weizmann Institute of Science, Rehovot Israel

    2017-05-23

    The radiative effects of biomass burning aerosols on regional and global scale is substantial. Accurate modeling of the radiative effects of smoke aerosols require wavelength-dependent measurements and parameterizations of their optical properties in the UV and visible spectral ranges along with improved description of their chemical composition. To address this issue, we used a recently developed approach to retrieve the time- and spectral-dependent optical properties of ambient biomass burning aerosols between 300 and 650 nm wavelength during a regional bonfire festival in Israel. During the biomass burning event, the overall absorption at 400 nm increased by about two orders of magnitude, changing the size-weighted single scattering albedo from a background level of 0.95 to 0.7. Based on the new retrieval method, we provide parameterizations of the wavelength-dependent effective complex refractive index from 350 to 650 nm for freshly emitted and aged biomass burning aerosols. In addition, PM2.5 filter samples were collected for detailed off-line chemical analysis of the water soluble organics that contribute to light absorption. Nitrophenols were identified as the main organic species responsible for the increased absorption at 400-500 nm. These include species such as 4- nitrocatechol, 4-nitrophenol, nitro-syringol and nitro-guaiacol; oxidation-nitration products of methoxyphenols, known products of lignin pyrolysis. Our findings emphasize the importance of both primary and secondary organic aerosol from biomass burning in absorption of solar radiation and in effective radiative forcing.

  8. Source term identification in atmospheric modelling via sparse optimization

    Science.gov (United States)

    Adam, Lukas; Branda, Martin; Hamburger, Thomas

    2015-04-01

    Inverse modelling plays an important role in identifying the amount of harmful substances released into atmosphere during major incidents such as power plant accidents or volcano eruptions. Another possible application of inverse modelling lies in the monitoring the CO2 emission limits where only observations at certain places are available and the task is to estimate the total releases at given locations. This gives rise to minimizing the discrepancy between the observations and the model predictions. There are two standard ways of solving such problems. In the first one, this discrepancy is regularized by adding additional terms. Such terms may include Tikhonov regularization, distance from a priori information or a smoothing term. The resulting, usually quadratic, problem is then solved via standard optimization solvers. The second approach assumes that the error term has a (normal) distribution and makes use of Bayesian modelling to identify the source term. Instead of following the above-mentioned approaches, we utilize techniques from the field of compressive sensing. Such techniques look for a sparsest solution (solution with the smallest number of nonzeros) of a linear system, where a maximal allowed error term may be added to this system. Even though this field is a developed one with many possible solution techniques, most of them do not consider even the simplest constraints which are naturally present in atmospheric modelling. One of such examples is the nonnegativity of release amounts. We believe that the concept of a sparse solution is natural in both problems of identification of the source location and of the time process of the source release. In the first case, it is usually assumed that there are only few release points and the task is to find them. In the second case, the time window is usually much longer than the duration of the actual release. In both cases, the optimal solution should contain a large amount of zeros, giving rise to the

  9. Radio identifications of IRAS point sources with b greater than 30 deg

    International Nuclear Information System (INIS)

    Condon, J.J.; Broderick, J.J.; Virginia Polytechnic Institute and State Univ., Blacksburg)

    1986-01-01

    The present radio identifications of IRAS point sources on the basis of Green Bank 1400 MHz survey maps notes that 365 hot IR sources are not detectable radio sources, and that nearly all cool high latitude IRAS sources are extragalactic. The fainter IR-source identifications encompass optically bright quasars, BL Lac objects, Seyfert galaxies, and elliptical galaxies. No IRAS sources could be identified with distant elliptical radio galaxies, so that although the radio and IR fluxes of most IRAS extragalactic sources are tightly correlated, complete samples of strong radio and IR sources are almost completely disjoint; no more than 1 percent of the IR sources are radio sources and less than 1 percent of the radio sources are IR ones. 35 references

  10. PIXE identification of fine and coarse particles of aerosol samples and their distribution across Beirut

    Energy Technology Data Exchange (ETDEWEB)

    Roumie, M., E-mail: mroumie@cnrs.edu.lb [Accelerator Laboratory, Lebanese Atomic Energy Commission, National Council for Scientific Research, P.O. Box 11-8281, Beirut (Lebanon); Saliba, N., E-mail: ns30@aub.edu.lb [Department of Chemistry, Faculty of Arts and Sciences, American University of Beirut, Beirut (Lebanon); Nsouli, B., E-mail: bnsouli@cnrs.edu.lb [Accelerator Laboratory, Lebanese Atomic Energy Commission, National Council for Scientific Research, P.O. Box 11-8281, Beirut (Lebanon); Younes, M., E-mail: myriam_younis@hotmail.com [Accelerator Laboratory, Lebanese Atomic Energy Commission, National Council for Scientific Research, P.O. Box 11-8281, Beirut (Lebanon); Noun, M., E-mail: manale_noun@hotmail.com [Accelerator Laboratory, Lebanese Atomic Energy Commission, National Council for Scientific Research, P.O. Box 11-8281, Beirut (Lebanon); Massoud, R., E-mail: rm84@aub.edu.lb [Department of Chemistry, Faculty of Arts and Sciences, American University of Beirut, Beirut (Lebanon)

    2011-12-15

    This study is the first national attempt to assess the levels of PMs in Beirut city and consequently understand air pollution distribution. Aerosol sampling was carried out using three PM{sub 10} and three PM{sub 2.5} samplers which were installed at three locations lying along the SE-NW direction over Beirut. The sampling of PM{sub 10} and PM{sub 2.5} was done during a period extending from May till December 2009. The random collection of the particles (1 in 6 days) was carried out on Teflon filters, for a period of 24-h. The elemental analysis of particulate matter was performed using proton induced X-ray emission technique PIXE at the Lebanese 1.7 MV Tandem-Pelletron accelerator of Beirut. Na, Mg, Al, Si, P, S and Cl were quantified using 1 MeV proton beam, while K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn and Pb were determined using 3 MeV-energy of proton beam.

  11. A Parameter Identification Method for Helicopter Noise Source Identification and Physics-Based Semi-Empirical Modeling

    Science.gov (United States)

    Greenwood, Eric, II; Schmitz, Fredric H.

    2010-01-01

    A new physics-based parameter identification method for rotor harmonic noise sources is developed using an acoustic inverse simulation technique. This new method allows for the identification of individual rotor harmonic noise sources and allows them to be characterized in terms of their individual non-dimensional governing parameters. This new method is applied to both wind tunnel measurements and ground noise measurements of two-bladed rotors. The method is shown to match the parametric trends of main rotor Blade-Vortex Interaction (BVI) noise, allowing accurate estimates of BVI noise to be made for operating conditions based on a small number of measurements taken at different operating conditions.

  12. Lead isotopic fingerprinting of aerosols to characterize the sources of atmospheric lead in an industrial city of India

    Science.gov (United States)

    Sen, Indra S.; Bizimis, Michael; Tripathi, Sachchida Nand; Paul, Debajyoti

    2016-03-01

    Anthropogenic Pb in the environment is primarily sourced from combustion of fossil fuel and high-temperature industries such as smelters. Identifying the sources and pathways of anthropogenic Pb in the environment is important because Pb toxicity is known to have adverse effects on human health. Pb pollution sources for America, Europe, and China are well documented. However, sources of atmospheric Pb are unknown in India, particularly after leaded gasoline was phased out in 2000. India has a developing economy with a rapidly emerging automobile and high temperature industry, and anthropogenic Pb emission is expected to rise in the next decade. In this study, we report on the Pb-isotope compositions and trace metal ratios of airborne particulates collected in Kanpur, a large city in northern part of India. The study shows that the PM10 aerosols had elevated concentration of Cd, Pb, Zn, As, and Cu in the Kanpur area, however their concentrations are well below the United States Environmental Protection Agency chronic exposure limit. Lead isotopic and trace metal data reveal industrial emission as the plausible source of anthropogenic Pb in the atmosphere in Kanpur. However, Pb isotopic compositions of potential source end-members are required to fully evaluate Pb contamination in India over time. This is the first study that characterizes the isotopic composition of atmospheric Pb in an Indian city after leaded gasoline was phased out by 2000.

  13. Toward Synchronous Evaluation of Source Apportionments for Atmospheric Concentration and Deposition of Sulfate Aerosol Over East Asia

    Science.gov (United States)

    Itahashi, S.

    2018-03-01

    Source apportionments for atmospheric concentration, dry deposition, and wet deposition of sulfate aerosol (SO42-) were synchronously evaluated over East Asia, a main source of anthropogenic sulfur dioxide (SO2) emissions. Estimating dry deposition was difficult owing to the difficulty of measuring deposition velocity directly; therefore, sensitivity simulations using two dry deposition schemes were conducted. Moreover, sensitivity simulations for different emission inventories, the largest uncertainty source in the air quality model, were also conducted. In total, four experimental settings were used. Model performance was verified for atmospheric concentration and wet deposition using a ground-based observation network in China, Korea, and Japan, and all four model settings captured the observations. The underestimation of wet deposition over China was improved by an adjusted approach that linearly scaled the modeled precipitation values to observations. The synchronous evaluation of source apportionments for atmospheric concentration and dry and wet deposition showed the dominant contribution of anthropogenic emissions from China to the atmospheric concentration and deposition in Japan. The contributions of emissions from volcanoes were more important for wet deposition than for atmospheric concentration. Differences in the dry deposition scheme and emission inventory did not substantially influence the relative ratio of source apportionments over Japan. Because the dry deposition was more attributed to local factors, the differences in dry deposition may be an important determinant of the source contributions from China to Japan. Verification of these findings, including the dry deposition velocity, is necessary for better understanding of the behavior of sulfur compound in East Asia.

  14. Characterization and source estimation of size-segregated aerosols during 2008-2012 in an urban environment in Beijing

    International Nuclear Information System (INIS)

    Yu, Lingda; Wang, Guangfu; Zhang, Renjiang

    2013-01-01

    Full text: During 2008-2012, size-segregated aerosol samples were collected using an eight-stage cascade impactor at Beijing Normal University (BNU) Site, China. These samples were analyzed using particle induced X-ray emission (PIXE) analysis for concentrations of 21 elements consisting of Mg, AI, Si, P, S, CI, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, As, Se, Br, Ba and Pb. The size-resolved data sets were then analyzed using the positive matrix factorization (PMF) technique in order to identify possible sources and estimate their contribution to particulate matter mass. Nine sources were resolved in eight size ranges (025 ∼ 16μm) and included secondary sulphur, motor vehicles, coal combustion; oil combustion, road dust, biomass burning, soil dust, diesel vehicles and metal processing. PMF analysis of size-resolved source contributions showed that natural sources represented by soil dust and road dust contributed about 57% to the predicted primary particulate matter (PM) mass in the coarse size range(>2μm). On the other hand, anthropogenic sources such as secondary sulphur, coal and oil combustion, biomass burning and motor vehicle contributed about 73% in the fine size range <2μm). The diesel vehicles and secondary sulphur source contributed the most in the ultra-fine size range (<0.25μm) and was responsible for about 52% of the primary PM mass. (author)

  15. Characterization and source estimation of size-segregated aerosols during 2008-2012 in an urban environment in Beijing

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Lingda [Key Laboratory of Beam Technology and Materiais Modification of Ministry of Education, College of Nuclear Science and Technology, Beijing Normal University, Beijing (China); Wang, Guangfu, E-mail: guangfuw@bnu.edu.cn [Beijing Radiation Center, Beijing (China); Zhang, Renjiang [Key Laboratory of Regional Climate-Environment Research for Temperate Eas tAsia (RCE-TEA), Institute of Atmospheric Physics, Chinese Academy of Science, Beijing (China)

    2013-07-01

    Full text: During 2008-2012, size-segregated aerosol samples were collected using an eight-stage cascade impactor at Beijing Normal University (BNU) Site, China. These samples were analyzed using particle induced X-ray emission (PIXE) analysis for concentrations of 21 elements consisting of Mg, AI, Si, P, S, CI, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, As, Se, Br, Ba and Pb. The size-resolved data sets were then analyzed using the positive matrix factorization (PMF) technique in order to identify possible sources and estimate their contribution to particulate matter mass. Nine sources were resolved in eight size ranges (025 ∼ 16μm) and included secondary sulphur, motor vehicles, coal combustion; oil combustion, road dust, biomass burning, soil dust, diesel vehicles and metal processing. PMF analysis of size-resolved source contributions showed that natural sources represented by soil dust and road dust contributed about 57% to the predicted primary particulate matter (PM) mass in the coarse size range(>2μm). On the other hand, anthropogenic sources such as secondary sulphur, coal and oil combustion, biomass burning and motor vehicle contributed about 73% in the fine size range <2μm). The diesel vehicles and secondary sulphur source contributed the most in the ultra-fine size range (<0.25μm) and was responsible for about 52% of the primary PM mass. (author)

  16. Stable lead isotope compositions in selected coals from around the world and implications for present day aerosol source tracing

    Energy Technology Data Exchange (ETDEWEB)

    M. Diaz-Somoano; M.E. Kylander; M.A. Lopez-Anton; I. Suarez-Ruiz; M.R. Martinez-Tarazona; M. Ferrat; B. Kober; D.J. Weiss [Instituto Nacional del Carbon (INCAR-CSIC), Oviedo (Spain)

    2009-02-15

    The phasing out of leaded gasoline in many countries around the world at the end of the last millennium has resulted in a complex mixture of lead sources in the atmosphere. Recent studies suggest that coal combustion has become an important source of Pb in aerosols in urban and remote areas. Lead concentration and isotopic composition is reported for 59 coal samples representing major coal deposits worldwide in an attempt to characterize this potential source. The average concentration in these coals is 35 {mu}g Pb g{sup -1}, with the highest values in coals from Spain and Peru and the lowest in coals from Australia and North America. The {sup 206}Pb/{sup 207}Pb isotope ratios range between 1.15 and 1.24, with less radiogenic Pb in coals from Europe and Asia compared to South and North America. Comparing the Pb isotopic signatures of coals from this and previous studies with those published for Northern and Southern Hemisphere aerosols, we hypothesize that coal combustion might now be an important Pb source in China, the eastern U.S., and to some extent, in Europe but not as yet in other regions including South Africa, South America, and western U.S. This supports the notion that 'old Pb pollution' from leaded gasoline reemitted into the atmosphere or long-range transport (i.e., from China to the western U.S.) is important. Comparing the isotope ratios of the coals, the age of the deposits, and Pb isotope evolution models for the major geochemical reservoirs suggests that the lead isotope ratios (PbIC) in coals is strongly influenced by the depositional coal forming environment. 47 refs., 3 figs., 1 tab.

  17. Pollutant source identification model for water pollution incidents in small straight rivers based on genetic algorithm

    Science.gov (United States)

    Zhang, Shou-ping; Xin, Xiao-kang

    2017-07-01

    Identification of pollutant sources for river pollution incidents is an important and difficult task in the emergency rescue, and an intelligent optimization method can effectively compensate for the weakness of traditional methods. An intelligent model for pollutant source identification has been established using the basic genetic algorithm (BGA) as an optimization search tool and applying an analytic solution formula of one-dimensional unsteady water quality equation to construct the objective function. Experimental tests show that the identification model is effective and efficient: the model can accurately figure out the pollutant amounts or positions no matter single pollution source or multiple sources. Especially when the population size of BGA is set as 10, the computing results are sound agree with analytic results for a single source amount and position identification, the relative errors are no more than 5 %. For cases of multi-point sources and multi-variable, there are some errors in computing results for the reasons that there exist many possible combinations of the pollution sources. But, with the help of previous experience to narrow the search scope, the relative errors of the identification results are less than 5 %, which proves the established source identification model can be used to direct emergency responses.

  18. Chemical composition, source, and process of urban aerosols during winter haze formation in Northeast China.

    Science.gov (United States)

    Zhang, Jian; Liu, Lei; Wang, Yuanyuan; Ren, Yong; Wang, Xin; Shi, Zongbo; Zhang, Daizhou; Che, Huizheng; Zhao, Hujia; Liu, Yanfei; Niu, Hongya; Chen, Jianmin; Zhang, Xiaoye; Lingaswamy, A P; Wang, Zifa; Li, Weijun

    2017-12-01

    The characteristics of aerosol particles have been poorly evaluated even though haze episodes frequently occur in winter in Northeast China. OC/EC analysis, ion chromatography, and transmission electron microscopy (TEM) were used to investigate the organic carbon (OC) and elemental carbon (EC), and soluble ions in PM 2.5 and the mixing state of individual particles during a severe wintertime haze episode in Northeast China. The organic matter (OM), NH 4 + , SO 4 2- , and NO 3 - concentrations in PM 2.5 were 89.5 μg/m 3 , 24.2 μg/m 3 , 28.1 μg/m 3 , and 32.8 μg/m 3 on the haze days, respectively. TEM observations further showed that over 80% of the haze particles contained primary organic aerosols (POAs). Based on a comparison of the data obtained during the haze formation, we generate the following synthetic model of the process: (1) Stable synoptic meteorological conditions drove the haze formation. (2) The early stage of haze formation (light or moderate haze) was mainly caused by the enrichment of POAs from coal burning for household heating and cooking. (3) High levels of secondary organic aerosols (SOAs), sulfates, and nitrates formation via heterogeneous reactions together with POAs accumulation promoted to the evolution from light or moderate to severe haze. Compared to the severe haze episodes over the North China Plain, the PM 2.5 in Northeast China analyzed in the present study contained similar sulfate, higher SOA, and lower nitrate contents. Our results suggest that most of the POAs and secondary particles were likely related to emissions from coal-burning residential stoves in rural outskirts and small boilers in urban areas. The inefficient burning of coal for household heating and cooking should be monitored during wintertime in Northeast China. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Carbonaceous aerosol particles from common vegetation in the Grand Canyon

    International Nuclear Information System (INIS)

    Hallock, K.A.; Mazurek, M.A.; Cass, G.R.

    1992-05-01

    The problem of visibility reduction in the Grand Canyon due to fine organic aerosol particles in the atmosphere has become an area of increased environmental concern. Aerosol particles can be derived from many emission sources. In this report, we focus on identifying organic aerosols derived from common vegetation in the Grand Canyon. These aerosols are expected to be significant contributors to the total atmospheric organic aerosol content. Aerosol samples from living vegetation were collected by resuspension of surface wax and resin components liberated from the leaves of vegetation common to areas of the Grand Canyon. The samples were analyzed using high-resolution gas chromatography/mass spectrometry (GC/MS). Probable identification of compounds was made by comparison of sample spectra with National Institute of Standards and Technology (NIST) mass spectral references and positive identification of compounds was made when possible by comparison with authentic standards as well as NIST references. Using these references, we have been able to positively identify the presence of n-alkane and n-alkanoic acid homolog series in the surface waxes of the vegetation sampled. Several monoterpenes, sesquiterpenes, and diterpenes were identified also as possible biogenic aerosols which may contribute to the total organic aerosol abundance leading to visibility reduction in the Grand Canyon

  20. Unspeciated organic emissions from combustion sources and their influence on the secondary organic aerosol budget in the United States

    Science.gov (United States)

    Secondary organic aerosol (SOA) formed from the atmospheric oxidation of nonmethane organic gases (NMOG) is a major contributor to atmospheric aerosol mass. Emissions and smog chamber experiments were performed to investigate SOA formation from gasoline vehicles, diesel vehicles,...

  1. Influences of emission sources and meteorology on aerosol chemistry in a polluted urban environment: results from DISCOVER-AQ California

    Science.gov (United States)

    Young, D. E.; Kim, H.; Parworth, C.; Zhou, S.; Zhang, X.; Cappa, C. D.; Seco, R.; Kim, S.; Zhang, Q.

