WorldWideScience

Sample records for aerosol monitoring

  1. Radiation monitoring by radiation effect of aerosol

    International Nuclear Information System (INIS)

    The high energy and high intensity accelerator facilities need the radiation monitoring with temporal and spatial resolutions. Numerical estimations are made for the radiation monitoring using the sampling method of aerosol Alanine. The aerosol Alanine put into the monitoring area through the duct. The intensity of radicals in the collected throughput Alanine of about 50 mg after passing through the monitoring area is measured by the ESR (Electron Spin Resonance) method. Key parameters in the system are the aerosol particle diameter and its intensity, the duct diameter and length, and the aerosol flow rate inside the duct. The maximum dose rate more than 108 Gy/h is possible to measure assuming the duct of 100 cm2 in area and 10 m in length, and the aerosol flow rate of 1000 L/min. The temporal resolution of the order of minutes is obtainable when the aerosol particle size is 0.1 μm. As a result of numerical estimation based on empirical simulations, it is to be promising to apply a proposed scheme to the radiation monitoring for accelerator fields. (Y. Tanaka)

  2. Monitoring biological aerosols using UV fluorescence

    Science.gov (United States)

    Eversole, Jay D.; Roselle, Dominick; Seaver, Mark E.

    1999-01-01

    An apparatus has been designed and constructed to continuously monitor the number density, size, and fluorescent emission of ambient aerosol particles. The application of fluorescence to biological particles suspended in the atmosphere requires laser excitation in the UV spectral region. In this study, a Nd:YAG laser is quadrupled to provide a 266 nm wavelength to excite emission from single micrometer-sized particles in air. Fluorescent emission is used to continuously identify aerosol particles of biological origin. For calibration, biological samples of Bacillus subtilis spores and vegetative cells, Esherichia coli, Bacillus thuringiensis and Erwinia herbicola vegetative cells were prepared as suspensions in water and nebulized to produce aerosols. Detection of single aerosol particles, provides elastic scattering response as well as fluorescent emission in two spectral bands simultaneously. Our efforts have focuses on empirical characterization of the emission and scattering characteristics of various bacterial samples to determine the feasibility of optical discrimination between different cell types. Preliminary spectroscopic evidence suggest that different samples can be distinguished as separate bio-aerosol groups. In addition to controlled sample results, we will also discuss the most recent result on the effectiveness of detection outdoor releases and variations in environmental backgrounds.

  3. Development of a Scheimpflug Lidar System for Atmospheric Aerosol Monitoring

    Science.gov (United States)

    Mei, Liang; Brydegaard, Mikkel

    2016-06-01

    This work presents a Scheimpflug lidar system which was employed for atmospheric aerosol monitoring in southern Sweden. Atmospheric aerosol fluctuation was observed around rush-hour. The extinction coefficient over 6 km was retrieved, i.e., 0.15 km-1, by employing the slop-method during the time when the atmosphere was relatively homogenous. The measurements successfully demonstrate the potential of using a Scheimpflug lidar technique for atmospheric aerosol monitoring applications.

  4. Resent Progress in Research on Calibration Instrument for Radioactive Aerosol Monitor

    Institute of Scientific and Technical Information of China (English)

    CHEN; Xi-lin; CHEN; Yong-yong; WU; Chang-ping; XING; Yu; MENG; Jun; YANG; Qiao-ling

    2013-01-01

    Radioactive aerosol monitors are widely used in monitoring the radioactivity concentration of the artificial nuclides in gaseous effluents from the nuclear facilities.An on-developing calibration instrument for radioactive aerosol monitors consists of an α and β aerosol generating unit,aerosol transferring unit,measurement unit of radioactivity concentration of aerosol for instruments calibrated and the waste gas

  5. Evaluation of the discmini personal aerosol monitor for submicrometer sodium chloride and metal aerosols

    Science.gov (United States)

    Mills, Jessica Breyan

    This work evaluated the robust, lightweight DiSCmini (DM) aerosol monitor for its ability to measure the concentration and mean diameter of submicrometer aerosols. Tests were conducted with monodispersed and polydispersed aerosols composed of two particle types (sodium chloride, NaCl, and spark generated metal particles, which simulate particles found in welding fume) at three different steady-state concentration ranges (Low, 104 particles/cm3). Particle number concentration, lung deposited surface area (LDSA) concentration, and mean size measured with the DM were compared to those measured with reference instruments, a scanning mobility particle sizer (SMPS) and a handheld condensation particle counter (CPC). Particle number concentrations measured with the DM were within 16% of those measured by the CPC for polydispersed aerosols. Poorer agreement was observed for monodispersed aerosols (+/-35% for most tests and +101% for 300-nm NaCl). LDSA concentrations measured by the DM were 96% to 155% of those estimated with the SMPS. The geometric mean diameters measured with the DM were within 30% of those measured with the SMPS for monodispersed aerosols and within 25% for polydispersed aerosols (except for the case when the aerosol contained a substantial number of particles larger than 300 nm). The accuracy of the DM is reasonable for particles smaller than 300 nm but caution should be exercised when particles larger than 300 nm are present.

  6. Monitoring of greenhouse gases and aerosols at Svalbard and Birkenes

    Energy Technology Data Exchange (ETDEWEB)

    Myhre, C.L.; Hermansen, O.; Fjaeraa, A.M.; Lunder, C.; Fiebig, M.; Schmidbauer, N.; Krognes, T.; Stebel, K.

    2012-07-01

    The report summaries the activities and results of the greenhouse gas monitoring at the Zeppelin and observatory situated on Svalbard in Arctic Norway during the period 2001-2010 and the greenhouse gas monitoring and aerosol observations from Birkenes for 2010. The monitoring programme is performed by the NILU - Norwegian Institute for Air Research and funded by the Norwegian Pollution Control Authority (SFT) (now Climate and Pollution Agency) and NILU - Norwegian Institute for Air Research.(Author)

  7. Atmospheric aerosol monitoring by an elastic Scheimpflug lidar system.

    Science.gov (United States)

    Mei, Liang; Brydegaard, Mikkel

    2015-11-30

    This work demonstrates a new approach - Scheimpflug lidar - for atmospheric aerosol monitoring. The atmospheric backscattering echo of a high-power continuous-wave laser diode is received by a Newtonian telescope and recorded by a tilted imaging sensor satisfying the Scheimpflug condition. The principles as well as the lidar equation are discussed in details. A Scheimpflug lidar system operating at around 808 nm is developed and employed for continuous atmospheric aerosol monitoring at daytime. Localized emission, atmospheric variation, as well as the changes of cloud height are observed from the recorded lidar signals. The extinction coefficient is retrieved according to the slope method for a homogeneous atmosphere. This work opens up new possibilities of using a compact and robust Scheimpflug lidar system for atmospheric aerosol remote sensing. PMID:26698808

  8. Beta aerosols beacon, a truly portable continuous air monitor

    International Nuclear Information System (INIS)

    The Beta Aerosols Beacon (BAB) is a portable (57 lbs) continuous air monitor designed to detect airborne radiation. Utilizing solid state detectors has eliminated the use of lead shielding usually necessary for achieving accurate readings in high background areas, making the monitor lightweight as well as portable. The size of a small suitcase, it can be carried into confined work areas, eliminating the requirement for workers to wear respirators for many maintenance tasks. This paper describes the operation and applications of the BAB

  9. Monitoring and tracking the trans-Pacific transport of aerosols using multi-satellite aerosol optical depth retrievals

    OpenAIRE

    A. R. Naeger; P. Gupta; B. Zavodsky; McGrath, K M

    2015-01-01

    The primary goal of this study was to generate a near-real time (NRT) aerosol optical depth (AOD) product capable of providing a comprehensive understanding of the aerosol spatial distribution over the Pacific Ocean in order to better monitor and track the trans-Pacific transport of aerosols. Therefore, we developed a NRT product that takes advantage of observations from both low-earth orbiting and geostationary satellites. In particular, we utilize AOD products from the M...

  10. Lessons Learned In Aerosol Monitoring With The RASA

    International Nuclear Information System (INIS)

    The Radionuclide Aerosol Sampler/Analyzer (RASA) is an automated aerosol collection and analysis system designed by Pacific Northwest National Laboratory (PNNL) in the 1990's and is deployed in several locations around the world as part of the International Monitoring System (IMS) required under the Comprehensive Nuclear-Test-Ban Treaty (CTBT). The RASA operates unattended, save for regularly scheduled maintenance, iterating samples through a three-step process on a 24-hour interval. In its 15-year history, much has been learned from the operation and maintenance of the RASA that can benefit engineering updates or future aerosol systems. On 11 March 2011, a 9.0 magnitude earthquake and tsunami rocked the eastern coast of Japan, resulting in power loss and cooling failures at the Daiichi nuclear power plants in Fukushima Prefecture. Aerosol collections were conducted with the RASA in Richland, WA. We present a summary of the lessons learned over the history of the RASA, including lessons taken from the Fukushima incident, regarding the RASA IMS stations operated by the United States.

  11. Radioactive aerosol air contamination monitor (MAFF)

    International Nuclear Information System (INIS)

    The MAFF is a highly sensitive monitor designed to measure and signal accidental air contamination at values well below those generally detectable, allowing for high-amplitude variations due to radon daughter products. It consists of a standard electronic rack, which has been designed for use under highly varied conditions: detection of α, β, X radiation, number of independent channels (from 1 to 4), internal or external sunction pump, internal or external threshold processing, on-line computer or self-contained operation. Air is drawn in continuously through a stationary filter paper by a single pump. Each channel includes a scintillation detector and photomultiplier, and delivers an output signal proportional to the activity of the radionuclides trapped by the filter. The single-channel version is equipped with an oversize scintillator and photomultiplier with very high sensitivity. The electronic equipment consists of plug-in units which are selected according to each configuration. The control and display section includes a large number of safety systems which guarantee high equipment operating reliability. The MAFF is currently used in several reactors and hot laboratories

  12. Design of automatic control and measurement software for radioactive aerosol continuity monitor

    International Nuclear Information System (INIS)

    The radioactive aerosol continuity measurement is very important for the development of nuclear industry, and it is the major method to measure and find out the leakage of radioactive material. Radioactive aerosol continuity monitor is the advanced method for the radioactive aerosol continuity measurement. With the development of nuclear industry and nuclear power station, it is necessary to design and automatic continuity measurement device. Because of this reason, the authors developed the first unit of radioactive aerosol continuity monitor and adopted the ministry appraisal. The design idea and method of automatic control and measurement for radioactive aerosol continuity monitor are discussed

  13. On the stability problem of radioactive aerosol monitors

    International Nuclear Information System (INIS)

    Sensitive monitoring of man-made aerosols, particularly 1st class radiotoxicity ones, is affected adversely by the occurrence of natural radionuclides and their time variations - the effect of radon and thoron daughter products deposited on the aerosol filter. A number of methods has been developed to minimize this adverse effect, such as the pseudo-coincidence compensation method with a comparison of the alpha and beta activity. The paper analyses the instability in the artificial radioactivity-measuring channels which is due to the non-equilibrium states of the radon daughter products and their variations. It is shown that the variations in the compensated channels are due to the compensation method as such. Therefore, a series of measurements should always be performed prior to the analysis, in order to test the accuracy of the chosen degree of compensation. The fact should be borne in mind that radon (thoron) diffusing from the building material gets to the workplace free of its daughter products (which are only formed by its decay). Its origin, however, is in the outer environment. The amount of daughter products borne by the air from the external environment is primarily determined by whether the air is passed through aerosol process filters or not and by the delay at which the air reaches the workplace. This implies that the ventilation rate should be kept constant. This problem also concerns the monitor pumping unit, whose flow rate should be kept constant as well. This is a bottleneck with the KOPR 06 monitor. (P.A.)

  14. Device for Testing and Calibrating Equipment for Monitoring Atmospheric Contamination by Aerosols

    International Nuclear Information System (INIS)

    A device for aerosol production and entrainment has been designed and built at the Physics Laboratory of the Radiation Protection Section of the Nuclear Studies Centre in Fontenay-aux-Roses for use in experiments with and calibration of various instruments for monitoring atmospheric contamination by radioactive aerosols. The paper describes the device for aerosol production and diffusion and refers to a number of experiments which illustrate its use. The unit consists of an aerosol generator which disperses inside a containment aerosols produced by drying a saline solution in dry air. The aerosols in the homogenization container have a definite and reproducible particle size. The concentration of natural daughter products of radon can be varied within certain limits. The first checks of aerosol particle size were made with a cascade impactor. Testing with a slit impactor can be used for checking on the collection of plutonium aerosols, while various other instruments with a mobile filter were tested with beta-emitting aerosols. The testing device can also be used for studying the distribution of aerosols on fixed filters and for investigating deposits in pipelines and sampling containers. (author)

  15. Development of aerosol retrieval algorithm for Geostationary Environmental Monitoring Spectrometer (GEMS)

    Science.gov (United States)

    Kim, Mijin; Kim, Jhoon; Park, Sang Seo; Jeong, Ukkyo; Ahn, Changwoo; Bhartia, Pawan. K.; Torres, Omar; Song, Chang-Keun; Han, Jin-Seok

    2014-05-01

    A scanning UV-Visible spectrometer, the GEMS (Geostationary Environment Monitoring Spectrometer) onboard the GEO-KOMPSAT2B (Geostationary Korea Multi-Purpose Satellite) is planned to be launched in geostationary orbit in 2018. The GEMS employs hyper-spectral imaging with 0.6 nm resolution to observe solar backscatter radiation in the UV and Visible range. In the UV range, the low surface contribution to the backscattered radiation and strong interaction between aerosol absorption and molecular scattering can be advantageous in retrieving aerosol optical properties such as aerosol optical depth (AOD) and single scattering albedo (SSA). This study presents a UV-VIS algorithm to retrieve AOD and SSA from GEMS. The algorithm is based on the general inversion method, which uses pre-calculated look-up table (LUT) with assumed aerosol properties and measurement condition. To calculate LUT, aerosol optical properties over Asia [70°E-145°E, 0°N-50°N] are obtained from AERONET inversion data (level 2.0) at 46 AERONET sites, and are applied to VLIDORT (spur, 2006). Because the backscattering radiance in UV-Visible range has significant sensitivity to radiance absorptivity and size distribution of loading aerosol, aerosol types are classified from AERONET inversion data by using aerosol classification method suggested in Lee et al. (2010). Then the LUTs are calculated with average optical properties for each aerosol type. The GEMS aerosol algorithm is tested with OMI level-1B dataset, a provisional data for GEMS measurement. The aerosol types for each measured scene are selected by using both of UVAI and VISAI, and AOD and SSA are simultaneously retrieved by comparing simulated radiance with selected aerosol type and the measured value. The AOD and SSA retrieved from GEMS aerosol algorithm are well matched with OMI products, although the retrieved AOD is slightly higher than OMI value. To detect cloud pixel, spatial standard deviation test of radiance is applied in the

  16. Design and performance of an automatic regenerating adsorption aerosol dryer for continuous operation at monitoring sites

    Science.gov (United States)

    Tuch, T. M.; Haudek, A.; Müller, T.; Nowak, A.; Wex, H.; Wiedensohler, A.

    2009-04-01

    Sizes of aerosol particles depend on the relative humidity of their carrier gas. Most monitoring networks require therefore that the aerosol is dried to a relative humidity below 50% RH to ensure comparability of measurements at different sites. Commercially available aerosol dryers are often not suitable for this purpose at remote monitoring sites. Adsorption dryers need to be regenerated frequently and maintenance-free single column Nafion dryers are not designed for high aerosol flow rates. We therefore developed an automatic regenerating adsorption aerosol dryer with a design flow rate of 1 m3/h. Particle transmission efficiency of this dryer has been determined during a 3 weeks experiment. The lower 50% cut-off was found to be below 3 nm at the design flow rate of the instrument. Measured transmission efficiencies are in good agreement with theoretical calculations. One drier has been successfully deployed in the Amazonas river basin. From this monitoring site, we present data from the first 6 months of measurements (February 2008-August 2008). Apart from one unscheduled service, this dryer did not require any maintenance during this time period. The average relative humidity of the dried aerosol was 27.1+/-7.5% RH compared to an average ambient relative humidity of nearly 80% and temperatures around 30°C. This initial deployment demonstrated that these dryers are well suitable for continuous operation at remote monitoring sites under adverse ambient conditions.

  17. Monitoring and tracking the trans-Pacific transport of aerosols using multi-satellite aerosol optical depth retrievals

    Science.gov (United States)

    Naeger, A. R.; Gupta, P.; Zavodsky, B.; McGrath, K. M.

    2015-10-01

    The primary goal of this study was to generate a near-real time (NRT) aerosol optical depth (AOD) product capable of providing a comprehensive understanding of the aerosol spatial distribution over the Pacific Ocean in order to better monitor and track the trans-Pacific transport of aerosols. Therefore, we developed a NRT product that takes advantage of observations from both low-earth orbiting and geostationary satellites. In particular, we utilize AOD products from the Moderate Resolution Imaging Spectroradiometer (MODIS) and Suomi National Polar-orbiting Partnership (NPP) Visible Infrared Imaging Radiometer Suite (VIIRS) satellites. Then, we combine these AOD products with our own retrieval algorithms developed for the NOAA Geostationary Operational Environmental Satellite (GOES-15) and Japan Meteorological Agency (JMA) Multi-functional Transport Satellite (MTSAT-2) to generate a NRT daily AOD composite product. We present examples of the daily AOD composite product for a case study of trans-Pacific transport of Asian pollution and dust aerosols in mid-March 2014. Overall, the new product successfully tracks this aerosol plume during its trans-Pacific transport to the west coast of North America. However, we identify several areas across the domain of interest from Asia to North America where the new product can encounter significant uncertainties due to the inclusion of the geostationary AOD retrievals. The uncertainties associated with geostationary AOD retrievals are expected to be minimized after the successful launch of the next-generation advanced NOAA GOES-R and recently launched JMA Himawari satellites. Observations from these advanced satellites will ultimately provide an enhanced understanding of the spatial and temporal distribution of aerosols over the Pacific.

  18. Monitoring and tracking the trans-Pacific transport of aerosols using multi-satellite aerosol optical depth retrievals

    Directory of Open Access Journals (Sweden)

    A. R. Naeger

    2015-10-01

    Full Text Available The primary goal of this study was to generate a near-real time (NRT aerosol optical depth (AOD product capable of providing a comprehensive understanding of the aerosol spatial distribution over the Pacific Ocean in order to better monitor and track the trans-Pacific transport of aerosols. Therefore, we developed a NRT product that takes advantage of observations from both low-earth orbiting and geostationary satellites. In particular, we utilize AOD products from the Moderate Resolution Imaging Spectroradiometer (MODIS and Suomi National Polar-orbiting Partnership (NPP Visible Infrared Imaging Radiometer Suite (VIIRS satellites. Then, we combine these AOD products with our own retrieval algorithms developed for the NOAA Geostationary Operational Environmental Satellite (GOES-15 and Japan Meteorological Agency (JMA Multi-functional Transport Satellite (MTSAT-2 to generate a NRT daily AOD composite product. We present examples of the daily AOD composite product for a case study of trans-Pacific transport of Asian pollution and dust aerosols in mid-March 2014. Overall, the new product successfully tracks this aerosol plume during its trans-Pacific transport to the west coast of North America. However, we identify several areas across the domain of interest from Asia to North America where the new product can encounter significant uncertainties due to the inclusion of the geostationary AOD retrievals. The uncertainties associated with geostationary AOD retrievals are expected to be minimized after the successful launch of the next-generation advanced NOAA GOES-R and recently launched JMA Himawari satellites. Observations from these advanced satellites will ultimately provide an enhanced understanding of the spatial and temporal distribution of aerosols over the Pacific.

  19. Comparison of Aerosol Single Scattering Albedo Derived from the Ozone Monitoring Instrument with Aerosol Robotic Network Observations

    Institute of Scientific and Technical Information of China (English)

    LIU Qi; HONG Yu-Lan

    2012-01-01

    The single-scattering albedo (SSA), which quantifies radiative absorption capability, is an important optical property of aerosols. Ground-based methods have been extensively exploited to determine aerosol SSA but there were no satellite-based SSA measurements available until the advent of advanced remote sensing techniques, such as the Ozone Monitoring Instrument (OMI). Although the overall accuracy of OMI SSA is estimated to approach 0.1, its regional availability is unclear. Four-year SSA daily measurements from three Aerosol Robotic Network (AERONET) sites in China (Xianghe, Taihu, and Hong Kong) are chosen to determine the accuracy of OMI SSA in specific locations. The results show that on a global scale, the OMI SSA is systematically higher (with a mean relative bias of 3.5% and a RMS difference of ~0.06) and has poor correlation with the AERONET observations. In the Xianghe, Taihu, and Hong Kong sites, the correlation coefficients are 0.16, 0.47, and 0.44, respectively, suggesting that the distinct qualities of OMI SSA depend on geographic locations and/or dominant aerosol environments. The two types of SSA data yield the best agreement in Taihu and the worst in Hong Kong; the differing behavior is likely caused by varying levels of cloud contamination. The good consistency of the aerosol variation between the two SSA datasets on a seasonal scale is promising. These findings suggest that the current-version OMI SSA product can be applied to qualitatively characterize climatological variations of aerosol properties despite its limited accuracy as an instantaneous measurement.

  20. Simplifying aerosol size distributions modes simultaneously detected at four monitoring sites during SAPUSS

    OpenAIRE

    M. Brines; Dall'Osto, M.; Beddows, D.C.S.; R. M. Harrison; X. Querol

    2014-01-01

    The analysis of aerosol size distributions is a useful tool for understanding the sources and the processes influencing particle number concentrations (N) in urban areas. Hence, during the one-month SAPUSS campaign (Solving Aerosol Problems by Using Synergistic Strategies, EU Marie Curie Action) in autumn 2010 in Barcelona (Spain), four SMPSs (Scanning Mobility Particle Sizer) were simultaneously deployed at four monitoring sites: a road side (RSsite), an urban background si...

  1. Simplifying aerosol size distributions modes simultaneously detected at four monitoring sites during SAPUSS

    OpenAIRE

    M. Brines; Dall'Osto, M.; Beddows, D.C.S.; R. M. Harrison; X. Querol

    2013-01-01

    The analysis of aerosol size distributions is a useful tool for understanding the sources and the processes influencing particle number concentrations (N) in urban areas. Hence, during the one month SAPUSS campaign (Solving Aerosol Problems by Using Synergistic Strategies, EU Marie Curie Action) in autumn 2010 in Barcelona (Spain), four SMPS (Scanning Mobility Particle Sizers) were simultaneously deployed at four monitoring sites: a road side (RSsite), an urban background site located ...

  2. 'Independent' monitoring of the aerosol effluents from NPP provided by SURO

    International Nuclear Information System (INIS)

    In this paper there are the results of the independent monitoring of the aerosol discharges into the environment from NPPs of Dukovany and Temelin, which SURO provided for many years. The aerosol discharges are followed in 2 ventilation stacks of the Dukovany NPP (each ventilation stack is common for 2 pressurised water reactors of PWR Novovoronezh, type 213, 440 MWe) and in 5 ventilation stacks of the Temelin NPP (2 pressurised water reactors of PWR Novovoronezh, type VVER-1000/320, 1000 MWe, each of them connected to the own inner ventilation stack and outer ventilation stack, which surrounds the inner one; 1 ventilation stack is for the building of active and instrumental services). A system of the pipelines, whereby a sample of the exhausted air with aerosols is led away for different analyses, begins at a height of 40 - 50 m above the bottom of the ventilation stack. The pipelines system ensures the isokinetic sampling. Besides independent monitoring of the aerosols SURO provides the independent monitoring of the noble gases including 85Kr and 14C in the effluents from the ventilation stacks, too. This monitoring isn't performed continuously, because sampling and monitoring are relatively demanding. SURO also performs over the frame of the independent monitoring the determination of the aerosol size distribution from the Temelin NPP in dependence on the kind of a radionuclide. These determinations are in the monitoring plan of the Temelin NPP, but they aren't quite routine. The similar measurements took place in Dukovany NPP (VK-1) in the time period 1999-2001. The results can enter to the models of radionuclide diffusion in the environment and they are also useful for research. The 'independent' monitoring of the NPPs is a significant part of the monitoring of the Czech Republic territory, it confirms the values presented by operator and provides also a valuable base for research tasks. (authors)

  3. Two years of aerosol pollution monitoring in Singapore: a review

    International Nuclear Information System (INIS)

    An aerosol sampling campaign was initiated more than two years ago in Singapore. The aim was to determine the average elemental concentrations in fine and coarse aerosol fractions as well as to identify major pollution sources and their impact. For that purpose, two air samplers were employed at two different sampling locations; one sampler was a fine particulate aerosol sampler (PM2.5) located at the vicinity of a major industrial area. The other was a stacked filter unit (SFU) sampler designed for collection of fine and coarse fractions (PM2.5 and PM10) and installed in the residential area. Samples were taken typically twice a week and in several occasions daily. During the period of two years more than 700 aerosol samples were collected and analyzed using PIXE and RBS techniques. All samples were analyzed for 18 elements ranging between Na, Mg, Al, etc. up to As and Pb. Large daily and seasonal variations were found for most of the elements. These variations are attributed mainly to meteorological changes, in particular changes in wind speed and direction. On several occasions, short term sampling was performed to identify fingerprints of major pollution sources such as road traffic, refineries, as well as the rain-forest fires in neighboring countries. A summary of our findings is presented and discussed

  4. Monitoring and tracking the trans-Pacific transport of aerosols using multi-satellite aerosol optical depth composites

    Science.gov (United States)

    Naeger, Aaron R.; Gupta, Pawan; Zavodsky, Bradley T.; McGrath, Kevin M.

    2016-06-01

    The primary goal of this study was to generate a near-real time (NRT) aerosol optical depth (AOD) product capable of providing a comprehensive understanding of the aerosol spatial distribution over the Pacific Ocean, in order to better monitor and track the trans-Pacific transport of aerosols. Therefore, we developed a NRT product that takes advantage of observations from both low-earth orbiting and geostationary satellites. In particular, we utilize AOD products from the Moderate Resolution Imaging Spectroradiometer (MODIS) and Suomi National Polar-orbiting Partnership (NPP) Visible Infrared Imaging Radiometer Suite (VIIRS) satellites. Then, we combine these AOD products with our own retrieval algorithms developed for the NOAA Geostationary Operational Environmental Satellite (GOES-15) and Japan Meteorological Agency (JMA) Multi-functional Transport Satellite (MTSAT-2) to generate a NRT daily AOD composite product. We present examples of the daily AOD composite product for a case study of trans-Pacific transport of Asian pollution and dust aerosols in mid-March 2014. Overall, the new product successfully tracks this aerosol plume during its trans-Pacific transport to the west coast of North America as the frequent geostationary observations lead to a greater coverage of cloud-free AOD retrievals equatorward of about 35° N, while the polar-orbiting satellites provide a greater coverage of AOD poleward of 35° N. However, we note several areas across the domain of interest from Asia to North America where the GOES-15 and MTSAT-2 retrieval algorithms can introduce significant uncertainties into the new product.

  5. Evaluation of coarse and fine particulate sources using a portable aerosol monitor in a desert community.

    Science.gov (United States)

    Phalen, Robert N; Coleman, Ted

    2012-08-01

    The purpose of this study was to use a portable aerosol monitor as a preliminary screening tool to identify local sources of coarse (PM(10-2.5)) and fine (PM(2.5)) particulate matter within the Coachella Valley, a low-elevation desert community. The portable aerosol monitor proved to be useful in identifying particle sources unique to the region, namely, sand dunes with sparse ground cover (vegetation), a river wash, and diesel truck and freight train traffic. The general limitations relate to discrepancies in the fraction of PM(10-2.5) when compared to regional air quality data and a lack of accurate mass-based data. PMID:22617941

  6. Uncertainty quantification in aerosol optical thickness retrieval from Ozone Monitoring Instrument (OMI) measurements

    Science.gov (United States)

    Määttä, A.; Laine, M.; Tamminen, J.; Veefkind, J. P.

    2013-10-01

    The space borne measurements provide global view of atmospheric aerosol distribution. The Ozone Monitoring Instrument (OMI) on board NASAs Earth Observing System (EOS) Aura satellite is a Dutch-Finnish nadir-viewing solar backscatter spectrometer measuring in the ultraviolet and visible wavelengths. OMI measures several trace gases and aerosols that are important in many air quality and climate studies. The OMI aerosol measurements are used, for example, for detecting volcanic ash plumes, wild fires and transportation of desert dust. We present a methodology for improving the uncertainty quantification in the aerosols retrieval algorithm. We have used the OMI measurements in this feasibility study. Our focus is on the uncertainties originating from the pre-calculated aerosol models. These models are never complete descriptions of the reality. This aerosol model uncertainty is estimated using Gaussian processes with computational tools from spatial statistics. Our approach is based on smooth systematic differences between the observed and modelled reflectances. When acknowledging this model inadequacy in the estimation of aerosol optical thickness (AOT), the uncertainty estimates are more realistic. We present here a real world example of applying the methodology.

  7. Effects of aerosol particle size on dispersion and continuous air monitor response in a plutonium laboratory

    International Nuclear Information System (INIS)

    The effectiveness of continuous air monitors (CAMs) in protecting plutonium workers depends on the efficiency of aerosol transport from the release point to the CAM. The main processes for aerosol transport are diffusion, forced convection, and gravitational settling. The transport of particles relative to each of these processes depends on particle size. Studies have shown that activity median aerodynamic diameters for plutonium aerosols can range from less than 0.1 μm to greater than 10 μm. The purpose of this study was to characterize the influence of particle size on aerosol transport and CAM response in a plutonium laboratory. Polydisperse dioctyl sebacate oil aerosols were released from multiple locations within a plutonium laboratory at Los Alamos National Laboratory. An array of Laser Particle counters (LPCs) positioned in the laboratory measured time resolved aerosol dispersion. Aerosol concentrations were binned into two size ranges: (1) 0.5 μm to 5.0 μm, and (2) those greater than 5.0 μm. Statistical comparisons were done and the results suggested that transport efficiency was greater for smaller particles than larger particles in this laboratory. This result suggested the importance of using particles of similar physical characteristics to those of the source when doing tests to decide optimal placement of CAMs

  8. Quantification of model uncertainty in aerosol optical thickness retrieval from Ozone Monitoring Instrument (OMI measurements

    Directory of Open Access Journals (Sweden)

    A. Määttä

    2013-09-01

    Full Text Available We study uncertainty quantification in remote sensing of aerosols in the atmosphere with top of the atmosphere reflectance measurements from the nadir-viewing Ozone Monitoring Instrument (OMI. Focus is on the uncertainty in aerosol model selection of pre-calculated aerosol models and on the statistical modelling of the model inadequacies. The aim is to apply statistical methodologies that improve the uncertainty estimates of the aerosol optical thickness (AOT retrieval by propagating model selection and model error related uncertainties more realistically. We utilise Bayesian model selection and model averaging methods for the model selection problem and use Gaussian processes to model the smooth systematic discrepancies from the modelled to observed reflectance. The systematic model error is learned from an ensemble of operational retrievals. The operational OMI multi-wavelength aerosol retrieval algorithm OMAERO is used for cloud free, over land pixels of the OMI instrument with the additional Bayesian model selection and model discrepancy techniques. The method is demonstrated with four examples with different aerosol properties: weakly absorbing aerosols, forest fires over Greece and Russia, and Sahara dessert dust. The presented statistical methodology is general; it is not restricted to this particular satellite retrieval application.

  9. Inverse atmospheric radiative transfer problems - A nonlinear minimization search method of solution. [aerosol pollution monitoring

    Science.gov (United States)

    Fymat, A. L.

    1976-01-01

    The paper studies the inversion of the radiative transfer equation describing the interaction of electromagnetic radiation with atmospheric aerosols. The interaction can be considered as the propagation in the aerosol medium of two light beams: the direct beam in the line-of-sight attenuated by absorption and scattering, and the diffuse beam arising from scattering into the viewing direction, which propagates more or less in random fashion. The latter beam has single scattering and multiple scattering contributions. In the former case and for single scattering, the problem is reducible to first-kind Fredholm equations, while for multiple scattering it is necessary to invert partial integrodifferential equations. A nonlinear minimization search method, applicable to the solution of both types of problems has been developed, and is applied here to the problem of monitoring aerosol pollution, namely the complex refractive index and size distribution of aerosol particles.

  10. First results of testing a stepwise rotated aerosol filter system for environmental monitoring

    International Nuclear Information System (INIS)

    The monitoring of the gross beta aerosol activity released from nuclear facilities is of great importance for environmental surveillance. In order to measure this activity by one monitor, both during normal operation (down to 10-2 Bq/m3) and in the case of an accident (up to 106 Bq/m3) this device must cover a range of more than eight orders of magnitude. Moreover this equipment should not be too expensive in construction and operation, it should be very simple in regard to the sampling technique and it should comply with all requirements made by national regulations and modern data handling. Until now no such monitor has been available. In the past few years the Nuclear Research Center Julich has developed a stepwise rotated aerosol filter system for environmental monitoring. The system and the first results of its tests will be reported in this paper

  11. Ground-based remote sensing scheme for monitoring aerosol-cloud interactions

    NARCIS (Netherlands)

    Sarna, K.; Russchenberg, H.W.J.

    2016-01-01

    A new method for continuous observation of aerosol–cloud interactions with ground-based remote sensing instruments is presented. The main goal of this method is to enable the monitoring of the change of the cloud droplet size due to the change in the aerosol concentration. We use high-resolution mea

  12. Aerosol composition and its application in air pollution monitoring

    International Nuclear Information System (INIS)

    Aerosol composition measurements have been carried out in our laboratory using nuclear and related techniques. A brief overview of results from the earlier studies and the scope of the present project are outlined. The analytical procedures in use along with the systems available are detailed. Changes envisaged in sampling and analysis are briefly discussed. Results of two case studies relating to air pollution which are investigated using INAA/EDXRF are presented. The work plan under the CRP is outlined. (author). 11 refs, 2 figs, 5 tabs

  13. Ground-based remote sensing scheme for monitoring aerosol-cloud interactions

    Science.gov (United States)

    Sarna, Karolina; Russchenberg, Herman W. J.