    2015-12-01

    The San Joaquin Valley (SJV) in California experiences persistent air quality problems associated with elevated particulate matter (PM) concentrations due to anthropogenic emissions, topography, and meteorological conditions. Thus it is important to unravel the various sources and processes that affect the physico-chemical properties of PM in order to better inform pollution abatement strategies and improve parameterizations in air quality models. positive matrix factorization (PMF) analysis of the AMS data: hydrocarbon-like OA (HOA; 9 % of total OA; O / C = 0.09) associated with local traffic, cooking OA (COA; 28 % of total OA; O / C = 0.19) associated with food cooking activities, two biomass burning OAs (BBOA1; 13 % of total OA; O / C = 0.33 and BBOA2; 20 % of total OA; O / C = 0.60) most likely associated with residential space heating from wood combustion, and semi-volatile oxygenated OA (SV-OOA; 16 % of total OA; O / C = 0.63) and low volatility oxygenated OA (LV-OOA; 24 % of total OA; O / C = 0.90) formed via chemical reactions in the atmosphere. Large differences in aerosol chemistry at Fresno were observed between the current campaign (winter 2013) and a~previous wintertime campaign (winter 2010), most notably that PM1 concentrations were nearly three times higher in 2013 than in 2010. These variations were attributed to differences in the meteorological conditions, which influenced primary emissions and secondary aerosol formation. In particular, COA and BBOA concentrations were greater in 2013 than 2010, where colder temperatures in 2013 likely resulted in increased biomass burning activities. The influence from a nighttime formed residual layer that mixed down in the morning was found to be much more intense in 2013 than 2010, leading to sharp increases in ground-level concentrations of secondary aerosol species including nitrate, sulfate, and OOA, in the morning between 08:00 to 12:00 PST. This is an indication that nighttime chemistry might also be

  2. Applications of lead isotope rations for identification and apportionment on pollution sources in food

    International Nuclear Information System (INIS)

    Zhao Duoyong; Wei Yimin; Guo Boli; Wei Shuai

    2011-01-01

    Lead is one of the toxic heavy metals which can accumulate to an adverse effect level in human bodies through ingestion, inhalation or other pathways. Because of the persistent lead contamination in farmland environment, large risk exists in the primary stage of 'from farm to table' chain. Environmental media such as soils, atmospheric aerosols were the possible lead sources of agro-food. To pinpoint the pollution sources exactly, cut off the contamination pathways in time, and reduce the risk of hazard, pollution sources tracing was very important. Lead isotope ratio combined with certain models is an effective method to discriminate correctly pollution sources and calculate the individual source contributions. In this review, to provide theoretical and technical reference for controlling lead pollution in environment and food, lead pollution sources in food, tracing principle and methods of lead isotope ratios, and its applications on vegetable, tea, wine, cereal and other food products were concerned. (authors)

  3. Aerosol Transport Over Equatorial Africa

    Science.gov (United States)

    Gatebe, C. K.; Tyson, P. D.; Annegarn, H. J.; Kinyua, A. M.; Piketh, S.; King, M.; Helas, G.

    1999-01-01

    Long-range and inter-hemispheric transport of atmospheric aerosols over equatorial Africa has received little attention so far. Most aerosol studies in the region have focussed on emissions from rain forest and savanna (both natural and biomass burning) and were carried out in the framework of programs such as DECAFE (Dynamique et Chimie Atmospherique en Foret Equatoriale) and FOS (Fires of Savanna). Considering the importance of this topic, aerosols samples were measured in different seasons at 4420 meters on Mt Kenya and on the equator. The study is based on continuous aerosol sampling on a two stage (fine and coarse) streaker sampler and elemental analysis by Particle Induced X-ray Emission. Continuous samples were collected for two seasons coinciding with late austral winter and early austral spring of 1997 and austral summer of 1998. Source area identification is by trajectory analysis and sources types by statistical techniques. Major meridional transports of material are observed with fine-fraction silicon (31 to 68 %) in aeolian dust and anthropogenic sulfur (9 to 18 %) being the major constituents of the total aerosol loading for the two seasons. Marine aerosol chlorine (4 to 6 %), potassium (3 to 5 %) and iron (1 to 2 %) make up the important components of the total material transport over Kenya. Minimum sulfur fluxes are associated with recirculation of sulfur-free air over equatorial Africa, while maximum sulfur concentrations are observed following passage over the industrial heartland of South Africa or transport over the Zambian/Congo Copperbelt. Chlorine is advected from the ocean and is accompanied by aeolian dust recirculating back to land from mid-oceanic regions. Biomass burning products are transported from the horn of Africa. Mineral dust from the Sahara is transported towards the Far East and then transported back within equatorial easterlies to Mt Kenya. This was observed during austral summer and coincided with the dying phase of 1997/98 El

  4. Origin of surface and columnar Indian Ocean Experiment (INDOEX) aerosols using source- and region-tagged emissions transport in a general circulation model

    Science.gov (United States)

    Verma, S.; Venkataraman, C.; Boucher, O.

    2008-12-01

    We study the relative influence of aerosols emitted from different sectors and geographical regions on aerosol loading in south Asia. Sectors contributing aerosol emissions include biofuel and fossil fuel combustion, open biomass burning, and natural sources. Geographical regions include India (the Indo-Gangetic plain, central India, south India, and northwest India), southeast Asia, east Asia, Africa-west Asia, and the rest of the world. Simulations of the Indian Ocean Experiment (INDOEX), from January to March 1999, are made in the general circulation model of Laboratoire de Météorologie Dynamique (LMD-ZT GCM) with emissions tagged by sector and geographical region. Anthropogenic emissions dominate (54-88%) the predicted aerosol optical depth (AOD) over all the receptor regions. Among the anthropogenic sectors, fossil fuel combustion has the largest overall influence on aerosol loading, primarily sulfate, with emissions from India (50-80%) and rest of the world significantly influencing surface concentrations and AOD. Biofuel combustion has a significant influence on both the surface and columnar black carbon (BC) in particular over the Indian subcontinent and Bay of Bengal with emissions largely from the Indian region (60-80%). Open biomass burning emissions influence organic matter (OM) significantly, and arise largely from Africa-west Asia. The emissions from Africa-west Asia affect the carbonaceous aerosols AOD in all receptor regions, with their largest influence (AOD-BC: 60%; and AOD-OM: 70%) over the Arabian Sea. Among Indian regions, the Indo-Gangetic Plain is the largest contributor to anthropogenic surface mass concentrations and AOD over the Bay of Bengal and India. Dust aerosols are contributed mainly through the long-range transport from Africa-west Asia over the receptor regions. Overall, the model estimates significant intercontinental incursion of aerosol, for example, BC, OM, and dust from Africa-west Asia and sulfate from distant regions (rest

  5. Field Measurements of Trace Gases and Aerosols Emitted by Undersampled Combustion Sources Including Wood and Dung Cooking Fires, Garbage and Crop Residue Burning, and Indonesian Peat Fires

    Science.gov (United States)

    Stockwell, C.; Jayarathne, T. S.; Goetz, D.; Simpson, I. J.; Selimovic, V.; Bhave, P.; Blake, D. R.; Cochrane, M. A.; Ryan, K. C.; Putra, E. I.; Saharjo, B.; Stone, E. A.; DeCarlo, P. F.; Yokelson, R. J.

    2017-12-01

    Field measurements were conducted in Nepal and in the Indonesian province of Central Kalimantan to improve characterization of trace gases and aerosols emitted by undersampled combustion sources. The sources targeted included cooking with a variety of stoves, garbage burning, crop residue burning, and authentic peat fires. Trace gas and aerosol emissions were studied using a land-based Fourier transform infrared spectrometer, whole air sampling, photoacoustic extinctiometers (405 and 870nm), and filter samples that were analyzed off-line. These measurements were used to calculate fuel-based emission factors (EFs) for up to 90 gases, PM2.5, and PM2.5 constituents. The aerosol optical data measured included EFs for the scattering and absorption coefficients, the single scattering albedo (at 870 and 405 nm), as well as the absorption Ångström exponent. The emissions varied significantly by source, although light absorption by both brown and black carbon (BrC and BC, respectively) was important for all non-peat sources. For authentic peat combustion, the emissions of BC were negligible and absorption was dominated by organic aerosol. The field results from peat burning were in reasonable agreement with recent lab measurements of smoldering Kalimantan peat and compare well to the limited data available from other field studies. The EFs can be used with estimates of fuel consumption to improve regional emissions inventories and assessments of the climate and health impacts of these undersampled sources.

  6. Seasonal variations in high time-resolved chemical compositions, sources, and evolution of atmospheric submicron aerosols in the megacity Beijing

    Directory of Open Access Journals (Sweden)

    W. Hu

    2017-08-01

    Full Text Available A severe regional haze problem in the megacity Beijing and surrounding areas, caused by fast formation and growth of fine particles, has attracted much attention in recent years. In order to investigate the secondary formation and aging process of urban aerosols, four intensive campaigns were conducted in four seasons between March 2012 and March 2013 at an urban site in Beijing (116.31° E, 37.99° N. An Aerodyne high-resolution time-of-flight aerosol mass spectrometry (HR-ToF-AMS was deployed to measure non-refractory chemical components of submicron particulate matter (NR-PM1. The average mass concentrations of PM1 (NR-PM1+black carbon were 45.1 ± 45.8, 37.5 ± 31.0, 41.3 ± 42.7, and 81.7 ± 72.4 µg m−3 in spring, summer, autumn, and winter, respectively. Organic aerosol (OA was the most abundant component in PM1, accounting for 31, 33, 44, and 36 % seasonally, and secondary inorganic aerosol (SNA, sum of sulfate, nitrate, and ammonium accounted for 59, 57, 43, and 55 % of PM1 correspondingly. Based on the application of positive matrix factorization (PMF, the sources of OA were obtained, including the primary ones of hydrocarbon-like (HOA, cooking (COA, biomass burning OA (BBOA and coal combustion OA (CCOA, and secondary component oxygenated OA (OOA. OOA, which can be split into more-oxidized (MO-OOA and less-oxidized OOA (LO-OOA, accounted for 49, 69, 47, and 50 % in four seasons, respectively. Totally, the fraction of secondary components (OOA+SNA contributed about 60–80 % to PM1, suggesting that secondary formation played an important role in the PM pollution in Beijing, and primary sources were also non-negligible. The evolution process of OA in different seasons was investigated with multiple metrics and tools. The average carbon oxidation states and other metrics show that the oxidation state of OA was the highest in summer, probably due to both strong photochemical and aqueous-phase oxidations

  7. Seasonal variations in high time-resolved chemical compositions, sources, and evolution of atmospheric submicron aerosols in the megacity Beijing

    Science.gov (United States)

    Hu, Wei; Hu, Min; Hu, Wei-Wei; Zheng, Jing; Chen, Chen; Wu, Yusheng; Guo, Song

    2017-08-01

    A severe regional haze problem in the megacity Beijing and surrounding areas, caused by fast formation and growth of fine particles, has attracted much attention in recent years. In order to investigate the secondary formation and aging process of urban aerosols, four intensive campaigns were conducted in four seasons between March 2012 and March 2013 at an urban site in Beijing (116.31° E, 37.99° N). An Aerodyne high-resolution time-of-flight aerosol mass spectrometry (HR-ToF-AMS) was deployed to measure non-refractory chemical components of submicron particulate matter (NR-PM1). The average mass concentrations of PM1 (NR-PM1+black carbon) were 45.1 ± 45.8, 37.5 ± 31.0, 41.3 ± 42.7, and 81.7 ± 72.4 µg m-3 in spring, summer, autumn, and winter, respectively. Organic aerosol (OA) was the most abundant component in PM1, accounting for 31, 33, 44, and 36 % seasonally, and secondary inorganic aerosol (SNA, sum of sulfate, nitrate, and ammonium) accounted for 59, 57, 43, and 55 % of PM1 correspondingly. Based on the application of positive matrix factorization (PMF), the sources of OA were obtained, including the primary ones of hydrocarbon-like (HOA), cooking (COA), biomass burning OA (BBOA) and coal combustion OA (CCOA), and secondary component oxygenated OA (OOA). OOA, which can be split into more-oxidized (MO-OOA) and less-oxidized OOA (LO-OOA), accounted for 49, 69, 47, and 50 % in four seasons, respectively. Totally, the fraction of secondary components (OOA+SNA) contributed about 60-80 % to PM1, suggesting that secondary formation played an important role in the PM pollution in Beijing, and primary sources were also non-negligible. The evolution process of OA in different seasons was investigated with multiple metrics and tools. The average carbon oxidation states and other metrics show that the oxidation state of OA was the highest in summer, probably due to both strong photochemical and aqueous-phase oxidations. It was indicated by the good correlations

  8. Single particle analysis of eastern Mediterranean aerosol particles: Influence of the source region on the chemical composition

    Science.gov (United States)

    Clemen, Hans-Christian; Schneider, Johannes; Köllner, Franziska; Klimach, Thomas; Pikridas, Michael; Stavroulas, Iasonas; Sciare, Jean; Borrmann, Stephan

    2017-04-01

    The Mediterranean region is one of the most climatically sensitive areas and is influenced by air masses of different origin. Aerosol particles are one important factor contributing to the Earth's radiative forcing, but knowledge about their composition and sources is still limited. Here, we report on results from the INUIT-BACCHUS-ACTRIS campaign, which was conducted at the Cyprus Atmospheric Observatory (CAO, Agia Marina Xyliatou) in Cyprus in April 2016. Our results show that the chemical composition of the aerosol particles in the eastern Mediterranean is strongly dependent on their source region. The composition of particles in a size range between 150 nm and 3 μm was measured using the Aircraft-based Laser ABlation Aerosol MAss spectrometer (ALABAMA), which is a single particle laser ablation instrument using a bipolar time-of-flight mass spectrometer. The mass spectral information on cations and anions allow for the analysis of different molecular fragments. The information about the source regions results from backward trajectories using HYSPLIT Trajectory Model (Trajectory Ensemble) on hourly basis. To assess the influence of certain source regions on the air masses arriving at CAO, we consider the number of trajectories that crossed the respective source region within defined time steps. For a more detailed picture also the height and the velocity of the air masses during their overpass above the source regions will be considered. During the campaign at CAO in April 2016 three main air mass source regions were observed: 1) Northern Central Europe, likely with an enhanced anthropogenic influence (e.g. sulfate and black carbon from combustion processes, fly ash particles from power plants, characterized by Sr and Ba), 2) Southwest Europe, with a higher influence of the Mediterranean Sea including sea salt particles (characterized by, e.g., NaxCly, NaClxNOy), 3) Northern Africa/Sahara, with air masses that are expected to have a higher load of mineral dust

  9. Identification of radioactive sources and devices. Reference manual

    International Nuclear Information System (INIS)

    2007-01-01

    This publication is intended to be a basic guide and not a comprehensive tool kit to identify and provide detailed emergency handling instructions for radioactive sources, devices and transport containers. In addition, this publication helps to identify sources and highlight the risks they present, and provides information on appropriate action. It is a small but significant step in the international community's continuing efforts to strengthen control of radioactive sources and nuclear material, increase safety and security, and thereby make the benefits of radioactive sources ever more broadly accessible. This publication was partly funded through the Nuclear Security Fund established under the Nuclear Security Plan

  10. Development of unauthorized airborne emission source identification procedure

    Science.gov (United States)

    Shtripling, L. O.; Bazhenov, V. V.; Varakina, N. S.; Kupriyanova, N. P.

    2018-01-01

    The paper presents the procedure for searching sources of unauthorized airborne emissions. To make reasonable regulation decisions on airborne pollutant emissions and to ensure the environmental safety of population, the procedure provides for the determination of a pollutant mass emission value from the source being the cause of high pollution level and the search of a previously unrecognized contamination source in a specified area. To determine the true value of mass emission from the source, the minimum of the mean-root-square mismatch criterion between the computed and measured pollutant concentration in the given location is used.

  11. Identification of Turbomachinery Noise Sources Using Acoustical Holography, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Evaluation and enhancement of the acoustical performance of turbomachinery requires knowledge of the acoustic sources. However, the noise generation mechanisms...

  12. Advanced source apportionment of carbonaceous aerosols by coupling offline AMS and radiocarbon size-segregated measurements over a nearly 2-year period

    Directory of Open Access Journals (Sweden)

    A. Vlachou

    2018-05-01

    Full Text Available Carbonaceous aerosols are related to adverse human health effects. Therefore, identification of their sources and analysis of their chemical composition is important. The offline AMS (aerosol mass spectrometer technique offers quantitative separation of organic aerosol (OA factors which can be related to major OA sources, either primary or secondary. While primary OA can be more clearly separated into sources, secondary (SOA source apportionment is more challenging because different sources – anthropogenic or natural, fossil or non-fossil – can yield similar highly oxygenated mass spectra. Radiocarbon measurements provide unequivocal separation between fossil and non-fossil sources of carbon. Here we coupled these two offline methods and analysed the OA and organic carbon (OC of different size fractions (particulate matter below 10 and 2.5 µm – PM10 and PM2.5, respectively from the Alpine valley of Magadino (Switzerland during the years 2013 and 2014 (219 samples. The combination of the techniques gave further insight into the characteristics of secondary OC (SOC which was rather based on the type of SOC precursor and not on the volatility or the oxidation state of OC, as typically considered. Out of the primary sources separated in this study, biomass burning OC was the dominant one in winter, with average concentrations of 5.36 ± 2.64 µg m−3 for PM10 and 3.83 ± 1.81 µg m−3 for PM2.5, indicating that wood combustion particles were predominantly generated in the fine mode. The additional information from the size-segregated measurements revealed a primary sulfur-containing factor, mainly fossil, detected in the coarse size fraction and related to non-exhaust traffic emissions with a yearly average PM10 (PM2.5 concentration of 0.20 ± 0.24 µg m−3 (0.05 ± 0.04 µg m−3. A primary biological OC (PBOC was also detected in the coarse mode peaking in spring and summer with a yearly average PM10

  13. Organic aerosol composition and sources in Pasadena, California, during the 2010 CalNex campaign

    Science.gov (United States)

    Hayes, P. L.; Ortega, A. M.; Cubison, M. J.; Froyd, K. D.; Zhao, Y.; Cliff, S. S.; Hu, W. W.; Toohey, D. W.; Flynn, J. H.; Lefer, B. L.; Grossberg, N.; Alvarez, S.; Rappenglück, B.; Taylor, J. W.; Allan, J. D.; Holloway, J. S.; Gilman, J. B.; Kuster, W. C.; de Gouw, J. A.; Massoli, P.; Zhang, X.; Liu, J.; Weber, R. J.; Corrigan, A. L.; Russell, L. M.; Isaacman, G.; Worton, D. R.; Kreisberg, N. M.; Goldstein, A. H.; Thalman, R.; Waxman, E. M.; Volkamer, R.; Lin, Y. H.; Surratt, J. D.; Kleindienst, T. E.; Offenberg, J. H.; Dusanter, S.; Griffith, S.; Stevens, P. S.; Brioude, J.; Angevine, W. M.; Jimenez, J. L.

    2013-08-01

    Organic aerosols (OA) in Pasadena are characterized using multiple measurements from the California Research at the Nexus of Air Quality and Climate Change (CalNex) campaign. Five OA components are identified using positive matrix factorization including hydrocarbon-like OA (HOA) and two types of oxygenated OA (OOA). The Pasadena OA elemental composition when plotted as H : C versus O : C follows a line less steep than that observed for Riverside, CA. The OOA components from both locations follow a common line, however, indicating similar secondary organic aerosol (SOA) oxidation chemistry at the two sites such as fragmentation reactions leading to acid formation. In addition to the similar evolution of elemental composition, the dependence of SOA concentration on photochemical age displays quantitatively the same trends across several North American urban sites. First, the OA/ΔCO values for Pasadena increase with photochemical age exhibiting a slope identical to or slightly higher than those for Mexico City and the northeastern United States. Second, the ratios of OOA to odd-oxygen (a photochemical oxidation marker) for Pasadena, Mexico City, and Riverside are similar, suggesting a proportional relationship between SOA and odd-oxygen formation rates. Weekly cycles of the OA components are examined as well. HOA exhibits lower concentrations on Sundays versus weekdays, and the decrease in HOA matches that predicted for primary vehicle emissions using fuel sales data, traffic counts, and vehicle emission ratios. OOA does not display a weekly cycle—after accounting for differences in photochemical aging —which suggests the dominance of gasoline emissions in SOA formation under the assumption that most urban SOA precursors are from motor vehicles.

  14. High time-resolved chemical compositions, sources and evolution for atmospheric submicron aerosols in the winter of Beijing

    Science.gov (United States)

    Min, H.; Hu, W.; Zheng, J.; Guo, S.; Wu, Y.; Zeng, L.; Lu, S.; Xie, S.; Zhang, Y.

    2017-12-01

    Severe regional haze problem in the megacity Beijing and surrounding areas has attracted much attention in recent years. In order to investigate the secondary formation and aging process of urban aerosols, intensive campaigns were conducted in the winter of 2010 and 2013 at an urban site in Beijing. An Aerodyne high resolution time-of-flight aerosol mass spectrometry (HR-ToF-AMS) was deployed to measure chemical components of PM1, coupled with multiple state of the art online instruments. In the winter of 2010, PM1 mass concentrations changed dramatically along with meteorological conditions. The high average fraction (58%) of primary species in PM1 indicated that primary emissions usually played a more important role. Based on the source apportionment results, 45% POA are from non-fossil sources, contributed by cooking OA and biomass burning OA (BBOA). Cooking OA, accounting for 13-24% of OA, is an important non-fossil carbon source in all years of Beijing and should not be neglected. The fossil sources of POA include hydrocarbon-like OA from vehicle emissions and coal combustion OA (CCOA). The CCOA and BBOA were the two main contributors (57% of OA) for the highest OA concentrations (>100 μg m-3). In the winter of 2013, OOA (MO-OOA and LO-OOA), accounted for 50% of PM1, while (OOA+SNA) contributed 60-80%, suggesting that secondary formation played an important role in the PM pollution. In the winter of 2010 higher OOA/Ox (= NO2 + O3) ratio (0.49 μg m-3 ppb-1) than these ratios from western cities (0.03-0.16 μg m-3 ppb-1) was observed, which may be due to the aqueous reaction or extra SOA formation contributed by semi-VOCs from various primary sources (e.g., BBOA or CCOA). However, aqueous chemistry resulting in efficient secondary formation during occasional periods with high relative humidity may also contribute substantially to haze in winter. CCOA was only identified in winter due to domestic heating. These results signified that the comprehensive

  15. Speciation of {sup 127}I and {sup 129}I in atmospheric aerosols at Risoe, Denmark. Insight into sources of iodine isotopes and their species transformations

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Luyuan; Hou, Xiaolin [Technical Univ. of Denmark, Roskilde (Denmark). Center for Nuclear Technologies; Chinese Academy of Sciences, Xi' an (China). State Key Laboratory of Loess and Quaternary Geology; Xu, Sheng [Scottish Universities Environmental Research Center, East Kilbride (United Kingdom)

    2016-07-01

    Speciation analysis of iodine in aerosols is a very useful approach for understanding geochemical cycling of iodine in the atmosphere. In this study, overall iodine species, including water-soluble iodine species (iodide, iodate and water-soluble organic iodine), NaOH-soluble iodine, and insoluble iodine have been determined for {sup 129}I and {sup 127}I in the aerosols collected at Risoe, Denmark, during March and May 2011 (shortly after the Fukushima nuclear accident) and in December 2014. The measured concentrations of total iodine are in the range of 1.04-2.48 ngm{sup -3} for {sup 127}I and (11.3-97.0) x 10{sup 5} atoms m{sup -3} for {sup 129}I, corresponding to {sup 129}I/{sup 127}I atomic ratios of (17.8-86.8) x 10{sup -8}. The contribution of Fukushima-derived {sup 129}I (peak value of 6.3 x 10{sup 4} atoms m{sup -3}) is estimated to be negligible (less than 6 %) compared to the total {sup 129}I concentration in northern Europe. The concentrations and species of {sup 129}I and {sup 127}I in the aerosols are found to be strongly related to their sources and atmospheric pathways. Aerosols that were transported over the contaminated seas contained higher concentrations of {sup 129}I than aerosols transported over the European continent. The high {sup 129}I concentrations of the marine aerosols are attributed to secondary emission of marine discharged {sup 129}I in the contaminated seawater in the North Sea, North Atlantic Ocean, English Channel, Kattegat, etc., rather than direct gaseous release from the European nuclear reprocessing plants (NRPs). Water-soluble iodine was found to be a minor fraction to the total iodine for both {sup 127}I (7.8-13.7 %) and {sup 129}I (6.5-14.1 %) in ocean-derived aerosols, but accounted for 20.2-30.3% for {sup 127}I and 25.6-29.5 % for {sup 129}I in land-derived aerosols. Iodide was the predominant form of water-soluble iodine, accounting for more than 97 % of the water-soluble iodine. NaOH-soluble iodine seems to be

  16. TOXICOLOGICAL EVALUATION OF REALISTIC EMISSIONS OF SOURCE AEROSOLS (TERESA): APPLICATION TO POWER PLANT-DERIVED PM2.5

    Energy Technology Data Exchange (ETDEWEB)

    Annette Rohr

    2005-03-31

    This report documents progress made on the subject project during the period of September 1, 2004 through February 28, 2005. The TERESA Study is designed to investigate the role played by specific emissions sources and components in the induction of adverse health effects by examining the relative toxicity of coal combustion and mobile source (gasoline and/or diesel engine) emissions and their oxidative products. The study involves on-site sampling, dilution, and aging of coal combustion emissions at three coal-fired power plants, as well as mobile source emissions, followed by animal exposures incorporating a number of toxicological endpoints. The DOE-EPRI Cooperative Agreement (henceforth referred to as ''the Agreement'') for which this technical progress report has been prepared covers the performance and analysis of field experiments at the first TERESA plant, located in the Upper Midwest and henceforth referred to as Plant 0, and at two additional coal-fired power plants (Plants 1 and 2) utilizing different coal types and with different plant configurations. During this reporting period, all fieldwork at Plant 0 was completed. Stack sampling was conducted in October to determine if there were significant differences between the in-stack PM concentrations and the diluted concentrations used for the animal exposures. Results indicated no significant differences and therefore confidence that the revised stack sampling methodology described in the previous semiannual report is appropriate for use in the Project. Animal exposures to three atmospheric scenarios were carried out. From October 4-7, we conducted exposures to oxidized emissions with the addition of secondary organic aerosol (SOA). Later in October, exposures to the most complex scenario (oxidized, neutralized emissions plus SOA) were repeated to ensure comparability with the results of the June/July exposures where a different stack sampling setup was employed. In November, exposures

  17. Future radiation sources and identification of irradiated foods

    International Nuclear Information System (INIS)

    Brynjolfsson, A.

    1989-01-01

    Two major questions regarding irradiation that are raised today are: (1) Which sources should be used for irradiating food? and (2) How can irradiated foods be identified? This article considers both questions. After briefly mentioning a few of the historical stepping stones in the development of radiation sources, present and future radiation sources are discussed. Next the changes in foods caused by irradiation are considered. These changes are extremely small-so minor in fact that it is difficult to detect if the food has been irradiated. Still, these are several detection methods available, and this article describes them

  18. Real-Time Observations of Secondary Aerosol Formation and Aging from Different Emission Sources and Environments

    Science.gov (United States)

    Ortega, A. M.; Palm, B. B.; Hayes, P. L.; Day, D. A.; Cubison, M.; Brune, W. H.; Hu, W.; Flynn, J. H.; Grossberg, N.; Lefer, B. L.; Rappenglueck, B.; Bon, D.; Graus, M.; Warneke, C.; Gilman, J.; Kuster, W.; De Gouw, J. A.; Jimenez, J. L.

    2013-12-01

    To investigate atmospheric processing of direct urban and wildfire emissions, we deployed a photochemical flow reactor (Potential Aerosol Mass, PAM) with submicron aerosol size and chemical composition measurements during FLAME-3, a biomass-burning study at USDA Fire Sciences Laboratory in Missoula, MT, and CalNex, a field study investigating the nexus of air quality and climate change at a receptor site in the LA-Basin at Pasadena, CA. The reactor produces OH concentrations up to 4 orders of magnitude higher than in ambient air, achieving equivalent aging of ~2 weeks in 5 minutes of processing. The OH exposure (OHexp) was stepped every 20 min in both field studies. Results show the value of this approach as a tool for in-situ evaluation of changes in OA concentration and composition due to photochemical processing. In FLAME-3, the average OA enhancement factor was 1.42 × 0.36 of the initial POA. Reactive VOCs, such as toluene, monoterpenes, and acetaldehyde, decreased with increased OHexp; however, formic acid, acetone, and some unidentified OVOCs increased after significant exposure. Net SOA formation in the photochemical reactor increased with OHexp, typically peaking around 3 days of equivalent atmospheric photochemical age (OHexp ~3.9e11 molecules cm-3 s), then leveling off at higher exposures. Unlike other studies, no decrease in OA is observed at high exposure, likely due to lower max OHexp in this study due to very high OH reactivity. The amount of additional OA mass added from aging is positively correlated with initial POA concentration, but not with the total VOC concentration or the concentration of known SOA precursors. The mass of SOA formed often exceeded the mass of the known VOC precursors, indicating the likely importance of primary semivolatile/intermediate volatility species, and possibly of unidentified VOCs as SOA precursors in biomass burning smoke. Results from CalNex show enhancement of OA and inorganic aerosol from gas-phase precursors

  19. ACTRIS ACSM intercomparison - Part 2: Intercomparison of ME-2 organic source apportionment results from 15 individual, co-located aerosol mass spectrometers

    Science.gov (United States)

    Fröhlich, R.; Crenn, V.; Setyan, A.; Belis, C. A.; Canonaco, F.; Favez, O.; Riffault, V.; Slowik, J. G.; Aas, W.; Aijälä, M.; Alastuey, A.; Artiñano, B.; Bonnaire, N.; Bozzetti, C.; Bressi, M.; Carbone, C.; Coz, E.; Croteau, P. L.; Cubison, M. J.; Esser-Gietl, J. K.; Green, D. C.; Gros, V.; Heikkinen, L.; Herrmann, H.; Jayne, J. T.; Lunder, C. R.; Minguillón, M. C.; Močnik, G.; O'Dowd, C. D.; Ovadnevaite, J.; Petralia, E.; Poulain, L.; Priestman, M.; Ripoll, A.; Sarda-Estève, R.; Wiedensohler, A.; Baltensperger, U.; Sciare, J.; Prévôt, A. S. H.

    2015-06-01

    Chemically resolved atmospheric aerosol data sets from the largest intercomparison of the Aerodyne aerosol chemical speciation monitors (ACSMs) performed to date were collected at the French atmospheric supersite SIRTA. In total 13 quadrupole ACSMs (Q-ACSM) from the European ACTRIS ACSM network, one time-of-flight ACSM (ToF-ACSM), and one high-resolution ToF aerosol mass spectrometer (AMS) were operated in parallel for about 3 weeks in November and December~2013. Part 1 of this study reports on the accuracy and precision of the instruments for all the measured species. In this work we report on the intercomparison of organic components and the results from factor analysis source apportionment by positive matrix factorisation (PMF) utilising the multilinear engine 2 (ME-2). Except for the organic contribution of mass-to-charge ratio m/z 44 to the total organics (f44), which varied by factors between 0.6 and 1.3 compared to the mean, the peaks in the organic mass spectra were similar among instruments. The m/z 44 differences in the spectra resulted in a variable f44 in the source profiles extracted by ME-2, but had only a minor influence on the extracted mass contributions of the sources. The presented source apportionment yielded four factors for all 15 instruments: hydrocarbon-like organic aerosol (HOA), cooking-related organic aerosol (COA), biomass burning-related organic aerosol (BBOA) and secondary oxygenated organic aerosol (OOA). ME-2 boundary conditions (profile constraints) were optimised individually by means of correlation to external data in order to achieve equivalent / comparable solutions for all ACSM instruments and the results are discussed together with the investigation of the influence of alternative anchors (reference profiles). A comparison of the ME-2 source apportionment output of all 15 instruments resulted in relative standard deviations (SD) from the mean between 13.7 and 22.7 % of the source's average mass contribution depending on the

  20. ACTRIS ACSM intercomparison – Part 2: Intercomparison of ME-2 organic source apportionment results from 15 individual, co-located aerosol mass spectrometers

    Directory of Open Access Journals (Sweden)

    R. Fröhlich

    2015-06-01

    Full Text Available Chemically resolved atmospheric aerosol data sets from the largest intercomparison of the Aerodyne aerosol chemical speciation monitors (ACSMs performed to date were collected at the French atmospheric supersite SIRTA. In total 13 quadrupole ACSMs (Q-ACSM from the European ACTRIS ACSM network, one time-of-flight ACSM (ToF-ACSM, and one high-resolution ToF aerosol mass spectrometer (AMS were operated in parallel for about 3 weeks in November and December~2013. Part 1 of this study reports on the accuracy and precision of the instruments for all the measured species. In this work we report on the intercomparison of organic components and the results from factor analysis source apportionment by positive matrix factorisation (PMF utilising the multilinear engine 2 (ME-2. Except for the organic contribution of mass-to-charge ratio m/z 44 to the total organics (f44, which varied by factors between 0.6 and 1.3 compared to the mean, the peaks in the organic mass spectra were similar among instruments. The m/z 44 differences in the spectra resulted in a variable f44 in the source profiles extracted by ME-2, but had only a minor influence on the extracted mass contributions of the sources. The presented source apportionment yielded four factors for all 15 instruments: hydrocarbon-like organic aerosol (HOA, cooking-related organic aerosol (COA, biomass burning-related organic aerosol (BBOA and secondary oxygenated organic aerosol (OOA. ME-2 boundary conditions (profile constraints were optimised individually by means of correlation to external data in order to achieve equivalent / comparable solutions for all ACSM instruments and the results are discussed together with the investigation of the influence of alternative anchors (reference profiles. A comparison of the ME-2 source apportionment output of all 15 instruments resulted in relative standard deviations (SD from the mean between 13.7 and 22.7 % of the source's average mass contribution depending on

  1. Source identification of a tar residue from Mumbai Beach

    Digital Repository Service at National Institute of Oceanography (India)

    Kadam, A; Rokade, M.A

    A tar residue from Mumbai Beach, Maharashtra, India was matched with the suspected source sample from a tanker using UV, IR and GLC techniques. Negligible differences in several ratios of UV absorbances and ratios of infrared transmittances...

  2. Optical identifications of flat-spectrum radio sources

    International Nuclear Information System (INIS)

    Condon, J.J.; Condon, M.A.; Broderick, J.J.; Davis, M.M.

    1983-01-01

    A complete sample of radio sources with S> or =0.3 Jy at 1400 MHz, +24 0 0 , and low-frequency spectral indices α(408, 1400) or =+0.5 are usually in empty fields. The lower limits that can be assigned to the radio-optical spectral indices α/sub RO/ of these sources are significantly higher than the median α/sub RO/ of the sources with flat high-frequency spectra, so the optical characteristics of the two classes of radio source are intrinsically different. The radio and optical fluxes of flat-spectrum QSO's appear to be correlated, at least when averaged over 10 2 --10 3 yr

  3. High Fidelity Tool for Noise Source Identification, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Thorough understanding of airframe and propulsion aerodynamic noise sources and the subsequent acoustic propagation to the farfield is necessary to the design and...

  4. Volatility of source apportioned wintertime organic aerosol in the city of Athens

    Science.gov (United States)

    Louvaris, Evangelos E.; Florou, Kalliopi; Karnezi, Eleni; Papanastasiou, Dimitrios K.; Gkatzelis, Georgios I.; Pandis, Spyros N.

    2017-06-01

    The volatility distribution of ambient organic aerosol (OA) and its components was measured during the winter of 2013 in the city of Athens combining a thermodenuder (TD) and a High Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS). Positive Matrix Factorization (PMF) analysis of both the ambient and the thermodenuder AMS-spectra resulted in a four-factor solution for the OA, namely: hydrocarbon-like OA (HOA), biomass burning OA (BBOA), cooking OA (COA), and oxygenated OA (OOA). The thermograms of the four factors were analyzed and the corresponding volatility distributions were estimated using the volatility basis set (VBS). All four factors included compounds with a wide range of effective volatilities from 10 to less than 10-4 μg m-3 at 298 K. Almost 40% of the HOA consisted of low-volatility organic compounds (LVOCs) with the semi-volatile compounds (SVOCs) representing roughly 30%, while the remaining 30% consisted of extremely low volatility organic compounds (ELVOCs). BBOA was more volatile than the HOA factor on average, with 10% ELVOCs, 40% LVOCs, and 50% SVOCs. 10% of the COA consisted of ELVOCs, another 65% LVOCs, and 50% SVOCs. Finally, the OOA was the least volatile factor and included 40% ELVOCs, 25% LVOCs, and 35% SVOCs. Combining the volatility distributions and the O:C ratios of the various factors, we placed our results in the 2D-VBS analysis framework of Donahue et al. (2012). HOA and BBOA are in the expected region but also include an ELVOC component. COA is in similar range as HOA, but on average is half an order of magnitude more volatile. The OOA in these wintertime conditions had a moderate O:C ratio and included both semi-volatile and extremely low volatility components. The above results are sensitive to the assumed values of the effective vaporization enthalpy and the accommodation coefficient. A reduction of the accommodation coefficient by an order of magnitude or the reduction of the vaporization enthalpy by 20 kJ mol-1

  5. Demonstration of an ethane spectrometer for methane source identification.

    Science.gov (United States)

    Yacovitch, Tara I; Herndon, Scott C; Roscioli, Joseph R; Floerchinger, Cody; McGovern, Ryan M; Agnese, Michael; Pétron, Gabrielle; Kofler, Jonathan; Sweeney, Colm; Karion, Anna; Conley, Stephen A; Kort, Eric A; Nähle, Lars; Fischer, Marc; Hildebrandt, Lars; Koeth, Johannes; McManus, J Barry; Nelson, David D; Zahniser, Mark S; Kolb, Charles E

    2014-07-15

    Methane is an important greenhouse gas and tropospheric ozone precursor. Simultaneous observation of ethane with methane can help identify specific methane source types. Aerodyne Ethane-Mini spectrometers, employing recently available mid-infrared distributed feedback tunable diode lasers (DFB-TDL), provide 1 s ethane measurements with sub-ppb precision. In this work, an Ethane-Mini spectrometer has been integrated into two mobile sampling platforms, a ground vehicle and a small airplane, and used to measure ethane/methane enhancement ratios downwind of methane sources. Methane emissions with precisely known sources are shown to have ethane/methane enhancement ratios that differ greatly depending on the source type. Large differences between biogenic and thermogenic sources are observed. Variation within thermogenic sources are detected and tabulated. Methane emitters are classified by their expected ethane content. Categories include the following: biogenic (6%), pipeline grade natural gas (30%). Regional scale observations in the Dallas/Fort Worth area of Texas show two distinct ethane/methane enhancement ratios bridged by a transitional region. These results demonstrate the usefulness of continuous and fast ethane measurements in experimental studies of methane emissions, particularly in the oil and natural gas sector.