    2016-03-01

    A new method for continuous observation of aerosol-cloud interactions with ground-based remote sensing instruments is presented. The main goal of this method is to enable the monitoring of the change of the cloud droplet size due to the change in the aerosol concentration. We use high-resolution measurements from a lidar, a radar and a radiometer, which allow us to collect and compare data continuously. This method is based on a standardised data format from Cloudnet and can be implemented at any observatory where the Cloudnet data set is available. Two example case studies were chosen from the Atmospheric Radiation Measurement (ARM) Program deployment on Graciosa Island, Azores, Portugal, in 2009 to present the method. We use the cloud droplet effective radius (re) to represent cloud microphysical properties and an integrated value of the attenuated backscatter coefficient (ATB) below the cloud to represent the aerosol concentration. All data from each case study are divided into bins of the liquid water path (LWP), each 10 g m-2 wide. For every LWP bin we present the correlation coefficient between ln re and ln ATB, as well as ACIr (defined as ACIr = -d ln re/d ln ATB, change in cloud droplet effective radius with aerosol concentration). Obtained values of ACIr are in the range 0.01-0.1. We show that ground-based remote sensing instruments used in synergy can efficiently and continuously monitor aerosol-cloud interactions.

  14. Elemental composition of aerosol particles from two atmospheric monitoring stations in the Amazon Basin

    International Nuclear Information System (INIS)

    One key region for the study of processes that are changing the composition of the global atmosphere is the Amazon Basin tropical rain forest. The high rate of deforestation and biomass burning is emitting large amounts of gases and fine-mode aerosol particles to the global atmosphere. Two background monitoring stations are operating continuously measuring aerosol composition, at Cuiaba, and Serra do Navio. Fine- and coarse-mode aerosol particles are being collected using stacked filter units. Particle induced X-ray emission (PIXE) was used to measure concentrations of up to 21 elements: Al, Si, P, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Se, Br, Rb, Sr, Zr, and Pb. The elemental composition was measured at the new PIXE facility from the University of Sao Paulo, using a dedicated 5SDH tandem Pelletron nuclear accelerator. Absolute principal factor analysis (APFA) has derived absolute elemental source profiles. At the Serra do Navio sampling site a very clean background aerosol is being observed. Biogenic aerosol dominates the fine-mode mass concentration, with the presence of K, P, S, Cl, Zn, Br, and FPM. Three components dominate the aerosol composition: Soil dust particles, the natural biogenic release by the forest, and a marine aerosol component. At the Cuiaba site, during the dry season, a strong component of biomass burning is observed. An aerosol mass concentration up to 120 μg/m3 was measured. APFA showed three components: Soil dust (Al, Ca, Ti, Mn, Fe), biomass burning (soot, FPM, K, Cl) and natural biogenic particles (K, S, Ca, Mn, Zn). The fine-mode biogenic component of both sites shows remarkable similarities, although the two sampling sites are 3000 km apart. Several essential plant nutrients like P, K, S, Ca, Ni and others are transported in the atmosphere as a result of biomass burning processes. (orig.)

  15. LOCAL AIR: Local Aerosol monitoring combining in-situ and Remote Sensing observations

    Science.gov (United States)

    Mona, Lucia; Caggiano, Rosa; Donvito, Angelo; Giannini, Vincenzo; Papagiannopoulos, Nikolaos; Sarli, Valentina; Trippetta, Serena

    2015-04-01

    The atmospheric aerosols have effects on climate, environment and health. Although the importance of the study of aerosols is well recognized, the current knowledge of the characteristics and their distribution is still insufficient, and there are large uncertainties in the current understanding of the role of aerosols on climate and the environment, both on a regional and local level. Overcoming these uncertainties requires a search strategy that integrates data from multiple platforms (eg, terrestrial, satellite, ships and planes) and the different acquisition techniques (for example, in situ measurements, remote sensing, modeling numerical and data assimilation) (Yu et al., 2006). To this end, in recent years, there have been many efforts such as the creation of networks dedicated to systematic observation of aerosols (eg, European Monitoring and Evaluation Programme-EMEP, European Aerosol Research Lidar NETwork-EARLINET, MicroPulse Lidar Network- MPLNET, and Aerosol Robotic NETwork-AERONET), the development and implementation of new satellite sensors and improvement of numerical models. The recent availability of numerous data to the ground, columnar and profiles of aerosols allows to investigate these aspects. An integrated approach between these different techniques could be able to provide additional information, providing greater insight into the properties of aerosols and their distribution and overcoming the limits of each single technique. In fact, the ground measurements allow direct determination of the physico-chemical properties of aerosols, but cannot be considered representative for large spatial and temporal scales and do not provide any information about the vertical profile of aerosols. On the other hand, the remote sensing techniques from the ground and satellite provide information on the vertical distribution of atmospheric aerosols both in the Planetary Boundary Layer (PBL), mainly characterized by the presence of aerosols originating from

  16. Calculation Of Aerosol Transport Efficiency For The Airborne Radioiodine Monitoring System - ''RIS125''

    International Nuclear Information System (INIS)

    Radioactive iodine is a typical fission product in nuclear power reactors. Of the many iodine isotopes that can be generated in nuclear reactors only four are considered as radiobiological significant. These are: 1251 (T1/2=60 days), '131I (T1/2=8d), 133I (T1/2=21h) and I35I (T1/27h). The chemical forms that have been identified in heavy water reactors are I2 (elemental), organic iodides (CH3I), Inorganic iodides (HOI, HI) and LiI. Radioiodine is, generally, released as a gas but can be adsorbed on air particulates to form radioiodine contained aerosols. Therefore. its monitoring has to include both gas and aerosol sampling. A new monitoring system, RIS (Radioactive iodine Sampler), has been developed at the NRCN to monitor radioactive iodine (gas and aerosol) on-line in workplaces. This system samples radioiodine at a 60 L/min rate through a transport line connected to a filter holder. The filter consists of a cartridge containing activated charcoal with TEDA for iodine gas adsorption with a membrane for aerosols' retention in from of it. The radioiodine filter cartridge (F and J product code: TE2C) has a diameter of 2 1/4 inch and height of 1 inch . The gas adsorbent is coconut shell carbon type activated charcoal with 5% (by weight) TEDA impregnation and has 30x50 mesh size. This paper presents the aerosols' sampling characteristics of the RIS system including their transport in the sampling line and filter holder. The adsorption of iodine gas on the transport system components is negligible

  17. Monitoring of urban air pollution from MODIS aerosol data: effect of meteorological parameters

    OpenAIRE

    Zha, Yong; Gao, Jay; Jiang, Jianjun; Lu, Heng; Huang, Jiazhu

    2011-01-01

    Remote sensors designed specifically for studying the atmosphere have been widely used to derive timely information on air pollution at various scales. Whether the satellite-generated aerosol optical thickness (AOT) data can be used to monitor air pollution, however, is subject to the effect of a number of meteorological parameters. This study analyses the influence of four meteorological parameters (air pressure, air temperature, relative humidity, and wind velocity) on estimating particulat...

  18. A new method of satellite-based haze aerosol monitoring over the North China Plain and a comparison with MODIS Collection 6 aerosol products

    Science.gov (United States)

    Yan, Xing; Shi, Wenzhong; Luo, Nana; Zhao, Wenji

    2016-05-01

    With worldwide urbanization, hazy weather has been increasingly frequent, especially in the North China Plain. However, haze aerosol monitoring remains a challenge. In this paper, MODerate resolution Imaging Spectroradiometer (MODIS) measurements were used to develop an enhanced haze aerosol retrieval algorithm (EHARA). This method can work not only on hazy days but also on normal weather days. Based on 12-year (2002-2014) Aerosol Robotic Network (AERONET) aerosol property data, empirical single scattering albedo (SSA) and asymmetry factor (AF) values were chosen to assist haze aerosol retrieval. For validation, EHARA aerosol optical thickness (AOT) values, along with MODIS Collection 6 (C6) dark-pixel and deep blue aerosol products, were compared with AERONET data. The results show that the EHARA can achieve greater AOT spatial coverage under hazy conditions with a high accuracy (73% within error range) and work a higher resolution (1-km). Additionally, this paper presents a comprehensive discussion of the differences between and limitations of the EHARA and the MODIS C6 DT land algorithms.

  19. Automated high-volume aerosol sampling station for environmental radiation monitoring

    International Nuclear Information System (INIS)

    An automated high-volume aerosol sampling station, known as CINDERELLA.STUK, for environmental radiation monitoring has been developed by the Radiation and Nuclear Safety Authority (STUK), Finland. The sample is collected on a glass fibre filter (attached into a cassette), the airflow through the filter is 800 m3/h at maximum. During the sampling, the filter is continuously monitored with Na(I) scintillation detectors. After the sampling, the large filter is automatically cut into 15 pieces that form a small sample and after ageing, the pile of filter pieces is moved onto an HPGe detector. These actions are performed automatically by a robot. The system is operated at a duty cycle of 1 d sampling, 1 d decay and 1 d counting. Minimum detectable concentrations of radionuclides in air are typically 1Ae10 x 10-6 Bq/m3. The station is equipped with various sensors to reveal unauthorized admittance. These sensors can be monitored remotely in real time via Internet or telephone lines. The processes and operation of the station are monitored and partly controlled by computer. The present approach fulfils the requirements of CTBTO for aerosol monitoring. The concept suits well for nuclear material safeguards, too

  20. Ground-based remote sensing scheme for monitoring aerosol-cloud interactions

    Science.gov (United States)

    Sarna, K.; Russchenberg, H. W. J.

    2015-11-01

    A method for continuous observation of aerosol-cloud interactions with ground-based remote sensing instruments is presented. The main goal of this method is to enable the monitoring of cloud microphysical changes due to the changing aerosol concentration. We use high resolution measurements from lidar, radar and radiometer which allow to collect and compare data continuously. This method is based on a standardised data format from Cloudnet and can be implemented at any observatory where the Cloudnet data set is available. Two example study cases were chosen from the Atmospheric Radiation Measurement (ARM) Program deployment at Graciosa Island, Azores, Portugal in 2009 to present the method. We show the Pearson Product-Moment Correlation Coefficient, r, and the Coefficient of Determination, r2 for data divided into bins of LWP, each of 10 g m-2. We explain why the commonly used way of quantity aerosol cloud interactions by use of an ACI index (ACIr,τ = dln re,τ/dlnα) is not the best way of quantifying aerosol-cloud interactions.

  1. A new constituting lidar network for global aerosol observation and monitoring: Leone

    Science.gov (United States)

    Lolli, Simone; Sauvage Laurent, Laurent

    2010-05-01

    In order to observe and monitoring the direct and indirect impact of natural and anthropogenic aerosols on the radiative transfer and climate changing, it is necessary a continuous worldwide observation of the microphysical aerosol properties. A global observation it is of great support to the actual research in climate and it is a complement in the effort of monitoring trans-boundary pollution, and satellite validation, valorizing the use of lidar and passive sensors networks. In this framework, we have created the LEONET program, a new constituting worldwide network of EZ Lidar™ instruments. These lidars, developed by the French company LEOSPHERE, are compact and rugged eye safe UV Lidars with cross-polarisation detection capabilities, designed to monitor and study the atmospheric vertical structure of aerosols and clouds in a continuous way, night and day, over long time period in order to investigate and contribute to the climate change studies. LEONET output data, in hdf format, have the same architecture of those of NASA Micro Pulse Lidar Network (MPLNET) and will be soon available to the scientific community through the AERONET data synergy tool which provides ground-based, satellite, and model data products to characterize aerosol optical and microphysical properties, spatial and temporal distribution, transport, and chemical and radiative properties. In this work, it is presented an overview of the LEONET products and methodologies as the backscattering and extinction coefficients; the depolarization ratio, cloud layer heights and subsequent optical depths, provided to the limit of detection capability from a range of 100 m up to 20 km as well as the recent automatic height retrieval method of the different Planetary Boundary Layers (PBL). The retrieval algorithm in the future will be improved integrating, when possible, a measured Lidar ratio by a co-located sun photometer Further are presented some data examples from several diverse sites in the

  2. Aerosol monitoring in the PBL over big cities using a mobile eye safe LIDAR

    Science.gov (United States)

    Sauvage, Laurent; Chazette, Patrick

    2005-10-01

    The Laboratory of Science of Climate and Environment (CEA/ CNRS) and LEOSPHERE Company have jointly developed an eye safe, rugged and unattended high resolution scanning lidar ("easy lidar", www.lidar.fr). This system has been used in the frame of the POVA program and has been used in a compact version during the LISAIR (LIdar to Survey the AIR) program in May 2005 in the Paris city, France. The mobile lidar has been used to follow aerosol particles in highways subject to heavy traffic. High spatial and temporal resolution data on the entire planetary boundary layer (1.5 m and 1s respectively) allowed to monitor for aerosol load variability on board a moving car and also to detect for local sources. We observed the doubling of the optical thickness in the morning when traffic is high in the city ring. We also have shown local effect of waste burning plants and train stations. This new type of eye safe lidar will allow to monitor continuously the entire area of a town and suburbs, in order to detect main sources of pollution (transport, traffic jams, industrial plants, natural dust), follow in real time the evolution of the PBL height and provide an estimation of the mass concentration of the aerosol in the PBL.

  3. The influence of salt aerosol on alpha radiation detection by WIPP continuous air monitors

    International Nuclear Information System (INIS)

    Alpha continuous air monitors (CAMs) will be used at the Waste Isolation Pilot Plant (WIPP) to measure airborne transuranic radioactivity that might be present in air exhaust or in work-place areas. WIPP CAMs are important to health and safety because they are used to alert workers to airborne radioactivity, to actuate air-effluent filtration systems, and to detect airborne radioactivity so that the radioactivity can be confined in a limited area. In 1993, the Environmental Evaluation Group (EEG) reported that CAM operational performance was affected by salt aerosol, and subsequently, the WIPP CAM design and usage were modified. In this report, operational data and current theories on aerosol collection were reviewed to determine CAM quantitative performance limitations. Since 1993, the overall CAM performance appears to have improved, but anomalous alpha spectra are present when sampling-filter salt deposits are at normal to high levels. This report shows that sampling-filter salt deposits directly affect radon-thoron daughter alpha spectra and overall monitor efficiency. Previously it was assumed that aerosol was mechanically collected on the surface of CAM sampling filters, but this review suggests that electrostatic and other particle collection mechanisms are more important than previously thought. The mechanism of sampling-filter particle collection is critical to measurement of acute releases of radioactivity. 41 refs

  4. Simplifying aerosol size distributions modes simultaneously detected at four monitoring sites during SAPUSS

    Directory of Open Access Journals (Sweden)

    M. Brines

    2013-10-01

    Full Text Available The analysis of aerosol size distributions is a useful tool for understanding the sources and the processes influencing particle number concentrations (N in urban areas. Hence, during the one month SAPUSS campaign (Solving Aerosol Problems by Using Synergistic Strategies, EU Marie Curie Action in autumn 2010 in Barcelona (Spain, four SMPS (Scanning Mobility Particle Sizers were simultaneously deployed at four monitoring sites: a road side (RSsite, an urban background site located in the city (UBsite, an urban background located in the nearby hills of the city (Torre Collserola, TCsite and a regional background site located about fifty km from the Barcelona urban areas (RBsite. The spatial distribution of sites allows study of the aerosol temporal variability as well as the spatial distribution, progressively moving away from urban aerosol sources. In order to interpret the datasets collected, a k-means cluster analysis was performed on the combined SMPS datasets. This resulted in nine clusters describing all aerosol size distributions from the four sites. In summary there were three main categories (with three clusters in each category: "Traffic" (Traffic 1 "Tclus1" – 8%, Traffic 2 "Tclus2" – 13%, Traffic 3, "Tclus3" – 9%, "Background Pollution" (Urban Background 1 "UBclus1" – 21%, Regional Background 1, "RBclus1" – 15%, Regional Background 2, "RBclus2" – 18% and "Special cases" (Nucleation "NUclus" – 5%, Regional Nitrate, "NITclus" – 6%, and Mix "MIXclus" – 5%. As expected, the frequency of traffic clusters (Tclus1–3 followed the order RSsite, UBsite, TCsite, and RBsite. These showed typical traffic modes mainly distributed at 20–40 nm. The urban background sites (UBsite and TCsite reflected also as expected urban background number concentrations (average values, N = 2.4×104 cm−3 relative to 1.2×105 cm−3 seen at RSsite. The cluster describing the urban background pollution (UBclus1 could be used to monitor the sea

  5. Detection of marine aerosols with IRS P4-Ocean Colour Monitor

    Indian Academy of Sciences (India)

    Indrani Das; M Mohan; K Krishnamoorthy

    2002-12-01

    The atmospheric correction bands 7 and 8 (765nm and 865nm respectively) of the Indian Remote Sensing Satellite IRS P4-OCM (Ocean Colour Monitor) can be used for deriving aerosol optical depth (AOD) over the oceans. A retrieval algorithm has been developed which computes the AOD using band 7 data by treating the ocean surface as a dark background after removing the Rayleigh path radiance in the sensor-detected radiances. This algorithm has been used to detect marine aerosol distributions at different coastal and offshore locations around India. A comparison between OCM derived AOD and the NOAA operational AOD shows a correlation ∼0.92 while that between OCM derived AOD and the ground-based sun photometer measurements near the coast of Trivandrum shows a correlation of ∼0.90.

  6. The influence of salt aerosol on alpha radiation detection by WIPP continuous air monitors

    Energy Technology Data Exchange (ETDEWEB)

    Bartlett, W.T.; Walker, B.A. [Environmental Evaluation Group, Albuquerque, NM (United States)

    1997-08-01

    Waste Isolation Pilot Plant (WIPP) alpha continuous air monitor (CAM) performance was evaluated to determine if CAMs could detect accidental releases of transuranic radioactivity from the underground repository. Anomalous alpha spectra and poor background subtraction were observed and attributed to salt deposits on the CAM sampling filters. Microscopic examination of salt laden sampling filters revealed that aerosol particles were forming dendritic structures on the surface of the sampling filters. Alpha CAM detection efficiency decreased exponentially as salt deposits increased on the sampling filters, suggesting that sampling-filter salt was performing like a fibrous filter rather than a membrane filter. Aerosol particles appeared to penetrate the sampling-filter salt deposits and alpha particle energy was reduced. These findings indicate that alpha CAMs may not be able to detect acute releases of radioactivity, and consequently CAMs are not used as part of the WIPP dynamic confinement system. 12 refs., 12 figs., 1 tab.

  7. Engineering upgrades to the Radionuclide Aerosol Sampler/Analyzer for the CTBT International Monitoring System

    International Nuclear Information System (INIS)

    The Radionuclide Aerosol Sampler/Analyzer (RASA) is an automated collection and analysis system designed for aerosol radionuclide monitoring for the Comprehensive Nuclear-Test-Ban Treaty (CTBT). The advantages of an automated system include minimal need for human intervention and consistent analytical data. However, maintainability and down time issues threaten this utility, even for systems with over 90 % data availability. Engineering upgrades to the RASA are currently being pursued to address these issues, as well as measures relevant to technical lessons learned from the Fukushima nuclear power plant event. Current work includes a new automation control unit and other potential improvements such as alternative detector cooling and sampling options. This paper presents the current state of upgrades and improvements under investigation. (author)

  8. Submicron aerosol source apportionment of wintertime pollution in Paris, France by Double Positive Matrix Factorization (PMF2 using Aerosol Chemical Speciation Monitor (ACSM and multi-wavelength Aethalometer

    Directory of Open Access Journals (Sweden)

    J.-E. Petit

    2014-06-01

    Full Text Available 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 deconvoluted to hydrocarbon-like OA (HOA, Biomass Burning OA (BBOA and Oxygenated OA (OOA with Positive Matrix Factorization, and black carbon was deconvolved 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 real-time 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.

  9. Long-term dust climatology in the western United States reconstructed from routine aerosol ground monitoring

    Directory of Open Access Journals (Sweden)

    D. Q. Tong

    2012-06-01

    Full Text Available This study introduces an observation-based dust identification approach and applies it to reconstruct long-term dust climatology in the western United States. Long-term dust climatology is important for quantifying the effects of atmospheric aerosols on regional and global climate. Although many routine aerosol monitoring networks exist, it is often difficult to obtain dust records from these networks, because these monitors are either deployed far away from dust active regions (most likely collocated with dense population or contaminated by anthropogenic sources and other natural sources, such as wildfires and vegetation detritus. Here we propose an approach to identify local dust events relying solely on aerosol mass and composition from general-purpose aerosol measurements. Through analyzing the chemical and physical characteristics of aerosol observations during satellite-detected dust episodes, we select five indicators to be used to identify local dust records: (1 high PM10 concentrations; (2 low PM2.5/PM10 ratio; (3 higher concentrations and percentage of crustal elements; (4 lower percentage of anthropogenic pollutants; and (5 low enrichment factors of anthropogenic elements. After establishing these identification criteria, we conduct hierarchical cluster analysis for all validated aerosol measurement data over 68 IMPROVE sites in the western United States. A total of 182 local dust events were identified over 30 of the 68 locations from 2000 to 2007. These locations are either close to the four US Deserts, namely the Great Basin Desert, the Mojave Desert, the Sonoran Desert, and the Chihuahuan Desert, or in the high wind power region (Colorado. During the eight-year study period, the total number of dust events displays an interesting four-year activity cycle (one in 2000–2003 and the other in 2004–2007. The years of 2003, 2002 and 2007 are the three most active dust periods, with 46, 31 and 24

  10. An observation-based approach to identify local natural dust events from routine aerosol ground monitoring

    Directory of Open Access Journals (Sweden)

    D. Q. Tong

    2012-02-01

    Full Text Available Dust is a major component of atmospheric aerosols in many parts of the world. Although there exist many routine aerosol monitoring networks, it is often difficult to obtain dust records from these networks, because these monitors are either deployed far away from dust active regions (most likely collocated with dense population or contaminated by anthropogenic sources and other natural sources, such as wildfires and vegetation detritus. Here we propose a new approach to identify local dust events relying solely on aerosol mass and composition from general-purpose aerosol measurements. Through analyzing the chemical and physical characteristics of aerosol observations during satellite-detected dust episodes, we select five indicators to be used to identify local dust records: (1 high PM10 concentrations; (2 low PM2.5/PM10 ratio; (3 higher concentrations and percentage of crustal elements; (4 lower percentage of anthropogenic pollutants; and (5 low enrichment factors of anthropogenic elements. After establishing these identification criteria, we conduct hierarchical cluster analysis for all validated aerosol measurement data over 68 IMPROVE sites in the Western United States. A total of 182 local dust events were identified over 30 of the 68 locations from 2000 to 2007. These locations are either close to the four US Deserts, namely the Great Basin Desert, the Mojave Desert, the Sonoran Desert, and the Chihuahuan Desert, or in the high wind power region (Colorado. During the eight-year study period, the total number of dust events displays an interesting four-year activity cycle (one in 2000–2003 and the other in 2004–2007. The years of 2003, 2002 and 2007 are the three most active dust periods, with 46, 31 and 24 recorded dust events, respectively, while the years of 2000, 2004 and 2005 are the calmest periods, all with single digit dust records. Among these deserts, the Chihuahua Desert (59 cases and the

  11. Aerosols Analysis by LIBS for Monitoring of Air Pollution by Industrial Sources

    International Nuclear Information System (INIS)

    In the context of the air quality improvement, there is an increasing need to monitor gas and particle emissions originating from exhaust stacks (incinerators, foundries, etc.) for regulation enforcement purposes. Lots of pollutants are targeted; among them, heavy metals are mostly found in particulate forms. Hence, there is a need to promote the development of suitable on line analytical techniques. To that end, laser-induced breakdown spectroscopy (LIBS) appears to be a good technique. Indeed, it is quantitative, fast (≤1 min), requires no sample preparation, and can be performed at remote distance. The instrumentation is compact and offers the possibility to be used for continuous and in-situ monitoring. Two different approaches have been tested by several authors to analyze aerosols by LIBS, by focusing the laser either on particles collected on a filter or directly into the aerosol. In this work, these two approaches, aiming at measuring the mass concentration of micrometer metallic particles in air, are investigated and compared. The experimental setup includes an aerosol source (an ultrasonic nebuliser producing a diluted aerosol of CuSO4 particles); two sampling lines for particle sizes and, for reference concentration measurements, a line for direct LIBS analysis; and a fourth one devoted to filter sampling for subsequent LIBS measurements. Calibration curves were obtained with those two experimental approaches and the results are compared. In terms of sampling particles number, indirect analysis appears to be more efficient than direct analysis for our experimental conditions. Better detection limits were found with direct analysis when comparing the two approaches under similar sampling conditions (analysis time and sampling flow). (authors)

  12. Multiwavelength lidar node development and simulation for a regional tropospheric aerosol monitoring network

    International Nuclear Information System (INIS)

    This work studies multiwavelength lidar node operation requirements to operate in a regional aerosol monitoring network. Some of the parameters taken into account are simplicity and robustness of the system in continuous and remote operation conditions. Sub-system modularity and accessibility is also contemplated. A numerical simulation is performed on a synthetic atmospheric signal to analyze the behaviour of this system in a) the visible (532 nm) and infrared (1064 nm) spectral regions; b) the main atmospheric compound Raman spectral region (nitrogen, oxygen water vapor). Adding depolarization channels in the 532 nm spectral region is also contemplated.

  13. Development and calibration of an on-line aerosol monitor for PHEBUS test FPT1

    International Nuclear Information System (INIS)

    An on-line aerosol monitor (OLAM2) has been developed and tested for PHEBUS test FPT1. OLAM2 utilizes new detachable fiber optic cables and sapphire light pipes for light transmission between the OLAM and the electronics. This light transmission system was tested and found to provide better signal-to-noise performance than was achieved with the continuous fibers used for test FPT0. An additional advantage of the detachable fiber/light pipe system is ease of installation. Aerosol testing (OLAM calibration) was performed in order to verify adequate signal-to-noise performance of the new fiber optic system over the specified operating conditions and to check the quantitative light attenuation measurements against theoretical predictions. Results of the testing indicated that light extinction measurements obtained during Phebus tests could be used to estimate aerosol volume concentrations, if diamond window fouling can be avoided. OLAM2 was also subjected to a proof pressure test and a long-term thermal stability test. These tests verified the mechanical and thermal integrity of the OLAM within design specifications. Long-term output signal stability was also verified with the system maintained at design temperature and half-design pressure

  14. Urban air quality assessment using monitoring data of fractionized aerosol samples, chemometrics and meteorological conditions.

    Science.gov (United States)

    Yotova, Galina I; Tsitouridou, Roxani; Tsakovski, Stefan L; Simeonov, Vasil D

    2016-06-01

    The present article deals with assessment of urban air by using monitoring data for 10 different aerosol fractions (0.015-16 μm) collected at a typical urban site in City of Thessaloniki, Greece. The data set was subject to multivariate statistical analysis (cluster analysis and principal components analysis) and, additionally, to HYSPLIT back trajectory modeling in order to assess in a better way the impact of the weather conditions on the pollution sources identified. A specific element of the study is the effort to clarify the role of outliers in the data set. The reason for the appearance of outliers is strongly related to the atmospheric condition on the particular sampling days leading to enhanced concentration of pollutants (secondary emissions, sea sprays, road and soil dust, combustion processes) especially for ultra fine and coarse particles. It is also shown that three major sources affect the urban air quality of the location studied-sea sprays, mineral dust and anthropogenic influences (agricultural activity, combustion processes, and industrial sources). The level of impact is related to certain extent to the aerosol fraction size. The assessment of the meteorological conditions leads to defining of four downwind patterns affecting the air quality (Pelagic, Western and Central Europe, Eastern and Northeastern Europe and Africa and Southern Europe). Thus, the present study offers a complete urban air assessment taking into account the weather conditions, pollution sources and aerosol fractioning. PMID:26942452

  15. Evaluation of the RSG-GAS Alpha-Beta Aerosol Contaminant Monitor Performance Under Reactor Operation Condition

    International Nuclear Information System (INIS)

    Analysis to evaluate the RSG-GAS alpha-beta aerosol contaminant monitor performance was done. The high potential radiation working area such as in RSG-GAS is important to monitored for personal safety. Further it is necessary to assure that the system monitor is reliable enough under normal conditions as well as emergency condition. The method uses in this analysis are monitoring and comparing with the standard source. The standard course indicator and panel in main control room indicate that the result is 1 x 110 exp 9 Ci/m exp 3. Based on data monitor observation, the RSG-GAS alpha-beta aerosol contaminant monitor system under reactor operation condition has a good enough performance

  16. The ToF-ACSM: a portable aerosol chemical speciation monitor with TOFMS detection

    Directory of Open Access Journals (Sweden)

    R. Fröhlich

    2013-07-01

    Full Text Available We present a new instrument for monitoring aerosol composition, the economy time-of-flight-aerosol chemical speciation monitor (ToF-ACSM, combining precision of state-of-the-art time-of-flight mass spectrometry with stability, reliability, and easy handling, which are necessities for long-term monitoring operations on the scale of months to years. Based on Aerodyne aerosol mass spectrometer (AMS technology, the ToF-ACSM provides continuous online measurements of chemical composition and mass of non-refractory submicron aerosol particles. In contrast to the larger AMS, the compact-sized and lower-priced ToF-ACSM does not feature particle sizing, similar to the widely-used quadrupole-ACSM (Q-ACSM. Compared to the Q-ACSM, the ToF-ACSM features a better mass resolution of M/ΔM = 600 and better detection limits on the order of −3 for a time resolution of 30 min. With simple upgrades these limits can be brought down by another factor of ~8. This allows for operation at higher time resolutions and in low concentration environments. The associated software packages (single packages for integrated operation & calibration and analysis provide a high degree of automation and remote access, minimising the need for trained personnel on site. Intercomparisons with Q-ACSM, C-ToF-AMS, nephelometer and scanning mobility particle sizer (SMPS measurements, performed during a first long-term deployment (>6 months on the Jungfraujoch mountain ridge (3580 m a.s.l. in the Swiss Alps agree quantitatively. Additionally, the mass resolution of the ToF-ACSM is sufficient for basic mass defect resolved peak fitting of the recorded spectra, providing a data stream not accessible to the Q-ACSM. This allows for quantification of certain hydrocarbon and oxygenated fragments (e.g. C3H7+ and C2H3O+, both occurring at m/Q = 43 Th, as well as improving inorganic/organic separation.

  17. The ToF-ACSM: a portable aerosol chemical speciation monitor with TOFMS detection

    Directory of Open Access Journals (Sweden)

    R. Fröhlich

    2013-11-01

    Full Text Available We present a new instrument for monitoring aerosol composition, the time-of-flight aerosol chemical speciation monitor (ToF-ACSM, combining precision state-of-the-art time-of-flight mass spectrometry with stability, reliability, and easy handling, which are necessities for long-term monitoring operations on the scale of months to years. Based on Aerodyne aerosol mass spectrometer (AMS technology, the ToF-ACSM provides continuous online measurements of chemical composition and mass of non-refractory submicron aerosol particles. In contrast to the larger AMS, the compact-sized and lower-priced ToF-ACSM does not feature particle sizing, similar to the widely-used quadrupole-ACSM (Q-ACSM. Compared to the Q-ACSM, the ToF-ACSM features a better mass resolution of M/ΔM = 600 and better detection limits on the order of −3 for a time resolution of 30 min. With simple upgrades these limits can be brought down by another factor of ~ 8. This allows for operation at higher time resolutions and in low concentration environments. The associated software packages (single packages for integrated operation and calibration and analysis provide a high degree of automation and remote access, minimising the need for trained personnel on site. Intercomparisons with Q-ACSM, C-ToF-AMS, nephelometer and scanning mobility particle sizer (SMPS measurements, performed during a first long-term deployment (> 10 months on the Jungfraujoch mountain ridge (3580 m a.s.l. in the Swiss Alps, agree quantitatively. Additionally, the mass resolution of the ToF-ACSM is sufficient for basic mass defect resolved peak fitting of the recorded spectra, providing a data stream not accessible to the Q-ACSM. This allows for quantification of certain hydrocarbon and oxygenated fragments (e.g. C3H7+ and C2H3O+, both occurring at m/Q = 43 Th, as well as improving inorganic/organic separation.

  18. Proceedings of the Department of Energy workshop on Workplace Aerosol Monitoring

    International Nuclear Information System (INIS)

    The workshop on Workshop Aerosol Monitoring was held October 28-30, 1985 in Napa, California and was sponsored by the US Department of Energy, Radiological Controls Division. This workshop brought together participants from the United States, England, France, and West Germany who represented government, research, and industry. The participants discussed the types of air sampling and air monitoring instrumentation that are currently being developed, the problems that need to be addressed in order to obtain ''representative'' samples, and the need for a lower minimum detectable activity to protect the worker from inhalation of radionuclides in a timely manner. This proceedings includes papers and speeches that were presented at the workshop, plus edited transcripts of panel and open discussions, and question and answer sessions

  19. Aerosol resuspension from fabric: implications for personal monitoring in the beryllium industry.

    Science.gov (United States)

    Bohne, J E; Cohen, B S

    1985-02-01

    The fabric used for work clothing at an industrial site can significantly influence personal monitor (PM) exposure estimates because dust resuspension from clothing can increase the concentration at the sampler inlet. The magnitude of the effect depends on removal forces and on the interaction of the contaminant particles with work garments. Aerosol deposition and resuspension on cotton and Nomex aramid fabrics was evaluated at a beryllium refinery. Electrostatically charged cotton backdrops collected more beryllium than neutral controls, but electronegative Nomex backdrops did not. Moving fabrics collected more beryllium than did stationary controls. When contaminated fabrics were agitated, PMs mounted 2.5 cm in front of the fabric collected more beryllium than monitors above the fabric, positioned to simulate the nose or mouth. The difference between the air concentrations measured by these PMs increased with Be loading and tended to level off for highly contaminated fabric. Cotton resuspended a larger fraction of its contaminant load than Nomex. These results are consistent with current knowledge of the behavior of particles on fabric fibers. Aerosol resuspension from garments is an important consideration in assessing inhalation exposure to toxic dusts. A garment may attract and retain toxic particles. This contamination is then available for later resuspension. PMID:3976498

  20. Demolition and removal of radioactively contaminated concrete soil: Aerosol control and monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Newton, G.J.; Hoover, M.D.; Grace, A.C. III

    1995-12-01

    From 1963 to 1985, two concrete-lined ponds were used to reduce the volume of radioactive liquids from the Institute`s research programs. Following withdrawal of the {open_quotes}hot ponds{close_quotes} from active use, the residual sludges and plastic liners of the ponds were removed and shipped to a radioactive waste disposal site. From 1987 to 1994, the concrete structures remained undisturbed pending environmental restoration on the site. Restoration began in 1994 and was completed in 1995. Restoration involved mechanical breakup and removal of the concrete structures and removal of areas of contaminated soils from the site. This report describes the design and results of the aerosol control and monitoring program that was conducted to ensure protection of workers and the environment during the restoration process. The aerosol control and monitoring strategy developed for remediation of the ITRI hot ponds was successful both in preventing dispersion of radioactive dusts and in demonstrating that exposures of workers and offsite releases were within statutory limits.