  6. Aerosol typing - key information from aerosol studies

    Science.gov (United States)

    Mona, Lucia; Kahn, Ralph; Papagiannopoulos, Nikolaos; Holzer-Popp, Thomas; Pappalardo, Gelsomina

    2016-04-01

    Aerosol typing is a key source of aerosol information from ground-based and satellite-borne instruments. Depending on the specific measurement technique, aerosol typing can be used as input for retrievals or represents an output for other applications. Typically aerosol retrievals require some a priori or external aerosol type information. The accuracy of the derived aerosol products strongly depends on the reliability of these assumptions. Different sensors can make use of different aerosol type inputs. A critical review and harmonization of these procedures could significantly reduce related uncertainties. On the other hand, satellite measurements in recent years are providing valuable information about the global distribution of aerosol types, showing for example the main source regions and typical transport paths. Climatological studies of aerosol load at global and regional scales often rely on inferred aerosol type. There is still a high degree of inhomogeneity among satellite aerosol typing schemes, which makes the use different sensor datasets in a consistent way difficult. Knowledge of the 4d aerosol type distribution at these scales is essential for understanding the impact of different aerosol sources on climate, precipitation and air quality. All this information is needed for planning upcoming aerosol emissions policies. The exchange of expertise and the communication among satellite and ground-based measurement communities is fundamental for improving long-term dataset consistency, and for reducing aerosol type distribution uncertainties. Aerosol typing has been recognized as one of its high-priority activities of the AEROSAT (International Satellite Aerosol Science Network, http://aero-sat.org/) initiative. In the AEROSAT framework, a first critical review of aerosol typing procedures has been carried out. The review underlines the high heterogeneity in many aspects: approach, nomenclature, assumed number of components and parameters used for the

  7. Source-Type Identification Analysis Using Regional Seismic Moment Tensors

    Science.gov (United States)

    Chiang, A.; Dreger, D. S.; Ford, S. R.; Walter, W. R.

    2012-12-01

    Waveform inversion to determine the seismic moment tensor is a standard approach in determining the source mechanism of natural and manmade seismicity, and may be used to identify, or discriminate different types of seismic sources. The successful applications of the regional moment tensor method at the Nevada Test Site (NTS) and the 2006 and 2009 North Korean nuclear tests (Ford et al., 2009a, 2009b, 2010) show that the method is robust and capable for source-type discrimination at regional distances. The well-separated populations of explosions, earthquakes and collapses on a Hudson et al., (1989) source-type diagram enables source-type discrimination; however the question remains whether or not the separation of events is universal in other regions, where we have limited station coverage and knowledge of Earth structure. Ford et al., (2012) have shown that combining regional waveform data and P-wave first motions removes the CLVD-isotropic tradeoff and uniquely discriminating the 2009 North Korean test as an explosion. Therefore, including additional constraints from regional and teleseismic P-wave first motions enables source-type discrimination at regions with limited station coverage. We present moment tensor analysis of earthquakes and explosions (M6) from Lop Nor and Semipalatinsk test sites for station paths crossing Kazakhstan and Western China. We also present analyses of smaller events from industrial sites. In these sparse coverage situations we combine regional long-period waveforms, and high-frequency P-wave polarity from the same stations, as well as from teleseismic arrays to constrain the source type. Discrimination capability with respect to velocity model and station coverage is examined, and additionally we investigate the velocity model dependence of vanishing free-surface traction effects on seismic moment tensor inversion of shallow sources and recovery of explosive scalar moment. Our synthetic data tests indicate that biases in scalar

  8. Coal Ash Aerosol in East Asian Outflow as a Source for Oceanic Deposition of Iron and Other Metals

    Science.gov (United States)

    Anderson, J. R.; Hua, X.

    2008-12-01

    While ocean deposition of East Asian dust is given significant emphasis as a source of biologically-active trace elements, iron in particular, dust events are episodic and highly seasonal. There is, however, a constant source of aerosol that is chemically similar to dust (albeit amorphous in structure rather than crystalline) in the ash particles emitted from many hundreds of coal-fired power plants that are sited along the entire coastal region of China and Korea. The emission controls on these facilities vary widely and, in even cases of state-of-the-art emission controls, the secondary release of ash can be significant. There are of course even more small industrial and household sources of coal combustion emissions, in most cases with little or no emissions controls. Ash from a modern coal-fired power facility in Korea has been examined chemically and morphologically with electron microscopic techniques. As is characteristic of all such facilities, two principal types of ash are present: (1) flyash, silicate glass spheres that are emitted with the smoke and removed by electrostatic precipitators; and (2) bottom ash, "clinkers" and noncombustible material sticking to the furnace walls that are mixed with water and ground after cooling, then removed as a slurry to a dumping area. In addition, iron sulfide (pyrite) is a common constituent of coal and provides both a source of sulfur dioxide gas and also molten iron spherical particles in the ash. The iron spheres then are rapidly oxidized upon cooling. Bottom ash is a more complex material than flyash in that it contains more iron and other trace metals, plus it contains varying amounts of uncombusted carbon. The post-combustion handling of bottom ash can lead to significant emissions despite the fact that little or none goes out the stack. The iron oxide spheres can also be emitted by this secondary method. The concentrations of ash can be very high in close proximity to power plants (PM10 of several hundred

  9. Insights into characteristics, sources, and evolution of submicron aerosols during harvest seasons in the Yangtze River delta region, China

    Science.gov (United States)

    Zhang, Y. J.; Tang, L. L.; Wang, Z.; Yu, H. X.; Sun, Y. L.; Liu, D.; Qin, W.; Canonaco, F.; Prévôt, A. S. H.; Zhang, H. L.; Zhou, H. C.

    2015-02-01

    Atmospheric submicron particulate matter (PM1) is one of the most significant pollution components in China. Despite its current popularity in the studies of aerosol chemistry, the characteristics, sources and evolution of atmospheric PM1 species are still poorly understood in China, particularly for the two harvest seasons, namely, the summer wheat harvest and autumn rice harvest. An Aerodyne Aerosol Chemical Speciation Monitor (ACSM) was deployed for online monitoring of PM1 components during summer and autumn harvest seasons in urban Nanjing, in the Yangtze River delta (YRD) region of China. PM1 components were shown to be dominated by organic aerosol (OA, 39 and 41%) and nitrate (23 and 20%) during the harvest seasons (the summer and autumn harvest). Positive matrix factorization (PMF) analysis of the ACSM OA mass spectra resolved four OA factors: hydrocarbon-like mixed with cooking-related OA (HOA + COA), fresh biomass-burning OA (BBOA), oxidized biomass-burning-influenced OA (OOA-BB), and highly oxidized OA (OOA); in particular the oxidized BBOA contributes ~80% of the total BBOA loadings. Both fresh and oxidized BBOA exhibited apparent diurnal cycles with peak concentration at night, when the high ambient relative humidity and low temperature facilitated the partitioning of semi-volatile organic species into the particle phase. The fresh BBOA concentrations for the harvests are estimated as BBOA = 15.1 × (m/z 60-0.26% × OA), where m/z (mass-to-charge ratio) 60 is a marker for levoglucosan-like species. The (BBOA + OOA-BB)/ΔCO, (ΔCO is the CO minus background CO), decreases as a function of f44 (fraction of m/z 44 in OA signal), which might indicate that BBOA was oxidized to less volatile OOA, e.g., more aged and low volatility OOA (LV-OOA) during the aging process. Analysis of air mass back trajectories indicates that the high BB pollutant concentrations are linked to the air masses from the western (summer harvest) and southern (autumn harvest) areas.

  10. Identification of sources and long term trends for pollutants in the arctic using isentropic trajectory analysis

    Energy Technology Data Exchange (ETDEWEB)

    Mahura, A.; Jaffe, D.; Harris, J.

    2003-07-01

    The understanding of factors driving climate and ecosystem changes in the Arctic requires careful consideration of the sources, correlation and trends for anthropogenic pollutants. The database from the NOAA-CMDL Barrow Observatory (71deg.17'N, 156deg.47'W) is the longest and most complete record of pollutant measurements in the Arctic. It includes observations of carbon dioxide (CO{sub 2}), methane (CH{sub 4}), carbon monoxide (CO), ozone (O{sub 3}), aerosol scattering coefficient ({sigma}{sub sp}), aerosol number concentration (NC{sub asl}), etc. The objectives of this study are to understand the role of long-range transport to Barrow in explaining: (1) the year-to-year variations, and (2) the trends in the atmospheric chemistry record at the NOAA-CMDL Barrow observatory. The key questions we try to answer are: 1. What is the relationship between various chemical species measured at Barrow Observatory, Alaska and transport pathways at various altitudes? 2. What are the trends of species and their relation to transport patterns from the source regions? 3. What is the impact of the Prudhoe Bay emissions on the Barrow's records? To answer on these questions we apply the following main research tools. First, it is an isentropic trajectory model used to calculate the trajectories arriving at Barrow at three altitudes of 0.5, 1.5 and 3 km above sea level. Second - clustering procedure used to divide the trajectories into groups based on source regions. Third - various statistical analysis tools such as the exploratory data analysis, two component correlation analysis, trend analysis, principal components and factor analysis used to identify the relationship between various chemical species vs. source regions as a function of time. In this study, we used the chemical data from the NOAA-CMDL Barrow observatory in combination with isentropic backward trajectories from gridded ECMWF data to understand the importance of various pollutant source regions on

  11. Identification of sources and long term trends for pollutants in the arctic using isentropic trajectory analysis

    International Nuclear Information System (INIS)

    Mahura, A.; Jaffe, D.; Harris, J.

    2003-01-01

    The understanding of factors driving climate and ecosystem changes in the Arctic requires careful consideration of the sources, correlation and trends for anthropogenic pollutants. The database from the NOAA-CMDL Barrow Observatory (71deg.17'N, 156deg.47'W) is the longest and most complete record of pollutant measurements in the Arctic. It includes observations of carbon dioxide (CO 2 ), methane (CH 4 ), carbon monoxide (CO), ozone (O 3 ), aerosol scattering coefficient (σ sp ), aerosol number concentration (NC asl ), etc. The objectives of this study are to understand the role of long-range transport to Barrow in explaining: (1) the year-to-year variations, and (2) the trends in the atmospheric chemistry record at the NOAA-CMDL Barrow observatory. The key questions we try to answer are: 1. What is the relationship between various chemical species measured at Barrow Observatory, Alaska and transport pathways at various altitudes? 2. What are the trends of species and their relation to transport patterns from the source regions? 3. What is the impact of the Prudhoe Bay emissions on the Barrow's records? To answer on these questions we apply the following main research tools. First, it is an isentropic trajectory model used to calculate the trajectories arriving at Barrow at three altitudes of 0.5, 1.5 and 3 km above sea level. Second - clustering procedure used to divide the trajectories into groups based on source regions. Third - various statistical analysis tools such as the exploratory data analysis, two component correlation analysis, trend analysis, principal components and factor analysis used to identify the relationship between various chemical species vs. source regions as a function of time. In this study, we used the chemical data from the NOAA-CMDL Barrow observatory in combination with isentropic backward trajectories from gridded ECMWF data to understand the importance of various pollutant source regions on atmospheric composition in the Arctic. We

  12. Technical Note: A new global database of trace gases and aerosols from multiple sources of high vertical resolution measurements

    Directory of Open Access Journals (Sweden)

    G. E. Bodeker

    2008-09-01

    Full Text Available A new database of trace gases and aerosols with global coverage, derived from high vertical resolution profile measurements, has been assembled as a collection of binary data files; hereafter referred to as the "Binary DataBase of Profiles" (BDBP. Version 1.0 of the BDBP, described here, includes measurements from different satellite- (HALOE, POAM II and III, SAGE I and II and ground-based measurement systems (ozonesondes. In addition to the primary product of ozone, secondary measurements of other trace gases, aerosol extinction, and temperature are included. All data are subjected to very strict quality control and for every measurement a percentage error on the measurement is included. To facilitate analyses, each measurement is added to 3 different instances (3 different grids of the database where measurements are indexed by: (1 geographic latitude, longitude, altitude (in 1 km steps and time, (2 geographic latitude, longitude, pressure (at levels ~1 km apart and time, (3 equivalent latitude, potential temperature (8 levels from 300 K to 650 K and time.

    In contrast to existing zonal mean databases, by including a wider range of measurement sources (both satellite and ozonesondes, the BDBP is sufficiently dense to permit calculation of changes in ozone by latitude, longitude and altitude. In addition, by including other trace gases such as water vapour, this database can be used for comprehensive radiative transfer calculations. By providing the original measurements rather than derived monthly means, the BDBP is applicable to a wider range of applications than databases containing only monthly mean data. Monthly mean zonal mean ozone concentrations calculated from the BDBP are compared with the database of Randel and Wu, which has been used in many earlier analyses. As opposed to that database which is generated from regression model fits, the BDBP uses the original (quality controlled measurements with no smoothing applied in any

  13. Review of areas that may require simultaneous coupled solution of the thermal hydraulic and fission product/aerosol behavior equations for source term determination

    International Nuclear Information System (INIS)

    Kress, T.S.

    1984-01-01

    In the determination of the behavior of nuclear aerosols in the reactor coolant system and in the containment for the development of severe accident source terms, present practice generally is to first perform thermal hydraulic calculations for specific plant types and sequences and then to utilize the results as input for separate fission product/aerosol dynamic transport calculations. It is recognized that there are several areas in which the thermal-hydraulics and the fission product/aerosol behavior may be significantly coupled and that it is then basically incorrect to do the analyses in a separated manner. This review paper produces a speculative list of these potentially coupled areas and attempts to assess the importance of the coupling for as many of the specific items that time has allowed before this conference

  14. Stable Isotope Identification of Nitrogen Sources for United ...

    Science.gov (United States)

    We used natural abundance stable isotope data to evaluate nitrogen sources to U.S. west coast estuaries. We collected δ15N of macroalgae data and supplemented this with available data from the literature for estuaries from Mexico to Alaska. Stable isotope ratios of green macroalgae were compared to δ15N of dissolved inorganic nitrogen of oceanic and watershed end members. There was a latitudinal gradient in δ15N of macroalgae with southern estuaries being 7 per mil heavier than northern estuaries. Gradients in isotope data were compared to nitrogen sources estimated by the USGS using the SPARROW model. In California estuaries, the elevation of isotope data appeared to be related to anthropogenic nitrogen sources. In Oregon systems, the nitrogen levels of streams flowing into the estuaries are related to forest cover, rather than to developed land classes. In addition, the δ15N of macroalgae suggested that the ocean and nitrogen-fixing trees in the watersheds were the dominant nitrogen sources. There was also a strong gradient in δ15N of macroalgae with heavier sites located near the estuary mouth. In some Oregon estuaries, there was an elevation an elevation of δ15N above marine end members in the vicinity of wastewater treatment facility discharge locations, suggesting isotopes may be useful for distinguishing inputs along an estuarine gradient. Nutrients are the leading cause of water quality impairments in the United States, and as a result too

  15. TOXICOLOGICAL EVALUATION OF REALISTIC EMISSIONS OF SOURCE AEROSOLS (TERESA): APPLICATION TO POWER PLANT-DERIVED PM2.5

    Energy Technology Data Exchange (ETDEWEB)

    Annette Rohr

    2006-03-01

    TERESA (Toxicological Evaluation of Realistic Emissions of Source Aerosols) involves exposing laboratory rats to realistic coal-fired power plant and mobile source emissions to help determine the relative toxicity of these PM sources. There are three coal-fired power plants in the TERESA program; this report describes the results of fieldwork conducted at the first plant, located in the Upper Midwest. The project was technically challenging by virtue of its novel design and requirement for the development of new techniques. By examining aged, atmospherically transformed aerosol derived from power plant stack emissions, we were able to evaluate the toxicity of PM derived from coal combustion in a manner that more accurately reflects the exposure of concern than existing methodologies. TERESA also involves assessment of actual plant emissions in a field setting--an important strength since it reduces the question of representativeness of emissions. A sampling system was developed and assembled to draw emissions from the stack; stack sampling conducted according to standard EPA protocol suggested that the sampled emissions are representative of those exiting the stack into the atmosphere. Two mobile laboratories were then outfitted for the study: (1) a chemical laboratory in which the atmospheric aging was conducted and which housed the bulk of the analytical equipment; and (2) a toxicological laboratory, which contained animal caging and the exposure apparatus. Animal exposures were carried out from May-November 2004 to a number of simulated atmospheric scenarios. Toxicological endpoints included (1) pulmonary function and breathing pattern; (2) bronchoalveolar lavage fluid cytological and biochemical analyses; (3) blood cytological analyses; (4) in vivo oxidative stress in heart and lung tissue; and (5) heart and lung histopathology. Results indicated no differences between exposed and control animals in any of the endpoints examined. Exposure concentrations for the

  16. INAA in combination with other analytical techniques in the study of urban aerosol sources

    International Nuclear Information System (INIS)

    Binh, N.T.; Truong, Y.; Ngo, N.T.; Sieu, L.N.; Hien, P.D.

    2000-01-01

    Concentrations of elements in fine and coarse PM10 samples collected in Ho Chi Minh City were determined by INAA for the purpose of characterising air pollution sources using multivariate receptor modeling techniques. Seven sources common to coarse and fine samples were identified. Resuspended soil dust is dominant in the coarse samples accounting for 41% of the particulate mass. In the fine samples, vehicle emissions and coal burning are most important accounting for about 20% each. Although a great number of elements were included in the input data for receptor modeling, the interpretation of emission sources was not always straightforward. Information on other source markers were needed. Therefore, a polarography method was used for quantifying lead, and recently, ion chromatography method became available for quantifying secondary sulphates, nitrates and other water soluble ions. (author)

  17. Source Apportionment of the Summer Time Carbonaceous Aerosol at Nordic Rural Background Sites

    Science.gov (United States)

    In the present study, natural and anthropogenic sources of particulate organic carbon (OCp) and elemental carbon (EC) have been quantified based on weekly filter samples of PM10 (particles with aerodynamic diameter Nordic rural backgro...

  18. Source apportionment of major and trace elements in aerosols during smog episodes in large cities in China

    Science.gov (United States)

    Furger, Markus; Rai, Pragati; Visser, Suzanne; Elser, Miriam; Canonaco, Francesco; Slowik, Jay G.; Huang, Ru-Jin; Prévôt, André S. H.; Baltensperger, Urs

    2017-04-01

    Air pollution in Chinese cities is one of the environmental problems China has to address to mitigate the impacts on human health, air quality and climate. Average concentrations of particulate matter exceed 100 μg m-3 in many places in China, and the government is developing and implementing strategies to reduce the load of pollutants by various measures. A characterization of airborne particulate matter (PM), especially its composition and sources, will help in optimizing reduction and mitigation strategies for air pollution. We collected PM10 aerosols with a rotating drum impactor (RDI) in Xi'an in December 2013 and in Beijing in January 2014 with 30-min time resolution and for three size ranges (cut-off sizes 10, 2.5 and 1 μm). Each campaign encompassed one or more high pollution episodes in the respective city. Elements from Na to Pb were analyzed with synchrotron radiation induced X-ray fluorescence spectrometry (SR-XRF), and the resulting time series were used for source apportionment performed with the Multilinear-Engine 2 (ME-2) implementation of the Positive Matrix Factorization algorithm. The preliminary computations yielded 5 factors for Beijing, namely road dust, sea salt, traffic-related, industrial, coal combustion. For Xi'an an additional desert dust factor was found. Further refinement could be expected from including the smaller size fractions, e.g. a sulfur-rich factor for secondary sulfate or a reacted chlorine factor in the fine mode fraction.

  19. Source identification of ambient PM2.5 during summer inhalation exposure studies in Detroit, MI

    Energy Technology Data Exchange (ETDEWEB)

    Morishita, M.; Keeler, G.J.; Wagner, J.G.; Harkema, J.R. [University of Michigan, Ann Arbor, MI (United States). Air Quality Laboratory

    2006-07-15

    Particulate air pollution is associated with cardiopulmonary morbidity and mortality in heavily populated urban centers of the United States. Because ambient fine particulate matter (aerodynamic diameter {<=} 2.5 {mu}m; PM2.5) is a complex mixture resulting from multiple sources and variable atmospheric conditions, it is difficult to identify specific components of PM2.5 that are responsible for adverse health effects. During four consecutive summers from 2000 to 2003 we characterized the ambient gaseous and PM2.5 air quality in an urban southwest Detroit community where childhood asthma hospitalization rates are more than twice the statewide average. Both integrated and continuous PM measurements together with gaseous air pollution measurements were performed using a mobile air research facility, AirCARE1, in which concurrent toxicological studies were being conducted. Chemical and physical characterizations of PM2.5 as well as receptor modeling using positive matrix factorization (PMF) were completed. Results from PMF indicated that six major sources contributed to the observed ambient PM2.5 mass during the summer months. Primary sources included (1) coal combustion/secondary sulfate aerosol, (2) motor vehicle/urban road dust, (3) municipal waste incinerators, (4) oil combustion/refineries, (5) sewage sludge incinerators, and (6) iron/steel manufacturing. Although the contribution of the coal/secondary sulfate aerosol source was greater than other factors, increased levels of urban PM2.5 from local combustion sources were also observed. In addition to characterization of ambient PM2.5 and their sources in southwest Detroit, this paper discusses possible associations of ambient PM2.5 from local combustion sources, specifically incinerator and refinery emissions and the observed adverse health effects during the inhalation exposure campaigns.

  20. Identification of resistant sources in chickpea against fusarium wilt

    International Nuclear Information System (INIS)

    Ahmad, M.A.; Ayub, N.; Akram, A.

    2010-01-01

    Wilt caused by Fusarium oxysporum Schlechtend.Fr. f. sp. ciceris is a devastating disease of chickpea in Pakistan. In the present study 321 genotypes from different sources were evaluated under controlled condition to identify genetic sources of resistance against this disease at seedling and reproductive stage. Disease reaction at two stages revealed considerable variation among the genotypes. At seedling stage disease incidence varied from 0 to 29.3% whereas at reproductive stage ranged from 0 to 57%. At seedling stage 173 genotypes were resistant, 54 were tolerant and 94 were susceptible, whereas at reproductive stage, 102 genotypes were resistant, 36 were tolerant and 183 were susceptible. Eighty two genotypes showed steady resistance at both stages. These genotypes may be exploited for the development of resistant cultivars against wilt. (author

  1. Preliminary investigation of processes that affect source term identification

    International Nuclear Information System (INIS)

    Wickliff, D.S.; Solomon, D.K.; Farrow, N.D.

    1991-09-01

    Solid Waste Storage Area (SWSA) 5 is known to be a significant source of contaminants, especially tritium ( 3 H), to the White Oak Creek (WOC) watershed. For example, Solomon et al. (1991) estimated the total 3 H discharge in Melton Branch (most of which originates in SWSA 5) for the 1988 water year to be 1210 Ci. A critical issue for making decisions concerning remedial actions at SWSA 5 is knowing whether the annual contaminant discharge is increasing or decreasing. Because (1) the magnitude of the annual contaminant discharge is highly correlated to the amount of annual precipitation (Solomon et al., 1991) and (2) a significant lag may exist between the time of peak contaminant release from primary sources (i.e., waste trenches) and the time of peak discharge into streams, short-term stream monitoring by itself is not sufficient for predicting future contaminant discharges. In this study we use 3 H to examine the link between contaminant release from primary waste sources and contaminant discharge into streams. By understanding and quantifying subsurface transport processes, realistic predictions of future contaminant discharge, along with an evaluation of the effectiveness of remedial action alternatives, will be possible. The objectives of this study are (1) to characterize the subsurface movement of contaminants (primarily 3 H) with an emphasis on the effects of matrix diffusion; (2) to determine the relative strength of primary vs secondary sources; and (3) to establish a methodology capable of determining whether the 3 H discharge from SWSA 5 to streams is increasing or decreasing

  2. Identification of Radiation Sources in a Peacetime Environment

    Science.gov (United States)

    1998-04-01

    Radionuclides in Medicine, Research, and Industry (continued) Isotope Symbol Polonium - 210 Po- 210 Promethium-147 Pr-147 Radium-226 Ra-226 Selenium-75 Se...equip- ment seen in a nuclear medicine department or nuclear pharmacy, radia- tion therapy sources, industrial food irradiation facilities, and small... Food Irradiator 28 Commercial Irradiator Facility 28 Appendix 1. Commonly Used Radionuclides in Medicine, Research, and Industry 29 General

  3. Vertical characteristics and source identification of PM10 in Tianjin

    Institute of Scientific and Technical Information of China (English)

    Zhimei Xiao; Jianhui Wu; Suqin Han; Yufen Zhang; Hong Xu; Xiaoyong Zhang; Guoliang Shi; Yinchang Feng

    2012-01-01

    Ambient PM10 (particulate matter with a diameter less than 10 μm) concentrations were measured on a 255 meter tower in Tianjin,China.The samples were collected at four vertical levels (10,40,120 and 220 m).Vertical characteristics for PM10 samples were studied.The results showed that the concentrations of PM10 and constituent species had a negative correlation with the sampling height.The highest concentrations of PM10 and species were obtained at the 10 m level,and the lowest concentrations were measured at the 220 m level.For the fractions of species to total mass,SO42- and NO3- had higher values (fraction) at greater height; while Ca had a higher fraction at lower height.Possible source categories for the PM10 ambient dataset were identified by the principal component analysis method.The possible source categories included crustal dust,vehicles,cement dust,and incineration as well as secondary sulfate and nitrate sources.Analysis of meteorological factors on PM10 concentrations indicated that wind speed and inversion may be the main factors contributing to different concentrations of PM10 at different heights.

  4. Seasonal variation and source estimation of organic compounds in urban aerosol of Augsburg, Germany

    International Nuclear Information System (INIS)

    Pietrogrande, Maria Chiara; Abbaszade, Guelcin; Schnelle-Kreis, Juergen; Bacco, Dimitri; Mercuriali, Mattia; Zimmermann, Ralf

    2011-01-01

    This study reports a general assessment of the organic composition of the PM 2.5 samples collected in the city of Augsburg, Germany in a summer (August-September 2007) and a winter (February-March 2008) campaign of 36 and 30 days, respectively. The samples were directly submitted to in-situ derivatisation thermal desorption gas chromatography coupled with time of flight mass spectrometry (IDTD-GC-TOFMS) to simultaneously determine the concentrations of many classes of molecular markers, such as n-alkanes, iso- and anteiso-alkanes, polycyclic aromatic hydrocarbons (PAHs), oxidized PAHs, n-alkanoic acids, alcohols, saccharides and others. The PCA analysis of the data identified the contributions of three emission sources, i.e., combustion sources, including fossil fuel emissions and biomass burning, vegetative detritus, and oxidized PAHs. The PM chemical composition shows seasonal trend: winter is characterized by high contribution of petroleum/wood combustion while the vegetative component and atmospheric photochemical reactions are predominant in the hot season. - Highlights: → 59 molecular markers were simultaneously determined by thermal desorption GC-MS. → Organic composition of urban PM 2.5 in Augsburg, Germany, was characterized. → Fossil fuel, vegetative detritus, coal/wood burning are the main sources. → Seasonal trends winter vs. summer were identified. - Organic composition of the urban PM 2.5 identifies seasonal trend of the main sources: fossil fuel and biomass combustion sources, vegetative detritus, atmospheric photochemical reactions.

  5. Sources, Composition, and Properties of Newly Formed and Regional Organic Aerosol in a Boreal Forest during the Biogenic Aerosol: Effects on Clouds and Climate Field Campaign Report

    Energy Technology Data Exchange (ETDEWEB)

    Thornton, Joel [Univ. of Washington, Seattle, WA (United States)

    2016-05-01

    The Thornton Laboratory participated in the U.S. Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) Climate Research Facility’s Biogenic Aerosol Effects on Clouds and Climate (BAECC) campaign in Finland by deploying our mass spectrometer. We then participated in environmental simulation chamber studies at Pacific Northwest National Laboratory (PNNL). Thereafter, we analyzed the results as demonstrated in the several presentations and publications. The field campaign and initial environmental chamber studies are described below.

  6. Identification of lead sources in residential environments: Sydney Australia

    International Nuclear Information System (INIS)

    Laidlaw, M.A.S.; Zahran, S.; Pingitore, N.; Clague, J.; Devlin, G.; Taylor, M.P.

    2014-01-01

    Interior and exterior dust, soil and paint were analysed at five brick urban Sydney homes over 15 months to evaluate temporal variations and discriminate sources of lead (Pb) exposure. Exterior dust gauge Pb loading rates (μg/m 2 /28 days), interior vacuum dust Pb concentrations (mg/kg) and interior petri-dish Pb loading rates (μg/m 2 /28 days), were correlated positively with soil Pb concentrations. Exterior dust gauge Pb loading rates and interior vacuum dust Pb concentrations peaked in the summer. Lead isotope and Pb speciation (XAS) were analysed in soil and vacuum dust samples from three of the five houses that had elevated Pb concentrations. Results show that the source of interior dust lead was primarily from soil in two of the three houses and from soil and Pb paint in the third home. IEUBK child blood Pb modelling predicts that children's blood Pb levels could exceed 5 μg/dL in two of the five houses. -- Highlights: • Exterior Pb loading and interior Pb dust loading and concentrations correlate with soil Pb. • Exterior dust gauge Pb loading rates and interior vacuum dust Pb concentrations peak in the summer. • Interior dust lead came from soil in two of the three houses and from soil and Pb paint in the third home. • Modelling predicts that children's blood Pb levels could exceed 5 μg/dL in two of the five houses. -- Interior and exterior dust, soil and paint were analysed at five brick urban Sydney homes over 15 months to evaluate temporal variations and discriminate sources of lead (Pb) exposure

  7. Development of a novel methodology for indoor emission source identification

    DEFF Research Database (Denmark)

    Han, K.H.; Zhang, J.S.; Knudsen, H.N.

    2011-01-01

    The objective of this study was to develop and evaluate a methodology to identify individual sources of emissions based on the measurements of mixed air samples and the emission signatures of individual materials previously determined by Proton Transfer Reaction-Mass Spectrometry (PTR-MS), an on......-line analytical device. The methodology based on signal processing principles was developed by employing the method of multiple regression least squares (MRLS) and a normalization technique. Samples of nine typical building materials were tested individually and in combination, including carpet, ceiling material...... experiments and investigation are needed for cases where the relative emission rates among different compounds may change over a long-term period....

  8. Sources of the PM10 aerosol in Flanders, Belgium, and re-assessment of the contribution from wood burning

    Energy Technology Data Exchange (ETDEWEB)

    Maenhaut, Willy, E-mail: willy.maenhaut@ugent.be [Ghent University (UGent), Department of Analytical Chemistry, Krijgslaan 281, S12, B-9000 Gent (Belgium); University of Antwerp - UA, Department of Pharmaceutical Sciences, Universiteitsplein 1, B-2610, Antwerpen (Belgium); Vermeylen, Reinhilde; Claeys, Magda [University of Antwerp - UA, Department of Pharmaceutical Sciences, Universiteitsplein 1, B-2610, Antwerpen (Belgium); Vercauteren, Jordy; Roekens, Edward [Flemish Environment Agency (VMM), Kronenburgstraat 45, B-2000, Antwerpen (Belgium)

    2016-08-15

    From 30 June 2011 to 2 July 2012 PM10 aerosol samples were simultaneously taken every 4th day at four urban background sites in Flanders, Belgium. The sites were in Antwerpen, Gent, Brugge, and Oostende. The PM10 mass concentration was determined by weighing; organic and elemental carbon (OC and EC) were measured by thermal-optical analysis, the wood burning tracers levoglucosan, mannosan and galactosan were determined by gas chromatography/mass spectrometry, 8 water-soluble ions were measured by ion chromatography, and 15 elements were determined by a combination of inductively coupled plasma atomic emission spectrometry and mass spectrometry. The multi-species dataset was subjected to receptor modeling by PMF. The 10 retained factors (with their overall average percentage contributions to the experimental PM10 mass) were wood burning (9.5%), secondary nitrate (24%), secondary sulfate (12.6%), sea salt (10.0%), aged sea salt (19.2%), crustal matter (9.7%), non-ferrous metals (1.81%), traffic (10.3%), non-exhaust traffic (0.52%), and heavy oil burning (3.0%). The average contributions of wood smoke for the four sites were quite substantial in winter and ranged from 12.5 to 20% for the PM10 mass and from 47 to 64% for PM10 OC. Wood burning appeared to be also a notable source of As, Cd, and Pb. The contribution from wood burning to the PM10 mass and OC was also assessed by making use of levoglucosan as single marker compound and the conversion factors of Schmidl et al. (2008), as done in our previous study on wood burning in Flanders (Maenhaut et al., 2012). However, the apportionments were much lower than those deduced from PMF. It seems that the conversion factors of Schmidl et al. (2008) may not be applicable to wood burning in Flanders. From scatter plots of the PMF-derived wood smoke OC and PM versus levoglucosan, we arrived at conversion factors of 9.7 and 22.6, respectively. - Highlights: • A one-year study with 4 urban background sites and a total of 372

  9. Sources of the PM10 aerosol in Flanders, Belgium, and re-assessment of the contribution from wood burning

    International Nuclear Information System (INIS)

    Maenhaut, Willy; Vermeylen, Reinhilde; Claeys, Magda; Vercauteren, Jordy; Roekens, Edward

    2016-01-01

    From 30 June 2011 to 2 July 2012 PM10 aerosol samples were simultaneously taken every 4th day at four urban background sites in Flanders, Belgium. The sites were in Antwerpen, Gent, Brugge, and Oostende. The PM10 mass concentration was determined by weighing; organic and elemental carbon (OC and EC) were measured by thermal-optical analysis, the wood burning tracers levoglucosan, mannosan and galactosan were determined by gas chromatography/mass spectrometry, 8 water-soluble ions were measured by ion chromatography, and 15 elements were determined by a combination of inductively coupled plasma atomic emission spectrometry and mass spectrometry. The multi-species dataset was subjected to receptor modeling by PMF. The 10 retained factors (with their overall average percentage contributions to the experimental PM10 mass) were wood burning (9.5%), secondary nitrate (24%), secondary sulfate (12.6%), sea salt (10.0%), aged sea salt (19.2%), crustal matter (9.7%), non-ferrous metals (1.81%), traffic (10.3%), non-exhaust traffic (0.52%), and heavy oil burning (3.0%). The average contributions of wood smoke for the four sites were quite substantial in winter and ranged from 12.5 to 20% for the PM10 mass and from 47 to 64% for PM10 OC. Wood burning appeared to be also a notable source of As, Cd, and Pb. The contribution from wood burning to the PM10 mass and OC was also assessed by making use of levoglucosan as single marker compound and the conversion factors of Schmidl et al. (2008), as done in our previous study on wood burning in Flanders (Maenhaut et al., 2012). However, the apportionments were much lower than those deduced from PMF. It seems that the conversion factors of Schmidl et al. (2008) may not be applicable to wood burning in Flanders. From scatter plots of the PMF-derived wood smoke OC and PM versus levoglucosan, we arrived at conversion factors of 9.7 and 22.6, respectively. - Highlights: • A one-year study with 4 urban background sites and a total of 372

  10. A new broadly tunable (7.4-10.2 eV) laser based VUV light source and its first application to aerosol mass spectrometry

    Science.gov (United States)

    Hanna, S. J.; Campuzano-Jost, P.; Simpson, E. A.; Robb, D. B.; Burak, I.; Blades, M. W.; Hepburn, J. W.; Bertram, A. K.

    2009-01-01

    A laser based vacuum ultraviolet (VUV) light source using resonance enhanced four wave difference mixing in xenon gas was developed for near threshold ionization of organics in atmospheric aerosol particles. The source delivers high intensity pulses of VUV light (in the range of 1010 to 1013 photons/pulse depending on wavelength, 5 ns FWHM) with a continuously tunable wavelength from 122 nm (10.2 eV) to 168 nm (7.4 eV)E The setup allows for tight (caffeine aerosols vaporized by a pulsed CO2 laser in an ion trap mass spectrometer. Mass spectra from single particles down to 300 nm in diameter were collected. Excellent signal to noise characteristics for these small particles give a caffeine detection limit of 8 × 105 molecules which is equivalent to a single 75 nm aerosol, or approximately 1.5% of a 300 nm particleE The appearance energy of caffeine originating from the aerosol was also measured and found to be 7.91 ± 0.05 eV, in good agreement with literature values.

  11. Utilisation of Rep-PCR to track microbes in aerosols collected adjacent to their source, a saline lake in Victoria, Australia.

    Science.gov (United States)

    Munday, Chris I; O'Loingsigh, Tadhg; Tapper, Nigel J; De Deckker, Patrick; Allison, Gwen E

    2013-04-15

    Dust storms are a major source of aerosolized bacteria, especially in the drought conditions experienced in Australia in the decade to 2009. The major aims of this project were to identify the culturable bacteria in environmental samples and to genetically fingerprint all isolates using repetitive element PCR (Rep-PCR) to investigate the possibility of tracking isolates from their source into the atmosphere. Four field trips were conducted to a dry lake in western Victoria, Australia to sample aerosols and sediments. Aerosols were collected at heights up to 150 m using vacuum pumps with filters attached to a tethered helium balloon, while corresponding sediments were collected in sterile polypropylene tubes. Isolates were cultivated on Tryptic Soy Agar, R2 Agar and Marine Agar, and grown in dark conditions at ambient temperature. By sequencing the 16S rRNA gene of 270 isolates, fifteen different bacterial families were identified, with both the aerosols and sediments dominated by the Bacillaceae family. Four sets of Rep-PCR primers were tested, with the ERIC and (GTG)5 primers proving to be the most suitable for fingerprinting the cultured taxa. Rep-PCR revealed very high strain diversity in the samples collected, however some strains were still able to be tracked from sediments up to 150 m in height. This shows the potential of Rep-PCR, however very large reference databases would be required for the technique to be more useful. Copyright © 2013 Elsevier B.V. All rights reserved.

  12. [Source identification of toxic wastewaters in a petrochemical industrial park].

    Science.gov (United States)

    Yang, Qian; Yu, Yin; Zhou, Yue-Xi; Chen, Xue-Min; Fu, Xiao-Yong; Wang, Miao

    2014-12-01

    Petrochemical wastewaters have toxic impacts on the microorganisms in biotreatment processes, which are prone to cause deterioration of effluent quality of the wastewater treatment plants. In this study, the inhibition effects of activated sludge's oxygen consumption were tested to evaluate the toxicity of production wastewaters in a petrochemical industrial park. The evaluation covered the wastewaters from not only different production units in the park, but also different production nodes in each unit. No direct correlation was observed between the toxicity effects and the organic contents, suggesting that the toxic properties of the effluents could not be predicted by the organic contents. In view of the variation of activated sludge sensitivity among different tests, the toxicity data were standardized according to the concentration-effect relationships of the standard toxic substance 3, 5-dichlorophenol on each day, in order to improve the comparability among the toxicity data. Furthermore, the Quality Emission Load (QEL) of corresponding standard toxic substance was calculated by multiplying the corresponding 3, 5-dichlorophenol concentration and the wastewater flow quantity, to indicate the toxicity emission contribution of each wastewater to the wastewater treatment plant. According to the rank list of the toxicity contribution of wastewater from different units and nodes, the sources of toxic wastewater in the petrochemical industrial park were clearly identified. This study provides effective guidance for source control of wastewater toxicity in the large industrial park.

  13. Blind source identification from the multichannel surface electromyogram

    International Nuclear Information System (INIS)

    Holobar, A; Farina, D

    2014-01-01

    The spinal circuitries combine the information flow from the supraspinal centers with the afferent input to generate the neural codes that drive the human skeletal muscles. The muscles transform the neural drive they receive from alpha motor neurons into motor unit action potentials (electrical activity) and force. Thus, the output of the spinal cord circuitries can be examined noninvasively by measuring the electrical activity of skeletal muscles at the surface of the skin i.e. the surface electromyogram (EMG). The recorded multi-muscle EMG activity pattern is generated by mixing processes of neural sources that need to be identified from the recorded signals themselves, with minimal or no a priori information available. Recently, multichannel source separation techniques that rely minimally on a priori knowledge of the mixing process have been developed and successfully applied to surface EMG. They act at different scales of information extraction to identify: (a) the activation signals shared by synergistic skeletal muscles, (b) the specific neural activation of individual muscles, separating it from that of nearby muscles i.e. from crosstalk, and (c) the spike trains of the active motor neurons. This review discusses the assumptions made by these methods, the challenges and limitations, as well as examples of their current applications. (topical review)

  14. Isotopic abundances relevant to the identification of magma sources

    International Nuclear Information System (INIS)

    O'Nions, R.K.