  1. Aerosol sampling and characterization for hazard evaluation. Progress report, October 1, 1977-September 30, 1978. [/sup 239/Pu aerosol monitor performance in work area

    Energy Technology Data Exchange (ETDEWEB)

    Scripsick, R.C.; Tillery, M.I.; Stafford, R.G.; Romero, P.O.

    1979-11-01

    Measurements of the dilution of air contaminants between worker breathing zone and area air samplers were made by releasing a test fluorescent aerosol in workrooms equipped with aerosol surveillance systems. These data were used to evaluate performance and suggest improvements in design of alarming air monitor systems. In one workroom studied, average half-hour breathing zone air concentration needed to trigger alarm was found to be 960 times the maximum permissible air concentration for occupational exposure to soluble /sup 239/Pu (MPC/sub a/). It was shown that alternative monitor placement in this room could result in decreasing average triggering concentration to 354 times the MPC/sub a/. Analysis of data from impaction-autoradiographic sizing comparison studies showed average disintegration to track ratio called track efficiency factor, to be 2.7 +- 0.4.

  2. TOMS Absorbing Aerosol Index

    Data.gov (United States)

    Washington University St Louis — TOMS_AI_G is an aerosol related dataset derived from the Total Ozone Monitoring Satellite (TOMS) Sensor. The TOMS aerosol index arises from absorbing aerosols such...

  3. Simplifying aerosol size distributions modes simultaneously detected at four monitoring sites during SAPUSS

    Science.gov (United States)

    Brines, M.; Dall'Osto, M.; Beddows, D. C. S.; Harrison, R. M.; Querol, X.

    2014-03-01

    The analysis of aerosol size distributions is a useful tool for understanding the sources and the processes influencing particle number concentrations (N) in urban areas. Hence, during the one-month SAPUSS campaign (Solving Aerosol Problems by Using Synergistic Strategies, EU Marie Curie Action) in autumn 2010 in Barcelona (Spain), four SMPSs (Scanning Mobility Particle Sizer) were simultaneously deployed at four monitoring sites: a road side (RSsite), an urban background site located in the city (UBsite), an urban background site located in the nearby hills of the city (Torre Collserola, TCsite) and a regional background site located about 50 km from the Barcelona urban areas (RBsite). The spatial distribution of sites allows study of the aerosol temporal variability as well as the spatial distribution, progressively moving away from urban aerosol sources. In order to interpret the data sets collected, a k-means cluster analysis was performed on the combined SMPS data sets. This resulted in nine clusters describing all aerosol size distributions from the four sites. In summary there were three main categories (with three clusters in each category): "Traffic" (Traffic 1, "Tclus_1" - 8%; Traffic 2, "Tclus_2" - 13%; and Traffic 3, "Tclus_3" - 9%) "Background Pollution" (Urban Background 1, "UBclus_1" - 21%; Regional Background 1, "RBclus_1" - 15%; and Regional Background 2, "RBclus_2" - 18%) and "Special Cases" (Nucleation, "NUclus" - 5%; Regional Nitrate, "NITclus" - 6%; and Mix, "MIXclus" - 5%). As expected, the frequency of traffic clusters (Tclus_1-3) followed the order RSsite, UBsite, TCsite, and RBsite. These showed typical traffic modes mainly distributed at 20-40 nm. The urban background sites (UBsite and TCsite) reflected also as expected urban background number concentrations (average values, N = 1.0 × 104 cm-3 and N = 5.5 × 103 cm-3, respectively, relative to 1.3 × 104 cm-3 seen at RSsite). The cluster describing the urban background pollution (UBclus_1

  4. Mobile monitors for aerosols, iodine, noble gases and dose rate measurements

    International Nuclear Information System (INIS)

    A system of mobile monitors has been developed for the application in the working environment. The surveillance in respect to aerosols, iodine, noble gases and dose rate is performed by independent trolley-mounted units which consist of identical components as far as possible. This reflects the users demands for uniform and simple operation, small number of different spare parts and high mobility. In all cases signal processing and data evaluation is done by the Digital Ratemeter FHT 1100 which can be integrated into a superior data acquisition system. In respect to the activity concentration measurements a detailed description is given of the applied mathematical algorithms and the measures taken against the interference of external gamma radiation. (orig.)

  5. Long-term Measurements of Submicrometer Aerosol Chemistry at the Southern Great Plains (SGP) Using an Aerosol Chemical Speciation Monitor (ACSM)

    Energy Technology Data Exchange (ETDEWEB)

    Parworth, Caroline; Fast, Jerome D.; Mei, Fan; Shippert, Timothy R.; Sivaraman, Chitra; Tilp, Alison; Watson, Thomas; Zhang, Qi

    2015-04-01

    In this study the long-term trends of non-refractory submicrometer aerosol (NR-PM1) composition and mass concentration measured by an Aerosol Chemical Speciation Monitor (ACSM) at the U.S. Department of Energy’s Southern Great Plains (SGP) site are discussed. Over the period of 19 months (Nov. 20, 2010 – June 2012) highly time resolved (~30 min.) NR-PM1 data was recorded. Using this dataset the value-added product (VAP) of deriving organic aerosol components (OACOMP) is introduced. With this VAP, multivariate analysis of the measured organic mass spectral matrix can be performed on long term data to return organic aerosol (OA) factors that are associated with distinct sources, evolution processes, and physiochemical properties. Three factors were obtained from this VAP including two oxygenated OA (OOA) factors, differing in degrees of oxidation, and a biomass burning OA (BBOA) factor. Back trajectory analyses were performed to investigate possible sources of major NR-PM1 species at the SGP site. Organics dominated NR-PM1 mass concentration for the majority of the study with the exception of winter, when nitrate increased due to transport of precursor species from surrounding urban and agricultural areas and also due to cooler temperatures. Sulfate mass concentrations showed little seasonal variation with mixed regional and local sources. In the spring BBOA emissions increased and were mainly associated with local fires. Isoprene and carbon monoxide emission rates were computed by the Model of Emissions of Gases and Aerosols from Nature (MEGAN) to represent the spatial distribution of biogenic and anthropogenic sources, respectively. From this model there is evidence to support that biogenic emissions from the southeast contribute to SOA formation at the SGP site during the summer.

  6. Retrieving tropospheric nitrogen dioxide over China from the Ozone Monitoring Instrument: effects of aerosols, surface reflectance anisotropy and vertical profile of nitrogen dioxide

    OpenAIRE

    J.-T. Lin; R. V. Martin; Boersma, K. F.; Sneep, M.; P. Stammes; R. Spurr; Wang, P.; Van Roozendael, M.; Clémer, K.; Irie, H.

    2013-01-01

    Retrievals of tropospheric nitrogen dioxide (NO2) from the Ozone Monitoring Instrument (OMI) are subject to errors in the treatments of aerosols, surface reflectance anisotropy, and vertical profile of NO2. Here we quantify the influences over China via an improved retrieval process. We explicitly account for aerosol optical effects (simulated by nested GEOS-Chem at 0.667° lon × 0.5° lat and constrained by aerosol measurements), surface reflectance anisotropy, and high-resolution...

  7. Retrieving tropospheric nitrogen dioxide from the Ozone Monitoring Instrument: effects of aerosols, surface reflectance anisotropy, and vertical profile of nitrogen dioxide

    OpenAIRE

    Lin, J.-T.; R. V. Martin; Boersma, K. F.; Sneep, M.; P. Stammes; R. Spurr; Wang, P.; Van Roozendael, M.; Clémer, K.; Irie, H.

    2014-01-01

    Retrievals of tropospheric nitrogen dioxide (NO2) from the Ozone Monitoring Instrument (OMI) are subject to errors in the treatments of aerosols, surface reflectance anisotropy, and vertical profile of NO2. Here we quantify the influences over China via an improved retrieval process. We explicitly account for aerosol optical effects (simulated by nested GEOS-Chem at 0.667° long. × 0.5° lat. and constrained by aerosol measurements), surface reflectance anisotropy, and high...

  8. Development of a calibration stand for the monitoring of atmospheric contamination by means of standard radioactive aerosols

    International Nuclear Information System (INIS)

    After a reminder of both the main physical laws governing aerosols and fluid mechanics, the methods and technologies used to develop a calibration equipment for the monitoring of atmospheric contamination by means of standard radioactive aerosols are presented. The preliminary tests checked the chief performances of the stand, the characteristics of which had been established for the purpose of the certification of atmospheric contamination monitors. These 'dynamic' tests were devised to measure the coefficient of the effect of natural radioactivity on the measurement of man-made activity and the measurement efficiency of artificial alpha and/or beta activity for a given installation. The tests conducted on the various components of the stand demonstrated the good operation of the installation, which allowed to carry out certification tests on three detectors

  9. Local - Air Project: Tropospheric Aerosol Monitoring by CALIPSO Lidar Satellite and Ground-Based Observations

    Science.gov (United States)

    Sarli, V.; Trippetta, S.; Bitonto, P.; Papagiannopoulos, N.; Caggiano, R.; Donvito, A.; Mona, L.

    2016-06-01

    A new method for the detection of the Planetary Boundary Layer (PBL) height from CALIPSO space-borne lidar data was developed and the possibility to infer the sub-micrometric aerosol particle (i.e., PM1) concentrations at ground level from CALIPSO observations was also explored. The comparison with ground-based lidar measurements from an EARLINET (European Aerosol Research LIdar Network) station showed the reliability of the developed method for the PBL. Moreover, empirical relationships between integrated backscatter values from CALIPSO and PM1 concentrations were found thanks to the combined use of the retrieved PBL heights, CALIPSO aerosol profiles and typing and PM1 insitu measurements.

  10. Adaptiv system for the quasi-on-line monitoring of radioactive aerosols with a fixed filter equipment

    International Nuclear Information System (INIS)

    Due to the low concentration of aeroslos systems which integrate the concentration on a filter must be used. A special computation algorithm was created. Since there are a lot of parameters, which influence the computation of the concentration, its time response has to be optimized for all possible values of the parameters. If all this influencing parameters are also measured it is possible to use an adaptive algorithm, which computes the concentration of radioactive aerosols at any time in an optimal way. This adaptive algorithm was used to design an aerosolmonitor which now works at the Technical University in Graz, Austria. It is also possible to monitor not only the total value of the concentration but also the two most important radioactive aerosols Radium C (Bi 214) and Thorium B (PB 212). Because of the simple hardware of the system this aerosolmonitor does not use the energy information of the radioactive radiation of the aerosols. But if you want to identify each nuclid it is also possible to compute all its concentrations. To do this many energy channals must be evaluated by the discribed algorithm. (Author, shortened by G.Q.)

  11. Remote monitoring of aerosol layers over Sofia during Sahara dust transport episode (April, 2012)

    Science.gov (United States)

    Stoyanov, Dimitar; Grigorov, Ivan; Deleva, Atanaska; Kolev, Nikolay; Peshev, Zahari; Kolarov, Georgi; Donev, Evgeni; Ivanov, Danko

    2013-03-01

    In this work we present results of lidar remote sensing of aerosol layers in the atmosphere above Sofia during an episode of Sahara dust transport, 02-07 April, 2012. The investigations were made using two lidar systems, one equipped with a CuBr-vapor laser, emitting at wavelength 510.6 nm, and a second one - with Nd:YAG laser, at wavelengths 1064 nm and 532 nm. The results of lidar measurements are presented in terms of vertical atmospheric backscatter coefficient profiles and color maps of the aerosol stratification evolution. The involved into discussions ceilometer data (CHM 15k ceilometer) and satellite data from CALIPSO lidar, enhance the synergy of observations. Conclusion about atmospheric aerosol's origin was made upon analyses of the information of weather-forecast maps provided by the Forecast system of Barcelona Supercomputing Centre, which are accessible via Internet. Additional information was provided by calculations of the backward air mass trajectories, using online software of NOAA about HYSPLIT model. The comparison between the data from the two lidars and the ceilometer showed similar behavior of aerosol layers development in the atmosphere above Sofia. All information about aerosol layers origin, their altitude above ground, persistence during lidar observations, confirmed the conclusion of observation of a long-distance Sahara dust transport beyond Balkans and Sofia. An interesting completion of CALIPSO lidar and ground based lidars results of measurement is presented in case of thick opaque cloud layer in the atmosphere, which slices the path of lidar sensing in both directions.

  12. Absolute calibration of the Jenoptik CHM15k-x ceilometer and its applicability for quantitative aerosol monitoring

    Science.gov (United States)

    Geiß, Alexander; Wiegner, Matthias

    2014-05-01

    The knowledge of the spatiotemporal distribution of atmospheric aerosols and its optical characterization is essential for the understanding of the radiation budget, air quality, and climate. For this purpose, lidar is an excellent system as it is an active remote sensing technique. As multi-wavelength research lidars with depolarization channels are quite complex and cost-expensive, increasing attention is paid to so-called ceilometers. They are simple one-wavelength backscatter lidars with low pulse energy for eye-safe operation. As maintenance costs are low and continuous and unattended measurements can be performed, they are suitable for long-term aerosol monitoring in a network. However, the signal-to-noise ratio is low, and the signals are not calibrated. The only optical property that can be derived from a ceilometer is the particle backscatter coefficient, but even this quantity requires a calibration of the signals. With four years of measurements from a Jenoptik ceilometer CHM15k-x, we developed two methods for an absolute calibration on this system. This advantage of our approach is that only a few days with favorable meteorological conditions are required where Rayleigh-calibration and comparison with our research lidar is possible to estimate the lidar constant. This method enables us to derive the particle backscatter coefficient at 1064 nm, and we retrieved for the first time profiles in near real-time within an accuracy of 10 %. If an appropriate lidar ratio is assumed the aerosol optical depth of e.g. the mixing layer can be determined with an accuracy depending on the accuracy of the lidar ratio estimate. Even for 'simple' applications, e.g. assessment of the mixing layer height, cloud detection, detection of elevated aerosol layers, the particle backscatter coefficient has significant advantages over the measured (uncalibrated) attenuated backscatter. The possibility of continuous operation under nearly any meteorological condition with temporal

  13. Assessing the measurement of aerosol single scattering albedo by Cavity Attenuated Phase-Shift Single Scattering Monitor (CAPS PMssa)

    Science.gov (United States)

    Perim de Faria, Julia; Bundke, Ulrich; Onasch, Timothy B.; Freedman, Andrew; Petzold, Andreas

    2016-04-01

    The necessity to quantify the direct impact of aerosol particles on climate forcing is already well known; assessing this impact requires continuous and systematic measurements of the aerosol optical properties. Two of the main parameters that need to be accurately measured are the aerosol optical depth and single scattering albedo (SSA, defined as the ratio of particulate scattering to extinction). The measurement of single scattering albedo commonly involves the measurement of two optical parameters, the scattering and the absorption coefficients. Although there are well established technologies to measure both of these parameters, the use of two separate instruments with different principles and uncertainties represents potential sources of significant errors and biases. Based on the recently developed cavity attenuated phase shift particle extinction monitor (CAPS PM_{ex) instrument, the CAPS PM_{ssa instrument combines the CAPS technology to measure particle extinction with an integrating sphere capable of simultaneously measuring the scattering coefficient of the same sample. The scattering channel is calibrated to the extinction channel, such that the accuracy of the single scattering albedo measurement is only a function of the accuracy of the extinction measurement and the nephelometer truncation losses. This gives the instrument an accurate and direct measurement of the single scattering albedo. In this study, we assess the measurements of both the extinction and scattering channels of the CAPS PM_{ssa through intercomparisons with Mie theory, as a fundamental comparison, and with proven technologies, such as integrating nephelometers and filter-based absorption monitors. For comparison, we use two nephelometers, a TSI 3563 and an Aurora 4000, and two measurements of the absorption coefficient, using a Particulate Soot Absorption Photometer (PSAP) and a Multi Angle Absorption Photometer (MAAP). We also assess the indirect absorption coefficient

  14. Monitoring of the aerosols produced during the sprinkler irrigation with treated wastewater

    International Nuclear Information System (INIS)

    The paper evaluates the microbiological content of the aerosols produced during the irrigation with treated wastewater coming from a disinfection pilot plant set up in order to reach the Italian limit for unrestricted irrigation wastewater reuse. This evaluation is extremely important for both the possible effects on the workers' health and the presence of inhabited centers, including the city of Pistoia (Italy), just in the shelter of the cultivated areas. According to the experimental results, the paper points out that aerosols produced during irrigation do not contain any faecal indicator bacteria. Therefore WWTP disinfected effluent appears to be suitable from a sanitary point of view. On the contrary, using the un disinfected secondary effluent the presence of faecal indicator bacteria in the aerosols produced during the sprinkler irrigation

  15. Astronomical site selection: On the use of satellite data for aerosol content monitoring

    CERN Document Server

    Varela, A M; Muñoz-Tuñón, C; Ortolani, S; Fuensalida, J J

    2008-01-01

    The main goal of this work is the analysis of new approaches to the study of the properties of astronomical sites. In particular, satellite data measuring aerosols have recently been proposed as a useful technique for site characterization and searching for new sites to host future very large telescopes. Nevertheless, these data need to be critically considered and interpreted in accordance with the spatial resolution and spectroscopic channels used. In this paper we have explored and retrieved measurements from satellites with high spatial and temporal resolutions and concentrated on channels of astronomical interest. The selected datasets are OMI on board the NASA Aura satellite and MODIS on board the NASA Terra and Aqua satellites. A comparison of remote sensing and in situ techniques is discussed. As a result, we find that aerosol data provided by satellites up to now are not reliable enough for aerosol site characterization, and in situ data are required.

  16. Continuous measurements at the urban roadside in an Asian megacity by Aerosol Chemical Speciation Monitor (ACSM): particulate matter characteristics during fall and winter seasons in Hong Kong

    Science.gov (United States)

    Sun, C.; Lee, B. P.; Huang, D.; Jie Li, Y.; Schurman, M. I.; Louie, P. K. K.; Luk, C.; Chan, C. K.

    2016-02-01

    Non-refractory submicron aerosol is characterized using an Aerosol Chemical Speciation Monitor (ACSM) in the fall and winter seasons of 2013 on the roadside in an Asian megacity environment in Hong Kong. Organic aerosol (OA), characterized by application of Positive Matrix Factorization (PMF), and sulfate are found to be dominant. Traffic-related organic aerosol shows good correlation with other vehicle-related species, and cooking aerosol displays clear mealtime concentration maxima and association with surface winds from restaurant areas. Contributions of individual species and OA factors to high NR-PM1 are analyzed for hourly data and daily data; while cooking emissions in OA contribute to high hourly concentrations, particularly during mealtimes, secondary organic aerosol components are responsible for episodic events and high day-to-day PM concentrations. Clean periods are either associated with precipitation, which reduces secondary OA with a lesser impact on primary organics, or clean oceanic air masses with reduced long-range transport and better dilution of local pollution. Haze events are connected with increases in contribution of secondary organic aerosol, from 30 to 50 % among total non-refractory organics, and the influence of continental air masses.

  17. Transuranic-aerosol-measurement system for the workplace or stack monitoring

    International Nuclear Information System (INIS)

    This compact transuranic-aerosol-measurement system, using alpha spectroscopy at vacuum, has a sensitivity of less than 0.5 MPC-h for 239Pu. In addition, a detector is mounted in the inlet pipe that responds immediately if there is a release of radioactivity; then, after an appropriate time, the filter is moved to the vacuum chamber for more sensitive off-line analysis. The system is very efficient for particles as large as 10 μ m in diameter. A microcomputer controls the filter transport, operates as a 256-channel pulse-height analyzer (PHA), performs calculations, checks calibration, and drives a matrix display and a central computer. This instrument, the Workplace Transuranic Aerosol Measurement System (WOTAMS), has been developed for use in facilities that process transuranics with the expectation it will further evolve into a commercial product to replace those less sensitive instruments now widely used. 10 references, 8 figures, 2 tables

  18. Data quality monitoring in the presence of aerosols and other adverse atmospheric conditions with H.E.S.S

    CERN Document Server

    Hahn, J; Bernlöhr, K; Krüger, P; Lo, Y T E; Chadwick, P M; Daniel, M K; Deil, C; Gast, H; Kosack, K; Marandon, V

    2015-01-01

    Cherenkov telescope experiments, such as H.E.S.S., have been very successful in astronomical observations in the very-high-energy (VHE; E $>$ 100 GeV) regime. As an integral part of the detector, such experiments use Earth's atmosphere as a calorimeter. For the calibration and energy determination, a standard model atmosphere is assumed. Deviations of the real atmosphere from the model may therefore lead to an energy misreconstruction of primary gamma rays. To guarantee satisfactory data quality with respect to difficult atmospheric conditions, several atmospheric data quality criteria are implemented in the H.E.S.S. software. These quantities are sensitive to clouds and aerosols. Here, the Cherenkov transparency coefficient will be presented. It is a new monitoring quantity that is able to measure long-term changes in the atmospheric transparency. The Cherenkov transparency coefficient derives exclusively from Cherenkov data and is quite hardware-independent. Furthermore, its positive correlation with indepe...

  19. Monitoring aerosol elemental composition in particle size fractions of long-range transport

    Science.gov (United States)

    Metternich, P.; Georgii, H.-W.; Groeneveld, K. O.

    1983-04-01

    Collection of atmospheric samples was performed at Malta, a semi-remote environment in the Mediterranean, in case of long-range transport studies of pollutants and natural substances. Using PIXE as a non-destructive trace-element analytical tool, the elemental composition of these samples was determined. Atmospheric concentrations obtained in this study were of one magnitude higher than those observed over the open North Alantic in purely marine air. For most of the anomalously enriched elements in the Mediterranean aerosol, the high concentrations can be explained by long-range transport.

  20. Monitoring the initial pulmonary absorption of two different beclomethasone dipropionate aerosols employing a human lung reperfusion model

    Directory of Open Access Journals (Sweden)

    Fritz Peter

    2005-02-01

    Full Text Available Abstract Background The pulmonary residence time of inhaled glucocorticoids as well as their rate and extend of absorption into systemic circulation are important facets of their efficacy-safety profile. We evaluated a novel approach to elucidate the pulmonary absorption of an inhaled glucocorticoid. Our objective was to monitor and compare the combined process of drug particle dissolution, pro-drug activation and time course of initial distribution from human lung tissue into plasma for two different glucocorticoid formulations. Methods We chose beclomethasone dipropionate (BDP delivered by two different commercially available HFA-propelled metered dose inhalers (Sanasthmax®/Becloforte™ and Ventolair®/Qvar™. Initially we developed a simple dialysis model to assess the transfer of BDP and its active metabolite from human lung homogenate into human plasma. In a novel experimental setting we then administered the aerosols into the bronchus of an extracorporally ventilated and reperfused human lung lobe and monitored the concentrations of BDP and its metabolites in the reperfusion fluid. Results Unexpectedly, we observed differences between the two aerosol formulations Sanasthmax®/Becloforte™ and Ventolair®/Qvar™ in both the dialysis as well as in the human reperfusion model. The HFA-BDP formulated as Ventolair®/Qvar™ displayed a more rapid release from lung tissue compared to Sanasthmax®/Becloforte™. We succeeded to explain and illustrate the observed differences between the two aerosols with their unique particle topology and divergent dissolution behaviour in human bronchial fluid. Conclusion We conclude that though the ultrafine particles of Ventolair®/Qvar™ are beneficial for high lung deposition, they also yield a less desired more rapid systemic drug delivery. While the differences between Sanasthmax®/Becloforte™ and Ventolair®/Qvar™ were obvious in both the dialysis and lung perfusion experiments, the latter

  1. Remote monitoring of atmospheric aerosol properties by using a multi-wavelength lidar system at Kwangju, Korea

    International Nuclear Information System (INIS)

    A multi-wavelength lidar system that can measure simultaneously spectral aerosol extinction coefficient and depolarization ratio has been developed and tested. Some results from lidar measurements aerosol extinction coefficient, lidar ratio, and depolarization ratio of aerosols are presented. Lidar transmit system generates 20 Hz laser pulses at 355 nm, 532 nm, and 1064 nm with an Nd;YAG laser. Backscattered light from atmospheric aerosol particles is collected with three Cassegrain type telescopes. Signal detection unit has 7-channels consisting of two 532 nm channels and one 1064 nm channel for measuring the stratospheric aerosols, two 532 nm channels for tropospheric aerosols, 387 nm channel for Raman scattering measurements. Aerosol observation has been conducted since December 2002 at Kwangju (35 .deg. 10'N, 126 .deg. 53'), Korea. Raman channel permitted better determination of optical properties of continental aerosols. The profile of the depolarization ratio is determined at 532 nm and used to investigate particle shape.

  2. Atmospheric aerosol monitoring and characterization: An emission control strategy to protect tropical forests

    Science.gov (United States)

    Mateus, V. L.; do Valles, T. V.; de Oliveira, T. B.; de Almeida, A. C.; Maia, L. F. P. G.; Saint'Pierre, T. D.; Gioda, A.

    2013-12-01

    Human activity represents one of the most harmful activities for biodiversity. Population growth has caused increasing interferences in natural areas suffering agriculture or urbanization. As a consequence, tropical forests are at risk, since they shelter more than half of the global biodiversity. In this context, protected areas are indeed important to preserve natural populations as well as threatened habitats. Aerosol samples were collected in two protected areas in Rio de Janeiro, Brazil, in order to quantify water-soluble species and evaluate anthropogenic influences considering secondary aerosol formation and organic compounds. Samplings were conducted at the National Park of Serra dos Orgãos (Parnaso) and the National Forest Mario Xavier (Flonamax) during 24 h every six days using a high-volume sampler from July 2010 to June 2012 (PM10) and from July 2011 to August 2012 (TSP), respectively. The aerosol mass was determined by Gravimetry. The water-soluble ionic composition (WSIC) was obtained by Ion Chromatography in order to determine the major anions (Br-, Cl-, F-, NO2-, NO3-, PO43-, SO42-) and cations (Li+, Ca2+, K+, Mg2+, Na+, NH4+); total water-soluble carbon (TWSC), water-soluble organic carbon (WSOC) were determined by a TOC analyzer and the elements were determined by Inductively Coupled Plasma Optical Emission Spectrometry. PM10 average concentrations ranged from 11.1 to 67.6 μg m-3 and TSP from 5.7 to 242.6 μg m-3. Regarding the ions, the highest cation concentration was measured for Na+ at both Parnaso and Flonamax sites, respectively, 2.9 and 6.1 μg m-3. Both sites are near to the coast, justifying these results. On the other hand, SO42- was the predominant anion measured at both sites with average concentrations ranged from 2.3 to 2.7 μg m-3. Around 50% of sulphate had a non-marine origin in the former site, while in the latter the percentage was of circa 40%. The correlation between NO3- and nss-SO42- was much stronger at Parnaso (r = 0

  3. A transuranic-aerosol-measurement system for the workplace or stack monitoring

    International Nuclear Information System (INIS)

    This compact transuranic-aerosol-measurement system, using alpha spectroscopy at vacuum, has a sensitivity of less than 0.5 MPC-hr for 239Pu. In addition, a detector is mounted in the inlet pipe that responds immediately if there is a release of radioactivity; then, after an appropriate time, the filter is moved to the vacuum chamber for more sensitive off-line analysis. The system is very efficient for particles as large as 10 μm in diameter. A micro-computer controls the filter transport, operates as a 256-channel PHA, performs calculations, checks calibration, and drives a matrix display and a central computer. This instrument, called WOTAMS, has been developed for use in facilities that process transuranics with the expectation it will further evolve into a commercial product to replace those less sensitive instruments now widely used

  4. Monitoring and modelling of biosphere/atmosphere exchange of gases and aerosols in Europe

    International Nuclear Information System (INIS)

    Monitoring and modelling of deposition of air pollutants is essential to develop and evaluate policies to abate the effects related to air pollution and to determine the losses of pollutants from the atmosphere. Techniques for monitoring wet deposition fluxes are widely applied. A recent intercomparison experiment, however, showed that the uncertainty in wet deposition is relatively high, up to 40%, apart from the fact that most samplers are biased because of a dry deposition contribution. Wet deposition amounts to about 80% of the total deposition in Europe with a range of 10-90% and uncertainty should therefore be decreased. During recent years the monitoring of dry deposition has become possible. Three sites have been operational for 5 years. The data are useful for model development, but also for model evaluation and monitoring of progress in policy. Data show a decline in SO2 dry deposition, whereas nitrogen deposition remained constant. Furthermore, surface affinities for pollutants changed leading to changes in deposition. Deposition models have been further developed and tested with dry deposition measurements and total deposition measurements on forests as derived from throughfall data. The comparison is reasonable given the measurement uncertainties. Progress in ozone surface exchange modelling and monitoring shows that stomatal uptake can be quantified with reasonable accuracy, but external surface uptake yields highest uncertainty. - Monitoring and modelling of the deposition of sulphur and nitrogen components and the exposure of ozone has gained much progress through the research within BIATEX

  5. Monitoring and modelling of biosphere/atmosphere exchange of gases and aerosols in Europe

    Energy Technology Data Exchange (ETDEWEB)

    Erisman, Jan Willem [Energy Research Centre of the Netherlands (ECN), P.O. Box 1, 1755 ZG Petten (Netherlands)]. E-mail: erisman@ecn.nl; Vermeulen, Alex [Energy Research Centre of the Netherlands (ECN), P.O. Box 1, 1755 ZG Petten (Netherlands); Hensen, Arjan [Energy Research Centre of the Netherlands (ECN), P.O. Box 1, 1755 ZG Petten (Netherlands); Flechard, Chris [Energy Research Centre of the Netherlands (ECN), P.O. Box 1, 1755 ZG Petten (Netherlands); Daemmgen, Ulrich [Federal Agricultural Research Centre, Institute of Agroecology, D-38116 Braunschweig, (Germany); Fowler, David [CEH, Bush Estate, Penicuik, Midlothian EH26 0QB (United Kingdom); Sutton, Mark [CEH, Bush Estate, Penicuik, Midlothian EH26 0QB (United Kingdom); Gruenhage, Ludger [Institute for Plant Ecology, Justus-Liebig-University, D-35392 Giessen (Germany); Tuovinen, Juha-Pekka [Finnish Meteorological Institute, FIN-00810 Helsinki (Finland)

    2005-02-01

    Monitoring and modelling of deposition of air pollutants is essential to develop and evaluate policies to abate the effects related to air pollution and to determine the losses of pollutants from the atmosphere. Techniques for monitoring wet deposition fluxes are widely applied. A recent intercomparison experiment, however, showed that the uncertainty in wet deposition is relatively high, up to 40%, apart from the fact that most samplers are biased because of a dry deposition contribution. Wet deposition amounts to about 80% of the total deposition in Europe with a range of 10-90% and uncertainty should therefore be decreased. During recent years the monitoring of dry deposition has become possible. Three sites have been operational for 5 years. The data are useful for model development, but also for model evaluation and monitoring of progress in policy. Data show a decline in SO{sub 2} dry deposition, whereas nitrogen deposition remained constant. Furthermore, surface affinities for pollutants changed leading to changes in deposition. Deposition models have been further developed and tested with dry deposition measurements and total deposition measurements on forests as derived from throughfall data. The comparison is reasonable given the measurement uncertainties. Progress in ozone surface exchange modelling and monitoring shows that stomatal uptake can be quantified with reasonable accuracy, but external surface uptake yields highest uncertainty. - Monitoring and modelling of the deposition of sulphur and nitrogen components and the exposure of ozone has gained much progress through the research within BIATEX.

  6. Two years of near real-time chemical composition of submicron aerosols in the region of Paris using an Aerosol Chemical Speciation Monitor (ACSM) and a multi-wavelength Aethalometer

    Science.gov (United States)

    Petit, J.-E.; Favez, O.; Sciare, J.; Crenn, V.; Sarda-Estève, R.; Bonnaire, N.; Močnik, G.; Dupont, J.-C.; Haeffelin, M.; Leoz-Garziandia, E.

    2015-03-01

    Aerosol mass spectrometer (AMS) measurements have been successfully used towards a better understanding of non-refractory submicron (PM1) aerosol chemical properties based on short-term campaigns. The recently developed Aerosol Chemical Speciation Monitor (ACSM) has been designed to deliver quite similar artifact-free chemical information but for low cost, and to perform robust monitoring over long-term periods. When deployed in parallel with real-time black carbon (BC) measurements, the combined data set allows for a quasi-comprehensive description of the whole PM1 fraction in near real time. Here we present 2-year long ACSM and BC data sets, between mid-2011 and mid-2013, obtained at the French atmospheric SIRTA supersite that is representative of background PM levels of the region of Paris. This large data set shows intense and time-limited (a few hours) pollution events observed during wintertime in the region of Paris, pointing to local carbonaceous emissions (mainly combustion sources). A non-parametric wind regression analysis was performed on this 2-year data set for the major PM1 constituents (organic matter, nitrate, sulfate and source apportioned BC) and ammonia in order to better refine their geographical origins and assess local/regional/advected contributions whose information is mandatory for efficient mitigation strategies. While ammonium sulfate typically shows a clear advected pattern, ammonium nitrate partially displays a similar feature, but, less expectedly, it also exhibits a significant contribution of regional and local emissions. The contribution of regional background organic aerosols (OA) is significant in spring and summer, while a more pronounced local origin is evidenced during wintertime, whose pattern is also observed for BC originating from domestic wood burning. Using time-resolved ACSM and BC information, seasonally differentiated weekly diurnal profiles of these constituents were investigated and helped to identify the main

  7. Monitored plutonium aerosols at a soil cleanup site on Johnston Atoll

    International Nuclear Information System (INIS)

    Suspended plutonium in air was monitored for four periods near the operation of a stationary sorting system used to open-quotes mineclose quotes contaminated soil on Johnston Atoll. The monitoring periods were 14 October-14 November 1992, 20 October-15 November 1993, 16 August-3 November 1994, and 17 February-27 February 1995. Pairs of high volume air samplers were located at each of four locations of the process stream: the open-quotes spoils pileclose quotes that was the feedstock, the open-quotes plant areaclose quotes near the hot soil gate of the sorter, the open-quotes clean pileclose quotes conveyer area where sorted clean soil was moved, and the open-quotes oversize soilclose quotes crushing area. These locations were monitored only during the working hours, while air monitoring was also done at an upwind, open-quotes backgroundclose quotes area 24-hours per day. The median concentrations of Pu in open-quotes workplaceclose quotes air (combined spoils pile, plant area, and clean pile sites) in 1992 was 397 aCi/m3 (15 μBq/m3), but increased to median values of 23000 aCi/m3 (852 μBq/m3) in August-November 1994 and 29800 aCi/m3 (1100 μBq/m3) in February 1995. The highest median value at the worksites (29800 aCi/m3) was more than 200 times lower than the regulatory level. The highest observed value was 84200 aCi/m3 at the spoils pile site, and this was more than 70 times lower than the regulatory level. The conclusion was that, in spite of the dusty environment, and the increased level of specific activity, we did not find that the soil processing posed any significant risk to workers during the observation periods 1992-1995

  8. Seasonal monitoring and estimation of regional aerosol distribution over Po valley, northern Italy, using a high-resolution MAIAC product

    Science.gov (United States)

    Arvani, Barbara; Pierce, R. Bradley; Lyapustin, Alexei I.; Wang, Yujie; Ghermandi, Grazia; Teggi, Sergio

    2016-09-01

    In this work, the new 1 km-resolved Multi-Angle Implementation of Atmospheric Correction (MAIAC) algorithm is employed to characterize seasonal PM10 - AOD correlations over northern Italy. The accuracy of the new dataset is assessed compared to the widely used Moderate Resolution Imaging Spectroradiometer (MODIS) Collection 5.1 Aerosol Optical Depth (AOD) data, retrieved at 0.55 μm with spatial resolution of 10 km (MYD04_L2). We focused on evaluating the ability of these two products to characterize both temporal and spatial distributions of aerosols within urban and suburban areas. Ground PM10 measurements were obtained from 73 of the Italian Regional Agency for Environmental Protection (ARPA) monitoring stations, spread across northern Italy, during a three-year period from 2010 to 2012. The Po Valley area (northern Italy) was chosen as the study domain because of its severe urban air pollution, resulting from it having the highest population and industrial manufacturing density in the country, being located in a valley where two surrounding mountain chains favor the stagnation of pollutants. We found that the global correlations between the bin-averaged PM10 and AOD are R2 = 0.83 and R2 = 0.44 for MYD04_L2 and for MAIAC, respectively, suggesting a greater sensitivity of the high-resolution product to small-scale deviations. However, the introduction of Relative Humidity (RH) and Planetary Boundary Layer (PBL) depth corrections allowed for a significant improvement to the bin-averaged PM - AOD correlation, which led to a similar performance: R2 = 0.96 for MODIS and R2 = 0.95 for MAIAC. Furthermore, the introduction of the PBL information in the corrected AOD values was found to be crucial in order to capture the clear seasonal cycle shown by measured PM10 values. The study allowed us to define four seasonal linear correlations that estimate PM10 concentrations satisfactorily from the remotely sensed MAIAC AOD retrieval. Overall, the results show that

  9. Trace elements in aerosols from background air pollution monitoring stations in the Amazon Basin using nuclear-related techniques

    International Nuclear Information System (INIS)

    In order to study the natural release of aerosol particles by the Amazon Basin tropical rain forest, the composition and size distribution of biogenic aerosol particles were analyzed. The role of the atmospheric emissions from the Amazon Basin rain forest in the global atmosphere will be investigated. The atmosphere was studied in long-term sampling stations in three different locations. The elemental composition of aerosol particles released during biomass burning was also measured in several different ecosystems, from primary forest to Savannah. One of the main focuses was to identify and quantify important physical and chemical processes in the generation, transformation and deposition of aerosol particles. Also important was to obtain a better understanding of natural aerosol sources concerning identification, their characteristics and strength, to be able to understand the natural chemistry in the atmosphere on a global scale. 36 refs, 3 figs, 3 tabs

  10. Application of the polarization Raman Mie lidar system to monitor the particulate matter and water vapor in the aerosol pollution and haze episodes

    Science.gov (United States)

    Xie, Chenbo; Zhao, Ming; Shang, Zhen; Wang, Bangxin; Zhong, Zhiqing; Liu, Dong; Wang, Yingjian

    2014-11-01

    To monitor the temporal and spatial characteristics of particulate matter and water vapor in the aerosol pollution and haze episodes, the polarization Raman Mie lidar system has been developed. The lidar system includes four detection channels and it can measure the extinction coefficient and depolarization ratio of particulate matter as well as water vapor mixing ratio. The extinction coefficient indicates the visibility of atmosphere and it associates with the concentration of particulate matter. The depolarization ratio demonstrates the nonsphericity of particulate matter and is useful to distinguish the dust and pollution aerosol. The water vapor mixing ratio denotes the content of water vapor in the air and it is an important factor to influence of the hygroscopic growth on the pollution aerosol. The lidar system can operate in the automatic and continuous modes through a window on the roof of the observation room regards of the weather, and it takes continuous measurement from 20 November 2013 to 6 February 2014 over Hefei, China. During the experiment, the typical results of particulate matter measured with lidar in clear air, aerosol pollution and haze, and dust episodes are analyzed and given. The lidar observations are also compared with the air quality data and the meteorological data on the ground.

  11. Nonlinear relationships between atmospheric aerosol and its gaseous precursors: Analysis of long-term air quality monitoring data by means of neural networks

    Directory of Open Access Journals (Sweden)

    I. B. Konovalov

    2003-01-01

    Full Text Available The nonlinear features of the relationships between concentrations of aerosol and volatile organic compounds (VOC and nitrogen oxides (NOx in urban environments are revealed directly from data of long-term routine measurements of NOx, VOC, and total suspended particulate matter (PM. The main idea of the method is development of special empirical models based on artificial neural networks. These models, that are basically, the nonlinear extension of the commonly used linear statistical models provide the best fit for the real (nonlinear PM-NOx-VOC relationships under different atmospheric conditions. Such models may be useful in the context of various scientific and practical problems related to atmospheric aerosols. The method is demonstrated on an example of two empirical models based on independent data-sets collected at two air quality monitoring stations at South Coast Air Basin, California. It is shown that in spite of a rather large distance between the monitoring stations (more than 50 km and thus substantially different environmental conditions, the empirical models demonstrate several common qualitative features. Specifically, under definite conditions, a decrease in the level of NOx or VOC may lead to an increase in mass concentration of aerosol. It is argued that these features are due to the nonlinear dependence of hydroxyl radical on VOC and NOx.

  12. Illustrating the benefit of using hourly monitoring data on secondary inorganic aerosol and its precursors for model evaluation

    Directory of Open Access Journals (Sweden)

    M. Schaap

    2011-11-01

    Full Text Available Secondary inorganic aerosol, most notably ammonium nitrate and ammonium sulphate, is an important contributor to ambient particulate mass and provides a means for long range transport of acidifying components. The modelling of the formation and fate of these components is challenging. Especially, the formation of the semi-volatile ammonium nitrate is strongly dependent on ambient conditions and the precursor concentrations. For the first time an hourly artefact free data set from the MARGA instrument is available for the period of a full year (1 August 2007 to 1 August 2008 at Cabauw, the Netherlands. This data set is used to verify the results of the LOTOS-EUROS model. The comparison showed that the model underestimates the SIA levels. Closer inspection revealed that base line values appear well estimated for ammonium and sulphate and that the underestimation predominantly takes place at the peak concentrations. For nitrate the variability towards high concentrations is much better captured, however, a systematic relative underestimation was found. The model is able to reproduce many features of the intra-day variability observed for SIA. Although the model captures the seasonal and average diurnal variation of the SIA components, the modelled variability for the nitrate precursor gas nitric acid is much too large. It was found that the thermodynamic equilibrium module produces a too stable ammonium nitrate in winter and during night time in summer, whereas during the daytime in summer it is too unstable. We recommend to improve the model by verification of the equilibrium module, inclusion of coarse mode nitrate and to address the processes concerning SIA formation combined with a detailed analysis of the data set at hand. The benefit of the hourly data with both particulate and gas phase concentrations is illustrated and a continuation of these measurements may prove to be very useful in future model evaluation and improvement studies. Based

  13. Illustrating the benefit of using hourly monitoring data on secondary inorganic aerosol and its precursors for model evaluation

    Directory of Open Access Journals (Sweden)

    M. Schaap

    2010-05-01

    Full Text Available Secondary inorganic aerosol, most notably ammonium nitrate and ammonium sulphate, is an important contributor to ambient particulate mass and provides a means for long range transport of acidifying components. The modelling of the formation and fate of these components is challenging. Especially, the formation of the semi-volatile ammonium nitrate is strongly dependent on ambient conditions and the precursor concentrations. For the first time an hourly artefact free data set from the MARGA instrument is available for the period of a full year (1 August 2007 to 1 August 2008 at Cabauw, the Netherlands. This data set is used to verify the results of the LOTOS-EUROS model. The comparison showed that the model underestimates the SIA levels. Closer inspection revealed that base line values appear well estimated for ammonium and sulphate and that the underestimation predominantly takes place at the peak concentrations. For nitrate the variability towards high concentrations is much better captured, however, a systematic relative underestimation was found. The model is able to reproduce many features of the intra-day variability observed for SIA. Although the model captures the seasonal and average diurnal variation of the SIA components, the modelled variability for the nitrate precursor gas nitric acid is much too large. It was found that the thermodynamic equilibrium module produces a too stable ammonium nitrate in winter and during night time in summer, whereas during the daytime in summer it is too unstable. We recommend to improve the model by verification of the equilibrium module, inclusion of coarse mode nitrate and to address the processes concerning SIA formation combined with a detailed analysis of the data set at hand. The benefit of the hourly data with both particulate and gas phase concentrations is illustrated and a continuation of these measurements may prove to be very useful in future model evaluation and improvement studies. Based

  14. Comparison of aerosol optical depth of UV-B Monitoring and Research Program (UVMRP), AERONET and MODIS over continental United States

    Institute of Scientific and Technical Information of China (English)

    Hongzhao TANG; Maosi CHEN; John DAVIS; Wei GAO

    2013-01-01

    The concern about the role of aerosols as to their effect in the Earth-Atmosphere system requires observation at multiple temporal and spatial scales.The Moderate Resolution Imaging Spectroradiameters (MODIS) is the main aerosol optical depth (AOD)monitoring satellite instrument,and its accuracy and uncertainty need to be validated against ground based measurements routinely.The comparison between two ground AOD measurement programs,the United States Department of Agriculture (USDA) Ultraviolet-B Monitoring and Research Program (UVMRP) and the Aerosol Robotic Network (AERONET) program,confirms the consistency between them.The intercomparison between the MODIS AOD,the AERONET AOD,and the UVMRP AOD suggests that the UVMRP AOD measurements are suited to be an alternative ground-based validation source for satellite AOD products.The experiments show that the spatial-temporal dependency between the MODIS AOD and the UVMRP AOD is positive in the sense that the MODIS AOD compare more favorably with the UVMRP AOD as the spatial and temporal intervals are increased.However,the analysis shows that the optimal spatial interval for all time windows is defined by an angular subtense of around 1° to 1.25°,while the optimal time window is around 423 to 483 minutes at most spatial intervals.The spatial-temporal approach around 1.25° & 423 minutes shows better agreement than the prevalent strategy of 0.25° & 60 minutes found in other similar investigations.Research Program (UVMRP),Aerosol Robotic Network (AERONET),Moderate Resolution Imaging Spectroradiameters (MODIS),validation,spatial-temporal approach

  15. Technical support for improved workplace monitoring solid aerosols with special attention to dust containing toxic trace elements

    International Nuclear Information System (INIS)

    The aim is to contribute to an improvement of measuring airborne particle, especially in the Third World, by reviewing the literature on particle behaviour in air of the workplace and in the human airways, the sampling theory for aerosols, and sampling equipment, which is currently in use and commercial available. The concepts and equations are given, which are necessary for understanding the often counter-intuitive behaviour of aerosols in the occupational setting and elsewhere. The mathematical manipulations of the equations have been kept at a minimum; instead transport properties are illustrated by a series of calculations for aerosols consisting of water, minerals, and uranium. The same concepts and equations are needed to explain and quantify the deposition of particle in the human airways and to design measurement devices. These devices are used for measuring the different aerosol fractions, which will deposit in different parts of the human airways. A brief description of the human airways is given, which is adequate for the understanding of particles' deposition. The human airways are divided into the extrathoracic, the thoracic, and the alveolar compartment. The Inhalable, the Thoracic, and the Alveoli Fractions of an aerosol are those fractions, which will penetrate into the extrathoratic, the thoracic, and the alveolar compartments. The available methods for collecting airborne particles are described and it is discussed to what extent each type of equipment is sampling the aerosol fraction of interest. (author)

  16. Technical support for improved workplace monitoring solid aerosols with special attention to dust containing toxic trace elements

    Energy Technology Data Exchange (ETDEWEB)

    E. Olsen; M.E. Nyeland; J.M. Christensen [National Institute of Occupational Health, Copenhagen (Denmark)

    2008-01-15

    The aim is to contribute to an improvement of measuring airborne particle, especially in the Third World, by reviewing the literature on particle behaviour in air of the workplace and in the human airways, the sampling theory for aerosols, and sampling equipment, which is currently in use and commercial available. The concepts and equations are given, which are necessary for understanding the often counter-intuitive behaviour of aerosols in the occupational setting and elsewhere. The mathematical manipulations of the equations have been kept at a minimum; instead transport properties are illustrated by a series of calculations for aerosols consisting of water, minerals, and uranium. The same concepts and equations are needed to explain and quantify the deposition of particle in the human airways and to design measurement devices. These devices are used for measuring the different aerosol fractions, which will deposit in different parts of the human airways. A brief description of the human airways is given, which is adequate for the understanding of particles' deposition. The human airways are divided into the extrathoracic, the thoracic, and the alveolar compartment. The Inhalable, the Thoracic, and the Alveoli Fractions of an aerosol are those fractions, which will penetrate into the extrathoratic, the thoracic, and the alveolar compartments. The available methods for collecting airborne particles are described and it is discussed to what extent each type of equipment is sampling the aerosol fraction of interest. 26 refs., 5 figs., 6 tabs., 2 apps.

  17. Comparison of UV irradiances from Aura/Ozone Monitoring Instrument (OMI with Brewer measurements at El Arenosillo (Spain – Part 2: Analysis of site aerosol influence

    Directory of Open Access Journals (Sweden)

    V. E. Cachorro

    2010-07-01

    Full Text Available Several validation studies have shown a notable overestimation of the clear sky ultraviolet (UV irradiance at the Earth's surface derived from satellite sensors such as the Total Ozone Mapping Spectrometer (TOMS and the Ozone Monitoring Instrument (OMI with respect to ground-based UV data at many locations. Most of this positive bias is attributed to boundary layer aerosol absorption that is not accounted for in the TOMS/OMI operational UV algorithm. Therefore, the main objective of this study is to analyse the aerosol effect on the bias between OMI erythemal UV irradiance (UVER and spectral UV (305 nm, 310 nm and 324 nm surface irradiances and ground-based Brewer spectroradiometer measurements from October 2004 to December 2008 at El Arenosillo station, with meteorological conditions representative of the south-west of Spain.

    The effect of other factors as clouds, ozone and the solar elevation over this intercomparison were analysed in detail in a companion paper (Antón et al., 2010. In that paper the aerosol effects were analysed making only a rough evaluation based on aerosol optical depth (AOD information at 440 nm wavelength (visible range without applying any correction. Here, the correction of the OMI UV data is proposed based on a detailed study about the determination of absorbing aerosols provided by AERONET data. Because of the difficulty to have reliable data about absorbing aerosol properties at many sites, first we consider AOD, Angstrom exponent and also OMI-Aerosol Index for this determination, but finally single scattering albedo (SSA from AERONET was used since it represents a much more precise information.

    An aerosol correction expression was applied to the OMI operational UV data using two approaches to estimate the UV absorption aerosol optical depth, AAOD. The first approach was based on an assumption of constant SSA value of 0.91. This approach reduces OMI UVER bias from 13.4 to 8.4%. Second approach

  18. Improved aerosol retrieval algorithm using Landsat images and its application for PM10 monitoring over urban areas

    Science.gov (United States)

    Luo, Nana; Wong, Man Sing; Zhao, Wenji; Yan, Xing; Xiao, Fei

    2015-02-01

    Aerosol retrieval using MODerate resolution Imaging Spectroradiometer (MODIS) has been well researched over the past decade. However, the application is limited to global- and regional-scale studies, which may not be applicable for urban areas due to its low spatial resolution. To overcome the limitation, this paper proposed an improved aerosol retrieval algorithm for Landsat images (ImAero-Landsat) at spatial resolution of 30 m. This ImAero-Landsat algorithm has been improved in the following two aspects: (i) it does not require a comprehensive look up table and thus it is more efficient in AOT retrieval; and (ii) it can be operated in both bright and dark surfaces. The derived aerosol optical thickness (AOT) images were validated with AErosol RObotic NETwork (AERONET) measurements as well as MODIS MOD04 AOT products. Small root mean square errors (RMSEs) of 0.11 and 0.14 and mean absolute difference (MAD) of 0.07 and 0.11 between ImAero-Landsat AOT, with MODIS MOD04 and AERONET products were observed. By correlating with ground based PM10 concentrations, the ImAero-Landsat method outperforms (r2 = 0.32) than MOD04 AOT products (r2 = 0.23). In addition, the accuracy of estimating PM10 can be improved to r2 = 0.55 when the derived AOT was integrated with meteorological parameters. The accuracy is similar to the results derived from AERONET AOT (r2 = 0.62). This study offers a simple and accurate method to investigate aerosol optical thickness at detailed city-scale. Environmental authorities may use the derived methods for deriving aerosol distribution maps and pinpointing the sources of pollutants in urban areas.

  19. Comparison of aerosol optical depths from the Ozone Monitoring Instrument (OMI on Aura with results from airborne sunphotometry, other space and ground measurements during MILAGRO/INTEX-B

    Directory of Open Access Journals (Sweden)

    J. M. Livingston

    2009-04-01

    Full Text Available Airborne sunphotometer measurements are used to evaluate retrievals of extinction aerosol optical depth (AOD from spatially coincident and temporally near-coincident measurements by the Ozone Monitoring Instrument (OMI aboard the Aura satellite during the March 2006 Megacity Initiative-Local And Global Research Observations/Phase B of the Intercontinental Chemical Transport Experiment (MILAGRO/INTEX-B. The 14-channel NASA Ames Airborne Tracking Sunphotometer (AATS flew on nine missions over the Gulf of Mexico and four in or near the Mexico City area. Retrievals of AOD from near-coincident AATS and OMI measurements are compared for three flights over the Gulf of Mexico for flight segments when the aircraft flew at altitudes 60–70 m a.s.l., and for one flight over Mexico City when the aircraft flew ~420–590 m a.g.l. OMI-measured top of atmosphere (TOA reflectances are routinely inverted to yield aerosol products such as AOD and aerosol absorption optical depth (AAOD using two different retrieval algorithms: a near-UV (OMAERUV and a multiwavelength (OMAERO technique. This study uses the archived Collection 3 data products from both algorithms. In particular, AATS and OMI AOD comparisons are presented for AATS data acquired in 20 OMAERUV retrieval pixels (15 over water and 19 OMAERO pixels (also 15 over water. At least four pixels for one of the over-water coincidences and all pixels for the over-land case were cloud-free. Coincident AOD retrievals from 17 pixels of the Moderate Resolution Imaging Spectroradiometer (MODIS aboard Aqua are available for two of the over-water flights and are shown to agree with AATS AODs to within root mean square (RMS differences of 0.00–0.06, depending on wavelength. Near-coincident ground-based AOD measurements from ground-based sun/sky radiometers operated as part of the Aerosol Robotic Network (AERONET at three sites in and near Mexico City are also shown and are generally consistent with the AATS AODs

  20. Comparison of aerosol optical depths from the Ozone Monitoring Instrument (OMI on Aura with results from airborne sunphotometry, other space and ground measurements during MILAGRO/INTEX-B

    Directory of Open Access Journals (Sweden)

    J. M. Livingston

    2009-09-01

    Full Text Available Airborne sunphotometer measurements are used to evaluate retrievals of extinction aerosol optical depth (AOD from spatially coincident and temporally near-coincident measurements by the Ozone Monitoring Instrument (OMI aboard the Aura satellite during the March 2006 Megacity Initiative-Local And Global Research Observations/Phase B of the Intercontinental Chemical Transport Experiment (MILAGRO/INTEX-B. The 14-channel NASA Ames Airborne Tracking Sunphotometer (AATS flew on nine missions over the Gulf of Mexico and four in or near the Mexico City area. Retrievals of AOD from near-coincident AATS and OMI measurements are compared for three flights over the Gulf of Mexico for flight segments when the aircraft flew at altitudes 60–70 m above sea level, and for one flight over the Mexico City area where the aircraft was restricted to altitudes ~320–800 m above ground level over the rural area and ~550–750 m over the city. OMI-measured top of atmosphere (TOA reflectances are routinely inverted to yield aerosol products such as AOD and aerosol absorption optical depth (AAOD using two different retrieval algorithms: a near-UV (OMAERUV and a multiwavelength (OMAERO technique. This study uses the archived Collection 3 data products from both algorithms. In particular, AATS and OMI AOD comparisons are presented for AATS data acquired in 20 OMAERUV retrieval pixels (15 over water and 19 OMAERO pixels (also 15 over water. At least four pixels for one of the over-water coincidences and all pixels for the over-land case were cloud-free. Coincident AOD retrievals from 17 pixels of the Moderate Resolution Imaging Spectroradiometer (MODIS aboard Aqua are available for two of the over-water flights and are shown to agree with AATS AODs to within root mean square (RMS differences of 0.00–0.06, depending on wavelength. Near-coincident ground-based AOD measurements from ground-based sun/sky radiometers operated as part of the Aerosol Robotic Network (AERONET

  1. An assessment of the performance of the Monitor for AeRosols and GAses in ambient air (MARGA: a semi-continuous method for soluble compounds

    Directory of Open Access Journals (Sweden)

    I. C. Rumsey

    2013-09-01

    Full Text Available Ambient air monitoring as part of the US Environmental Protection Agency's (US EPA's Clean Air Status and Trends Network (CASTNet currently uses filter packs to measure weekly integrated concentrations. The US EPA is interested in supplementing CASTNet with semi-continuous monitoring systems at select sites to characterize atmospheric chemistry and deposition of nitrogen and sulfur compounds at higher time resolution than the filter pack. The Monitor for AeRosols and GAses in ambient air (MARGA measures water-soluble gases and aerosols at hourly temporal resolution. The performance of the MARGA was assessed under the US EPA Environmental Technology Verification (ETV program. The assessment was conducted in Research Triangle Park, North Carolina from 8 September–8 October 2010 and focused on gaseous SO2, HNO3 and NH3 and aerosol SO4−, NO3− and NH4+. Precision of the MARGA was evaluated by calculating the median absolute relative percent difference (MARPD between paired hourly results from duplicate MARGA units (MUs, with a performance goal of 2, SO42− and NH4+, with all three compounds passing the accuracy and precision goals by a significant margin. The performance of the MARGA in measuring NO3− could not be evaluated due to the different sampling efficiency of coarse NO3− by the MUs and the filter pack. Estimates of "fine" NO3− were calculated for the MUs and the filter pack. Using this and results from a previous study, it is concluded that if the MUs and the filter pack were sampling the same particle size, the MUs would have good agreement in terms of precision and accuracy. The MARGA performed moderately well in measuring HNO3 and NH3, though neither met the linear regression slope goals. However, recommendations for improving the measurement of HNO3 and NH3 are discussed. It is concluded that SO42−, SO2, NO3−, HNO3, NH4+ and NH3 concentrations can be measured with acceptable accuracy and precision when the MARGA is

  2. Monitoring Airborne Dust from Source to Sink Using the e-Deep Blue Aerosol Products from VIIRS, MODIS, and Seawifs

    Science.gov (United States)

    Carletta, N.; Hsu, N. Y. C.; Bettenhausen, C.; Sayer, A. M.; Lee, J.

    2014-12-01

    Mineral dust sources are typically located in very bright, arid desert regions across the globe. In the past, aerosol retrieval algorithms were unable to properly handle these bright surfaces which lead to large, persistent data gaps. In order to eliminate these gaps, the Deep Blue algorithm was developed and first entered into the MODIS operational stream in Collection 5.1. Since then, the Deep Blue algorithm has evolved to retrieve not only over bright surfaces, but also vegetated surfaces. This updated algorithm has been named the enhanced Deep Blue (e-Deep Blue) algorithm and has been successfully applied to reflectances from the Sea-viewing, Wide Field-of-view Sensor (SeaWiFS, 1997-2010), Moderate Resolution Imaging Spectroradiometer (MODIS, 2000/2002-present), and now the Visible Infrared Imaging Radiometer Suite (VIIRS, 2012-present) aboard the Suomi-NPP platform. This algorithm has been partnered with a new over-ocean algorithm for our SeaWiFS and VIIRS datasets. Due to the broad swath of VIIRS, daily global coverage is achieved at higher spatial resolution compared to MODIS and SeaWiFS. Thus, the evolution of dust can be tracked from source to sink, across both land and ocean using these satellite products. We introduce the basics of the e-Deep Blue algorithm along with our preliminary VIIRS e-Deep Blue products, including aerosol optical thickness at 550nm and Ǻngström exponent. Validation with AErosol RObotic NETwork (AERONET) data are also presented along with the intercomparisons between VIIRS Deep Blue and other satellite products.

  3. Rotational raman lidar for aerosol scattering coefficients

    International Nuclear Information System (INIS)

    Two channel lidar signals which are composed of the total rotational scattering and elastic signals provide good information for the aerosol scattering coefficients. We can calculate the aerosol backscattering coefficient and extinction coefficient directly without any assumption and calibration process. Generally, a high spectral resolution lidar is used for an aerosol monitoring. But we have designed a new normal spectral receiving lidar system which contains the scattering information simultaneously, and we have retrieved the aerosol scattering coefficient. The results show that there is no need to assume any relation between the aerosol backscattering and extinction and to consider any wavelength calibration process for the aerosol scattering coefficient

  4. Using the OMI aerosol index and absorption aerosol optical depth to evaluate the NASA MERRA Aerosol Reanalysis

    OpenAIRE

    Buchard, V.; A. M. Silva; P. R. Colarco; Darmenov, A.; C. A. Randles; Govindaraju, R.; O. Torres; Campbell, J.; R. Spurr

    2015-01-01

    A radiative transfer interface has been developed to simulate the UV aerosol index (AI) from the NASA Goddard Earth Observing System version 5 (GEOS-5) aerosol assimilated fields. The purpose of this work is to use the AI and aerosol absorption optical depth (AAOD) derived from the Ozone Monitoring Instrument (OMI) measurements as independent validation for the Modern Era Retrospective analysis for Research and Applications Aerosol Reanalysis (MERRAero). MERRAero is based on...

  5. Organic aerosols

    International Nuclear Information System (INIS)

    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

  6. Monitoring of inorganic ions, carbonaceous matter and mass in ambient aerosol particles with online and offline methods

    Directory of Open Access Journals (Sweden)

    H. Timonen

    2011-10-01

    Full Text Available Year-long high timeresolution measurements of major chemical components in atmospheric sub-micrometer particles were conducted at an urban background station in Finland 2006–2007. Ions were analyzed using a particle-into-liquid sampler combined with an ion chromatograph (PILS-IC, organic and elemental carbon (OC and EC by using a semicontinuos OC/EC aerosol carbon analyzer (RT-OCEC, and PM2.5 mass with a tapered element oscillating microbalance (TEOM. Long time series provides information on differences between the used measurement techniques as well as information about the diurnal and seasonal changes. Chemical mass closure was constructed by comparing the identified aerosol mass with the measured PM2.5. The sum of all components measured online (ions, particulate organic matter (POM, EC represented only 65% of the total PM2.5 mass. The difference can be explained by the difference in cutoff sizes (PM1 for online measurements, PM2.5 for total mass and by evaporation of the semivolatile/volatile components. In general, some differences in results were observed when the results of the continuous/semicontinuous instruments were compared with those of the conventional filter samplings. For non-volatile compounds, like sulfate and potassium, correlation between the filter samples and the PILS was good but greater differences were observed for the semivolatile compounds like nitrate and ammonium. For OC the results of the RT-OCEC were on average 10% larger than those of the filters. When compared to filter measurements, high resolution measurements provide important data on short pollution plumes as well as on diurnal changes. Clear seasonal and diurnal cycles were observed for nitrate and EC.

  7. Monitoring of inorganic ions, carbonaceous matter and mass in ambient aerosol particles with online and offline methods

    Science.gov (United States)

    Timonen, H.; Aurela, M.; Saarnio, K.; Frey, A.; Saarikoski, S.; Teinilä, K.; Kulmala, M.; Hillamo, R.

    2011-10-01

    Year-long high timeresolution measurements of major chemical components in atmospheric sub-micrometer particles were conducted at an urban background station in Finland 2006-2007. Ions were analyzed using a particle-into-liquid sampler combined with an ion chromatograph (PILS-IC), organic and elemental carbon (OC and EC) by using a semicontinuos OC/EC aerosol carbon analyzer (RT-OCEC), and PM2.5 mass with a tapered element oscillating microbalance (TEOM). Long time series provides information on differences between the used measurement techniques as well as information about the diurnal and seasonal changes. Chemical mass closure was constructed by comparing the identified aerosol mass with the measured PM2.5. The sum of all components measured online (ions, particulate organic matter (POM), EC) represented only 65% of the total PM2.5 mass. The difference can be explained by the difference in cutoff sizes (PM1 for online measurements, PM2.5 for total mass) and by evaporation of the semivolatile/volatile components. In general, some differences in results were observed when the results of the continuous/semicontinuous instruments were compared with those of the conventional filter samplings. For non-volatile compounds, like sulfate and potassium, correlation between the filter samples and the PILS was good but greater differences were observed for the semivolatile compounds like nitrate and ammonium. For OC the results of the RT-OCEC were on average 10% larger than those of the filters. When compared to filter measurements, high resolution measurements provide important data on short pollution plumes as well as on diurnal changes. Clear seasonal and diurnal cycles were observed for nitrate and EC.

  8. Marine aerosols

    OpenAIRE

    Saltzman, Es

    2009-01-01

    The aerosol over the world oceans plays an important role in determining the physical and chemical characteristics of the Earth's atmosphere and its interactions with the climate system. The oceans contribute to the aerosols in the overlying atmosphere by the production and emission of aerosol particles and precursor gases. The marine aerosol, in turn, influences the biogeochemistry of the surface ocean through long distance transport and deposition of terrestrial and marine-derived nutrients...

  9. α放射性气溶胶快速监测仪响应时间的研究%Study on Responding Time of α Rapid Radioactive Aerosol Monitors

    Institute of Scientific and Technical Information of China (English)

    谷铁男; 邵贝贝; 张燕; 段再煜; 李洋; 刘翠红; 薛涛

    2013-01-01

    Energy discrimination is an important method to eliminate the interference of measurement caused by natural radioactivity.Through the methods of theoretical derivation as well as numerical calculation,the article established the relationships between responding rime of radioactive aerosol monitor with equalization coefficient K,instrument detecting efficiency,sampling flow,detection limit as well as the concentration of radon daughter.Results show that responding time of radioactive aerosol monitor can be shorten by decreasing equalization coefficient K,improving instrument detecting efficiency,increasing sampling flow,raising detection limit of artificial radioactive aerosol and lowering concentration of natural radioactive aerosol.This is beneficial to optimizing the design of radioactive aerosol monitor.%能量甄别法是消除天然放射性对测量干扰最常用的方法之一.通过理论推导和数值计算的方法建立了补偿系数K、仪器探测效率、取样流量、探测下限及环境中天然氡子体浓度与放射性气溶胶监测仪响应时间的关系.结果表明,减小补偿系数K,提高探测效率,增大取样流量,提高人工放射性气溶胶探测下限,降低天然放射性气溶胶浓度,均可缩短仪器的响应时间.结果可为设计优化放射性气溶胶监测装置提供参考.