    1984-01-01

    The behaviour of natural radiogenic isotope tracers in the Earth that have lithophile and atmophile geochemical affinity is reviewed. The isotope tracer signature of oceanic and continental crust may in favourable circumstances by sufficiently distinct from that of the mantle to render a contribution from these sources resolvable within the isotopic composition of the magma. Components derived from the sedimentary and altered basaltic portion of oceanic crust are recognized in some island arc magmas from their Sr, Nd and Pb isotopic signatures. The rare-gas isotope tracers (He, Ar, Xe in particular) are not readily recycled into the mantle and thus provide the basis of an approach that is complementary to that based on the lithophile tracers. In particular, a small mantle-derived helium component may be readily recognized in the presence of a predominant radiogenic component generated in the continents. The importance of assessing the mass balance of these interactions rather than merely a qualitative recognition is emphasized. The question of the relative, contribution of continental-oceanic crust and mantle to magma sources is an essential part of the problem of generation and evolution of continental crust. An approach to this problem through consideration of the isotopic composition of sediments is briefly discussed. (author)

  15. Characteristics and source apportionment of fine haze aerosol in Beijing during the winter of 2013

    Directory of Open Access Journals (Sweden)

    X. Shang

    2018-02-01

    Full Text Available For PM2.5 filter samples collected daily at the Chinese Research Academy of Environmental Sciences (Beijing, China from December of 2013 to February of 2014 (the winter period, chemical characteristics and sources were investigated with an emphasis on haze events in different alert levels. During the 3 months, the average PM2.5 concentration was 89 µg m−3, exceeding the Chinese national standard of 75 µg m−3 in 24  h. The maximum PM2.5 concentration was 307 µg m−3, which characterizes developed-type pollution (PM2.5 / PM10>0.5 in the World Health Organization criteria. PM2.5 was dominated by SO42−, NO3−, and pseudo-carbonaceous compounds with obvious differences in concentrations and proportions between non-haze and haze episodes. The non-negative matrix factorization (NMF analysis provided reasonable PM2.5 source profiles, by which five sources were identified: soil dust, traffic emission, biomass combustion, industrial emission, and coal combustion accounting for 13, 22, 12, 28, and 25  % of the total, respectively. The dust impact increased with northwesterlies during non-haze periods and decreased under stagnant conditions during haze periods. A blue alert of heavy air pollution was characterized by the greatest contribution from industrial emissions (61  %. During the Chinese Lantern Festival, an orange alert was issued and biomass combustion was found to be the major source owing to firework explosions. Red-alert haze was almost equally contributed by local traffic and transported coal combustion emissions from the vicinity of Beijing (approximately 40  % each that was distinguished by the highest levels of NO3− and SO42−, respectively. This study also reveals that the severity and source of haze are largely dependent on meteorological conditions.

  16. Source apportionment of secondary organic aerosol in China using a regional source-oriented chemical transport model and two emission inventories.

    Science.gov (United States)

    Wang, Peng; Ying, Qi; Zhang, Hongliang; Hu, Jianlin; Lin, Yingchao; Mao, Hongjun

    2018-06-01

    A Community Multiscale Air Quality (CMAQ) model with source-oriented lumped SAPRC-11 (S11L) photochemical mechanism and secondary organic aerosol (SOA) module was applied to determine the contributions of anthropogenic and biogenic sources to SOA concentrations in China. A one-year simulation of 2013 using the Multi-resolution Emission Inventory for China (MEIC) shows that summer SOA are generally higher (10-15 μg m -3 ) due to large contributions of biogenic (country average 60%) and industrial sources (17%). In winter, SOA formation was mostly due to anthropogenic emissions from industries (40%) and residential sources (38%). Emissions from other countries in southeast China account for approximately 14% of the SOA in both summer and winter, and 46% in spring due to elevated open biomass burning in southeast Asia. The Regional Emission inventory in ASia v2.1 (REAS2) was applied in this study for January and August 2013. Two sets of simulations with the REAS2 inventory were conducted using two different methods to speciate total non-methane carbon into model species. One approach uses total non-methane hydrocarbon (NMHC) emissions and representative speciation profiles from the SPECIATE database. The other approach retains the REAS2 speciated species that can be directly mapped to S11L model species and uses source specific splitting factors to map other REAS2 lumped NMHC species. Biogenic emissions are still the most significant contributor in summer based on these two sets of simulations. However, contributions from the transportation sector to SOA in January are predicted to be much more important based on the two REAS2 emission inventories (∼30-40% vs. ∼5% by MEIC), and contributions from residential sources according to REAS2 was much lower (∼21-24% vs. ∼42%). These discrepancies in source contributions to SOA need to be further investigated as the country seeks for optimal emission control strategies to fight severe air pollution. Copyright

  17. Radon in houses - identification of sources and pathways of transfer

    International Nuclear Information System (INIS)

    Robe, M.C.; Rannou, A.; Le Bronec, J.

    1992-01-01

    The Institut de Protection et de Surete Nucleaire (IPSN) is studying the remedial actions to reduce high concentration of radon in houses. The first step to know how to modify houses is to identify radon sources and pathways of transfer to upper floors. A pilot study in Brittany was designed to develop a simple method of diagnosis. This investigation was based on indoor and outdoor measurements of 222 Rn activity concentration in the air and 222 Rn area exhalation rate from the soils and walls, measurements of the potential alpha energy concentration of 222 Rn daughters and the ventilation rate. The structural characteristics of houses and the influence of the life style of the inhabitants were examined. Analysis of the results showed that a limited number of parameters can be selected for use in a rapid radon diagnosis. (author)

  18. PM2.5 source apportionment with organic markers in the Southeastern Aerosol Research and Characterization (SEARCH) study.

    Science.gov (United States)

    Watson, John G; Chow, Judith C; Lowenthal, Douglas H; Antony Chen, L-W; Shaw, Stephanie; Edgerton, Eric S; Blanchard, Charles L

    2015-09-01

    . Organic markers can be measured on currently acquired PM(2.5) filter samples by thermal methods. These markers can complement element, ion, and carbon fraction measurements from long-term speciation networks. Applying the positive matrix factorization and effective variance solutions for the chemical mass balance equations provides useful information on the accuracy of the source contribution estimates. Nonpolar compounds need to be complemented with polar compounds to better apportion cooking and secondary organic aerosol contributors.

  19. Characterization and source apportionment of organic aerosol at 260 m on a meteorological tower in Beijing, China

    Directory of Open Access Journals (Sweden)

    W. Zhou

    2018-03-01

    Full Text Available Despite extensive efforts toward the characterization of submicron aerosols at ground level in the megacity of Beijing, our understanding of aerosol sources and processes at high altitudes remains low. Here we conducted a 3-month real-time measurement of non-refractory submicron aerosol (NR-PM1 species at a height of 260 m from 10 October 2014 to 18 January 2015 using an aerosol chemical speciation monitor. Our results showed a significant change in aerosol composition from the non-heating period (NHP to the heating period (HP. Organics and chloride showed clear increases during HP due to coal combustion emissions, while nitrate showed substantial decreases from 28 to 15–18 %. We also found that NR-PM1 species in the heating season can have average mass differences of 30–44 % under similar emission sources yet different meteorological conditions. Multi-linear engine 2 (ME-2 using three primary organic aerosol (OA factors as constraints, i.e., fossil-fuel-related OA (FFOA dominantly from coal combustion emissions, cooking OA (COA, and biomass burning OA (BBOA resolved from ground high-resolution aerosol mass spectrometer measurements, was applied to OA mass spectra of ACSM. Two types of secondary OA (SOA that were well correlated with nitrate and chloride–CO, respectively, were identified. SOA played a dominant role in OA during all periods at 260 m although the contributions were decreased from 72 % during NHP to 58–64 % during HP. The SOA composition also changed significantly from NHP to HP. While the contribution of oxygenated OA (OOA was decreased from 56–63 to 32–40 %, less oxidized OOA (LO-OOA showed a large increase from 9–16 to 24–26 %. COA contributed a considerable fraction of OA at high altitude, and the contribution was relatively similar across different periods (10–13 %. In contrast, FFOA showed a large increase during HP due to the influences of coal combustion emissions. We also

  20. Source identification of individual soot agglomerates in Arctic air by transmission electron microscopy

    Science.gov (United States)

    Weinbruch, S.; Benker, N.; Kandler, K.; Schütze, K.; Kling, K.; Berlinger, B.; Thomassen, Y.; Drotikova, T.; Kallenborn, R.

    2018-01-01

    Individual soot agglomerates collected at four different locations on the Arctic archipelago Svalbard (Norway) were characterised by transmission electron microscopy and energy-dispersive X-ray microanalysis. For source identification of the ambient soot agglomerates, samples from different local sources (coal burning power plants in Longyearbyen and Barentsburg, diesel and oil burning for power generation in Sveagruva and Ny Ålesund, cruise ship) as well as from other sources which may contribute to Arctic soot concentrations (biomass burning, aircraft emissions, diesel engines) were investigated. Diameter and graphene sheet separation distance of soot primary particles were found to be highly variable within each source and are not suited for source identification. In contrast, concentrations of the minor elements Si, P, K, Ca and Fe showed significant differences which can be used for source attribution. The presence/absence of externally mixed particle groups (fly ashes, tar balls, mercury particles) gives additional hints about the soot sources. Biomass/wood burning, ship emissions and coal burning in Barentsburg can be excluded as major source for ambient soot at Svalbard. The coal power plant in Longyearbyen is most likely a major source of soot in the settlement of Longyearbyen but does not contribute significantly to soot collected at the Global Atmosphere Watch station Zeppelin Mountain near Ny Ålesund. The most probable soot sources at Svalbard are aircraft emissions and diesel exhaust as well as long range transport of coal burning emissions.

  1. Source characterization of urban particles from meat smoking activities in Chongqing, China using single particle aerosol mass spectrometry.

    Science.gov (United States)

    Chen, Yang; Wenger, John C; Yang, Fumo; Cao, Junji; Huang, Rujin; Shi, Guangming; Zhang, Shumin; Tian, Mi; Wang, Huanbo

    2017-09-01

    A Single Particle Aerosol Mass Spectrometer (SPAMS) was deployed in the urban area of Chongqing to characterize the particles present during a severe particulate pollution event that occurred in winter 2014-2015. The measurements were made at a time when residents engaged in traditional outdoor meat smoking activities to preserve meat before the Chinese Spring Festival. The measurement period was predominantly characterized by stagnant weather conditions, highly elevated levels of PM 2.5 , and low visibility. Eleven major single particle types were identified, with over 92.5% of the particles attributed to biomass burning emissions. Most of the particle types showed appreciable signs of aging in the stagnant air conditions. To simulate the meat smoking activities, a series of controlled smoldering experiments was conducted using freshly cut pine and cypress branches, both with and without wood logs. SPAMS data obtained from these experiments revealed a number of biomass burning particle types, including an elemental and organic carbon (ECOC) type that proved to be the most suitable marker for meat smoking activities. The traditional activity of making preserved meat in southwestern China is shown here to be a major source of particulate pollution. Improved measures to reduce emissions from the smoking of meat should be introduced to improve air quality in regions where smoking meat activity prevails. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Iron selenide films by aerosol assisted chemical vapor deposition from single source organometallic precursor in the presence of surfactants

    Energy Technology Data Exchange (ETDEWEB)

    Hussain, Raja Azadar [Department of Chemistry, Quaid-i-Azam University, 45320 Islamabad (Pakistan); Badshah, Amin, E-mail: aminbadshah@yahoo.com [Department of Chemistry, Quaid-i-Azam University, 45320 Islamabad (Pakistan); Younis, Adnan [School of Materials Science and Engineering, University of New South Wales, Sydney 2052, NSW (Australia); Khan, Malik Dilshad [Department of Chemistry, Quaid-i-Azam University, 45320 Islamabad (Pakistan); Akhtar, Javeed [Department of Physics, COMSATS Institute of Information Technology, Park Road, Chak Shahzad, Islamabad (Pakistan)

    2014-09-30

    This article presents the synthesis and characterization (multinuclear nuclear magnetic resonance, Fourier transform infrared spectroscopy, carbon–hydrogen–nitrogen–sulfur analyzer, atomic absorption spectrometry and thermogravimetric analysis) of a single source organometallic precursor namely 1-acetyl-3-(4-ferrocenylphenyl)selenourea for the fabrication of iron selenide (FeSe) films on glass substrates using aerosol assisted chemical vapor deposition (AACVD). The changes in the morphologies of the films have been monitored by the use of two different surfactants i.e. triton X-100 and tetraoctylphosphonium bromide during AACVD. The role of surfactant has been evaluated by examining the interaction of the surfactants with the precursor by using UV–vis spectroscopy and cyclic voltammetry. The fabricated FeSe films have been characterized with powder X-ray diffraction, scanning electron microscopy and energy dispersive spectroscopy. - Highlights: • Ferrocene incorporated selenourea (FIS) has been synthesized and characterized. • FeSe thin films have been fabricated from FIS. • Mechanism of film growth was studied with cyclic voltammetry and UV–vis spectroscopy.

  3. PAH diagnostic ratios for the identification of pollution emission sources

    International Nuclear Information System (INIS)

    Tobiszewski, Marek; Namieśnik, Jacek

    2012-01-01

    Polycyclic aromatic hydrocarbon (PAH) diagnostic ratios have recently come into common use as a tool for identifying and assessing pollution emission sources. Some diagnostic ratios are based on parent PAHs, others on the proportions of alkyl-substituted to non-substituted molecules. The ratios are applicable to PAHs determined in different environmental media: air (gas + particle phase), water, sediment, soil, as well as biomonitor organisms such as leaves or coniferous needles, and mussels. These ratios distinguish PAH pollution originating from petroleum products, petroleum combustion and biomass or coal burning. The compounds involved in each ratio have the same molar mass, so it is assumed they have similar physicochemical properties. Numerous studies show that diagnostic ratios change in value to different extents during phase transfers and environmental degradation. The paper reviews applications of diagnostic ratios, comments on their use and specifies their limitations. - Highlights: ► PAH diagnostic ratios may identify pollution coming from petroleum spills, fuel combustion and coal or biomass burning. ► They are sensitive to changes during PAHs environmental fate processes. ► Some diagnostic ratios are of limited value due to fast photodegradation of one of the compounds. - The paper reviews PAH diagnostic ratios that are applied to identify pollution emission originating from petroleum products, fuel combustion or coal and biomass burning.

  4. Source identification of soil mercury in the Spanish islands.

    Science.gov (United States)

    Rodríguez Martín, José Antonio; Carbonell, Gregoria; Nanos, Nikos; Gutiérrez, Carmen

    2013-02-01

    This study spatially analysed the relation between mercury (Hg) content in soil and Hg in rock fragment for the purpose of assessing natural soil Hg contribution compared with Hg from human inputs. We present the Hg content of 318 soil and rock fragment samples from 11 islands distributed into two Spanish archipelagos (the volcanic Canary Islands [Canaries] and the Mediterranean Balearic [Balearic] islands). Assumedly both are located far enough away from continental Hg sources to be able to minimise the effects of diffuse pollution. Physical and chemical soil properties were also specified for the samples. Hg contents were significantly greater in the Balearic limestone soils (61 μg kg(-1)) than in the volcanic soils of the Canaries (33 μg kg(-1)). Hg levels were also greater in topsoil than in rocky fragments, especially on the Balearics. The soil-to-rock ratios varied between 1 and 30. Interestingly, the highest topsoil-to-rock Hg ratio (>16 ×) was found in the vicinity of a coal-fired power plant in Majorca, whereas no similar areas in the Canary archipelago were identified.

  5. Source Apportionment of the Size-Fractionated Urban Aerosols in and around Kolkata, India

    Science.gov (United States)

    Sarkar, Ujjaini; Haque, Monirul; Roy, Rajdeep; Chakraborty, Sanjoy

    Our main objective was to estimate the heavy metals like the Lead, Mercury, Cadmium, Sodium, Potassium, Calcium, Aluminium, and Iron, in addition to ammonium, chloride, nitrate, and sulphate ions, by Atomic Absorption Spectrophotometry and Ion Chromatography and apportion the most probable sources using the Chemical Mass Balance Model. The three urban locations of Behala Chowrasta, Rabindra Sadan, and Shyam Bazaar Five Points were chosen within the city of Kolkata. One rural location was chosen at the Indian Institute of Technology campus, Kharagpur, a rural site in the Midnapur District of the state of West Bengal, India. The results look quite encouraging.

  6. Variability of Surface pollutants and aerosol concentration over Abu Dhabi, UAE - sources, transport and current levels

    Science.gov (United States)

    Phanikumar, Devulapalli V.; Basha, Ghouse; Ouarda, Taha B. M. J.

    2015-04-01

    In the view of recent economic, industrial, and rapid development, Abu Dhabi (24.4oN; 54.4oE; 27m msl) has become one of the most populated regions in the world despite of extreme heat, frequent dust storms, and with distinctive topography. The major sources of air pollution are from the dust and sand storms, greenhouse gas emissions, and to some extent from industrial pollution. In order to realize the accurate and comprehensive understanding of air quality and plausible sources over this region, we have made a detailed analysis of three years simultaneous measurements during 2011-13 of pollutants such as O3, SO2, NO2, CO, and PM10 concentrations. Diurnal variation of meteorological parameters such as temperature and wind speed/relative humidity clearly shows daytime maximum/minimum in summer followed by pre-monsoon, post-monsoon and winter. The prevailing winds over this region are mostly from northwesterly direction (Shamal wind). Diurnal wind pattern showed a clear contrast with the majority of the wind pattern during nighttime and early morning is from the westerly/northwesterly and daytime is from southwesterly/southeasterly directions. The diurnal pattern of O3 shows minimum during 08 LT and increases thereafter reaching maximum at 17 LT and decreases during nighttime. However, the diurnal pattern of SO2 and NO2 show a peak at ~ 08 LT and dip at ~ 14 LT during all the seasons with some variability in each season. On the other hand, the diurnal pattern of CO shows a peculiar picture of elevated levels during daytime peaking at ~ 10 LT (prominent in summer and post-monsoon) followed by a sharp decrease and minimum is ~14 LT. PM10 concentration has an early morning peak at ~ 02 LT and then decreases to a minimum value at ~11 LT and again increases in the afternoon hours (maximum at ~17 LT) depicting a forenoon-afternoon asymmetry. Monthly variation of PM10 shows maximum in pre-monsoon season and minimum in winter. Our observations show the diurnal pattern of

  7. TOXICOLOGICAL EVALUATION OF REALISTIC EMISSIONS OF SOURCE AEROSOLS (TERESA): APPLICATION TO POWER PLANT-DERIVED PM2.5

    Energy Technology Data Exchange (ETDEWEB)

    Annette C. Rohr; Petros Koutrakis; John Godleski

    2011-03-31

    Determining the health impacts of different sources and components of fine particulate matter (PM2.5) is an important scientific goal, because PM is a complex mixture of both inorganic and organic constituents that likely differ in their potential to cause adverse health outcomes. The TERESA (Toxicological Evaluation of Realistic Emissions of Source Aerosols) study focused on two PM sources - coal-fired power plants and mobile sources - and sought to investigate the toxicological effects of exposure to realistic emissions from these sources. The DOE-EPRI Cooperative Agreement covered the performance and analysis of field experiments at three power plants. The mobile source component consisted of experiments conducted at a traffic tunnel in Boston; these activities were funded through the Harvard-EPA Particulate Matter Research Center and will be reported separately in the peer-reviewed literature. TERESA attempted to delineate health effects of primary particles, secondary (aged) particles, and mixtures of these with common atmospheric constituents. The study involved withdrawal of emissions directly from power plant stacks, followed by aging and atmospheric transformation of emissions in a mobile laboratory in a manner that simulated downwind power plant plume processing. Secondary organic aerosol (SOA) derived from the biogenic volatile organic compound {alpha}-pinene was added in some experiments, and in others ammonia was added to neutralize strong acidity. Specifically, four scenarios were studied at each plant: primary particles (P); secondary (oxidized) particles (PO); oxidized particles + secondary organic aerosol (SOA) (POS); and oxidized and neutralized particles + SOA (PONS). Extensive exposure characterization was carried out, including gas-phase and particulate species. Male Sprague Dawley rats were exposed for 6 hours to filtered air or different atmospheric mixtures. Toxicological endpoints included (1) breathing pattern; (2) bronchoalveolar lavage

  8. Identification of neutron noise sources in a boiling water reactor

    International Nuclear Information System (INIS)

    Sides, W.H. Jr.; Mathis, M.V.; Smith, C.M.