  10. Biological aerosol background characterization

    Science.gov (United States)

    Blatny, Janet; Fountain, Augustus W., III

    2011-05-01

    To provide useful information during military operations, or as part of other security situations, a biological aerosol detector has to respond within seconds or minutes to an attack by virulent biological agents, and with low false alarms. Within this time frame, measuring virulence of a known microorganism is extremely difficult, especially if the microorganism is of unknown antigenic or nucleic acid properties. Measuring "live" characteristics of an organism directly is not generally an option, yet only viable organisms are potentially infectious. Fluorescence based instruments have been designed to optically determine if aerosol particles have viability characteristics. Still, such commercially available biological aerosol detection equipment needs to be improved for their use in military and civil applications. Air has an endogenous population of microorganisms that may interfere with alarm software technologies. To design robust algorithms, a comprehensive knowledge of the airborne biological background content is essential. For this reason, there is a need to study ambient live bacterial populations in as many locations as possible. Doing so will permit collection of data to define diverse biological characteristics that in turn can be used to fine tune alarm algorithms. To avoid false alarms, improving software technologies for biological detectors is a crucial feature requiring considerations of various parameters that can be applied to suppress alarm triggers. This NATO Task Group will aim for developing reference methods for monitoring biological aerosol characteristics to improve alarm algorithms for biological detection. Additionally, they will focus on developing reference standard methodology for monitoring biological aerosol characteristics to reduce false alarm rates.

  11. Nuclear aerosol test facility studies using plasma torch aerosol generator

    International Nuclear Information System (INIS)

    In order to study the behavior of aerosols released into the reactor containment following accidents, an experimental simulation facility, called Nuclear Aerosol Test Facility (NATF) has recently been built and commissioned in BARC. It mainly consists of a Test vessel for simulating the containment, plasma torch aerosol generator (PTAG) system for generating metal-based aerosols and aerosol monitoring instrumentation. The main component of the PTAG is a 40 kW dc plasma torch, powered by a constant current power supply, operating in a non-transferred arc mode. Optimal operating conditions of PTAG have been established. Experiments consist of injecting the aerosols of a given material for about 20 minutes into the vessel, simultaneously monitoring the concentrations at various points in the vessel. The measurements of the size distribution and mass concentrations in the vessel are carried out at periodic intervals. Various combination of experiments with different metals such as zinc, tin and manganese, under varying turbulence conditions (with and without keeping the fan continuously on) have been performed. The aerosols were generally found to be fractal aggregates with low fractal dimension (∼1.6). The mass depletion data have been subjected to theoretical analysis and validation exercises with available aerosol behavior codes. The results are further discussed. (author)

  12. High Sensitivity α-β Aerosol Monitor with Novel Pseudo-Coincidence Circuitry for Compensation of Natural Radioactivity

    International Nuclear Information System (INIS)

    The assay of artificial a emitters in air is complicated by the fact that levels of natural a activity are frequently one or two orders of magnitude larger than those permissible for artificial a emitters. The β-α-pseudo-coincidence method has proved to be an excellent method for eliminating the influence of natural activity; however, so far, there has been a drawback - the compensation circuit is disturbed by high β or γ count rates. In the present paper a new pseudo-coincidence circuit is described which is virtually independent of these disturbances. For continuous air sampling, glass fibre filters, 20 cm diam., are used. A special design ensures practically homogeneous airflow over the entire filter surface. Flow rates are 60 m3/h for stationary, and 20 m3/h for mobile installations. On top of the filter are stacked successively: (1) the a detector with a 0.4 mg/cm2 entrance window; (2) the β detector separated from the α detector by a 3 mg/cm2 foil; and (3) a γ detector for γ compensation of the β channel, if this is necessary. All detectors are large-window flow proportional counters of 20 cm active diameter. Since the radioactive aerosols are accumulated on the filter, a differentiating circuit with time constants of up to two hours has been designed so that the actual concentration in μCi/cm3 can be derived. Under typical ambient conditions, a concentration of 10-12 μCi/cm3 of 239Pu is detected and may trigger an alarm after 45 min. A β count rate of 360 000 counts/min or a γ level of 1 mR/h produce only a 2% too high reading for the artificial a activity, and at still higher β or γ rates the system always remains on the safe side, giving readings somewhat too high. (author)

  13. Monitoring of air radioactivity at the Jungfraujoch research station: Test of a new high volume aerosol sampler

    OpenAIRE

    Flury, Thomas; Völkle, Hansruedi

    2008-01-01

    The Swiss Federal Office of Public Health (SFOPH) is responsible for the surveillance of environmental radioactivity in Switzerland and for the protection of the public from ionizing and non-ionizing radiation. In order to improve the Swiss radioactivity monitoring network, a new high volume air sampler (DIGITEL DHA-80) was tested in Fribourg and at the Jungfraujoch High Altitude Research Station at 3454 m. The filters are analyzed in the laboratory by a high purity coaxial germanium detector...

  14. Analysis of Aerosol Properties in Beijing Based on Ground-Based Sun Photometer and Air Quality Monitoring Observations from 2005 to 2014

    OpenAIRE

    Wei Chen; Hongzhao Tang; Haimeng Zhao; Lei Yan

    2016-01-01

    Aerosol particles are the major contributor to the deterioration of air quality in China’s capital, Beijing. Using ground-based sun photometer observations from 2005 to 2014, the long-term variations in optical properties and microphysical properties of aerosol in and around Beijing were investigated in this study. The results indicated little inter-annual variations in aerosol optic depth (AOD) but an increase in the fine mode AODs both in and outside Beijing. Furthermore, the single scatter...

  15. Aerosol and fallout monitoring in France from 1959 to 2014: 55 years of improvement of the surveillance, from the sampling to the measurement

    Energy Technology Data Exchange (ETDEWEB)

    De Vismes Ott, A.; Masson, O. [Institute for Radioprotection and Nuclear Safety, IRSN (France)

    2014-07-01

    As a support for the public authorities the French Institute of Radioprotection and Nuclear Safety (IRSN) is in charge of the environment surveillance in France. The OPERA-Air (Observatoire Permanent de la Radioactivite) sampling network is part of this monitoring activity and includes, in addition to 40 low flow (10 to 80 m{sup 3}.h{sup -1}) samplers, 8 high and very high flow (namely 300 and 700 m{sup 3}.h{sup -1}) aerosol samplers. This network also comprises rain and cloud water samplers in order to observe and study the atmospheric fallout in a general way. This paper will focus on these last kinds of samples and the aerosol filters taken by the high flow and very high flow samplers and measured at trace levels in the laboratory of environmental radioactivity measurement by low level gamma ray spectrometry. The developments made during the last decades both in the sampling process and in the measurement techniques will be described. The improvement on the air samplers with higher flow, larger surface or thinner filters for a smaller counting geometry went in concert with the metrology improvements, with new measurement equipments such as low background detectors, well-type detectors or anti cosmic set up. All these implementations were and are still made in order to deal with the decreasing anthropogenic radioactivity levels in the environment, especially in its atmospheric part, and to keep the OPERA-Air network meeting its dual purpose of surveillance as well as research. The improvements in sampling and measuring will be presented as well as some results obtained thanks to them: - Determination of {sup 137}Cs at trace level in fog/clouds waters in order to study the rainout scavenging mechanism and to improve our capability in modeling radionuclide deposition. - Determination over France of trace elements at a few μBq.m{sup -3} during the Fukushima Daiichi accident such as {sup 129m}Te-{sup 129}Te, {sup 132}Te-{sup 132}I, {sup 136}Cs and {sup 140}La

  16. Aerosol and fallout monitoring in France from 1959 to 2014: 55 years of improvement of the surveillance, from the sampling to the measurement

    International Nuclear Information System (INIS)

    As a support for the public authorities the French Institute of Radioprotection and Nuclear Safety (IRSN) is in charge of the environment surveillance in France. The OPERA-Air (Observatoire Permanent de la Radioactivite) sampling network is part of this monitoring activity and includes, in addition to 40 low flow (10 to 80 m3.h-1) samplers, 8 high and very high flow (namely 300 and 700 m3.h-1) aerosol samplers. This network also comprises rain and cloud water samplers in order to observe and study the atmospheric fallout in a general way. This paper will focus on these last kinds of samples and the aerosol filters taken by the high flow and very high flow samplers and measured at trace levels in the laboratory of environmental radioactivity measurement by low level gamma ray spectrometry. The developments made during the last decades both in the sampling process and in the measurement techniques will be described. The improvement on the air samplers with higher flow, larger surface or thinner filters for a smaller counting geometry went in concert with the metrology improvements, with new measurement equipments such as low background detectors, well-type detectors or anti cosmic set up. All these implementations were and are still made in order to deal with the decreasing anthropogenic radioactivity levels in the environment, especially in its atmospheric part, and to keep the OPERA-Air network meeting its dual purpose of surveillance as well as research. The improvements in sampling and measuring will be presented as well as some results obtained thanks to them: - Determination of 137Cs at trace level in fog/clouds waters in order to study the rainout scavenging mechanism and to improve our capability in modeling radionuclide deposition. - Determination over France of trace elements at a few μBq.m-3 during the Fukushima Daiichi accident such as 129mTe-129Te, 132Te-132I, 136Cs and 140La. - Detection of 134Cs due to the Fukushima accident in the rain water samples

  17. Design of electric focusing preconcentration device for in-time monitoring of element composition of atmospheric aerosols by atomic emission spectroscopy

    Czech Academy of Sciences Publication Activity Database

    Dočekal, Bohumil; Večeřa, Zbyněk; Mikuška, Pavel; Šikola, T.; Zlámal, J.

    Salzburg : Universität Salzburg, 2007. LP 27. [European Aerosol Conference 2007. 09.09.2007-14.09.2007, Salzburg] R&D Projects: GA AV ČR IAA400310505 Institutional research plan: CEZ:AV0Z40310501 Keywords : aerosol characterization * electrical effects * elemental composition Subject RIV: CB - Analytical Chemistry, Separation

  18. Analysis of Aerosol Properties in Beijing Based on Ground-Based Sun Photometer and Air Quality Monitoring Observations from 2005 to 2014

    Directory of Open Access Journals (Sweden)

    Wei Chen

    2016-02-01

    Full Text Available Aerosol particles are the major contributor to the deterioration of air quality in China’s capital, Beijing. Using ground-based sun photometer observations from 2005 to 2014, the long-term variations in optical properties and microphysical properties of aerosol in and around Beijing were investigated in this study. The results indicated little inter-annual variations in aerosol optic depth (AOD but an increase in the fine mode AODs both in and outside Beijing. Furthermore, the single scattering albedo in urban Beijing is larger, while observations at the site that is southeast of Beijing suggested that the aerosol there has become more absorbing. The intra-annual aspects were as follow: The largest AOD and high amount of fine mode aerosols are observed in the summer. However, the result of air pollution index (API that mainly affected by the dry density of near-surface aerosol indicated that the air quality has been improving since 2006. Winter and spring were the most polluted seasons considering only the API values. The inconsistency between AOD and API suggested that fine aerosol particles may have a more important role in the deterioration of air quality and that neglecting particulate matter with aerodynamic diameter less than 2.5 μm (PM2.5 in the calculation of API might not be appropriate in air quality evaluation. Through analysis of the aerosol properties in high API days, the results suggested that the fine mode aerosol, especially PM2.5 has become a major contributor to the aerosol pollution in Beijing.

  19. Aerosol studies

    International Nuclear Information System (INIS)

    As part of the continuing studies of the effects of very severe reactor accidents, an effort was made to develop, test, and improve simple, effective, and inexpensive methods by which the average citizen, using only materials readily available, could protect his residence, himself, and his family from injury by toxic aerosols. The methods for protection against radioactive aerosols should be equally effective against a clandestine biological attack by terrorists. The results of the tests to date are limited to showing that spores of the harmless bacterium, bacillus globegii (BG), can be used as a simulant for the radioactive aerosols. An aerosol generator of Lauterbach type was developed which will produce an essentially monodisperse aerosol at the rate of 109 spores/min. Analytical techniques have been established which give reproducible results. Preliminary field tests have been conducted to check out the components of the system. Preliminary tests of protective devices, such as ordinary vacuum sweepers, have given protection factors of over 1000

  20. Stratospheric aerosols

    International Nuclear Information System (INIS)

    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

  1. Instrumentation for tropospheric aerosol characterization

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Z.; Young, S.E.; Becker, C.H.; Coggiola, M.J. [SRI International, Menlo Park, CA (United States); Wollnik, H. [Giessen Univ. (Germany)

    1997-12-31

    A new instrument has been developed that determines the abundance, size distribution, and chemical composition of tropospheric and lower stratospheric aerosols with diameters down to 0.2 {mu}m. In addition to aerosol characterization, the instrument also monitors the chemical composition of the ambient gas. More than 25.000 aerosol particle mass spectra were recorded during the NASA-sponsored Subsonic Aircraft: Contrail and Cloud Effects Special Study (SUCCESS) field program using NASA`s DC-8 research aircraft. (author) 7 refs.

  2. 放射性α气溶胶监测仪数据采集系统的设计%Design of data acquisition system for radioactiveα aerosols monitor

    Institute of Scientific and Technical Information of China (English)

    陈峰; 夏晓彬; 张志宏; 蔡军; 陈明明; 涂传火

    2015-01-01

    在核设施的工作场所中要求对放射性α气溶胶进行快速、连续的监测,以保护工作人员的辐射安全。针对放射性α气溶胶的监测需求,介绍一种放射性α气溶胶监测仪多通道数据采集系统的设计。该系统采用现场可编程门阵列(Field Programmable Gate Array, FPGA)为控制核心,完成对A/D转换器、数据存储器、数据通信等模块的控制。将采集的数据放入到存储器中,实现了对探测系统产生的电压脉冲信号的连续采样,并进行模拟仿真和采样实验的验证。实验结果表明,该数据采集系统能实时、快速、高精度地完成对信号幅度的获取,满足了放射性α气溶胶监测仪的要求。%Background: In the workplace of the nuclear facilities, radioactiveα aerosols monitoring in a fast, continuous way is required for protecting workers against radiation exposure. Purpose: Based on concentrations level ofα aerosols in the workplace,α aerosol monitor was designed. The overall design scheme of the data acquisition system of the radioactiveα aerosol monitor was introduced.Methods:A Cyclonell series FPGA (Field Programmable Gate Array) chip EP2C8Q208C8 from Altera corporation was applied as the control core to complete the A/D converter of AD678, data storage, and data communication with remote computervia RS485 interface. The sample data was stored in the data memory of 64 Mbit SDRAM (Synchronous Dynamic Random Access Memory) for continuous and fast sampling. Both the numerical simulation and experimental measurements were carried out to verify the reliability of the data acquisition system.Results and Conclusion:Results show that the data acquisition system can acquire and control the detector signal for the radioactiveα aerosols monitor in real-time, high-precision and fast-speed.

  3. [The institutional promotion of good practices in the operational management of health and safety: the experience of Italy Crown Aerosols on the monitoring of behavior].

    Science.gov (United States)

    de Merich, D; Pellicci, M; Serignoli, R

    2010-01-01

    Within the intelligence support and training to small and medium-sized enterprises (SMEs) and promoting a culture of health and safety at work, ISPESL is engaged on two fundamental pillars of activity: Consolidation of the national surveillance system of injuries through the promotion of methods and tools for the reconstruction of the dynamics incidental identification of causal determinants, with the aim of improving the capabilities of risk assessment of systems to prevent corporate. The promotion of good working practices, as Focal Point of the European Health and Safety at Work in Bilbao, the goal is to support prevention activities by providing business application examples of measures for improvement (technical, organizational, procedural) made in the proposing firms and validated by a technical appraisal conducted by ISPESL. Among the methodologies and tools that can be made available to companies in the operational management of health and safety in work activities, the approach to analyze and evaluate the behavior implemented by all persons within the company (managers, employees, workers) is a the most innovative preventive strategies that can be implemented to correct any improper practices behavioral wrongly tolerated in everyday work practice. The experience of Crown Aerosol Italy, the program "STOP TO ACCIDENTS, 2009 Best Practices award in the competition on the theme" Risk Assessment ", aims to demonstrate how the application of a method for monitoring behavior at work, shared in its planning with all those business, has not only reached but would assist the organization has developed at an individual level greater awareness and sense of responsibility also to their colleagues, by promoting good working practices. PMID:20518217

  4. Pulmonary deposition and clearance of aerosolized interferon.

    OpenAIRE

    Wyde, P.R.; Wilson, S Z; M.J. Kramer; Sun, C S; Knight, V

    1984-01-01

    Small particle aerosols of a hybrid DNA recombinant human alpha interferon, A/D bgl, and a related DNA recombinant leukocyte interferon, A, were generated and delivered to mice for 23.5 h a day for 4 consecutive days. The antiviral activity of these interferons in delivery reservoirs, in the aerosols generated, and in the lungs of test mice was monitored during and after aerosol administration in cytopathic effect inhibition assays, using vesicular stomatitis virus as the indicator virus. In ...

  5. Atmospheric aerosol light scattering and polarization peculiarities

    CERN Document Server

    Patlashenko, Zh I

    2015-01-01

    This paper considers environmental problems of natural and anthropogenic atmospheric aerosol pollution and its global and regional monitoring. Efficient aerosol investigations may be achieved by spectropolarimetric measurements. Specifically second and fourth Stokes parameters spectral dependencies carry information on averaged refraction and absorption indexes and on particles size distribution functions characteristics.

  6. Tropospheric Aerosols

    Science.gov (United States)

    Buseck, P. R.; Schwartz, S. E.

    2003-12-01

    It is widely believed that "On a clear day you can see forever," as proclaimed in the 1965 Broadway musical of the same name. While an admittedly beautiful thought, we all know that this concept is only figurative. Aside from Earth's curvature and Rayleigh scattering by air molecules, aerosols - colloidal suspensions of solid or liquid particles in a gas - limit our vision. Even on the clearest day, there are billions of aerosol particles per cubic meter of air.Atmospheric aerosols are commonly referred to as smoke, dust, haze, and smog, terms that are loosely reflective of their origin and composition. Aerosol particles have arisen naturally for eons from sea spray, volcanic emissions, wind entrainment of mineral dust, wildfires, and gas-to-particle conversion of hydrocarbons from plants and dimethylsulfide from the oceans. However, over the industrial period, the natural background aerosol has been greatly augmented by anthropogenic contributions, i.e., those produced by human activities. One manifestation of this impact is reduced visibility (Figure 1). Thus, perhaps more than in other realms of geochemistry, when considering the composition of the troposphere one must consider the effects of these activities. The atmosphere has become a reservoir for vast quantities of anthropogenic emissions that exert important perturbations on it and on the planetary ecosystem in general. Consequently, much recent research focuses on the effects of human activities on the atmosphere and, through them, on the environment and Earth's climate. For these reasons consideration of the geochemistry of the atmosphere, and of atmospheric aerosols in particular, must include the effects of human activities. (201K)Figure 1. Impairment of visibility by aerosols. Photographs at Yosemite National Park, California, USA. (a) Low aerosol concentration (particulate matter of aerodynamic diameter less than 2.5 μm, PM2.5=0.3 μg m-3; particulate matter of aerodynamic diameter less than 10

  7. METHODS OF CALCULATINAG LUNG DELIVERY AND DEPOSITION OF AEROSOL PARTICLES

    Science.gov (United States)

    Lung deposition of aerosol is measured by a variety of methods. Total lung deposition can be measured by monitoring inhaled and exhaled aerosols in situ by laser photometry or by collecting the aerosols on filters. The measurements can be performed accurately for stable monod...

  8. Monitor

    Data.gov (United States)

    US Agency for International Development — A custom-built, dual-language (English and Spanish) system (http://www.monitor.net.co/) developed by DevTech that debuted in January 2011. It features a central PMP...

  9. ACTRIS ACSM intercomparison - Part 1: Reproducibility of concentration and fragment results from 13 individual Quadrupole Aerosol Chemical Speciation Monitors (Q-ACSM) and consistency with co-located instruments

    Science.gov (United States)

    Crenn, V.; Sciare, J.; Croteau, P. L.; Verlhac, S.; Fröhlich, R.; Belis, C. A.; Aas, W.; Äijälä, M.; Alastuey, A.; Artiñano, B.; Baisnée, D.; Bonnaire, N.; Bressi, M.; Canagaratna, M.; Canonaco, F.; Carbone, C.; Cavalli, F.; Coz, E.; Cubison, M. J.; Esser-Gietl, J. K.; Green, D. C.; Gros, V.; Heikkinen, L.; Herrmann, H.; Lunder, C.; Minguillón, M. C.; Močnik, G.; O'Dowd, C. D.; Ovadnevaite, J.; Petit, J.-E.; Petralia, E.; Poulain, L.; Priestman, M.; Riffault, V.; Ripoll, A.; Sarda-Estève, R.; Slowik, J. G.; Setyan, A.; Wiedensohler, A.; Baltensperger, U.; Prévôt, A. S. H.; Jayne, J. T.; Favez, O.

    2015-12-01

    As part of the European ACTRIS project, the first large Quadrupole Aerosol Chemical Speciation Monitor (Q-ACSM) intercomparison study was conducted in the region of Paris for 3 weeks during the late-fall - early-winter period (November-December 2013). The first week was dedicated to the tuning and calibration of each instrument, whereas the second and third were dedicated to side-by-side comparison in ambient conditions with co-located instruments providing independent information on submicron aerosol optical, physical, and chemical properties. Near real-time measurements of the major chemical species (organic matter, sulfate, nitrate, ammonium, and chloride) in the non-refractory submicron aerosols (NR-PM1) were obtained here from 13 Q-ACSM. The results show that these instruments can produce highly comparable and robust measurements of the NR-PM1 total mass and its major components. Taking the median of the 13 Q-ACSM as a reference for this study, strong correlations (r2 > 0.9) were observed systematically for each individual Q-ACSM across all chemical families except for chloride for which three Q-ACSMs showing weak correlations partly due to the very low concentrations during the study. Reproducibility expanded uncertainties of Q-ACSM concentration measurements were determined using appropriate methodologies defined by the International Standard Organization (ISO 17025, 1999) and were found to be 9, 15, 19, 28, and 36 % for NR-PM1, nitrate, organic matter, sulfate, and ammonium, respectively. However, discrepancies were observed in the relative concentrations of the constituent mass fragments for each chemical component. In particular, significant differences were observed for the organic fragment at mass-to-charge ratio 44, which is a key parameter describing the oxidation state of organic aerosol. Following this first major intercomparison exercise of a large number of Q-ACSMs, detailed intercomparison results are presented, along with a discussion of some

  10. A global aerosol classification algorithm incorporating multiple satellite data sets of aerosol and trace gas abundances

    Science.gov (United States)

    Penning de Vries, M. J. M.; Beirle, S.; Hörmann, C.; Kaiser, J. W.; Stammes, P.; Tilstra, L. G.; Tuinder, O. N. E.; Wagner, T.

    2015-09-01

    Detecting the optical properties of aerosols using passive satellite-borne measurements alone is a difficult task due to the broadband effect of aerosols on the measured spectra and the influences of surface and cloud reflection. We present another approach to determine aerosol type, namely by studying the relationship of aerosol optical depth (AOD) with trace gas abundance, aerosol absorption, and mean aerosol size. Our new Global Aerosol Classification Algorithm, GACA, examines relationships between aerosol properties (AOD and extinction Ångström exponent from the Moderate Resolution Imaging Spectroradiometer (MODIS), UV Aerosol Index from the second Global Ozone Monitoring Experiment, GOME-2) and trace gas column densities (NO2, HCHO, SO2 from GOME-2, and CO from MOPITT, the Measurements of Pollution in the Troposphere instrument) on a monthly mean basis. First, aerosol types are separated based on size (Ångström exponent) and absorption (UV Aerosol Index), then the dominating sources are identified based on mean trace gas columns and their correlation with AOD. In this way, global maps of dominant aerosol type and main source type are constructed for each season and compared with maps of aerosol composition from the global MACC (Monitoring Atmospheric Composition and Climate) model. Although GACA cannot correctly characterize transported or mixed aerosols, GACA and MACC show good agreement regarding the global seasonal cycle, particularly for urban/industrial aerosols. The seasonal cycles of both aerosol type and source are also studied in more detail for selected 5° × 5° regions. Again, good agreement between GACA and MACC is found for all regions, but some systematic differences become apparent: the variability of aerosol composition (yearly and/or seasonal) is often not well captured by MACC, the amount of mineral dust outside of the dust belt appears to be overestimated, and the abundance of secondary organic aerosols is underestimated in comparison

  11. Aerosol observation in Fengtai area, Beijing

    Institute of Scientific and Technical Information of China (English)

    Zengdong Liu; Jianguo Liu; Bei Wang; Fan Lu; Shuhua Huang; Dexia Wu; Daowen Han

    2008-01-01

    Measurements of aerosol number concentration and particulate matter with diameter less than 10μm (PM10) mass concentrations of urban background aerosols were performed in Fengtai area, Beijing in 2006. Black carbon (BC) was collected simultaneously from the ground and analyzed to determine the particulate matter components. To satisfy the interest in continuous monitoring of temporal and spatial distribution of aerosols, the relationship between extinction coefficient (visibility) measured by lidar remote sensing and the aerosol number concentration measured from the ground was derived by using statistical method. Vertical particle number concentration profile within the planetary boundary layer could be inversed through the lidar data as well as the statistical relation.

  12. ACTRIS ACSM intercomparison - Part I: Reproducibility of concentration and fragment results from 13 individual Quadrupole Aerosol Chemical Speciation Monitors (Q-ACSM) and consistency with Time-of-Flight ACSM (ToF-ACSM), High Resolution ToF Aerosol Mass Spectrometer (HR-ToF-AMS) and other co-located instruments

    Science.gov (United States)

    Crenn, V.; Sciare, J.; Croteau, P. L.; Verlhac, S.; Fröhlich, R.; Belis, C. A.; Aas, W.; Äijälä, M.; Alastuey, A.; Artiñano, B.; Baisnée, D.; Bonnaire, N.; Bressi, M.; Canagaratna, M.; Canonaco, F.; Carbone, C.; Cavalli, F.; Coz, E.; Cubison, M. J.; Esser-Gietl, J. K.; Green, D. C.; Gros, V.; Heikkinen, L.; Herrmann, H.; Lunder, C.; Minguillón, M. C.; Močnik, G.; O'Dowd, C. D.; Ovadnevaite, J.; Petit, J.-E.; Petralia, E.; Poulain, L.; Priestman, M.; Riffault, V.; Ripoll, A.; Sarda-Estève, R.; Slowik, J. G.; Setyan, A.; Wiedensohler, A.; Baltensperger, U.; Prévôt, A. S. H.; Jayne, J. T.; Favez, O.

    2015-07-01

    As part of the European ACTRIS project, the first large Quadrupole Aerosol Chemical Speciation Monitor (Q-ACSM) intercomparison study was conducted in the region of Paris for three weeks during the late fall-early winter period (November-December 2013). The first week was dedicated to tuning and calibration of each instrument whereas the second and third were dedicated to side-by-side comparison in ambient conditions with co-located instruments providing independent information on submicron aerosol optical, physical and chemical properties. Near real-time measurements of the major chemical species (organic matter, sulfate, nitrate, ammonium and chloride) in the non-refractory submicron aerosols (NR-PM1) were obtained here from 13 Q-ACSM. The results show that these instruments can produce highly comparable and robust measurements of the NR-PM1 total mass and its major components. Taking the median of the 13 Q-ACSM as a reference for this study, strong correlations (r2 > 0.9) were observed systematically for each individual ACSM across all chemical families except for chloride for which three ACSMs showing weak correlations partly due to the very low concentrations during the study. Reproducibility expanded uncertainties of Q-ACSM concentration measurements were determined using appropriate methodologies defined by the International Standard Organization (ISO 17025) and were found to be of 9, 15, 19, 28 and 36 % for NR-PM1, nitrate, organic matter, sulfate and ammonium respectively. However, discrepancies were observed in the relative concentrations of the constituent mass fragments for each chemical component. In particular, significant differences were observed for the organic fragment at mass-to-charge ratio 44, which is a key parameter describing the oxidation state of organic aerosol. Following this first major intercomparison exercise of a large number of ACSMs, detailed intercomparison results are presented as well as a discussion of some recommendations

  13. Monitoring

    Czech Academy of Sciences Publication Activity Database

    Ložek, Vojen; Němec, J.

    Praha : Consult, 2003 - (Němec, J.), s. 111-115 ISBN 80-902132-4-3 Grant ostatní: Magistrát hlavního města Prahy(CZ) DAG/67/04/000176/2001 Institutional research plan: CEZ:AV0Z3013912 Keywords : monitoring * environmental quality * Prague Subject RIV: DB - Geology ; Mineralogy

  14. Monitoring

    Science.gov (United States)

    ... its main source of fuel. To keep your blood sugar level on target and avoid problems with your eyes, kidneys, heart and feet, you should eat right ... better. And monitoring doesn’t stop at measuring blood sugar levels. Because ... blood testing) Eye health (eye exams) Foot health (foot exams and ...

  15. Indoor aerosols

    DEFF Research Database (Denmark)

    Morawska, L.; Afshari, Alireza; N. Bae, G.;

    2013-01-01

    understanding of the risks posed by personal exposure to indoor aerosols. Limited studies assessing integrated daily residential exposure to just one particle size fraction, ultrafine particles, show that the contribution of indoor sources ranged from 19% to 76%. This indicates a strong dependence on resident...

  16. Influence of crustal dust and sea spray supermicron particle concentrations and acidity on inorganic NO3− aerosol during the 2013 Southern Oxidant and Aerosol Study

    OpenAIRE

    H. M. Allen; D. C. Draper; B. R. Ayres; A. Ault; A. Bondy; Takahama, S; Modini, R. L.; K. Baumann; Edgerton, E.; Knote, C.; Laskin, A.; Wang, B; Fry, J. L

    2015-01-01

    Inorganic aerosol composition was measured in the southeastern United States, a region that exhibits high aerosol mass loading during the summer, as part of the 2013 Southern Oxidant and Aerosol Study (SOAS) campaign. Measurements using a Monitor for AeRosols and GAses (MARGA) revealed two periods of high aerosol nitrate (NO3−) concentrations during the campaign. These periods of high nitrate were correlated with increased concentrations of supermicron crustal and sea ...

  17. Nonlinear relationships between atmospheric aerosol and its gaseous precursors: Analysis of long-term air quality monitoring data by means of neural networks

    OpenAIRE

    I. B. Konovalov

    2002-01-01

    The nonlinear features of the relationships between concentrations of aerosol and volatile organic compounds (VOC) and nitrogen oxides (NOx) in urban environments are revealed directly from data of long-term routine measurements of NOx, VOC, and total suspended particulate matter (PM). The main idea of the method is development of special empirical models based on artificial neural networks. These models, that are basically, the nonlinear extension...

  18. Limitation on electrical measures of aerosols

    International Nuclear Information System (INIS)

    Based upon the assumption that there is a constant, natural, background ion source, atmospheric conductivity has been used as a measure of the presence of aerosol particles because such particles remove the effective charge carriers from the atmosphere. Another variety of electrical measure is the total charge acquired by the aerosol under either natural or artificial charging conditions. Currently, the most widely cited electrical method for aerosol size distribution analysis is the diffusion charging mobility analysis method in which the electrical current due to the controlled unipolar charging of the aerosol is measured while increasing mobility fractions of that aerosol are removed. The hypothesis is that by monitoring the diminution of aerosol current as a function of the known particle electrical mobilities removed, a measure of the aerosol size distribution is derived. Fundamental to all such measures of aerosol size is the assumption that any aerosol can be put in a well-defined charge state. This note presents an examination of that assumption

  19. Aerosol filtration

    International Nuclear Information System (INIS)

    This report summarizes the work on the development of fibre metallic prefilters to be placed upstream of HEPA filters for the exhaust gases of nuclear process plants. Investigations at ambient and high temperature were carried out. Measurements of the filtration performance of Bekipor porous webs and sintered mats were performed in the AFLT (aerosol filtration at low temperature) unit with a throughput of 15 m3/h. A parametric study on the influence of particle size, fibre diameter, number of layers and superficial velocity led to the optimum choice of the working parameters. Three selected filter types were then tested with polydisperse aerosols using a candle-type filter configuration or a flat-type filter configuration. The small-diameter candle type is not well suited for a spraying nozzles regeneration system so that only the flat-type filter was retained for high-temperature tests. A high-temperature test unit (AFHT) with a throughput of 8 to 10 m3/h at 4000C was used to test the three filter types with an aerosol generated by high-temperature calcination of a simulated nitric acid waste solution traced with 134Cs. The regeneration of the filter by spray washing and the effect of the regeneration on the filter performance was studied for the three filter types. The porous mats have a higher dust loading capacity than the sintered web which means that their regeneration frequency can be kept lower

  20. Aerosol Observation System

    Data.gov (United States)

    Oak Ridge National Laboratory — The aerosol observation system (AOS) is the primary Atmospheric Radiation Measurement (ARM) platform for in situ aerosol measurements at the surface. The principal...

  1. Aerosol/Cloud Measurements Using Coherent Wind Doppler Lidars

    Science.gov (United States)

    Royer, Philippe; Boquet, Matthieu; Cariou, Jean-Pierre; Sauvage, Laurent; Parmentier, Rémy

    2016-06-01

    The accurate localization and characterization of aerosol and cloud layers is crucial for climate studies (aerosol indirect effect), meteorology (Planetary Boundary Layer PBL height), site monitoring (industrial emissions, mining,…) and natural hazards (thunderstorms, volcanic eruptions). LEOSPHERE has recently developed aerosol/cloud detection and characterization on WINDCUBE long range Coherent Wind Doppler Lidars (CWDL). These new features combine wind and backscatter intensity informations (Carrier-to-Noise Ratio CNR) in order to detect (aerosol/cloud base and top, PBL height) and to characterize atmospheric structures (attenuated backscatter, depolarization ratio). For each aerosol/cloud functionality the method is described, limitations are discussed and examples are given to illustrate the performances.

  2. Monitoring of the Eyjafjallajökull volcanic aerosol plume over the Iberian Peninsula by means of four EARLINET lidar stations

    OpenAIRE

    Sicard, M.; J. L. Guerrero-Rascado; F. Navas-Guzmán; Preißler, J; F. Molero; S. Tomás; Bravo-Aranda, J. A.; A. Comerón; Rocadenbosch, F.; Wagner, F.; M. Pujadas; Alados-Arboledas, L.

    2011-01-01

    Lidar and sun-photometer measurements were performed intensively over the Iberian Peninsula (IP) during the eruption of Eyjafjallajökull volcano (Iceland) in April–May 2010. The volcanic plume hit all the IP stations for the first time on 5 May 2010. A thorough study of the event is conducted for the period 5–8 May. Firstly the spatial and temporal evolution of the plume is described by means of lidar and sun-photometer measurements supported with backtrajectories. The volcanic aerosol l...

  3. [Ultraviolet Mie lidar observations of aerosol extinction in a dust storm case over Macao].

    Science.gov (United States)

    Liu, Qiao-jun; Cheng, A Y S; Zhu, Jian-hua; Fong, S K; Chang, S W; Tam, K S; Viseu, A

    2012-03-01

    Atmospheric aerosol over Macao was monitored by using a 355 nm Mie scattering lidar during the dust event on March 22nd, 2010. Vertical profiles of aerosol extinction coefficients were obtained and correlated with local PM10 concentration. The near-surface aerosol extinction coefficients have good agreement with PM10 concentration values. The aerosol extinction vertical profiles showed that there were distinct layers of dust aerosol concentration. The source and tracks of dust aerosol were analyzed by back-trajectory simulation. Observations showed that this lidar could run well even in dust storm episode, and it would help to further the study on aerosol properties over Macao. PMID:22582620

  4. Capstone Depleted Uranium Aerosols: Generation and Characterization

    Energy Technology Data Exchange (ETDEWEB)

    Parkhurst, MaryAnn; Szrom, Fran; Guilmette, Ray; Holmes, Tom; Cheng, Yung-Sung; Kenoyer, Judson L.; Collins, John W.; Sanderson, T. Ellory; Fliszar, Richard W.; Gold, Kenneth; Beckman, John C.; Long, Julie

    2004-10-19

    In a study designed to provide an improved scientific basis for assessing possible health effects from inhaling depleted uranium (DU) aerosols, a series of DU penetrators was fired at an Abrams tank and a Bradley fighting vehicle. A robust sampling system was designed to collect aerosols in this difficult environment and continuously monitor the sampler flow rates. Aerosols collected were analyzed for uranium concentration and particle size distribution as a function of time. They were also analyzed for uranium oxide phases, particle morphology, and dissolution in vitro. The resulting data provide input useful in human health risk assessments.

  5. Electrical aerosol spectrometer of Tartu University

    Science.gov (United States)

    Tammet, H.; Mirme, A.; Tamm, E.

    The electrical aerosol spectrometer (EAS) of the parallel measuring principle at Tartu University is an efficient instrument for rapid measurement of the unstable size spectrum of aerosol particles. The measuring range from 10 nm to 10 μm is achieved by simultaneously using a pair of differential mobility analyzers with two different particle chargers. The particle spectrum is calculated and measurement errors are estimated in real time by using a least-squares method. Experimental calibration ensures reliability of measurement. The instrument is well suited for continuous monitoring of atmospheric aerosol.

  6. Retrieval of Aerosol Height with TROPOMI

    Science.gov (United States)

    Sanders, A. F. J.; de Haan, J. F.; Veefkind, J. P.

    2012-04-01

    The Tropospheric Monitoring Instrument (TROPOMI), to be launched in 2015, will feature a new aerosol product providing the height of aerosol layers. Aerosol Layer Height will be one of two aerosol products, the other one being the Absorbing Aerosol Index. TROPOMI is a UV-VIS-NIR imaging spectrometer with daily global coverage. It will be part of ESA's Sentinel-5 Precursor mission. Algorithm development for the aerosol height product is currently underway at KNMI. In this presentation we will introduce the algorithm, highlight some of the development issues and discuss possible applications and example aerosol cases. Aerosol height observations from the near-infrared wavelength range will improve retrieval of other aerosol properties, particularly retrieval of absorption optical thickness. An increase in absorption in the ultraviolet wavelength range can be due to a higher imaginary part of the refractive index or to the aerosol layer being at a higher altitude. Independent height observations will therefore further constrain retrieval of the single scattering albedo. Furthermore, aerosol profile information is an important parameter when estimating radiative forcings and climate impacts of aerosol, it is a significant source of uncertainty in trace gas retrieval and it helps in understanding atmospheric transport mechanisms. Finally, timely available, global observations of aerosol height will be of interest to aviation safety agencies. The retrieval algorithm for aerosol height will be based on absorption by oxygen in the A-band (759-770 nm). Aerosols are assumed to be contained in a single layer. A spectral fit of reflectance (resolution 0.5 nm) across the absorption band provides layer height. The retrieval method will be optimal estimation to ensure a proper error analysis. Sensitivity studies have indicated that accuracy and precision of retrieved height for cloud-free scenes will be well below the TROPOMI science requirements (1 km). They have also shown that

  7. Evaluation of a radioactive aerosol surveillance system

    Energy Technology Data Exchange (ETDEWEB)

    Scripsick, R.C.; Stafford, R.G.; Beckman, R.J.; Tillery, M.I.; Romero, P.O.

    1978-06-26

    Measurements of the dilution of air contaminants between worker breathing zone and area air samplers were made by releasing a test aerosol in a workroom equipped with an aerosol surveillance system. The data were used to evaluate performance, and suggest improvements in design of the workroom's alarming air monitor system. It was found that a breathing zone concentration of 960 times the maximum permissible concentration in air (MPC/sub a/) for a half-hour was required to trigger alarms of the existing monitoring system under some release conditions. Alternative air monitor placement, suggested from dilution measurements, would reduce this average triggering concentration to 354 MPC/sub a/. Deployment of additional air monitors could further reduce the average triggering concentration to 241 MPC/sub a/. The relation between number of monitors and triggering concentration was studied. No significant decrease in average triggering concentration was noted for arrays containing greater than five monitors.

  8. Evaluation of a radioactive aerosol surveillance system

    International Nuclear Information System (INIS)

    Measurements of the dilution of air contaminants between worker breathing zone and area air samplers were made by releasing a test aerosol in a workroom equipped with an aerosol surveillance system. The data were used to evaluate performance, and suggest improvements in design of the workroom's alarming air monitor system. It was found that a breathing zone concentration of 960 times the maximum permissible concentration in air (MPC/sub a/) for a half-hour was required to trigger alarms of the existing monitoring system under some release conditions. Alternative air monitor placement, suggested from dilution measurements, would reduce this average triggering concentration to 354 MPC/sub a/. Deployment of additional air monitors could further reduce the average triggering concentration to 241 MPC/sub a/. The relation between number of monitors and triggering concentration was studied. No significant decrease in average triggering concentration was noted for arrays containing greater than five monitors

  9. The impacts of aerosol loading, composition, and water uptake on aerosol extinction variability in the Baltimore–Washington, D.C. region

    OpenAIRE

    A. J. Beyersdorf; L. D. Ziemba; G. Chen; C. A. Corr; J. H. Crawford; G. S. Diskin; Moore, R H; K. L. Thornhill; E. L. Winstead; Anderson, B E

    2016-01-01

    In order to utilize satellite-based aerosol measurements for the determination of air quality, the relationship between aerosol optical properties (wavelength-dependent, column-integrated extinction measured by satellites) and mass measurements of aerosol loading (PM2.5 used for air quality monitoring) must be understood. This connection varies with many factors including those specific to the aerosol type – such as composition, size, and hygroscopicity – and to the surround...

  10. 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

  11. A general circulation model (GCM) parameterization of Pinatubo aerosols

    Energy Technology Data Exchange (ETDEWEB)

    Lacis, A.A.; Carlson, B.E.; Mishchenko, M.I. [NASA Goddard Institute for Space Studies, New York, NY (United States)

    1996-04-01

    The June 1991 volcanic eruption of Mt. Pinatubo is the largest and best documented global climate forcing experiment in recorded history. The time development and geographical dispersion of the aerosol has been closely monitored and sampled. Based on preliminary estimates of the Pinatubo aerosol loading, general circulation model predictions of the impact on global climate have been made.

  12. Evaluation of Polarized Remote Sensing of Aerosol Optical Thickness Retrieval over China

    Directory of Open Access Journals (Sweden)

    Hao Chen

    2015-10-01

    Full Text Available The monitoring capability of a polarized instrument (POLDER under high aerosol loading conditions over China is investigated. The aerosol optical thickness (AOT, which infers the aerosol burden, is used to measure the satellite monitoring capabilities. AOT products retrieved from POLDER on low aerosol loading days, and products from a radiometric instrument (MODIS on high and low aerosol loading days, are presented for comparison. Our study reveals that for high aerosol days, the monitoring capability of the polarized instrument is lower than that of the traditional instrument. The accuracy of matched POLDER fine-AOTs is lower than that of MODIS-matched AOTs. On low aerosol loading days, the performance of the polarized instrument is good when monitoring the aerosol optical thickness. Further analysis reveals that for the high aerosol loading days, the mean relative errors of matched POLDER fine AOTs and MODIS AOTs with respect to AERONET measurements are 44% and 16%, respectively. For the low aerosol loading days, the mean relative errors of POLDER and MODIS measurements with respect to AERONET measurements are 41% and 40%, respectively. During high aerosol days, POLDER-retrieved fine-AOTs reveal a poor accuracy with only 14% of matches falling within the error range, which is nearly one fourth of the MODIS regression results (51.59%. For the low aerosol loading days, the POLDER regression results are good. Approximately 62% of the POLDER measurements fall within the expected error range ±(0.05 + 15% compared with the AERONET observed values.

  13. Whole-body nanoparticle aerosol inhalation exposures.

    Science.gov (United States)

    Yi, Jinghai; Chen, Bean T; Schwegler-Berry, Diane; Frazer, Dave; Castranova, Vince; McBride, Carroll; Knuckles, Travis L; Stapleton, Phoebe A; Minarchick, Valerie C; Nurkiewicz, Timothy R

    2013-01-01

    Inhalation is the most likely exposure route for individuals working with aerosolizable engineered nano-materials (ENM). To properly perform nanoparticle inhalation toxicology studies, the aerosols in a chamber housing the experimental animals must have: 1) a steady concentration maintained at a desired level for the entire exposure period; 2) a homogenous composition free of contaminants; and 3) a stable size distribution with a geometric mean diameter generation of aerosols containing nanoparticles is quite challenging because nanoparticles easily agglomerate. This is largely due to very strong inter-particle forces and the formation of large fractal structures in tens or hundreds of microns in size (6), which are difficult to be broken up. Several common aerosol generators, including nebulizers, fluidized beds, Venturi aspirators and the Wright dust feed, were tested; however, none were able to produce nanoparticle aerosols which satisfy all criteria (5). A whole-body nanoparticle aerosol inhalation exposure system was fabricated, validated and utilized for nano-TiO2 inhalation toxicology studies. Critical components: 1) novel nano-TiO2 aerosol generator; 2) 0.5 m(3) whole-body inhalation exposure chamber; and 3) monitor and control system. Nano-TiO2 aerosols generated from bulk dry nano-TiO2 powders (primary diameter of 21 nm, bulk density of 3.8 g/cm(3)) were delivered into the exposure chamber at a flow rate of 90 LPM (10.8 air changes/hr). Particle size distribution and mass concentration profiles were measured continuously with a scanning mobility particle sizer (SMPS), and an electric low pressure impactor (ELPI). The aerosol mass concentration (C) was verified gravimetrically (mg/m(3)). The mass (M) of the collected particles was determined as M = (Mpost-Mpre), where Mpre and Mpost are masses of the filter before and after sampling (mg). The mass concentration was calculated as C = M/(Q*t), where Q is sampling flowrate (m(3)/min), and t is the sampling

  14. Aerosol mobility size spectrometer

    Science.gov (United States)

    Wang, Jian; Kulkarni, Pramod

    2007-11-20

    A device for measuring aerosol size distribution within a sample containing aerosol particles. The device generally includes a spectrometer housing defining an interior chamber and a camera for recording aerosol size streams exiting the chamber. The housing includes an inlet for introducing a flow medium into the chamber in a flow direction, an aerosol injection port adjacent the inlet for introducing a charged aerosol sample into the chamber, a separation section for applying an electric field to the aerosol sample across the flow direction and an outlet opposite the inlet. In the separation section, the aerosol sample becomes entrained in the flow medium and the aerosol particles within the aerosol sample are separated by size into a plurality of aerosol flow streams under the influence of the electric field. The camera is disposed adjacent the housing outlet for optically detecting a relative position of at least one aerosol flow stream exiting the outlet and for optically detecting the number of aerosol particles within the at least one aerosol flow stream.

  15. Effect of some natural processes on the generation and characteristics of aerosols over radioactive polluted areas

    International Nuclear Information System (INIS)

    The formation of radioactive aerosols over contaminated areas results from some natural and technogenic factors. Results of several years investigations of physicochemical properties of secondary aerosols, such as volume activity, radionuclide composition, dispersity, are presented taking Chernobyl accident as an example. The results of monitoring of the aerosol from traffic, dust storms and forest fires are presented. Data of aerosol monitoring in the 30 km controlled area near Chernobyl power plant and controlled areas in other regions (Belarus, Lithuania) are compared. Some methodical aspects of the sampling and analyses of aerosols are considered. The recommendations for choice of the personal respirators are given

  16. Facility of aerosol filtration

    International Nuclear Information System (INIS)

    Said invention relates to a facility of aerosol filtration, particularly of sodium aerosols. Said facility is of special interest for fast reactors where sodium fires involve the possibility of high concentrations of sodium aerosols which soon clog up conventional filters. The facility intended for continuous operation, includes at the pre-filtering stage, means for increasing the size of the aerosol particles and separating clustered particles (cyclone separator)

  17. Compact LIDAR for Aerosol Extinction Profiling from Small UAV's Project

    Data.gov (United States)

    National Aeronautics and Space Administration — It is increasingly recognized that the Arctic is a bellwether for climate change. As the Arctic region responds to climate forcings, monitoring how aerosol...

  18. Characterization of gas-aerosol interaction kinetics using morphology dependent stimulated Raman scattering. Final technical report

    Energy Technology Data Exchange (ETDEWEB)

    Aker, P.M.

    1992-12-31

    A research program on the influence of aerosol surface structure on the kinetics of gas-aerosol interactions is proposed. The experiments involve measuring changes in gas phase chemical reaction rates as a function of exposure to a specific aerosol. Aerosols with differing surface properties will be generated by changing the composition and/or temperature of the material making up the aerosol. Kinetic data generated can be used directly in atmospheric modelling calculations. The surface structure of the aerosol will be measured, both before and after reaction, using morphology-dependent enhancement of simulated Raman scattering (MDSRS). Information about the detailed dynamics of gas-aerosol interactions can be obtained by correlating the change in the reaction rate with change in surface structure and by monitoring the change in aerosol surface structure during the course of the reaction. Studies will focus on the condensation and oxidation of sulfur species (sulfur dioxide and dimethyl sulfide) on water aerosols.

  19. Characterization of gas-aerosol interaction kinetics using morphology dependent stimulated Raman scattering

    Energy Technology Data Exchange (ETDEWEB)

    Aker, P.M.

    1992-01-01

    A research program on the influence of aerosol surface structure on the kinetics of gas-aerosol interactions is proposed. The experiments involve measuring changes in gas phase chemical reaction rates as a function of exposure to a specific aerosol. Aerosols with differing surface properties will be generated by changing the composition and/or temperature of the material making up the aerosol. Kinetic data generated can be used directly in atmospheric modelling calculations. The surface structure of the aerosol will be measured, both before and after reaction, using morphology-dependent enhancement of simulated Raman scattering (MDSRS). Information about the detailed dynamics of gas-aerosol interactions can be obtained by correlating the change in the reaction rate with change in surface structure and by monitoring the change in aerosol surface structure during the course of the reaction. Studies will focus on the condensation and oxidation of sulfur species (sulfur dioxide and dimethyl sulfide) on water aerosols.

  20. Climatology of Aerosol Optical Properties in Southern Africa

    Science.gov (United States)

    Queface, Antonio J.; Piketh, Stuart J.; Eck, Thomas F.; Tsay, Si-Chee

    2011-01-01

    A thorough regionally dependent understanding of optical properties of aerosols and their spatial and temporal distribution is required before we can accurately evaluate aerosol effects in the climate system. Long term measurements of aerosol optical depth, Angstrom exponent and retrieved single scattering albedo and size distribution, were analyzed and compiled into an aerosol optical properties climatology for southern Africa. Monitoring of aerosol parameters have been made by the AERONET program since the middle of the last decade in southern Africa. This valuable information provided an opportunity for understanding how aerosols of different types influence the regional radiation budget. Two long term sites, Mongu in Zambia and Skukuza in South Africa formed the core sources of data in this study. Results show that seasonal variation of aerosol optical thicknesses at 500 nm in southern Africa are characterized by low seasonal multi-month mean values (0.11 to 0.17) from December to May, medium values (0.20 to 0.27) between June and August, and high to very high values (0.30 to 0.46) during September to November. The spatial distribution of aerosol loadings shows that the north has high magnitudes than the south in the biomass burning season and the opposite in none biomass burning season. From the present aerosol data, no long term discernable trends are observable in aerosol concentrations in this region. This study also reveals that biomass burning aerosols contribute the bulk of the aerosol loading in August-October. Therefore if biomass burning could be controlled, southern Africa will experience a significant reduction in total atmospheric aerosol loading. In addition to that, aerosol volume size distribution is characterized by low concentrations in the non biomass burning period and well balanced particle size contributions of both coarse and fine modes. In contrast high concentrations are characteristic of biomass burning period, combined with

  1. Attachment of radon progeny to cigarette-smoke aerosols

    Energy Technology Data Exchange (ETDEWEB)

    Biermann, A.H.; Sawyer, S.R.

    1995-05-01

    The daughter products of radon gas are now recognized as a significant contributor to radiation exposure to the general public. It is also suspected that a synergistic effect exists with the combination cigarette smoking and radon exposure. We have conducted an experimental investigation to determine the physical nature of radon progeny interactions with cigarette smoke aerosols. The size distributions of the aerosols are characterized and attachment rates of radon progeny to cigarette-smoke aerosols are determined. Both the mainstream and sidestream portions of the smoke aerosol are investigated. Unattached radon progeny are very mobile and, in the presence of aerosols, readily attach to the particle surfaces. In this study, an aerosol chamber is used to contain the radon gas, progeny and aerosol mixture while allowing the attachment process to occur. The rate of attachment is dependent on the size distribution, or diffusion coefficient, of the radon progeny as well as the aerosol size distribution. The size distribution of the radon daughter products is monitored using a graded-screen diffusion battery. The diffusion battery also enables separation of the unattached radon progeny from those attached to the aerosol particles. Analysis of the radon decay products is accomplished using alpha spectrometry. The aerosols of interest are size fractionated with the aid of a differential mobility analyzer and cascade impactor. The measured attachment rates of progeny to the cigarette smoke are compared to those found in similar experiments using an ambient aerosol. The lowest attachment coefficients observed, {approximately}10{sup {minus}6} cm{sup 3}/s, occurred for the ambient aerosol. The sidestream and mainstream smoke aerosols exhibited higher attachment rates in that order. The results compared favorably with theories describing the coagulation process of aerosols.

  2. A survey of aerosol research in European community programmes

    International Nuclear Information System (INIS)

    In the European Commission's (EC) 3rd Framework Programme (1990-1994) of community research and technological development, aerosol problems are of particular importance in the specific programmes Environment, Nuclear Fission Safety (with emphasis on Reactor Safety and on the Decommissioning of Nuclear Installations), Industrial and Materials Technologies, and Measurement and Testing. Under Environment, significant efforts are directed towards monitoring natural and anthropogenic aerosols in the atmosphere, understanding the role played by aerosols in ecosystem regulation, and the development of techniques to reduce aerosol emission from industrial plants. To ensure Nuclear Fission Safety, investigations are necessary to identify the mechanisms and determine the quantities of fission product aerosols released in the event of an accident and to develop measures for aerosol retention in such cases. The release of radioactive aerosols from nuclear installations in case of fire has been studied, and methods of aerosol abatement by acoustic techniques are under investigation. In decommissioning of nuclear installations the problem of aerosol formation and dispersion arises during dismantling operations. Industrial and Materials Technologies require information on aerosols ranging from welding fumes, asbestos fibres, lead compounds and quartz particles to aerosol/vapour mixtures of toxic products, aerosols from biotechnology industries and airborne micro-organisms. Finally, for Measurement and Testing, reference aerosols are needed for calibration purposes and to improve and harmonize particle counting characterisation. A brief summary of examples for each of the above activities, carried out in the form of EC cost shared actions or at the Commission's Joint Research Centre, will be given, together with a description of some aerosol problems still to be solved. (Author)

  3. Aerosol satellite remote sensing

    NARCIS (Netherlands)

    Veefkind, Joris Pepijn

    2001-01-01

    Aerosols are inportant for many processes in the atmosphere. Aerosols are a leading uncertainty in predicting global climate change, To a large extent this uncertainty is caused by a lack of knowledge on the occurrence and concentration of aerosols. On global scale, this information can only be o

  4. Aerosol composition and variability in the Baltimore–Washington, DC region

    OpenAIRE

    A. J. Beyersdorf; L. D. Ziemba; G. Chen; C. A. Corr; J. H. Crawford; G. S. Diskin; Moore, R H; K. L. Thornhill; E. L. Winstead; Anderson, B E

    2015-01-01

    In order to utilize satellite-based aerosol measurements for the determination of air quality, the relationship between aerosol optical properties (wavelength-dependent, column-integrated extinction measured by satellites) and mass measurements of aerosol loading (PM2.5 used for air quality monitoring) must be understood. This connection varies with many factors including those specific to the aerosol type, such as composition, size and hygroscopicity, and to the surrounding at...

  5. Continuous monitoring α-activity on aerosol filters by the pseudo-coincidence-technique. Explicitly taking into account the short lived Po-218 activity

    International Nuclear Information System (INIS)

    Pseudo-coincidence-technique is applied to continuous monitoring of α-activity on aerosolfilters by proportional counters. Filter activity can markedly increase or decrease by changing air conditions especially by the amount of short lived Po-218 activity. Conditions of constant proportions of activity concentrations for the short lived species for operating this technique are seldom fulfilled. The dynamic behavior of artificial (long lived) and natural (short lived) activity is mathematically modelled and the measured moving count rates are analyzed under this model by a multivariate regression analysis for activity concentrations of artificial resp. short lived activity. Results are compared to standard recommendations of DIN ISO 11929.

  6. Atmospheric pressure flow reactor / aerosol mass spectrometer studies of tropospheric aerosol nucleat and growth kinetics. Final report, June, 2001

    Energy Technology Data Exchange (ETDEWEB)

    Worsnop, Douglas R.

    2001-06-01

    The objective of this program was to determine the mechanisms and rates of growth and transformation and growth processes that control secondary aerosol particles in both the clear and polluted troposphere. The experimental plan coupled an aerosol mass spectrometer (AMS) with a chemical ionization mass spectrometer to provide simultaneous measurement of condensed and particle phases. The first task investigated the kinetics of tropospheric particle growth and transformation by measuring vapor accretion to particles (uptake coefficients, including mass accommodation coefficients and heterogeneous reaction rate coefficients). Other work initiated investigation of aerosol nucleation processes by monitoring the appearance of submicron particles with the AMS as a function of precursor gas concentrations. Three projects were investigated during the program: (1) Ozonolysis of oleic acid aerosols as model of chemical reactivity of secondary organic aerosol; (2) Activation of soot particles by measurement deliquescence in the presence of sulfuric acid and water vapor; (3) Controlled nucleation and growth of sulfuric acid aerosols.

  7. Non-destructive infrared spectroscopic analysis of IMPROVE aerosol samples

    Science.gov (United States)

    Ruthenburg, T. C.; Dillner, A. M.

    2011-12-01

    The use of mid-infrared (MIR) spectroscopy is of increasing interest for determining organic functional group composition of aerosols. The organic fraction of aerosols is thought to affect visibility, climate and toxicity. Organic functional group composition can provide insights into aerosol sources and aging. The Interagency Monitoring of Protected Visual Environments (IMPROVE) program, established in 1985, operates a long term particulate matter monitoring network primarily in National Parks and Wilderness Areas. IMRPROVE samples collected on polytetrafluoroethylene (PTFE) filters are analyzed via IR spectroscopy to determine organic functional group composition. Organic carbon (OC) mass determined by MIR spectroscopy is compared to OC derived from a thermal-optical method.

  8. New satellite project Aerosol-UA: Remote sensing of aerosols in the terrestrial atmosphere

    Science.gov (United States)

    Milinevsky, G.; Yatskiv, Ya.; Degtyaryov, O.; Syniavskyi, I.; Mishchenko, M.; Rosenbush, V.; Ivanov, Yu.; Makarov, A.; Bovchaliuk, A.; Danylevsky, V.; Sosonkin, M.; Moskalov, S.; Bovchaliuk, V.; Lukenyuk, A.; Shymkiv, A.; Udodov, E.

    2016-06-01

    We discuss the development of the Ukrainian space project Aerosol-UA which has the following three main objectives: (1) to monitor the spatial distribution of key characteristics of terrestrial tropospheric and stratospheric aerosols; (2) to provide a comprehensive observational database enabling accurate quantitative estimates of the aerosol contribution to the energy budget of the climate system; and (3) quantify the contribution of anthropogenic aerosols to climate and ecological processes. The remote sensing concept of the project is based on precise orbital measurements of the intensity and polarization of sunlight scattered by the atmosphere and the surface with a scanning polarimeter accompanied by a wide-angle multispectral imager-polarimeter. Preparations have already been made for the development of the instrument suite for the Aerosol-UA project, in particular, of the multi-channel scanning polarimeter (ScanPol) designed for remote sensing studies of the global distribution of aerosol and cloud properties (such as particle size, morphology, and composition) in the terrestrial atmosphere by polarimetric and spectrophotometric measurements of the scattered sunlight in a wide range of wavelengths and viewing directions from which a scene location is observed. ScanPol is accompanied by multispectral wide-angle imager-polarimeter (MSIP) that serves to collect information on cloud conditions and Earth's surface image. Various components of the polarimeter ScanPol have been prototyped, including the opto-mechanical and electronic assemblies and the scanning mirror controller. Preliminary synthetic data simulations for the retrieval of aerosol parameters over land surfaces have been performed using the Generalized Retrieval of Aerosol and Surface Properties (GRASP) algorithm. Methods for the validation of satellite data using ground-based observations of aerosol properties are also discussed. We assume that designing, building, and launching into orbit a multi

  9. New Satellite Project Aerosol-UA: Remote Sensing of Aerosols in the Terrestrial Atmosphere

    Science.gov (United States)

    Milinevsky, G.; Yatskiv, Ya.; Degtyaryov, O.; Syniavskyi, I.; Mishchenko, Michael I.; Rosenbush, V.; Ivanov, Yu.; Makarov, A.; Bovchaliuk, A.; Danylevsky, V.; Sosonkin, M.; Moskalov, S.; Bovchaliuk, V; Lukenyuk, A.; Shymkiv, A.

    2016-01-01

    We discuss the development of the Ukrainian space project Aerosol-UA which has the following three main objectives: (1) to monitor the spatial distribution of key characteristics of terrestrial tropospheric and stratospheric aerosols; (2) to provide a comprehensive observational database enabling accurate quantitative estimates of the aerosol contribution to the energy budget of the climate system; and (3) quantify the contribution of anthropogenic aerosols to climate and ecological processes. The remote sensing concept of the project is based on precise orbital measurements of the intensity and polarization of sunlight scattered by the atmosphere and the surface with a scanning polarimeter accompanied by a wide-angle multispectral imager-polarimeter. Preparations have already been made for the development of the instrument suite for the Aerosol-UA project, in particular, of the multi-channel scanning polarimeter (ScanPol) designed for remote sensing studies of the global distribution of aerosol and cloud properties (such as particle size, morphology, and composition) in the terrestrial atmosphere by polarimetric and spectrophotometric measurements of the scattered sunlight in a wide range of wavelengths and viewing directions from which a scene location is observed. ScanPol is accompanied by multispectral wide-angle imager-polarimeter (MSIP) that serves to collect information on cloud conditions and Earths surface image. Various components of the polarimeter ScanPol have been prototyped, including the opto-mechanical and electronic assemblies and the scanning mirror controller. Preliminary synthetic data simulations for the retrieval of aerosol parameters over land surfaces have been performed using the Generalized Retrieval of Aerosol and Surface Properties (GRASP) algorithm. Methods for the validation of satellite data using ground-based observations of aerosol properties are also discussed. We assume that designing, building, and launching into orbit a multi

  10. Aerosol measurements and nuclear accidents: a reconsideration

    International Nuclear Information System (INIS)

    Within its radioactivity environmental monitoring programme, the Commission of the European Communities and in particular its Joint Research Centre wants to encourage the qualitative improvement of radioactivity monitoring. On 3 and 4 December 1987 an experts' meeting has been organized by the Ispra Joint Research Centre in collaboration with the Gesellschaft fuer Aerosolforschung, in order to discuss measuring techniques for radioactive aerosols in the environment in case of a nuclear accident. During the workshop, current practices in routine monitoring programmes in the near and far field of nuclear power plants were confronted with the latest developments in the metrology of aerosols and radioactivity. The need and feasibility of implementing advanced aerosol and radioactivity techniques in routine monitoring networks have been discussed. This publication gives the full text of 12 presentations and a report of the roundtable discussion being held afterwards. It does not intend to give a complete picture of all activities going on in the field of radioactive aerosol metrology; it rather collects a number of common statements of people who approach the problem from quite different directions

  11. Personal exposures to acidic aerosols and ammonia

    International Nuclear Information System (INIS)

    Indoor, outdoor, and personal exposures to acidic aerosols, sulfates, and ammonia were monitored for twenty-four children living in Uniontown, Pennsylvania. Adolescent children, age 11, participated in an investigation of air pollution (PM10, sulfates, acid aerosols, ozone) and pulmonary performance during the Summer of 1990. 92% of the participants (all from non-smoking homes) volunteered to wear personal monitors and record daily activities over two twelve-hour daytime periods. Similar air pollution measurements were made inside and immediately outside their homes. Indoor and outdoor concentrations were measured using the Harvard-EPA annular denuder system (HEADS), while personal exposures were measured using the Personal Annular Denuder system (PADS). All exposure measurements were compared to measurements collected at a centrally located ambient monitoring site. The paper reports the relationships among personal, indoor home, outdoor home, and central site measurements of acidic aerosols, sulfate particles, and ammonia. During days where personal monitoring occurred, hydrogen ion concentrations range from 0 to 520 nmoles/m3 at the central site. There was not substantial spatial variation in ambient acidity over this Western Pennsylvania community. Indoor concentrations were substantially lower than outdoors, with a mean ratio of 0.14. Personal exposures were typically greater than indoor exposures, but averaged only 29% of the outdoor concentrations. Time activity, housing factors, sulfate particles, and ammonia concentrations are analyzed. The impact of this study on the characterization of population exposures to acidic aerosols in epidemiologic studies and modeling also are discussed

  12. KTA 1503.3: Measuring and monitoring of gaseous releases and aerosol-borne radioactive material. Pt. 3. Measuring and monitoring of radioactive material released other than through the vent stack

    International Nuclear Information System (INIS)

    The KTA safety guide explains in detail the requirements for technical equipment and measuring methods, to be applied for continuous radiation monitoring of light-water type nuclear power plants during normal operation and in the event of accidents, as well as the data acquisition and documentation requirements. (orig./CB)

  13. Long term aerosol and trace gas measurements in Central Amazonia

    Science.gov (United States)

    Artaxo, Paulo; Barbosa, Henrique M. J.; Ferreira de Brito, Joel; Carbone, Samara; Rizzo, Luciana V.; Andreae, Meinrat O.; Martin, Scot T.

    2016-04-01

    The central region of the Amazonian forest is a pristine region in terms of aerosol and trace gases concentrations. In the wet season, Amazonia is actually one of the cleanest continental region we can observe on Earth. A long term observational program started 20 years ago, and show important features of this pristine region. Several sites were used, between then ATTO (Amazon Tall Tower Observatory) and ZF2 ecological research site, both 70-150 Km North of Manaus, receiving air masses that traveled over 1500 km of pristine tropical forests. The sites are GAW regional monitoring stations. Aerosol chemical composition (OC/EC and trace elements) is being analysed using filters for fine (PM2.5) and coarse mode aerosol as well as Aerodyne ACSM (Aerosol Chemical Speciation Monitors). VOCs are measured using PTR-MS, while CO, O3 and CO2 are routinely measured. Aerosol absorption is being studied with AE33 aethalometers and MAAP (Multi Angle Absorption Photometers). Aerosol light scattering are being measured at several wavelengths using TSI and Ecotech nephelometers. Aerosol size distribution is determined using scanning mobility particle sizer at each site. Lidars measure the aerosol column up to 12 Km providing the vertical profile of aerosol extinction. The aerosol column is measures using AERONET sun photometers. In the wet season, organic aerosol comprises 75-85% of fine aerosol, and sulfate and nitrate concentrations are very low (1-3 percent). Aerosols are dominated by biogenic primary particles as well as SOA from biogenic precursors. Black carbon in the wet season accounts for 5-9% of fine mode aerosol. Ozone in the wet season peaks at 10-12 ppb at the middle of the day, while carbon monoxide averages at 50-80 ppb. Aerosol optical thickness (AOT) is a low 0.05 to 0.1 at 550 nm in the wet season. Sahara dust transport events sporadically enhance the concentration of soil dust aerosols and black carbon. In the dry season (August-December), long range transported

  14. Influence of crustal dust and sea spray supermicron particle concentrations and acidity on inorganic NO3- aerosol during the 2013 Southern Oxidant and Aerosol Study

    Energy Technology Data Exchange (ETDEWEB)

    Allen, Hannah M.; Draper, Danielle C.; Ayres, Benjamin R.; Ault, Andrew P.; Bondy, Amy L.; Takahama, S.; Modini, Robert; Baumann, K.; Edgerton, Eric S.; Knote, Christoph; Laskin, Alexander; Wang, Bingbing; Fry, Juliane L.