    1977-01-01

    Measurements were made at units 2 and 3 of the Browns Ferry Nuclear Power Plant in order to characterize the noise signatures of the neutron and process signals and to determine the usefulness of such signatures for anomaly detection in BWR-4s. Previous measurements and theoretical analyses of BWR noise by others were concerned with the determination of steam velocity and void fraction (using the local component of neutron noise) and with the sources of global noise. The work described is under a five-part program to develop a complete and systematic analysis and representation of BWR neutron and process noise through complementary measurements and stochastic model developments. The parts are: (1) recording as many neutron detector and process noise signals as are available in a BWR-4; (2) reducing these data to noise signatures in order to perform an empirical analysis of these signatures, and documenting the relationships between the signals from spatially separated neutron detectors and between neutron and process variables; (3) developing spatially dependent neutronic models coupled with thermal-hydraulic models to aid in interpreting the observed relationships among the measured noise signatures, (4) comparing measured noise signatures with model predictions to obtain additional insight into BWR-4 dynamic behavior and to validate the models; and (5) using these models to predict the sensitivity of noise monitoring for detection, surveillance, and diagnosis of postulated in-core anomalies in BWRs. The paper describes the procedures used to obtain the noise recordings and presents initial empirical analysis and observations pertaining to the noise signatures and the relationships between several noise variables in the 0.01- to 1-Hz range. The mathematical models have not been developed sufficiently to report theoretical results or to compare measured spectra with model predictions at this time

  9. The aerosols and the greenhouse effect; Aerosoler og klimaeffekten

    Energy Technology Data Exchange (ETDEWEB)

    Iversen, Trond; Kirkevaag, Alf; Seland, Oeyvind; Debernard, Jens Boldingh; Kristjansson, Jon Egill; Storelvmo, Trude

    2008-07-01

    The article discussed the aerosol effects on the climatic changes and points out that the climate models do not incorporate these components satisfactorily mostly due to insufficient knowledge of the aerosol pollution sources. The direct and indirect effects of aerosols are mentioned as well as the climate response (tk)

  10. Investigation of the relationships between DCS cloud properties, lifecycle, and precipitation with meteorological regimes and aerosol sources at the ARM SGP Site

    Energy Technology Data Exchange (ETDEWEB)

    Dong, Xiquan [Univ. of North Dakota, Grand Forks, ND (United States). Dept. of Atmospheric Sciences; Univ. of Arizona, Tucson, AZ (United States). Dept. of Hydrology and Atmospheric Sciences

    2016-10-26

    In this proposed research, we will investigate how different meteorological regimes and aerosol sources affect DCS properties, diurnal and life cycles, and precipitation using multiple observational platforms (surface, satellite, and aircraft) and NARR reanalysis at the ARM SGP site. The Feng et al. (2011, 2012) DCS results will serve as a starting point for this proposed research, and help us to address some fundamental issues of DCSs, such as convective initiation, rain rate, areal extent (including stratiform and convective regions), and longevity. Convective properties will be stratified by meteorological regime (synoptic/mesoscale patterns) identified by reanalysis. Aerosol information obtained from the ARM SGP site will also be stratified by meteorological regimes to understand their effects on convection. Finally, the aircraft in-situ measurements and various radar observations and retrievals during the MC3E campaign will provide a “cloud-truth” dataset and are an invaluable data source for verifying the findings and investigating the proposed hypotheses in Objective 1.

  11. Optical identifications of IRAS point sources: the Fornax, Hydra I and Coma clusters

    International Nuclear Information System (INIS)

    Wang, G.; Leggett, S.K.; Savage, A.

    1991-01-01

    We present optical identifications for 66 IRAS point sources in the region of the Fornax cluster of galaxies, 106 IRAS point sources in the region of the Hydra I cluster of galaxies (Abell 1060) and 59 IRAS point sources in the region of the Coma cluster of galaxies (Abell 1656). Eight other sources in Hydra I do not have optical counterparts and are very probably due to infrared cirrus. Twenty-three (35 per cent) of the Fornax sources are associated with stars and 43 (65 per cent) with galaxies; 48 (42 per cent) of the Hydra I sources are associated with stars and 58 (51 per cent) with galaxies; 18 (31 per cent) of the Coma sources are associated with stars and 41 (69 per cent) with galaxies. The stellar and infrared cirrus surface density is consistent with the galactic latitude of each field. (author)

  12. The occurrence and source identification of bisphenol compounds in wastewaters.

    Science.gov (United States)

    Česen, Marjeta; Lenarčič, Kaja; Mislej, Vesna; Levstek, Meta; Kovačič, Ana; Cimrmančič, Bernardka; Uranjek, Nataša; Kosjek, Tina; Heath, David; Dolenc, Marija Sollner; Heath, Ester

    2018-03-01

    This study reports the occurrence of eight bisphenols (BPs): bisphenol AF (BPAF), bisphenol AP (BPAP), bisphenol B (BPB), bisphenol C (BPC), bisphenol E (BPE), bisphenol F (BPF), bisphenol S (BPS) and bisphenol Z (BPZ) in wastewaters (WWs). Sample preparation involved pre-concentration with SPE cartridges (Oasis HLB), followed by derivatization using N-(tert-butyldimethylsilyl)-N-methyltrifluoroacetamide with 1% tert-butyldimethylchlorosilane. Chemical analysis was based on gas chromatography-mass spectrometry. A validated method with limits of detection (LODs) at ngL -1 range was applied to WWs collected at five Slovene wastewater treatment plants (WWTPs) and WW inflows from industrial, commercial and residential sources entering the sewerage systems of two catchments (Domžale-Kamnik (DK) and Ljubljana (LJ)). The presence of all BPs was confirmed in three inflows in DK and two inflows in the LJ catchments. High cumulative concentrations of all BPs were determined in WW from food processing facilities (LJ: 3030ngL -1 and DK: 599ngL -1 ). A high detection frequency was observed in the WW from two textile cleaning companies (6 BPs for LJ and 8 BPs for DK). The analysis of WW from WWTPs revealed that only BPF (36.7ngL -1 ) and BPS (40.6ngL -1 ) were >LODs in the influents, whereas other BPs were detected also in the effluents. BPZ was found in the highest concentration (403ngL -1 at WWTP-DK). WW collected at this WWTP also contained the highest amount of BPE (238ngL -1 ). Although BPs removal could not be directly compared between the WWTPs, with the exception of BPAP and BPB in the case of two smaller WWTPs (6.39%-43.2%) bisphenols were in general highly removed (≥96.2%). Finally, levels of BPC>LOD are reported for first time (WWTP in the DK catchment: 1.01ngL -1 -11.8ngL -1 ; LJ inflow from food processing plant up to 2560ngL -1 ). Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

  13. Numerical method of identification of an unknown source term in a heat equation

    Directory of Open Access Journals (Sweden)

    Fatullayev Afet Golayo?lu

    2002-01-01

    Full Text Available A numerical procedure for an inverse problem of identification of an unknown source in a heat equation is presented. Approach of proposed method is to approximate unknown function by polygons linear pieces which are determined consecutively from the solution of minimization problem based on the overspecified data. Numerical examples are presented.

  14. Source Identification in Structural Acoustics with an Inverse Frequency Response Function Technique

    NARCIS (Netherlands)

    Visser, Rene

    2002-01-01

    Inverse source identification based on acoustic measurements is essential for the investigation and understanding of sound fields generated by structural vibrations of various devices and machinery. Acoustic pressure measurements performed on a grid in the nearfield of a surface can be used to

  15. Aerosol Study over the Gulf of Guinea Region during DACCIWA Using a Mini Lidar onboard the French Aircraft ATR42

    Science.gov (United States)

    Shang, X.; Chazette, P.; Flamant, C.; Totems, J.; Denjean, C.; Meynadier, R.; Perrin, T.; Laurens, M.

    2016-12-01

    The EU-funded project DACCIWA (Dynamics-Aerosol-Chemistry-Cloud Interactions in West Africa) aims to investigate the relationship between weather, climate and air pollution in southern West Africa. As part of this campaign, three research aircraft based in Lomé (Togo) flew targeted missions over West Africa from 27 June to 16 July 2016. In this area aerosols, having a mixing of natural and anthropogenic sources, exert an important influence on the local weather and climate, mainly due to the aerosol-cloud interactions. A mini backscattered lidar system onboard one research aircraft (the French aircraft ATR42) performed aerosols measurements over the Gulf of Guinea region. The main objective was to study aerosol properties in different chemical landscapes: from the background state over the Gulf of Guinea (marine aerosols or mix between marine aerosols and biomass burning aerosols) to ship/flaring emissions to the coastal strip of polluted megacities to the agricultural areas and forest areas further north, and eventually dust from Sahel/Sahara. Different aerosol origins were identified by using the coupling between the lidar cross-polarized channels and a set of back trajectories analyses. The aircraft conducted flights at low ( 1 km above the mean sea level -amsl) and high altitudes ( 5 km amsl), allowing the coupling of in situ and remote sensing data to assess the properties of the aerosol layers. During several flights, depolarizing aerosol layers from the northeast were observed between 2.5 and 4 km amsl, which highlight the significant contribution of dust-like particles to the aerosol load in the coastal region. The air masses originating from the southeast were loaded with biomass burning aerosols from Central Africa, which seem to be mixed with other aerosol types. The flight sampling strategy and related lidar investigations will be presented. The retrieved aerosol distributions and properties, and the aerosol type identification will be discussed.

  16. ATMOSPHERIC AEROSOL SOURCE-RECEPTOR RELATIONSHIPS: THE ROLE OF COAL-FIRED POWER PLANTS; SEMIANNUAL

    International Nuclear Information System (INIS)

    Allen L. Robinson; Spyros N. Pandis; Cliff I. Davidson

    2002-01-01

    This report describes the technical progress made on the Pittsburgh Air Quality Study (PAQS) during the period of August 2001 through January of 2002. The major activity during this project period was the continuation of the ambient monitoring effort. Work also progressed on organizing the upcoming source characterization effort, and there was continued development of several three-dimensional air quality models. The first PAQS data analysis workshop for the project was held at Carnegie Mellon in December 2001. Two new instruments were added to site during this project period: a single particle mass spectrometer and an in situ VOC instrument. The single particle mass spectrometer has been deployed since the middle of September and has collected more than 150 days of data. The VOC instrument was only deployed during the intensive sampling period. Several instruments experienced operational issues during this project period. The overall data recovery rate for the project has been high

  17. Sources of atmospheric aerosols controlling PM10 levels in Heraklion, Crete during winter time

    Science.gov (United States)

    Kalivitis, Nikolaos; Kouvarakis, Giorgos; Stavroulas, Iasonas; Kandilogiannaki, Maria; Vavadaki, Katerina; Mihalopoulos, Nikolaos

    2016-04-01

    High concentrations of Particulate Matter (PM) in the atmosphere have negative impact to human health. Thresholds for ambient concentrations that are defined by the directive 2008/50/EC are frequently exceeded even at background conditions in the Mediterranean region as shown in earlier studies. The sources of atmospheric particles in the urban environment of a medium size city of eastern Mediterranean are studied in the present work in order to better understand the causes and characteristics of exceedances of the daily mean PM10limit value of 50 μg m-3. Measurements were performed at the atmospheric quality measurement station of the Region of Crete, at the Heraklion city center on Crete island, during the winter/spring period of 2014-2015 and 2015-2016. Special emphasis was given to the study of the contribution of Black Carbon (BC) to the levels of PM10. Continuous measurements were performed using a beta-attenuation PM10monitor and a 7-wavelength Aethalometer with a time resolution of 30 and 5 minutes respectively. For direct comparison to background regional conditions, concurrent routine measurements at the atmospheric research station of University of Crete at Finokalia were used as background reference. Analysis of exceedances in the daily PM10 mass concentration showed that the total of the exceedances was related to long range transport of Saharan dust rather than local sources. However, compared to the Finokalia station it was found that there were 20% more exceedances in Heraklion, the addition of transported dust on the local pollution was the reason for the additional exceedance days. Excluding dust events, it was found that the PM10variability was dependent on the BC abundance, traffic during rush hours in the morning and biomass burning for domestic heating in the evening contributed significantly to PM10levels in Heraklion.

  18. Influences of natural emission sources (wildfires and Saharan dust) on the urban organic aerosol in Barcelona (Western Mediterranean Basis) during a PM event.

    Science.gov (United States)

    van Drooge, Barend L; Lopez, Jordi F; Grimalt, Joan O

    2012-11-01

    The urban air quality in Barcelona in the Western Mediterranean Basin is characterized by overall high particulate matter (PM) concentrations, due to intensive local anthropogenic emissions and specific meteorological conditions. Moreover, on several days, especially in summer, natural PM sources, such as long-range transported Saharan dust from Northern Africa or wildfires on the Iberian Peninsula and around the Mediterranean Basin, may influence the levels and composition of the organic aerosol. In the second half of July 2009, daily collected PM(10) filter samples in an urban background site in Barcelona were analyzed on organic tracer compounds representing several emission sources. During this period, an important PM peak event was observed. Individual organic compound concentrations increased two to five times during this event. Although highest increase was observed for the organic tracer of biomass burning, the contribution to the organic aerosol was estimated to be around 6 %. Organic tracers that could be related to Saharan dust showed no correlation with the PM and OC levels, while this was the case for those related to fossil fuel combustion from traffic emissions. Moreover, a change in the meteorological conditions gave way to an overall increase of the urban background contamination. Long-range atmospheric transport of organic compounds from primary emissions sources (i.e., wildfires and Saharan dust) has a relatively moderate impact on the organic aerosol in an urban area where the local emissions are dominating.

  19. Wintertime organic and inorganic aerosols in Lanzhou, China: sources, processes, and comparison with the results during summer

    Directory of Open Access Journals (Sweden)

    J. Xu

    2016-12-01

    Full Text Available Lanzhou, which is located in a steep alpine valley in western China, is one of the most polluted cities in China during the wintertime. In this study, an Aerodyne high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS, a seven-wavelength aethalometer, and a scanning mobility particle sizer (SMPS were deployed during 10 January to 4 February 2014 to study the mass concentrations, chemical processes, and sources of submicrometer particulate matter (PM1. The average PM1 concentration during this study was 57.3 µg m−3 (ranging from 2.1 to 229.7 µg m−3 for hourly averages, with organic aerosol (OA accounting for 51.2 %, followed by nitrate (16.5 %, sulfate (12.5 %, ammonium (10.3 %, black carbon (BC, 6.4 %, and chloride (3.0 %. The mass concentration of PM1 during winter was more than twice the average value observed at the same site in summer 2012 (24.5 µg m−3, but the mass fraction of OA was similar in the two seasons. Nitrate contributed a significantly higher fraction to the PM1 mass in winter than summer (16.5 % vs. 10 %, largely due to more favored partitioning to the particle phase at low air temperature. The mass fractions of both OA and nitrate increased by  ∼  5 % (47 to 52 for OA and 13 to 18 % for nitrate with the increase of the total PM1 mass loading, while the average sulfate fraction decreased by 6 % (17 to 11 %, indicating the importance of OA and nitrate for the heavy air pollution events in Lanzhou. The size distributions of OA, nitrate, sulfate, ammonium, and chloride all peaked at  ∼  500 nm, with OA being slightly broader, suggesting that aerosol particles were internally mixed during winter, likely due to frequently calm and stagnant air conditions during wintertime in Lanzhou (average wind speed: 0.82 m s−1.The average mass spectrum of OA showed a medium oxidation degree (average O ∕ C ratio of 0.28, which was lower than that during summer

  20. Error sources in the retrieval of aerosol information over bright surfaces from satellite measurements in the oxygen A band

    Science.gov (United States)

    Nanda, Swadhin; de Graaf, Martin; Sneep, Maarten; de Haan, Johan F.; Stammes, Piet; Sanders, Abram F. J.; Tuinder, Olaf; Pepijn Veefkind, J.; Levelt, Pieternel F.

    2018-01-01

    Retrieving aerosol optical thickness and aerosol layer height over a bright surface from measured top-of-atmosphere reflectance spectrum in the oxygen A band is known to be challenging, often resulting in large errors. In certain atmospheric conditions and viewing geometries, a loss of sensitivity to aerosol optical thickness has been reported in the literature. This loss of sensitivity has been attributed to a phenomenon known as critical surface albedo regime, which is a range of surface albedos for which the top-of-atmosphere reflectance has minimal sensitivity to aerosol optical thickness. This paper extends the concept of critical surface albedo for aerosol layer height retrievals in the oxygen A band, and discusses its implications. The underlying physics are introduced by analysing the top-of-atmosphere reflectance spectrum as a sum of atmospheric path contribution and surface contribution, obtained using a radiative transfer model. Furthermore, error analysis of an aerosol layer height retrieval algorithm is conducted over dark and bright surfaces to show the dependence on surface reflectance. The analysis shows that the derivative with respect to aerosol layer height of the atmospheric path contribution to the top-of-atmosphere reflectance is opposite in sign to that of the surface contribution - an increase in surface brightness results in a decrease in information content. In the case of aerosol optical thickness, these derivatives are anti-correlated, leading to large retrieval errors in high surface albedo regimes. The consequence of this anti-correlation is demonstrated with measured spectra in the oxygen A band from the GOME-2 instrument on board the Metop-A satellite over the 2010 Russian wildfires incident.

  1. Heterogeneous conversion of NO2 on secondary organic aerosol surfaces: A possible source of nitrous acid (HONO in the atmosphere?

    Directory of Open Access Journals (Sweden)

    R. Bröske

    2003-01-01

    Full Text Available The heterogeneous conversion of NO2 on different secondary organic aerosols (SOA was investigated with the focus on a possible formation of nitrous acid (HONO. In one set of experiments different organic aerosols were produced in the reactions of O3 with alpha-pinene, limonene or catechol and OH radicals with toluene or limonene, respectively. The aerosols were sampled on filters and exposed to humidified NO2  mixtures under atmospheric conditions. The estimated upper limits for the uptake coefficients of NO2  and the reactive uptake coefficients NO2  -> HONO are in the range of 10-6 and 10-7, respectively. The integrated HONO formation for 1 h reaction time was 13 cm-2 geometrical surface and 17 g-1 particle mass. In a second set of experiments the conversion of NO2 into HONO in the presence of organic particles was carried out in an aerosol flow tube under atmospheric conditions. In this case the aerosols were produced in the reaction of O3 with beta-pinene, limonene or catechol, respectively. The upper limits for the reactive uptake coefficients NO2 -> HONO were in the range of 7 x 10-7 - 9 x 10-6. The results from the present study show that heterogeneous formation of nitrous acid on secondary organic aerosols (SOA is unimportant for the atmosphere.

  2. Stable hydrogen isotopic composition of n-alkanes in atmospheric aerosols as a tracer for the source region of terrestrial plant waxes

    Science.gov (United States)

    Yamamoto, S.; Kawamura, K.