    2015-09-25

    The inorganic aerosol composition was measured in the southeastern United States, a region that exhibits high aerosol mass loading during the summer, as part of the 1 June to 15 July 2013 Southern Oxidant and Aerosol Study (SOAS) campaign. Measurements using a Monitor for AeRosols and GAses (MARGA), an ion chromatograph coupled with a wet rotating denuder and a steam-jet aerosol collector for monitoring of ambient inorganic gas and aerosol species, revealed two periods of high aerosol nitrate (NO3 ) concentrations during the campaign. These periods of high nitrate were correlated with increased concentrations of coarse mode mineral or sea spray aerosol species, particularly Na+ and Ca2+, and with a shift towards aerosol with larger (1 to 2.5 um) diameters. We suggest this nitrate aerosol forms by multiphase reactions of HNO3 and particles, reactions that are facilitated by transport of mineral dust and sea spray aerosol from a source within the United States. The observed high aerosol acidity prevents the formation of NH4NO3, the inorganic nitrogen species often dominant in fine-mode aerosol at higher pH. Calculation of the rate of the heterogeneous uptake of HNO3 on mineral aerosol supports the conclusion that aerosol NO3 is produced primarily by this process, and is likely limited by the availability of mineral dust surface area. Modeling of NO3 and HNO3 by thermodynamic equilibrium models (ISORROPIA II and E-AIM) reveals the importance of including mineral cations in the southeastern United States to accurately balance ion species and predict gas/aerosol phase partitioning.

  15. Papers of the 15. french congress on the aerosols CFA 99; Actes du 15. congres francais sur les aerosols CFA 99

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-07-01

    This french congress on the aerosols took place in Paris the 8 and 9 december 1999. It was presented in four main themes: bio-aerosols and filtering; the aerosols metrology; the aerosols in the environment; aerosols physic and applications. Seven papers have been analyzed in INIS data base for their specific interest in nuclear industry. The four papers selected for ETDE cover a larger domain: annular slot samplers in turbulent flow, the air quality monitoring in France, suspension particles characterization in an urban area, application of the remote sensing to the atmospheric pollution. (A.L.B.)

  16. Studies on aerosol properties during ICARB–2006 campaign period at Hyderabad, India using ground-based measurements and satellite data

    Indian Academy of Sciences (India)

    K V S Badarinath; Shailesh Kumar Kharol

    2008-07-01

    Continuous and campaign-based aerosol field measurements are essential in understanding fundamental atmospheric aerosol processes and for evaluating their effect on global climate, environment and human life. Synchronous measurements of Aerosol Optical Depth (AOD), Black Carbon (BC) aerosol mass concentration and aerosol particle size distribution were carried out during the campaign period at tropical urban regions of Hyderabad, India. Daily satellite datasets of DMSP-OLS were processed for night-time forest fires over the Indian region in order to understand the additional sources (forest fires) of aerosol. The higher values in black carbon aerosol mass concentration and aerosol optical depth correlated well with forest fires occurring over the region. Ozone Monitoring Instrument (OMI) aerosol index (AI) variations showed absorbing aerosols over the region and correlated with ground measurements.

  17. Aerosol Chemistry Between Two Oceans: Auckland’s Urban Aerosol

    Czech Academy of Sciences Publication Activity Database

    Coulson, G.; Olivares, G.; Salmond, J.; Talbot, Nicholas

    -: Italian Aerosol Society, 2015. ISBN N. [European Aerosol Conference EAC 2015. Milano (IT), 06.09.2015-11.09.2015] Institutional support: RVO:67985858 Keywords : urban pollution * aerosol processing * New Zealand Subject RIV: CF - Physical ; Theoretical Chemistry

  18. Organization of radiological monitoring

    International Nuclear Information System (INIS)

    Monitoring of environment in Lithuania is regulated by Law on Environment Monitoring adopted in 1997. Permanent gamma monitoring is the milestone in the system for pre-warning of a radiation incident. There are several organizations in Lithuania implementing gamma monitoring. A network of automated gamma monitoring stations is maintained by United Centre of Research of the Ministry of Environment. In cooperation with Denmark and Sweden there was implemented 12 fully automated monitoring stations, four of them are located around Ignalina NPP. Monitoring of radioactivity in precipitation is carried out in five meteorological stations, aerosols monitoring is performed at two stations. There are four monitoring places in the Baltic Sea. Analysis of the water, deposits on the bottom, aquatic plants and fish is in progress there. As regards rivers and lakes monitoring of four lakes is in progress and monitoring of rivers waters is carried out in the rivers crossing boards of Lithuania

  19. Sensitivity of aerosol direct radiative forcing to aerosol vertical profile

    OpenAIRE

    Chung, Chul E.; Choi, Jung-Ok

    2014-01-01

    Aerosol vertical profile significantly affects the aerosol direct radiative forcing at the TOA level. The degree to which the aerosol profile impacts the aerosol forcing depends on many factors such as presence of cloud, surface albedo and aerosol single scattering albedo (SSA). Using a radiation model, we show that for absorbing aerosols (with an SSA of 0.7–0.8) whether aerosols are located above cloud or below induces at least one order of magnitude larger changes of the aerosol forcing tha...

  20. Aerosols Science and Technology

    CERN Document Server

    Agranovski, Igor

    2011-01-01

    This self-contained handbook and ready reference examines aerosol science and technology in depth, providing a detailed insight into this progressive field. As such, it covers fundamental concepts, experimental methods, and a wide variety of applications, ranging from aerosol filtration to biological aerosols, and from the synthesis of carbon nanotubes to aerosol reactors.Written by a host of internationally renowned experts in the field, this is an essential resource for chemists and engineers in the chemical and materials disciplines across multiple industries, as well as ideal supplementary

  1. Accelerator based techniques for aerosol analysis

    International Nuclear Information System (INIS)

    At the 3 MV Tandetron accelerator of the LABEC laboratory of INFN (Florence, Italy) an external beam facility is fully dedicated to PIXE-PIGE measurements of elemental composition of atmospheric aerosols. Examples regarding recent monitoring campaigns, performed in urban and remote areas, both on a daily basis and with high time resolution, as well as with size selection, will be presented. It will be evidenced how PIXE can provide unique information in aerosol studies or can play a complementary role to traditional chemical analysis. Finally a short presentation of 14C analysis of the atmospheric aerosol by Accelerator Mass Spectrometry (AMS) for the evaluation of the contributions from either fossil fuel combustion or modern sources (wood burning, biogenic activity) will be given. (author)

  2. Microbiological aerosols from the application of liquid sludge to land

    Energy Technology Data Exchange (ETDEWEB)

    Sorber, C.A.; Moore, B.E.; Johnson, D.E.; Harding, H.J.; Thomas, R.E.

    1984-07-01

    A detailed aerosol study was conducted at four locations: two sites with tank truck application, and two sites with spray application. From five to eight aerosol monitoring runs were made at each of the four sites, and a special enterovirus aerosol run was conducted at one of the spray sites. There was some evidence of aerosolization at the tank truck sites and strong evidence at the spray sites, particularly of fecal coliform and fecal streptococci. Modeling of the results proved difficult and there is considerable statistical uncertainty in the data presented. No human enteric viruses were detected (less than 0.0016 pfu/cubic m) at a distance of 40 m downwind from the spray gun. The inability to detect enteric viruses in the air was most likely the result of low concentration in the sludge and adsorption into the solid matter in the sludge which is not readily aerosolized. 10 references.

  3. Design of a portable aerosol deposition coupon for the Nuclear Aerosol Test Facility (NATF)

    International Nuclear Information System (INIS)

    Nuclear Aerosol Test Facility (NATF) is being set up near Hall-5, BARC to study aerosol transport behavior and its removal (natural as well as engineered) in simulated containment atmospheric conditions. Besides conventional instrumentation consisting of about 50 temperature measurements, 2 pressure and humidity measurements, the facility will also have systems to monitor air-borne and surface deposited aerosol concentrations at various locations in the test vessel. The aerosol deposition coupons are special devices required for measurement of aerosol deposition rates in conjunction with the prevailing thermal- hydraulic conditions viz., gas temperature (within the boundary layer) and coupon wall temperature (both inner and outer) in the vicinity of the coupons. The design of such a coupon must meet several other stringent process requirements. This paper describes the detailed design of a portable aerosol deposition coupon and highlights all the constraints and their solutions. Typical coupon specifications are also included in the paper. Six numbers of such coupons were fabricated and installed at predetermined locations in the experimental vessels. (author)

  4. Aerosol in the containment

    International Nuclear Information System (INIS)

    The US program LACE (LWR Aerosol Containment Experiments), in which Italy participates together with several European countries, Canada and Japan, aims at evaluating by means of a large scale experimental activity at HEDL the retention in the pipings and primary container of the radioactive aerosol released following severe accidents in light water reactors. At the same time these experiences will make available data through which the codes used to analyse the behaviour of the aerosol in the containment and to verify whether by means of the codes of thermohydraulic computation it is possible to evaluate with sufficient accuracy variable influencing the aerosol behaviour, can be validated. This report shows and compares the results obtained by the participants in the LACE program with the aerosol containment codes NAVA 5 and CONTAIN for the pre-test computations of the test LA 1, in which an accident called containment by pass is simulated

  5. Sea Spray Aerosols

    DEFF Research Database (Denmark)

    Butcher, Andrew Charles

    Aerosols are important climactically. Their specific emissions are key to reducing the uncertainty in global climate models. Marine aerosols make up the largest source of primary aerosols to the Earth's atmosphere. Uncertainty in marine aerosol mass and number flux lies in separating primary...... emissions produced directly from bubble bursting as the result of air entrainment from breaking waves and particles generated from secondary emissions of volatile organic compounds. In the first paper, we study the chemical properties of particles produced from several sea water proxies with the use of a...... cloud condensation nuclei ounter. Proxy solutions with high inorganic salt concentrations and some organics produce sea spray aerosol particles with little change in cloud condensation activity relative to pure salts. Comparison is made between a frit based method for bubble production and a plunging...

  6. Preliminary results of the aerosol optical depth retrieval in Johor, Malaysia

    International Nuclear Information System (INIS)

    Monitoring of atmospheric aerosols over the urban area is important as tremendous amounts of pollutants are released by industrial activities and heavy traffic flow. Air quality monitoring by satellite observation provides better spatial coverage, however, detailed aerosol properties retrieval remains a challenge. This is due to the limitation of aerosol retrieval algorithm on high reflectance (bright surface) areas. The aim of this study is to retrieve aerosol optical depth over urban areas of Iskandar Malaysia; the main southern development zone in Johor state, using Moderate Resolution Imaging Spectroradiometer (MODIS) 500 m resolution data. One of the important steps is the aerosol optical depth retrieval is to characterise different types of aerosols in the study area. This information will be used to construct a Look Up Table containing the simulated aerosol reflectance and corresponding aerosol optical depth. Thus, in this study we have characterised different aerosol types in the study area using Aerosol Robotic Network (AERONET) data. These data were processed using cluster analysis and the preliminary results show that the area is consisting of coastal urban (65%), polluted urban (27.5%), dust particles (6%) and heavy pollution (1.5%) aerosols

  7. Aerosol sensing technologies in the mining industry

    Science.gov (United States)

    Janisko, Samuel J.; Noll, James D.; Cauda, Emanuele E.

    2011-06-01

    Recent health, safety and environmental regulations are causing an increased demand for monitoring of aerosols in the mining industry. Of particular concern are airborne concentrations of combustible and toxic rock dusts as well as particulate matter generated from diesel engines in underground mines. In response, the National Institute for Occupational Safety and Health (NIOSH) has been evaluating a number of real time sensing technologies for potential use in underground mines. In particular, extensive evaluation has been done on filter-based light extinction using elemental carbon (EC) as a surrogate measurement of total diesel particulate matter (DPM) mass concentration as well as mechanical tapered element oscillating microbalance (TEOM) technology for measurement of both DPM and rock dust mass concentrations. Although these technologies are promising in their ability to accurately measure mine aerosols for their respective applications, there are opportunities for design improvements or alternative technologies that may significantly enhance the monitoring of mine aerosols. Such alterations can lead to increases in sensitivity or a reduction in the size and cost of these devices. This paper provides a brief overview of current practices and presents results of NIOSH research in this area. It concludes with a short discussion of future directions in mine aerosol sensing research.

  8. 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.

  9. Weekly patterns of aerosol in the United States

    Directory of Open Access Journals (Sweden)

    D. M. Murphy

    2008-05-01

    Full Text Available Data from the Interagency Monitoring of Protected Visual Environments (IMPROVE network of aerosol samplers and NOAA monitoring sites are examined for weekly cycles. At remote and rural sites, fine particle elemental carbon, crustal elements, and coarse particle mass had pronounced (up to 20% weekly cycles with minima on Sunday or Monday. Fine particle organic carbon and mass had smaller amplitude cycles, also with Sunday or Monday minima. There was no statistically significant weekly cycle in fine particle sulfate despite a 5 to 15% weekly cycle in power plant SO2 emissions. Although results for nitrate may be more susceptible to sampling artifacts, nitrate also showed a pronounced weekly cycle with an amplitude similar to elemental carbon. The only species found with a weekend maximum was Pb, probably from general aviation on weekends. Aerosol optical properties at NOAA monitoring sites were consistent with the IMPROVE chemical data, with significant weekly cycles in aerosol light absorption but not light scattering. These results support a large role of diesel emissions in elemental carbon aerosol over the entire United States and suggest that a large fraction of the airborne soil dust is anthropogenic. They also suggest that studies of weekly cycles in temperature, cloudiness, precipitation, or other meteorological variables should look for causes more in light-absorbing particles and possible ice nucleation by dust rather than sulfate or total aerosol. There are also implications for personal exposure and epidemiological studies of aerosol health effects.

  10. Weekly patterns of aerosol in the United States

    Directory of Open Access Journals (Sweden)

    D. M. Murphy

    2008-01-01

    Full Text Available Data from the Interagency Monitoring of Protected Visual Environments (IMPROVE network of aerosol samplers and NOAA monitoring sites are examined for weekly cycles. Fine particle elemental carbon, crustal elements, and coarse particle mass had pronounced (up to 20% weekly cycles with minima on Sunday or Monday. Fine particle organic carbon and mass had smaller amplitude cycles, also with Sunday or Monday minima. There was no statistically significant weekly cycle in fine particle sulfate despite a 10 to 15% weekly cycle in power plant SO2 emissions. Although results for nitrate must be treated with caution, it showed a pronounced weekly cycle with an amplitude similar to elemental carbon. The only species found with a weekend maximum was Pb, probably from general aviation on weekends. Aerosol optical properties at NOAA monitoring sites were consistent with the IMPROVE chemical data, with significant weekly cycles in aerosol light absorption but not light scattering. These results support a large role of diesel emissions in elemental carbon aerosol over the entire United States and suggest that a large fraction of the airborne soil dust is anthropogenic. They also suggest that studies of weekly cycles in temperature, cloudiness, or precipitation should look for causes more in light-absorbing particles and dust rather than sulfate or total aerosol. There are also implications for personal exposure and epidemiological studies of aerosol health effects.

  11. Sugars in Antarctic aerosol

    Science.gov (United States)

    Barbaro, Elena; Kirchgeorg, Torben; Zangrando, Roberta; Vecchiato, Marco; Piazza, Rossano; Barbante, Carlo; Gambaro, Andrea

    2015-10-01

    The processes and transformations occurring in the Antarctic aerosol during atmospheric transport were described using selected sugars as source tracers. Monosaccharides (arabinose, fructose, galactose, glucose, mannose, ribose, xylose), disaccharides (sucrose, lactose, maltose, lactulose), alcohol-sugars (erythritol, mannitol, ribitol, sorbitol, xylitol, maltitol, galactitol) and anhydrosugars (levoglucosan, mannosan and galactosan) were measured in the Antarctic aerosol collected during four different sampling campaigns. For quantification, a sensitive high-pressure anion exchange chromatography was coupled with a single quadrupole mass spectrometer. The method was validated, showing good accuracy and low method quantification limits. This study describes the first determination of sugars in the Antarctic aerosol. The total mean concentration of sugars in the aerosol collected at the "Mario Zucchelli" coastal station was 140 pg m-3; as for the aerosol collected over the Antarctic plateau during two consecutive sampling campaigns, the concentration amounted to 440 and 438 pg m-3. The study of particle-size distribution allowed us to identify the natural emission from spores or from sea-spray as the main sources of sugars in the coastal area. The enrichment of sugars in the fine fraction of the aerosol collected on the Antarctic plateau is due to the degradation of particles during long-range atmospheric transport. The composition of sugars in the coarse fraction was also investigated in the aerosol collected during the oceanographic cruise.

  12. Aerosol physical and optical properties in the Eastern Mediterranean Basin, Crete, from Aerosol Robotic Network data

    Directory of Open Access Journals (Sweden)

    A. Fotiadi

    2006-01-01

    Full Text Available In this study, we investigate the aerosol optical properties, namely aerosol extinction optical thickness (AOT, Angström parameter and size distribution over the Eastern Mediterranean Basin, using spectral measurements from the recently established FORTH (Foundation for Research and Technology-Hellas AERONET station in Crete, for the two-year period 2003–2004. The location of the FORTH-AERONET station offers a unique opportunity to monitor aerosols from different sources. Maximum values of AOT are found primarily in spring, which together with small values of the Angström parameter indicate dust transported from African deserts, whereas the minimum values of AOT occur in winter. In autumn, large AOT values observed at near-infrared wavelengths arise also from dust transport. In summer, large AOT values at ultraviolet (340 nm and visible wavelengths (500 nm, together with large values of the Angström parameter, are associated with transport of fine aerosols of urban/industrial and biomass burning origin. The Angström parameter values vary on a daily basis within the range 0.05–2.20, and on a monthly basis within the range 0.68–1.9. This behaviour, together with broad frequency distributions and back-trajectory analyses, indicates a great variety of aerosol types over the study region including dust, urban-industrial and biomass-burning pollution, and maritime, as well as mixed aerosol types. Large temporal variability is observed in AOT, Angström parameter, aerosol content and size. The fine and coarse aerosol modes persist throughout the year, with the coarse mode dominant except in summer. The highest values of AOT are related primarily to southeasterly winds, associated with coarse aerosols, and to a less extent to northwesterly winds associated with fine aerosols. The results of this study show that the FORTH AERONET station in Crete is well suited for studying the transport and mixing of different types of aerosols from a variety

  13. Submicron aerosols: a review

    International Nuclear Information System (INIS)

    Submicron aerosols, ranging in particle diameter from 0.1 μm to 0.001 μm, and in number concentration from 10,000 to 100,000 per cm3, are more or less continuously suspended in the atmosphere we breathe. They usually require in situ measurement of concentration and size distribution with instruments such as diffusion batteries and condensation nucleus counters. Laboratory measurements require the development of submicron aerosol generators. The development of several of these devices and their use in the laboratory and field to measure radioactive as well as inactive aerosols is described

  14. Atmospheric aerosol source identification and estimates of source contributions to air pollution in Dundee, UK

    Science.gov (United States)

    Qin, Y.; Oduyemi, K.

    Anthropogenic aerosol (PM 10) emission sources sampled at an air quality monitoring station in Dundee have been analysed. However, the information on local natural aerosol emission sources was unavailable. A method that combines receptor model and atmospheric dispersion model was used to identify aerosol sources and estimate source contributions to air pollution. The receptor model identified five sources. These are aged marine aerosol source with some chlorine replaced by sulphate, secondary aerosol source of ammonium sulphate, secondary aerosol source of ammonium nitrate, soil and construction dust source, and incinerator and fuel oil burning emission source. For the vehicle emission source, which has been comprehensively described in the atmospheric emission inventory but cannot be identified by the receptor model, an atmospheric dispersion model was used to estimate its contributions. In Dundee, a significant percentage, 67.5%, of the aerosol mass sampled at the study station could be attributed to the six sources named above.

  15. Real-time observation of secondary aerosol formation during a fog event in London

    Directory of Open Access Journals (Sweden)

    M. Dall'Osto

    2008-11-01

    Full Text Available A fog event was monitored with state-of-the art real-time aerosol mass spectrometers in an urban background location in London (England during the REPARTEE-I experiment. Specific particle types rich in hydroxymethanesulphonate (HMS were found only during the fog event. Formation of inorganic and organic secondary aerosol was observed as soon as fog was detected and two different mechanisms are suggested to be responsible for the production of two different types of aerosol. Humic-like substances (HULIS appear to be produced in the gas phase and condense into the interstitial aerosol, while nitrate aerosol is produced in the liquid phase within the droplet. Not only are secondary aerosol constituents produced during the fog event, but the primary aerosol is observed to be processed by the fog event, dramatically changing its chemical properties.

  16. The Global Ozone and Aerosol Profiles and Aerosol Hygroscopic Effect and Absorption Optical Depth (GOA2HEAD) Network Initiative

    Science.gov (United States)

    Gao, R. S.; Elkins, J. W.; Frost, G. J.; McComiskey, A. C.; Murphy, D. M.; Ogren, J. A.; Petropavlovskikh, I. V.; Rosenlof, K. H.

    2014-12-01

    Inverse modeling using measurements of ozone (O3) and aerosol is a powerful tool for deriving pollutant emissions. Because they have relatively long lifetimes, O3 and aerosol are transported over large distances. Frequent and globally spaced vertical profiles rather than ground-based measurements alone are therefore highly desired. Three requirements necessary for a successful global monitoring program are: Low equipment cost, low operation cost, and reliable measurements of known uncertainty. Conventional profiling using aircraft provides excellent data, but is cost prohibitive on a large scale. Here we describe a new platform and instruments meeting all three global monitoring requirements. The platform consists of a small balloon and an auto-homing glider. The glider is released from the balloon at about 5 km altitude, returning the light instrument package to the launch location, and allowing for consistent recovery of the payload. Atmospheric profiling can be performed either during ascent or descent (or both) depending on measurement requirements. We will present the specifications for two instrument packages currently under development. The first measures O3, RH, p, T, dry aerosol particle number and size distribution, and aerosol optical depth. The second measures dry aerosol particle number and size distribution, and aerosol absorption coefficient. Other potential instrument packages and the desired spatial/temporal resolution for the GOA2HEAD monitoring initiative will also be discussed.

  17. Whole-Body Nanoparticle Aerosol Inhalation Exposures

    Science.gov (United States)

    Yi, Jinghai; Chen, Bean T.; Schwegler-Berry, Diane; Frazer, Dave; Castranova, Vince; McBride, Carroll; Knuckles, Travis L.; Stapleton, Phoebe A.; Minarchick, Valerie C.; Nurkiewicz, Timothy R.

    2013-01-01

    Inhalation is the most likely exposure route for individuals working with aerosolizable engineered nano-materials (ENM). To properly perform nanoparticle inhalation toxicology studies, the aerosols in a chamber housing the experimental animals must have: 1) a steady concentration maintained at a desired level for the entire exposure period; 2) a homogenous composition free of contaminants; and 3) a stable size distribution with a geometric mean diameter < 200 nm and a geometric standard deviation σg < 2.5 5. The generation of aerosols containing nanoparticles is quite challenging because nanoparticles easily agglomerate. This is largely due to very strong inter-particle forces and the formation of large fractal structures in tens or hundreds of microns in size 6, which are difficult to be broken up. Several common aerosol generators, including nebulizers, fluidized beds, Venturi aspirators and the Wright dust feed, were tested; however, none were able to produce nanoparticle aerosols which satisfy all criteria 5. A whole-body nanoparticle aerosol inhalation exposure system was fabricated, validated and utilized for nano-TiO2 inhalation toxicology studies. Critical components: 1) novel nano-TiO2 aerosol generator; 2) 0.5 m3 whole-body inhalation exposure chamber; and 3) monitor and control system. Nano-TiO2 aerosols generated from bulk dry nano-TiO2 powders (primary diameter of 21 nm, bulk density of 3.8 g/cm3) were delivered into the exposure chamber at a flow rate of 90 LPM (10.8 air changes/hr). Particle size distribution and mass concentration profiles were measured continuously with a scanning mobility particle sizer (SMPS), and an electric low pressure impactor (ELPI). The aerosol mass concentration (C) was verified gravimetrically (mg/m3). The mass (M) of the collected particles was determined as M = (Mpost-Mpre), where Mpreand Mpost are masses of the filter before and after sampling (mg). The mass concentration was calculated as C = M/(Q*t), where Q is

  18. Dark Targets, Aerosols, Clouds and Toys

    Science.gov (United States)

    Remer, L. A.

    2015-12-01

    Today if you use the Thomson-Reuters Science Citations Index to search for "aerosol*", across all scientific disciplines and years, with no constraints, and you sort by number of citations, you will find a 2005 paper published in the Journal of the Atmospheric Sciences in the top 20. This is the "The MODIS Aerosol Algorithm, Products and Validation". Although I am the first author, there are in total 12 co-authors who each made a significant intellectual contribution to the paper or to the algorithm, products and validation described. This paper, that algorithm, those people lie at the heart of a lineage of scientists whose collaborations and linked individual pursuits have made a significant contribution to our understanding of radiative transfer and climate, of aerosol properties and the global aerosol system, of cloud physics and aerosol-cloud interaction, and how to measure these parameters and maximize the science that can be obtained from those measurements. The 'lineage' had its origins across the globe, from Soviet Russia to France, from the U.S. to Israel, from the Himalayas, the Sahel, the metropolises of Sao Paulo, Taipei, and the cities of east and south Asia. It came together in the 1990s and 2000s at the NASA Goddard Space Flight Center, using cultural diversity as a strength to form a common culture of scientific creativity that continues to this day. The original algorithm has spawned daughter algorithms that are being applied to new satellite and airborne sensors. The original MODIS products have been fundamental to analyses as diverse as air quality monitoring and aerosol-cloud forcing. AERONET, designed originally for the need of validation, is now its own thriving institution, and the lineage continues to push forward to provide new technology for the coming generations.

  19. Aerosols from biomass combustion

    Energy Technology Data Exchange (ETDEWEB)

    Nussbaumer, T.

    2001-07-01

    This report is the proceedings of a seminar on biomass combustion and aerosol production organised jointly by the International Energy Agency's (IEA) Task 32 on bio energy and the Swiss Federal Office of Energy (SFOE). This collection of 16 papers discusses the production of aerosols and fine particles by the burning of biomass and their effects. Expert knowledge on the environmental impact of aerosols, formation mechanisms, measurement technologies, methods of analysis and measures to be taken to reduce such emissions is presented. The seminar, visited by 50 participants from 11 countries, shows, according to the authors, that the reduction of aerosol emissions resulting from biomass combustion will remain a challenge for the future.

  20. Sodium oxide aerosol filtration

    International Nuclear Information System (INIS)

    In the scope of the sodium aerosol trapping research effort by the CEA/DSN, the retention capacity and yield were measured for very high efficiency fiberglass filters and several types of prefilters (cyclone agglomerator, fabric prefilters, water scrubbers). (author)

  1. Emergency protection from aerosols

    International Nuclear Information System (INIS)

    Expedient methods were developed that could be used by an average person, using only materials readily available, to protect himself and his family from injury by toxic (e.g., radioactive) aerosols. The most effective means of protection was the use of a household vacuum cleaner to maintain a small positive pressure on a closed house during passage of the aerosol cloud. Protection factors of 800 and above were achieved

  2. Emergency Protection from Aerosols

    Energy Technology Data Exchange (ETDEWEB)

    Cristy, G.A.

    2001-11-13

    Expedient methods were developed that could be used by an average person, using only materials readily available, to protect himself and his family from injury by toxic (e.g., radioactive) aerosols. The most effective means of protection was the use of a household vacuum cleaner to maintain a small positive pressure on a closed house during passage of the aerosol cloud. Protection factors of 800 and above were achieved.

  3. MISR Aerosol Typing

    Science.gov (United States)

    Kahn, Ralph A.

    2014-01-01

    AeroCom is an open international initiative of scientists interested in the advancement of the understanding of global aerosol properties and aerosol impacts on climate. A central goal is to more strongly tie and constrain modeling efforts to observational data. A major element for exchanges between data and modeling groups are annual meetings. The meeting was held September 20 through October 2, 1014 and the organizers would like to post the presentations.

  4. Aerosol classification using EARLINET measurements for an intensive observational period

    Science.gov (United States)

    Papagiannopoulos, Nikolaos; Mona, Lucia; Pappalardo, Gelsomina

    2016-04-01

    ACTRIS (Aerosols, Clouds and Trace gases Research Infrastructure Network) organized an intensive observation period during summer 2012. This campaign aimed at the provision of advanced observations of physical and chemical aerosol properties, at the delivery of information about the 3D distribution of European atmospheric aerosols, and at the monitoring of Saharan dust intrusions events. EARLINET (European Aerosol Research Lidar Network) participated in the ACTRIS campaign through the addition of measurements according to the EARLINET schedule as well as daily lidar-profiling measurements around sunset by 11 selected lidar stations for the period from 8 June - 17 July. EARLINET observations during this almost two-month period are used to characterize the optical properties and vertical distribution of long-range transported aerosol over the broader area of Mediterranean basin. The lidar measurements of aerosol intensive parameters (lidar ratio, depolarization, Angstrom exponents) are shown to vary with location and aerosol type. A methodology based on EARLINET observations of frequently observed aerosol types is used to classify aerosols into seven separate types. The summertime Mediterranean basin is prone to African dust aerosols. Two major dust events were studied. The first episode occurred from the 18 to 21 of the June and the second one lasted from 28 June to 6 July. The lidar ratio within the dust layer was found to be wavelength independent with mean values of 58±14 sr at 355 nm and 57±11 sr at 532 nm. For the particle linear depolarization ratio, mean values of 0.27±0.04 at 532 nm have been found. Acknowledgements. The financial support for EARLINET in the ACTRIS Research Infrastructure Project by the European Union's Horizon 2020 research and innovation programme under grant agreement no. 654169 and previously under grant agreement no. 262254 in the Seventh Framework Programme (FP7/2007-2013) is gratefully acknowledged.

  5. Interpretation of FRESCO cloud retrievals in case of absorbing aerosol events

    Directory of Open Access Journals (Sweden)

    P. Wang

    2012-10-01

    Full Text Available Cloud and aerosol information is needed in trace gas retrievals from satellite measurements. The Fast REtrieval Scheme for Clouds from the Oxygen A band (FRESCO cloud algorithm employs reflectance spectra of the O2 A band around 760 nm to derive cloud pressure and effective cloud fraction. In general, clouds contribute more to the O2 A band reflectance than aerosols. Therefore, the FRESCO algorithm does not correct for aerosol effects in the retrievals and attributes the retrieved cloud information entirely to the presence of clouds, and not to aerosols. For events with high aerosol loading, aerosols may have a dominant effect, especially for almost cloud free scenes. We have analysed FRESCO cloud data and Absorbing Aerosol Index (AAI data from the Global Ozone Monitoring Experiment (GOME-2 instrument on the Metop-A satellite for events with typical absorbing aerosol types, such as volcanic ash, desert dust and smoke. We find that the FRESCO effective cloud fractions are correlated with the AAI data for these absorbing aerosol events and that the FRESCO cloud pressure contains information on aerosol layer pressure. For cloud free scenes, the derived FRESCO cloud pressure is close to the aerosol layer pressure, especially for optically thick aerosol layers. For cloudy scenes, if the strongly absorbing aerosols are located above the clouds, then the retrieved FRESCO cloud pressure may represent the height of the aerosol layer rather than the height of the clouds. Combining FRESCO and AAI data, an estimate for the aerosol layer pressure can be given.

  6. Interpretation of FRESCO cloud retrievals in case of absorbing aerosol events

    Directory of Open Access Journals (Sweden)

    P. Wang

    2011-12-01

    Full Text Available Cloud and aerosol information is needed in trace gas retrievals from satellite measurements. The Fast REtrieval Scheme for Clouds from the Oxygen A band (FRESCO cloud algorithm employs reflectance spectra of the O2 A band around 760 nm to derive cloud pressure and effective cloud fraction. In general, clouds contribute more to the O2 A band reflectance than aerosols. Therefore, the FRESCO algorithm does not correct for aerosol effects in the retrievals and attributes the retrieved cloud information entirely to the presence of clouds, and not to aerosols. For events with high aerosol loading, aerosols may have a dominant effect, especially for almost cloud-free scenes. We have analysed FRESCO cloud data and Absorbing Aerosol Index (AAI data from the Global Ozone Monitoring Experiment (GOME-2 instrument on the Metop-A satellite for events with typical absorbing aerosol types, such as volcanic ash, desert dust and smoke. We find that the FRESCO effective cloud fractions are correlated with the AAI data for these absorbing aerosol events and that the FRESCO cloud pressures contain information on aerosol layer pressure. For cloud-free scenes, the derived FRESCO cloud pressures are close to those of the aerosol layer for optically thick aerosols. For cloudy scenes, if the strongly absorbing aerosols are located above the clouds, then the retrieved FRESCO cloud pressures may represent the height of the aerosol layer rather than the height of the clouds. Combining FRESCO cloud data and AAI, an estimate for the aerosol layer pressure can be given, which can be beneficial for aviation safety and operations in case of e.g. volcanic ash plumes.

  7. Comparative Study of Aerosol and Cloud Detected by CALIPSO and OMI

    Science.gov (United States)

    Chen, Zhong; Torres, Omar; McCormick, M. Patrick; Smith, William; Ahn, Changwoo

    2012-01-01

    The Ozone Monitoring Instrument (OMI) on the Aura Satellite detects the presence of desert dust and smoke particles (also known as aerosols) in terms of a parameter known as the UV Aerosol Index (UV AI). The Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) mission measures the vertical distribution of aerosols and clouds. Aerosols and clouds play important roles in the atmosphere and climate system. Accurately detecting their presence, altitude, and properties using satellite radiance measurements is a very important task. This paper presents a comparative analysis of the CALIPSO Version 2 Vertical Feature Mask (VFM) product with the (OMI) UV Aerosol Index (UV AI) and reflectivity datasets for a full year of 2007. The comparison is done at regional and global scales. Based on CALIPSO arid OMI observations, the vertical and horizontal extent of clouds and aerosols are determined and the effects of aerosol type selection, load, cloud fraction on aerosol identification are discussed. It was found that the spatial-temporal correlation found between CALIPSO and OMI observations, is strongly dependent on aerosol types and cloud contamination. CALIPSO is more sensitivity to cloud and often misidentifies desert dust aerosols as cloud, while some small scale aerosol layers as well as some pollution aerosols are unidentified by OMI UV AI. Large differences in aerosol distribution patterns between CALIPSO and OMI are observed, especially for the smoke and pollution aerosol dominated areas. In addition, the results found a significant correlation between CALIPSO lidar 1064 nm backscatter and the OMI UV AI over the study regions.