    2009-12-01

    Studies on molecular composition and compound-specific carbon isotopic ratio (δ13C) of leaf wax n-alkanes in atmospheric aerosols have revealed a long-range atmospheric transport of terrestrial higher plant materials over the south Atlantic and western Pacific oceans. However, molecular and δ13C compositions of terrestrial plant waxes in the eastern part of the Asian continent are relatively constant reflecting C3-dominated vegetation, which makes it difficult to specify the source regions of plant materials in the atmospheric aerosols over the East Asia and northwest Pacific regions. Recent observation displays a large (>100‰) spatial variation in hydrogen isotopic composition (δD) of rainwater in East Asia. Because δD values of terrestrial higher plants sensitively reflect those of precipitation waters, δD of leaf waxes are expected to provide information on their source region. In this study, we measured the δD of n-alkanes in atmospheric aerosols from Tokyo to better understand the origin of leaf wax n-alkanes in atmospheric aerosols. The δD values of fossil fuel n-alkanes (C21 to C24) in Tokyo aerosols range from -65 to -94‰, which are in a range of those reported in marine crude oils. In contrast, the δD of higher molecular weight (C29 and C31) n-alkanes (δDHMW) show much larger values by ~70‰ than those of fossil fuel n-alkanes. Their values were found to exhibit concomitant variations with carbon preference index (CPI), suggesting that the δDHMW reflect the δD of leaf wax n-alkanes with a variable contribution from fossil fuel n-alkanes. Nevertheless, good positive correlation (r = 0.89, p < 0.01) between the δDHMW and CPI values enable us to remove the contribution of fossil fuels using a mass balance approach by assuming that CPI of fossil fuel is 1 and CPI of plant waxes is 5-15. Calculated n-alkane δD values averaged from -170 to -185‰ for C29 and from -155 to -168‰ for C31. These values are consistent with those reported from

  3. Characterizing the Sources and Processing of Submicron Aerosols at a Coastal Site near Houston, TX, with a Specific Focus on the Impact of Regional Shipping Emissions

    Science.gov (United States)

    Schulze, B.; Wallace, H. W., IV; Bui, A.; Flynn, J. H., III; Erickson, M. H.; Griffin, R. J.

    2017-12-01

    The Texas Gulf Coast region historically has been influenced heavily by regional shipping emissions. However, the effects of the recent establishment of the North American Emissions Control Area (ECA) on aerosol properties in this region are presently unknown. In order to understand better the current sources and processing mechanisms influencing coastal aerosol near Houston, a high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) was deployed for three weeks at a coastal location during May-June 2016. Total mass loadings of organic and inorganic non-refractory aerosol components during onshore flow periods were similar to those published before establishment of the regulations. Using estimated methanesulfonic acid (MSA) mass loadings and published biogenic MSA:non-sea-salt-sulfate (nss-SO4) ratios, we determined that over 70% of nss-SO4 over the Gulf was from anthropogenic sources, predominantly shipping emissions. Mass spectral analysis indicated that for periods with similar backward-trajectory-averaged meteorological conditions, air masses influenced by shipping emissions have an increased mass fraction of ions related to carboxylic acids and a significantly larger oxygen-to-carbon (O:C) ratio than air masses that stay within the ECA boundary, suggesting that shipping emissions impact marine organic aerosol (OA) oxidation state. Amine fragment mass loadings were positively correlated with anthropogenic nss-SO4 during onshore flow, implying anthropogenic-biogenic interaction in marine OA production. Five OA factors were resolved by positive matrix factorization, corresponding to a hydrocarbon-like OA, a semi-volatile OA, and three different oxygenated organic aerosols ranked by their O:C ratio (OOA-1, OOA-2, and OOA-3). OOA-1 constituted the majority of OA mass during a period likely influenced by aqueous-phase processing and may be linked to local glyoxal/methylglyoxal-related sources. OOA-2 was produced within the Houston urban region and was

  4. Radio Galaxy Zoo: Machine learning for radio source host galaxy cross-identification

    Science.gov (United States)

    Alger, M. J.; Banfield, J. K.; Ong, C. S.; Rudnick, L.; Wong, O. I.; Wolf, C.; Andernach, H.; Norris, R. P.; Shabala, S. S.

    2018-05-01

    We consider the problem of determining the host galaxies of radio sources by cross-identification. This has traditionally been done manually, which will be intractable for wide-area radio surveys like the Evolutionary Map of the Universe (EMU). Automated cross-identification will be critical for these future surveys, and machine learning may provide the tools to develop such methods. We apply a standard approach from computer vision to cross-identification, introducing one possible way of automating this problem, and explore the pros and cons of this approach. We apply our method to the 1.4 GHz Australian Telescope Large Area Survey (ATLAS) observations of the Chandra Deep Field South (CDFS) and the ESO Large Area ISO Survey South 1 (ELAIS-S1) fields by cross-identifying them with the Spitzer Wide-area Infrared Extragalactic (SWIRE) survey. We train our method with two sets of data: expert cross-identifications of CDFS from the initial ATLAS data release and crowdsourced cross-identifications of CDFS from Radio Galaxy Zoo. We found that a simple strategy of cross-identifying a radio component with the nearest galaxy performs comparably to our more complex methods, though our estimated best-case performance is near 100 per cent. ATLAS contains 87 complex radio sources that have been cross-identified by experts, so there are not enough complex examples to learn how to cross-identify them accurately. Much larger datasets are therefore required for training methods like ours. We also show that training our method on Radio Galaxy Zoo cross-identifications gives comparable results to training on expert cross-identifications, demonstrating the value of crowdsourced training data.

  5. Radar Emission Sources Identification Based on Hierarchical Agglomerative Clustering for Large Data Sets

    Directory of Open Access Journals (Sweden)

    Janusz Dudczyk

    2016-01-01

    Full Text Available More advanced recognition methods, which may recognize particular copies of radars of the same type, are called identification. The identification process of radar devices is a more specialized task which requires methods based on the analysis of distinctive features. These features are distinguished from the signals coming from the identified devices. Such a process is called Specific Emitter Identification (SEI. The identification of radar emission sources with the use of classic techniques based on the statistical analysis of basic measurable parameters of a signal such as Radio Frequency, Amplitude, Pulse Width, or Pulse Repetition Interval is not sufficient for SEI problems. This paper presents the method of hierarchical data clustering which is used in the process of radar identification. The Hierarchical Agglomerative Clustering Algorithm (HACA based on Generalized Agglomerative Scheme (GAS implemented and used in the research method is parameterized; therefore, it is possible to compare the results. The results of clustering are presented in dendrograms in this paper. The received results of grouping and identification based on HACA are compared with other SEI methods in order to assess the degree of their usefulness and effectiveness for systems of ESM/ELINT class.

  6. Premonsoon aerosol optical properties from AERONET retrievals and its probable source fields in Eastern India urban environment (Kolkata): evaluating spatial variability and its comparison with MODIS retrievals.

    Science.gov (United States)

    Priyadharshini, B.; Verma, S.

    2015-12-01

    Aerosol characteristics were examined using Aerosol Robotic Network (AERONET) and MODIS retrievals (Moderate Resolution Imaging Spectroradiometer) during the period, February to June 2009 in Eastern India, Kolkata (KOL). AERONET retrievals results for the study period manifested an aerosol optical depth - AOD (Angstrom exponent - α) in the range 0.65 - 0.81 (0.66 - 0.97) with an intermittent influence of dust. A substantial dominance of finer (coarser) particles were found in February (April) and an equal dominance of both in June. Aerosol size distribution (ASD) revealed a high volume in fine mode during June and that in April for the coarse mode. A few areas of in and around KOL, Odisha, and Sikkim influenced AOD ascertained using the Potential source contribution function (PSCF). Cluster analysis revealed preferred pathway as continental during February and both continental and marine during March to June. Episodic days identified for dust occurrence was examined and was further corroborated by MODIS Rapid response images. Further, comparative results of seven collateral AERONET sites in India, revealed a high AOD (α) at KOL during February to May (March and April) with Fine mode - FM (Coarse mode - CM) AOD of KOL being high during March and April (February to April) than other locations. Single scattering albedo (SSA) at 0.67 μm at KOL was slightly lower during February and March, with being equivalent and or higher than other sites during April to June. Comparison of AERONET - MODIS AOD at 0.55 µm for KOL (entire study period) for the collateral days revealed underestimation of MODIS during February to April and overestimation during May and June than AERONET. AERONET - MODIS AOD comparison for seven locations, during low (February) and high (June) aerosol loading, showed good agreement for few stations and divulged discrepancy for other sites.

  7. Speciation of 127I and 129I in atmospheric aerosols at Risø, Denmark: insight into sources of iodine isotopes and their species transformations

    Directory of Open Access Journals (Sweden)

    L. Zhang

    2016-02-01

    Full Text Available Speciation analysis of iodine in aerosols is a very useful approach for understanding geochemical cycling of iodine in the atmosphere. In this study, overall iodine species, including water-soluble iodine species (iodide, iodate and water-soluble organic iodine, NaOH-soluble iodine, and insoluble iodine have been determined for 129I and 127I in the aerosols collected at Risø, Denmark, during March and May 2011 (shortly after the Fukushima nuclear accident and in December 2014. The measured concentrations of total iodine are in the range of 1.04–2.48 ng m−3 for 127I and (11.3–97.0  ×  105 atoms m−3 for 129I, corresponding to 129I ∕ 127I atomic ratios of (17.8–86.8  ×  10−8. The contribution of Fukushima-derived 129I (peak value of 6.3  ×  104 atoms m−3 is estimated to be negligible (less than 6 % compared to the total 129I concentration in northern Europe. The concentrations and species of 129I and 127I in the aerosols are found to be strongly related to their sources and atmospheric pathways. Aerosols that were transported over the contaminated seas contained higher concentrations of 129I than aerosols transported over the European continent. The high 129I concentrations of the marine aerosols are attributed to secondary emission of marine discharged 129I in the contaminated seawater in the North Sea, North Atlantic Ocean, English Channel, Kattegat, etc., rather than direct gaseous release from the European nuclear reprocessing plants (NRPs. Water-soluble iodine was found to be a minor fraction to the total iodine for both 127I (7.8–13.7 % and 129I (6.5–14.1 % in ocean-derived aerosols, but accounted for 20.2–30.3 % for 127I and 25.6–29.5 % for 129I in land-derived aerosols. Iodide was the predominant form of water-soluble iodine, accounting for more than 97 % of the water-soluble iodine. NaOH-soluble iodine seems to be independent of the sources of aerosols. The significant

  8. Suggestibility and state anxiety: how the two concepts relate in a source identification paradigm.

    Science.gov (United States)

    Ridley, Anne M; Clifford, Brian R

    2006-01-01

    Source identification tests provide a stringent method for testing the suggestibility of memory because they reduce response bias and experimental demand characteristics. Using the techniques and materials of Maria Zaragoza and her colleagues, we investigated how state anxiety affects the ability of undergraduates to identify correctly the source of misleading post-event information. The results showed that individuals high in state anxiety were less likely to make source misattributions of misleading information, indicating lower levels of suggestibility. This effect was strengthened when forgotten or non-recognised misleading items (for which a source identification task is not possible) were excluded from the analysis. Confidence in the correct attribution of misleading post-event information to its source was significantly less than confidence in source misattributions. Participants who were high in state anxiety tended to be less confident than those lower in state anxiety when they correctly identified the source of both misleading post-event information and non-misled items. The implications of these findings are discussed, drawing on the literature on anxiety and cognition as well as suggestibility.

  9. STATE OF THE ART TECHNIQUES USED FOR NOISE SOURCE IDENTIFICATION ON COMPLEX BODIES

    Directory of Open Access Journals (Sweden)

    Corneliu STOICA

    2010-03-01

    Full Text Available Over the last few decades, many approaches have been undertaken in order to asses detailed noise source identification on complex bodies, i.e. aircrafts, cars, machinery. Noise source identification implies to accurately obtain the position and frequency of the dominant noise sources. There are cases where traditional testing methods can not be applied at all or their use involves some limitations. Optical systems used for near field analysis require a line of sight that may not be available. The state-of-the-art technology for this purpose is the use of a large number of microphones whose signals are acquired simultaneously, i.e. microphone phased array. Due to the excessive cost of the instruments and the data acquisition system required, the implementation of this technology was restricted to governmental agencies (NASA, DLR and big companies such as Boeing and Airbus. During the past years, this technique was developed in wind tunnels and some universities to perform noise source identification on scale airframes, main landing gear models, and aerodynamic profiles (used on airplanes, helicopter rotors and wind mills.

  10. Simultaneous identification of unknown groundwater pollution sources and estimation of aquifer parameters

    Science.gov (United States)

    Datta, Bithin; Chakrabarty, Dibakar; Dhar, Anirban

    2009-09-01

    Pollution source identification is a common problem encountered frequently. In absence of prior information about flow and transport parameters, the performance of source identification models depends on the accuracy in estimation of these parameters. A methodology is developed for simultaneous pollution source identification and parameter estimation in groundwater systems. The groundwater flow and transport simulator is linked to the nonlinear optimization model as an external module. The simulator defines the flow and transport processes, and serves as a binding equality constraint. The Jacobian matrix which determines the search direction in the nonlinear optimization model links the groundwater flow-transport simulator and the optimization method. Performance of the proposed methodology using spatiotemporal hydraulic head values and pollutant concentration measurements is evaluated by solving illustrative problems. Two different decision model formulations are developed. The computational efficiency of these models is compared using two nonlinear optimization algorithms. The proposed methodology addresses some of the computational limitations of using the embedded optimization technique which embeds the discretized flow and transport equations as equality constraints for optimization. Solution results obtained are also found to be better than those obtained using the embedded optimization technique. The performance evaluations reported here demonstrate the potential applicability of the developed methodology for a fairly large aquifer study area with multiple unknown pollution sources.

  11. Preliminary study on air pollution source identification in Xinzhen, Beijing, using NAA and PIXE

    International Nuclear Information System (INIS)

    Caijin Xiao; Guiying Zhang; Donghui Huang; Bangfa Ni; Cunxiong Liu; Yali Qin; Hongchao Sun; Pingsheng Wang; Weizhi Tian

    2012-01-01

    A total of 178 aerosol samples in two size fractions, PM10-2.5 (coarse) and PM2.5 (fine), were collected on nucleopore films using a Gent stacked filter unit sampler at the Graduate School of China Nuclear Industrial Group during May 2007 to November of 2009. Black carbon was determined by a reflectometer. A total of 16 elements, Mg, Al, S, Si, P, Cl, Ca, K, Ti, Mn, Fe, Ni, Cu, Zn, As and Pb, were determined by Particle Induced X-ray Emission. Mg, Al, Ca, K and Mn were also determined by Neutron Activation Analysis. Concentrations of all these elements were used to identify possible pollution sources and directions of the airborne particulate matter by means of softwares PMF and CPF. Some extraordinary events, such as sandstorms, firework and transboundary fire smoke were pinpointed by a combination of time series of multielement, relevant meteorological data and softwares Wind rose, Hysplit, and Google earth. (author)

  12. Observation of an unusual mid-stratospheric aerosol layer in the Arctic: possible sources and implications for polar vortex dynamics

    Directory of Open Access Journals (Sweden)

    M. Gerding

    Full Text Available By the beginning of winter 2000/2001, a mysterious stratospheric aerosol layer had been detected by four different Arctic lidar stations. The aerosol layer was observed first on 16 November 2000, at an altitude of about 38 km near Søndre Strømfjord, Greenland (67° N, 51° W and on 19 November 2000, near Andenes, Norway (69°  N, 16°  E. Subsequently, in early December 2000, the aerosol layer was observed near Kiruna, Sweden (68°  N, 21°  E and Ny-Ålesund, Spitsbergen (79°  N, 12°  E. No mid-latitude lidar station observed the presence of aerosols in this altitude region. The layer persisted throughout the winter 2000/2001, at least up to 12 February 2001. In November 2000, the backscatter ratio at a wavelength of 532 nm was up to 1.1, with a FWHM of about 2.5 km. By early February 2001, the layer had sedimented from an altitude of 38 km to about 26 km. Measurements at several wavelengths by the ALOMAR and Koldewey lidars indicate the particle size was between 30 and 50 nm. Depolarisation measurements reveal that the particles in the layer are aspherical, hence solid. In the mid-stratosphere, the ambient atmospheric temperature was too high to support in situ formation or existence of cloud particles consisting of ice or an acid-water solution. Furthermore, in the year 2000 there was no volcanic eruption, which could have injected aerosols into the upper stratosphere. Therefore, other origins of the aerosol, such as meteoroid debris, condensed rocket fuel, or aerosols produced under the influence of charged solar particles, will be discussed in the paper. Trajectory calculations illustrate the path of the aerosol cloud within the polar vortex and are used to link the observations at the different lidar sites. From the descent rate of  the layer and particle sedimentation rates, the mean down-ward motion of air within the polar vortex was estimated to be about 124 m/d between 35 and 30 km, with higher values at the edge of the

  13. Observation of an unusual mid-stratospheric aerosol layer in the Arctic: possible sources and implications for polar vortex dynamics

    Directory of Open Access Journals (Sweden)

    M. Gerding

    2003-04-01

    Full Text Available By the beginning of winter 2000/2001, a mysterious stratospheric aerosol layer had been detected by four different Arctic lidar stations. The aerosol layer was observed first on 16 November 2000, at an altitude of about 38 km near Søndre Strømfjord, Greenland (67° N, 51° W and on 19 November 2000, near Andenes, Norway (69°  N, 16°  E. Subsequently, in early December 2000, the aerosol layer was observed near Kiruna, Sweden (68°  N, 21°  E and Ny-Ålesund, Spitsbergen (79°  N, 12°  E. No mid-latitude lidar station observed the presence of aerosols in this altitude region. The layer persisted throughout the winter 2000/2001, at least up to 12 February 2001. In November 2000, the backscatter ratio at a wavelength of 532 nm was up to 1.1, with a FWHM of about 2.5 km. By early February 2001, the layer had sedimented from an altitude of 38 km to about 26 km. Measurements at several wavelengths by the ALOMAR and Koldewey lidars indicate the particle size was between 30 and 50 nm. Depolarisation measurements reveal that the particles in the layer are aspherical, hence solid. In the mid-stratosphere, the ambient atmospheric temperature was too high to support in situ formation or existence of cloud particles consisting of ice or an acid-water solution. Furthermore, in the year 2000 there was no volcanic eruption, which could have injected aerosols into the upper stratosphere. Therefore, other origins of the aerosol, such as meteoroid debris, condensed rocket fuel, or aerosols produced under the influence of charged solar particles, will be discussed in the paper. Trajectory calculations illustrate the path of the aerosol cloud within the polar vortex and are used to link the observations at the different lidar sites. From the descent rate of  the layer and particle sedimentation rates, the mean down-ward motion of air within the polar vortex was estimated to be about 124 m/d between 35 and 30 km, with higher values at the edge of the

  14. Sources of increase in lowermost stratospheric sulphurous and carbonaceous aerosol background concentrations during 1999–2008 derived from CARIBIC flights

    Directory of Open Access Journals (Sweden)

    Johan Friberg

    2014-03-01

    Full Text Available This study focuses on sulphurous and carbonaceous aerosol, the major constituents of particulate matter in the lowermost stratosphere (LMS, based on in situ measurements from 1999 to 2008. Aerosol particles in the size range of 0.08–2 µm were collected monthly during intercontinental flights with the CARIBIC passenger aircraft, presenting the first long-term study on carbonaceous aerosol in the LMS. Elemental concentrations were derived via subsequent laboratory-based ion beam analysis. The stoichiometry indicates that the sulphurous fraction is sulphate, while an O/C ratio of 0.2 indicates that the carbonaceous aerosol is organic. The concentration of the carbonaceous component corresponded on average to approximately 25% of that of the sulphurous, and could not be explained by forest fires or biomass burning, since the average mass ratio of Fe to K was 16 times higher tha