  8. A case study on biomass burning aerosols: effects on aerosol optical properties and surface radiation levels

    Directory of Open Access Journals (Sweden)

    A. Arola

    2007-08-01

    Full Text Available In spring 2006, biomass burning aerosols from eastern Europe were transported extensively to Finland, and to other parts of northern Europe. They were observed as far as in the European Arctic. In the first part of this paper, temporal and spatial evolution and transport of these biomass burning aerosols are monitored with MODIS retrieved aerosol optical depth (AOD imagery at visible wavelengths (0.55 μm. Comparison of MODIS and AERONET AOD is conducted at Tõravere, Estonia. Then trajectory analyses, as well as MODIS Fire Mapper products are used to better understand the type and origin of the air masses. During the studied four-week period AOD values ranged from near zero up to 1.2 at 0.55 μm and the linear correlation between MODIS and AERONET was very high (~0.97. Temporal variability observed within this four-week period was also rather well explained by the trajectory analysis in conjunction with the fire detections produced by the MODIS Rapid Response System. In the second part of our study, the surface measurements of global and UV radiation at Jokioinen, Finland are used to study the effect of this haze episode on the levels of surface radiation. We found reductions up to 35% in noon-time surface UV irradiance (at 340 nm as compared to typical aerosol conditions. For global (total solar radiation, the reduction was always smaller, in line with the expected wavelength dependence of the aerosol effect.

  9. Improvements to the OMI near UV aerosol algorithm using A-train CALIOP and AIRS observations

    Directory of Open Access Journals (Sweden)

    O. Torres

    2013-06-01

    Full Text Available The height of desert dust and carbonaceous aerosols layers and, to a lesser extent, the difficulty in determining the predominant size mode of these absorbing aerosol types, are sources of uncertainty in the retrieval of aerosol properties from near UV satellite observations. The availability of independent, near-simultaneous measurements of aerosol layer height, and aerosol-type related parameters derived from observations by other A-train sensors, makes possible the use of this information as input to the OMI (Ozone Monitoring Instrument near UV aerosol retrieval algorithm (OMAERUV. A monthly climatology of aerosol layer height derived from observations by the CALIOP (Cloud–Aerosol Lidar with Orthogonal Polarization sensor, and real-time AIRS (Atmospheric Infrared Sounder CO observations are used in an upgraded version of the OMAERUV algorithm. AIRS CO measurements are used as a reliable tracer of carbonaceous aerosols, which allows the identification of smoke layers in regions and seasons when the dust-smoke differentiation is difficult in the near-UV. The use of CO measurements also enables the identification of elevated levels of boundary layer pollution undetectable by near UV observations alone. In this paper we discuss the combined use of OMI, CALIOP and AIRS observations for the characterization of aerosol properties, and show an improvement in OMI aerosol retrieval capabilities.

  10. Assessment of 10-Year Global Record of Aerosol Products from the OMI Near-UV Algorithm

    Science.gov (United States)

    Ahn, C.; Torres, O.; Jethva, H. T.

    2014-12-01

    Global observations of aerosol properties from space are critical for understanding climate change and air quality applications. The Ozone Monitoring Instrument (OMI) onboard the EOS-Aura satellite provides information on aerosol optical properties by making use of the large sensitivity to aerosol absorption and dark surface albedo in the UV spectral region. These unique features enable us to retrieve both aerosol extinction optical depth (AOD) and single scattering albedo (SSA) successfully from radiance measurements at 354 and 388 nm by the OMI near UV aerosol algorithm (OMAERUV). Recent improvements to algorithms in conjunction with the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) and Atmospheric Infrared Sounder (AIRS) carbon monoxide data also reduce uncertainties due to aerosol layer heights and types significantly in retrieved products. We present validation results of OMI AOD against space and time collocated Aerosol Robotic Network (AERONET) measured AOD values over multiple stations representing major aerosol episodes and regimes. We also compare the OMI SSA against the inversion made by AERONET as well as an independent network of ground-based radiometer called SKYNET in Japan, China, South-East Asia, India, and Europe. The outcome of the evaluation analysis indicates that in spite of the "row anomaly" problem, affecting the sensor since mid-2007, the long-term aerosol record shows remarkable sensor stability. The OMAERUV 10-year global aerosol record is publicly available at the NASA data service center web site (http://disc.sci.gsfc.nasa.gov/Aura/data-holdings/OMI/omaeruv_v003.shtml).

  11. During air cool process aerosol absorption detection with photothermal interferometry

    Science.gov (United States)

    Li, Baosheng; Xu, Limei; Huang, Junling; Ma, Fei; Wang, Yicheng; Li, Zhengqiang

    2014-11-01

    This paper studies the basic principle of laser photothermal interferometry method of aerosol particles absorption coefficient. The photothermal interferometry method with higher accuracy and lower uncertainty can directly measure the absorption coefficient of atmospheric aerosols and not be affected by scattered light. With Jones matrix expression, the math expression of a special polarization interferometer is described. This paper using folded Jamin interferometer, which overcomes the influence of vibration on measuring system. Interference come from light polarization beam with two orthogonal and then combine to one beam, finally aerosol absorption induced refractive index changes can be gotten with four beam of phase orthogonal light. These kinds of styles really improve the stability of system and resolution of the system. Four-channel detections interact with interference fringes, to reduce the light intensity `zero drift' effect on the system. In the laboratory, this device typical aerosol absorption index, it shows that the result completely agrees with actual value. After heated by laser, cool process of air also show the process of aerosol absorption. This kind of instrument will be used to monitor ambient aerosol absorption and suspended particulate matter chemical component. Keywords: Aerosol absorption coefficient; Photothermal interferometry; Suspended particulate matter.

  12. Radiation Transfer Model for Aerosol Events in the Earth Atmosphere

    Science.gov (United States)

    Mukai, Sonoyo; Yokomae, Takuma; Nakata, Makiko; Sano, Itaru

    Recently large scale-forest fire, which damages the Earth environment as biomass burning and emission of carbonaceous particles, frequently occurs due to the unstable climate and/or global warming tendency. It is also known that the heavy soil dust is transported from the China continent to Japan on westerly winds, especially in spring. Furthermore the increasing emis-sions of anthropogenic particles associated with continuing economic growth scatter serious air pollutants. Thus atmospheric aerosols, especially in Asia, are very complex and heavy loading, which is called aerosol event. In the case of aerosol events, it is rather difficult to do the sun/sky photometry from the ground, however satellite observation is an effective for aerosol monitoring. Here the detection algorithms from space for such aerosol events as dust storm or biomass burn-ing are dealt with multispectral satellite data as ADEOS-2/GLI, Terra/Aqua/MODIS and/or GOSAT/CAI first. And then aerosol retrieval algorithms are examined based on new radiation transfer code for semi-infinite atmosphere model. The derived space-based results are validated with ground-based measurements and/or model simulations. Namely the space-or surface-based measurements, multiple scattering calculations and model simulations are synthesized together for aerosol retrieval in this work.

  13. Analysis of atmospheric aerosols by PIXE: the importance of real time and complementary measurements

    International Nuclear Information System (INIS)

    Particle-Induced X-ray Emission (PIXE) has been used for more than 30 yr in many urban and background air pollution studies. The technique has certainly contributed to the understanding of source-receptor relationship for aerosol particles as well as to aerosol physics and chemistry. In the last few years, where aerosol issues were strongly linked to global climate change through the relationship between aerosol and atmospheric radiation points to new challenges in atmospheric sciences, where PIXE could play an important role. Also the recognition for the inter-relationship between aerosol and liquid and gas phases in the atmosphere makes important to integrate PIXE aerosol analysis with other complementary measurements. The use of Nephelometers and Aethalometers to measure scattering and absorption of radiation by aerosol particles can be done in parallel with particle filter collection for PIXE analysis. Parallel measurements of trace gases using traditional monitors as well as with new techniques such as Differential Optical Absorption Spectroscopy (DOAS) that can provide concentration of O3, SO2, NO3, NO2, HCHO, HNO3, Benzene, Toluene, and Xylene, is also important for both urban and remote aerosol studies. They provide information that allows a much richer interpretation of PIXE data. Recently developed instruments that provide real time aerosol data such as the Tapered Element Oscillating Microbalance (TEOM) PM10 monitor and automatic real time organic and elemental carbon analyzers provide extremely useful data to complement PIXE aerosol analysis. The concentrations of trace elements measured by PIXE comprise only 10-30% of the aerosol mass, leaving the organic aerosol characterization and measurement with an important role. The aerosol source apportionment provided by PIXE analysis can be extended with other aerosol measurements such as scattering and absorption, estimating for example, the radiative impact of each discriminated aerosol source. The aerosol

  14. Physical metrology of aerosols; Metrologie physique des aerosols

    Energy Technology Data Exchange (ETDEWEB)

    Boulaud, D.; Vendel, J. [CEA Saclay, 91 - Gif-sur-Yvette (France). Inst. de Protection et de Surete Nucleaire

    1996-12-31

    The various detection and measuring methods for aerosols are presented, and their selection is related to aerosol characteristics (size range, concentration or mass range), thermo-hydraulic conditions (carrier fluid temperature, pressure and flow rate) and to the measuring system conditions (measuring frequency, data collection speed, cost...). Methods based on aerosol dynamic properties (inertial, diffusional and electrical methods) and aerosol optical properties (localized and integral methods) are described and their performances and applications are compared

  15. Atmospheric aerosols at the Pierre Auger Observatory and environmental implications

    CERN Document Server

    Louedec, K

    2012-01-01

    The Pierre Auger Observatory detects the highest energy cosmic rays. Calorimetric measurements of extensive air showers induced by cosmic rays are performed with a fluorescence detector. Thus, one of the main challenges is the atmospheric monitoring, especially for aerosols in suspension in the atmosphere. Several methods are described which have been developed to measure the aerosol optical depth profile and aerosol phase function, using lasers and other light sources as recorded by the fluorescence detector. The origin of atmospheric aerosols traveling through the Auger site is also presented, highlighting the effect of surrounding areas to atmospheric properties. In the aim to extend the Pierre Auger Observatory to an atmospheric research platform, a discussion about a collaborative project is presented.

  16. Variability of Biomass Burning Aerosols Layers and Near Ground

    Science.gov (United States)

    Vasilescu, Jeni; Belegante, Livio; Marmureanu, Luminita; Toanca, Flori

    2016-06-01

    The aim of this study is to characterize aerosols from both chemical and optical point of view and to explore the conditions to sense the same particles in elevated layers and at the ground. Three days of continuous measurements using a multi-wavelength depolarization lidar(RALI) and a C-ToF-AMS aerosol mass spectrometer are analyzed. The presence of smoke particles was assessed in low level layers from RALI measurements. Chemical composition of submicronic volatile/semi-volatile aerosols at ground level was monitored by the CTOF AMS Several episodes of biomass burning aerosols have been identified by both techniques due to the presence of specific markers (f60, linear particle depolarization ratio, Ängström exponent).

  17. Monitoring the Impacts of Wildfires on Forest Ecosystems and Public Health in the Exo-Urban Environment Using High-Resolution Satellite Aerosol Products from the Visible Infrared Imaging Radiometer Suite (VIIRS)

    OpenAIRE

    Amy K. Huff; Shobha Kondragunta; Hai Zhang; Hoff, Raymond M

    2015-01-01

    Increasing development of exo-urban environments and the spread of urbanization into forested areas is making humans and forest ecosystems more susceptible to the risks associated with wildfires. Larger and more damaging wildfires are having a negative impact on forest ecosystem services, and smoke from wildfires adversely affects the public health of people living in exo-urban environments. Satellite aerosol measurements are valuable tools that can track the evolution of wildfires and monito...

  18. Variability of aerosol vertical distribution in the Sahel

    Directory of Open Access Journals (Sweden)

    O. Cavalieri

    2010-07-01

    Full Text Available We present and discuss ground-based and satellite observations of aerosol optical properties over Sahelian Africa for the years 2006, 2007 and 2008.

    This study combines data acquired by three ground-based micro lidar systems located in Banizoumbou (Niger, Cinzana (Mali and M'Bour (Senegal in the framework of the African Monsoon Multidisciplinary Analysis (AMMA, by the AEROsol RObotic NETwork (AERONET sun-photometers and by the space-based Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP onboard Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO.

    The 2006 seasonal pattern of the aerosols vertical distribution is presented. It shows the presence of aerosol mainly confined in the lower levels of the atmosphere during the dry season, with the aerosol layer increasing in vertical extension and absolute values in spring, reaching the largest values in summer in correspondence with a progressive clearing up of the atmosphere at the lowermost levels.

    Aerosol produced by biomass burning are observed mainly during the dry season, when north-easterly air masses pass over large biomass burning areas before recirculating over the measurement sites. This kind of aerosol is present mainly in layers between 2 and 6 km of altitude, although episodically it may show also below 2 km, as observed in Banizoumbou (Niger in 2006. Biomass burning aerosol is also observed during spring when air masses originating from North and East Africa pass over sparse biomass burning sources, and during summer when biomass burning aerosol is transported from the southern part of the continent by the monsoon flow.

    The summer season on the whole is characterized by a large presence of desert dust along the entire Sahelian region, widespread in altitude with Aerosol Optical Depths above 0.2.

    The interannual variability in the three year monitoring period is not very significant. An analysis of the aerosol

  19. Analysis of intensive aerosol optical properties measured at the Jungfraujoch station

    Energy Technology Data Exchange (ETDEWEB)

    Li, F.; Nyeki, S.; Baltensperger, U.; Weingartner, E.; Lugauer, M. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1997-09-01

    Characterisation of atmospheric aerosol optical properties at the Jungfraujoch has been conducted to deliver basic data for comparison with those from NOAA baseline atmospheric monitoring stations. (author) 2 figs., 2 refs.

  20. The Seasonal Variations of Aerosols over East Asia as Jointly Inferred from MODIS and OMI

    Institute of Scientific and Technical Information of China (English)

    LIU Qi; DING Wei-Dong; FU Yun-Fei

    2011-01-01

    Data on aerosol optical thickness (AOT) and single scattering albedo (SSA) derived from Moderate Resolution Imaging Spectrometer (MODIS) and Ozone Monitoring Instrument (OMI) measurements, respectively, are used jointly to examine the seasonal variations of aerosols over East Asia. The seasonal signals of the total AOT are well defined and nearly similar over the land and over the ocean. These findings indicate a natural cycle of aerosols that originate primarily from natural emissions. In contrast, the small-sized aerosols represented by the fine-mode AOT, which are primarily generated over the land by human activities, do not have evident seasonalscale fluctuations. A persistent maximum of aerosol load- ings centered over the Sichuan basin is associated with considerable amounts of fine-mode aerosols throughout the year. Most regions exhibit a general spring maximum. During the summer, however, the aerosol loadings are the most marked over north central China. This occurrence may result from anthropogenic fine particles, such as sulfate and nitrate. Four typical regions were selected to perform a covariation analysis of the monthly gridded AOT and SSA. Over southwestern and southeastern China, if the aerosol loadings are small to moderate they are composed primarily of the highly absorptive aerosols. However, more substantial aerosol loadings probably represent less-absorptive aerosols. The opposite covaria- tion pattern occurring over the coastal-adjacent oceans suggests that the polluted oceanic atmosphere is closely correlated with the windward terrestrial aerosols. North central China is strongly affected by dust aerosols that show moderate absorption. This finding may explain the lower variability in the SSA that accompanies increasing aerosol loadings in this region.

  1. Indoor aerosol size distributions in a gymnasium.

    Science.gov (United States)

    Castro, Amaya; Calvo, Ana I; Alves, Célia; Alonso-Blanco, Elisabeth; Coz, Esther; Marques, Liliana; Nunes, Teresa; Fernández-Guisuraga, Jose Manuel; Fraile, Roberto

    2015-08-15

    In this study, an indoor/outdoor monitoring program was carried out in a gymnasium at the University of Leon, Spain. The main goal was a characterization of aerosol size distributions in a university gymnasium under different conditions and sports activities (with and without magnesia alba) and the study of the mass fraction deposited in each of the parts of the respiratory tract. The aerosol particles were measured in 31 discrete channels (size ranges) using a laser spectrometer probe. Aerosol size distributions were studied under different conditions: i) before sports activities, ii) activities without using magnesia alba, iii) activities using magnesia alba, iv) cleaning procedures, and v) outdoors. The aerosol refractive index and density indoors were estimated from the aerosol composition: 1.577-0.003i and 2.055 g cm(-3), respectively. Using the estimated density, the mass concentration was calculated, and the evolution of PM1, PM2.5 and PM10 for different activities was assessed. The quality of the air in the gymnasium was strongly influenced by the use of magnesia alba (MgCO3) and the number of gymnasts who were training. Due to the climbing chalk and the constant process of resuspension, average PM10 concentrations of over 440 μg m(-3) were reached. The maximum daily concentrations ranged from 500 to 900 μg m(-3). Particle size determines the place in the respiratory tract where the deposition occurs. For this reason, the inhalable, thoracic, tracheobronchial and respirable fractions were assessed for healthy adults and high risk people, according to international standards. The estimations show that, for healthy adults, up to 300 μg m(-3) can be retained by the trachea and bronchi, and 130 μg m(-3) may reach the alveolar region. The different physical activities and the attendance rates in the sports facility have a significant influence on the concentration and size distributions observed. PMID:25897726

  2. Light absorption by secondary organic aerosol from α-pinene: Effects of oxidants, seed aerosol acidity, and relative humidity

    Energy Technology Data Exchange (ETDEWEB)

    Song, Chen [Atmospheric Sciences and Global Change Division, Pacific Northwest National Laboratory, Richland Washington USA; Now at R. J. Reynolds Tobacco Company, Winston-Salem North Carolina USA; Gyawali, Madhu [Department of Physics, University of Nevada Reno, Nevada System of Higher Education, Reno Nevada USA; Now at Desert Research Institute, Nevada System of Higher Education, Reno Nevada USA; Zaveri, Rahul A. [Atmospheric Sciences and Global Change Division, Pacific Northwest National Laboratory, Richland Washington USA; Shilling, John E. [Atmospheric Sciences and Global Change Division, Pacific Northwest National Laboratory, Richland Washington USA; Arnott, W. Patrick [Department of Physics, University of Nevada Reno, Nevada System of Higher Education, Reno Nevada USA

    2013-10-25

    It is well known that light absorption from dust and black carbon aerosols has a warming effect on climate while light scattering from sulfate, nitrate, and sea salt aerosols has a cooling effect. However, there are large uncertainties associated with light absorption and scattering by different types of organic aerosols, especially in the near-UV and UV spectral regions. In this paper, we present the results from a systematic laboratory study focused on measuring light absorption by secondary organic aerosols (SOAs) generated from dark α-pinene + O3 and α-pinene + NOx + O3 systems in the presence of neutral and acidic sulfate seed aerosols. Light absorption was monitored using photoacoustic spectrometers at four different wavelengths: 355, 405, 532, and 870 nm. Significant light absorption at 355 and 405 nm was observed for the SOA formed from α-pinene + O3 + NO3 system only in the presence of highly acidic sulfate seed aerosols under dry conditions. In contrast, no absorption was observed when the relative humidity was elevated to greater than 27% or in the presence of neutral sulfate seed aerosols. Organic nitrates in the SOA formed in the presence of neutral sulfate seed aerosols were found to be nonabsorbing, while the light-absorbing compounds are speculated to be aldol condensation oligomers with nitroxy organosulfate groups that are formed in highly acidic sulfate aerosols. Finally and overall, these results suggest that dark α-pinene + O3 and α-pinene + NOx + O3 systems do not form light-absorbing SOA under typical atmospheric conditions.

  3. Light absorption by secondary organic aerosol from α-pinene: Effects of oxidants, seed aerosol acidity, and relative humidity

    Science.gov (United States)

    Song, Chen; Gyawali, Madhu; Zaveri, Rahul A.; Shilling, John E.; Arnott, W. Patrick

    2013-10-01

    is well known that light absorption from dust and black carbon aerosols has a warming effect on climate while light scattering from sulfate, nitrate, and sea salt aerosols has a cooling effect. However, there are large uncertainties associated with light absorption and scattering by different types of organic aerosols, especially in the near-UV and UV spectral regions. In this paper, we present the results from a systematic laboratory study focused on measuring light absorption by secondary organic aerosols (SOAs) generated from dark α-pinene + O3 and α-pinene + NOx + O3 systems in the presence of neutral and acidic sulfate seed aerosols. Light absorption was monitored using photoacoustic spectrometers at four different wavelengths: 355, 405, 532, and 870 nm. Significant light absorption at 355 and 405 nm was observed for the SOA formed from α-pinene + O3 + NO3 system only in the presence of highly acidic sulfate seed aerosols under dry conditions. In contrast, no absorption was observed when the relative humidity was elevated to greater than 27% or in the presence of neutral sulfate seed aerosols. Organic nitrates in the SOA formed in the presence of neutral sulfate seed aerosols were found to be nonabsorbing, while the light-absorbing compounds are speculated to be aldol condensation oligomers with nitroxy organosulfate groups that are formed in highly acidic sulfate aerosols. Overall, these results suggest that dark α-pinene + O3 and α-pinene + NOx + O3 systems do not form light-absorbing SOA under typical atmospheric conditions.

  4. Determination of elemental composition and probable sources of atmospheric aerosol in Tirana by EDXRF analysis

    International Nuclear Information System (INIS)

    Full text: The importance of aerosol composition study is directly related with the specific role that aerosol particles play on human health and in different atmospheric parameters. The air pollution monitoring in Tirana has started long ago by measuring some common pollutants, but only during the last years a few attempts have been made for the study of aerosol composition. These were based on the analysis of total aerosol samples collected on cellulose filters using energy dispersive X ray fluorescence (EDXRF) spectrometry. Recently, with the support of the Albanian Ministry of Environment, an aerosol sampling campaign was organized in Tirana. Two different stations were selected for collecting aerosol samples. The first was situated in the centre of the city while the second, in a clean area, near the top of the mountain Dajti. In each of the stations total and size-fractionated aerosol samples were collected respectively on TFA-41 cellulose filters using high volume pumps and on Nuclepore filters using stacked filter unit sampler. An experimental EDXRF system was used for the determination of the concentrations of about 15 elements in the aerosol-loaded filters. The analytical data obtained allowed the calculation of the mean elemental concentrations in the aerosol and their crustal enrichment factors. The application of multivariate methods (Factor Analysis) allowed the identification of the main aerosol sources. (author)

  5. Organic nitrate aerosol formation via NO3 + BVOC in the Southeastern US

    Science.gov (United States)

    Ayres, B. R.; Allen, H. M.; Draper, D. C.; Brown, S. S.; Wild, R. J.; Jimenez, J. L.; Day, D. A.; Campuzano-Jost, P.; Hu, W.; de Gouw, J.; Koss, A.; Cohen, R. C.; Duffey, K. C.; Romer, P.; Baumann, K.; Edgerton, E.; Takahama, S.; Thornton, J. A.; Lee, B. H.; Lopez-Hilfiker, F. D.; Mohr, C.; Goldstein, A. H.; Olson, K.; Fry, J. L.

    2015-06-01

    Gas- and aerosol-phase measurements of oxidants, biogenic volatile organic compounds (BVOC) and organic nitrates made during the Southern Oxidant and Aerosol Study (SOAS campaign, Summer 2013) in central Alabama show that nitrate radical (NO3) reaction with monoterpenes leads to significant secondary aerosol formation. Cumulative losses of NO3 to terpenes are calculated and correlated to gas and aerosol organic nitrate concentrations made during the campaign. Correlation of NO3 radical consumption to organic nitrate aerosol as measured by Aerosol Mass Spectrometry (AMS) and Thermal Dissociation - Laser Induced Fluorescence (TD-LIF) suggests a range of molar yield of aerosol phase monoterpene nitrates of 23-44 %. Compounds observed via chemical ionization mass spectrometry (CIMS) are correlated to predicted nitrate loss to terpenes and show C10H17NO5, likely a hydroperoxy nitrate, is a major nitrate oxidized terpene product being incorporated into aerosols. The comparable isoprene product C5H9NO5 was observed to contribute less than 0.5 % of the total organic nitrate in the aerosol-phase and correlations show that it is principally a gas-phase product from nitrate oxidation of isoprene. Organic nitrates comprise between 30 and 45 % of the NOy budget during SOAS. Inorganic nitrates were also monitored and showed that during incidents of increased coarse-mode mineral dust, HNO3 uptake produced nitrate aerosol mass loading comparable to that of organic nitrate produced via NO3 + BVOC.

  6. Organic nitrate aerosol formation via NO3 + biogenic volatile organic compounds in the southeastern United States

    Science.gov (United States)

    Ayres, B. R.; Allen, H. M.; Draper, D. C.; Brown, S. S.; Wild, R. J.; Jimenez, J. L.; Day, D. A.; Campuzano-Jost, P.; Hu, W.; de Gouw, J.; Koss, A.; Cohen, R. C.; Duffey, K. C.; Romer, P.; Baumann, K.; Edgerton, E.; Takahama, S.; Thornton, J. A.; Lee, B. H.; Lopez-Hilfiker, F. D.; Mohr, C.; Wennberg, P. O.; Nguyen, T. B.; Teng, A.; Goldstein, A. H.; Olson, K.; Fry, J. L.

    2015-12-01

    Gas- and aerosol-phase measurements of oxidants, biogenic volatile organic compounds (BVOCs) and organic nitrates made during the Southern Oxidant and Aerosol Study (SOAS campaign, Summer 2013) in central Alabama show that a nitrate radical (NO3) reaction with monoterpenes leads to significant secondary aerosol formation. Cumulative losses of NO3 to terpenes are correlated with increase in gas- and aerosol-organic nitrate concentrations made during the campaign. Correlation of NO3 radical consumption to organic nitrate aerosol formation as measured by aerosol mass spectrometry and thermal dissociation laser-induced fluorescence suggests a molar yield of aerosol-phase monoterpene nitrates of 23-44 %. Compounds observed via chemical ionization mass spectrometry (CIMS) are correlated to predicted nitrate loss to BVOCs and show C10H17NO5, likely a hydroperoxy nitrate, is a major nitrate-oxidized terpene product being incorporated into aerosols. The comparable isoprene product C5H9NO5 was observed to contribute less than 1 % of the total organic nitrate in the aerosol phase and correlations show that it is principally a gas-phase product from nitrate oxidation of isoprene. Organic nitrates comprise between 30 and 45 % of the NOy budget during SOAS. Inorganic nitrates were also monitored and showed that during incidents of increased coarse-mode mineral dust, HNO3 uptake produced nitrate aerosol mass loading at a rate comparable to that of organic nitrate produced via NO3 + BVOCs.

  7. Organic nitrate aerosol formation via NO3 + BVOC in the Southeastern US

    Directory of Open Access Journals (Sweden)

    B. R. Ayres

    2015-06-01

    Full Text Available Gas- and aerosol-phase measurements of oxidants, biogenic volatile organic compounds (BVOC and organic nitrates made during the Southern Oxidant and Aerosol Study (SOAS campaign, Summer 2013 in central Alabama show that nitrate radical (NO3 reaction with monoterpenes leads to significant secondary aerosol formation. Cumulative losses of NO3 to terpenes are calculated and correlated to gas and aerosol organic nitrate concentrations made during the campaign. Correlation of NO3 radical consumption to organic nitrate aerosol as measured by Aerosol Mass Spectrometry (AMS and Thermal Dissociation – Laser Induced Fluorescence (TD-LIF suggests a range of molar yield of aerosol phase monoterpene nitrates of 23–44 %. Compounds observed via chemical ionization mass spectrometry (CIMS are correlated to predicted nitrate loss to terpenes and show C10H17NO5, likely a hydroperoxy nitrate, is a major nitrate oxidized terpene product being incorporated into aerosols. The comparable isoprene product C5H9NO5 was observed to contribute less than 0.5 % of the total organic nitrate in the aerosol-phase and correlations show that it is principally a gas-phase product from nitrate oxidation of isoprene. Organic nitrates comprise between 30 and 45 % of the NOy budget during SOAS. Inorganic nitrates were also monitored and showed that during incidents of increased coarse-mode mineral dust, HNO3 uptake produced nitrate aerosol mass loading comparable to that of organic nitrate produced via NO3 + BVOC.

  8. The reaction of nitrogen dioxide with sea salt aerosol

    International Nuclear Information System (INIS)

    It is estimated that sea salt is the largest source of tropospheric aerosol particulate matter with 1012 kg introduced into the atmosphere from wave action over the oceans each year. Recently, considerable attention has been given to heterogeneous reactions between salts and nitrogen oxides and their possible roles in atmospheric chemistry, primarily as potential sources of tropospheric halogens. The reaction of sea salt aerosol with NO2 under ambient conditions was explored using particles that were generated by atomizing an aqueous solution of synthetic sea salt. The aerosol at 9--30% relative humidity, was mixed with 1--3 mbar of NO2 and then passed through an optical cell where reactants and products were monitored by infrared spectroscopy. The duration times of the reaction, partial pressure of NO2, and relative humidity were systematically varied in order to explore the aerosol heterogeneous chemistry. Infrared spectra of the aerosol revealed that a substantial fraction of the particulate Cl- was replaced by NO3- and that there was a significant production of ClNO, consistent with the stoichiometry 2 NO2 + Cl- → NO3- + ClNO. The rate of the reaction was found to increase both with NO2 pressure and relative humidity. The infrared spectra also revealed that, even under arid conditions, the sea salt aerosol particles contain more water than can be explained by the various hydrates in sea salt, suggesting that the particles possess a complex structure. This complex structure involves microcrystalline and amorphous regions with pockets for water inclusions

  9. Contributions of dust and smoke to aerosol extinction coefficient

    Science.gov (United States)

    Kavouras, I. G.; Xu, J.; Etyemezian, V.; Dubois, D.; Green, M.; Pitchford, M.

    2006-12-01

    Estimating scattering and absorption of light by atmospheric particles is critical for evaluating effects on regional and global climate. The magnitude of the interaction between aerosol and light is strongly related to the aerosol chemical composition among other factors. Dust and smoke are major sources of atmospheric aerosol, especially in the western United States. The importance of those sources has increased in recent decades due to the extensive man-made disturbance of natural ecosystems and land management practices. The objectives of this study were to specifically estimate the impact of dust and smoke on aerosol extinction coefficient measured in the Class I areas of the western states and identify the major causes of dust and types of smoke by using: (i) positive matrix factorization (PMF) to apportion ambient aerosols by source type; (ii) air mass backward trajectory analyses; (iii) land use/soil properties and; (iv) wildlife/prescribed fire data. The study included sites from the Interagency Monitoring of Protected Visual Environments (IMPROVE) network located in western United States. For days with the worst reconstructed light extinction when dust was the major component, contributions from transcontinental transport from Asia, windblown dust from local sources and regional transport from upwind sources were identified. Based on the analysis for days with smoke being the major component of aerosol visibility extinction, the contributions of the following types of fires were determined: (a) wildfires near the site ("hot" emissions); (b) wildfires upwind of the site (aged smoke); (c) agricultural burn emissions; (d) rangeland fires.

  10. Size Resolved Measurements of Springtime Aerosol Particles over the Northern South China Sea

    Science.gov (United States)

    Atwood, Samuel A.; Reid, Jeffrey S.; Kreidenweis, Sonia M.; Cliff, Stephen S.; Zhao, Yongjing; Lin, Neng-Huei; Tsay, Si-Chee; Chu, Yu-Chi; Westphal, Douglas L.

    2012-01-01

    Large sources of aerosol particles and their precursors are ubiquitous in East Asia. Such sources are known to impact the South China Sea (henceforth SCS), a sometimes heavily polluted region that has been suggested as particularly vulnerable to climate change. To help elucidate springtime aerosol transport into the SCS, an intensive study was performed on the remote Dongsha (aka Pratas) Islands Atoll in spring 2010. As part of this deployment, a Davis Rotating-drum Uniform size-cut Monitor (DRUM) cascade impactor was deployed to collect size-resolved aerosol samples at the surface that were analyzed by X-ray fluorescence for concentrations of selected elements. HYSPLIT backtrajectories indicated that the transport of aerosol observed at the surface at Dongsha was occurring primarily from regions generally to the north and east. This observation was consistent with the apparent persistence of pollution and dust aerosol, along with sea salt, in the ground-based dataset. In contrast to the sea-level observations, modeled aerosol transport suggested that the westerly flow aloft (w700 hPa) transported smoke-laden air toward the site from regions from the south and west. Measured aerosol optical depth at the site was highest during time periods of modeled heavy smoke loadings aloft. These periods did not coincide with elevated aerosol concentrations at the surface, although the model suggested sporadic mixing of this free-tropospheric aerosol to the surface over the SCS. A biomass burning signature was not clearly identified in the surface aerosol composition data, consistent with this aerosol type remaining primarily aloft and not mixing strongly to the surface during the study. Significant vertical wind shear in the region also supports the idea that different source regions lead to varying aerosol impacts in different vertical layers, and suggests the potential for considerable vertical inhomogeneity in the SCS aerosol environment.

  11. Aerosol remote sensing in East Asia : Motivation for NASA/AERONET/DRAGON-Asia

    Science.gov (United States)

    Mukai, S.; Nakata, M.; Sano, I.; Holben, B. N.

    2013-12-01

    It is known that the air pollution in East Asia becomes to be severe due to both the increasing emissions of the anthropogenic aerosols associated with economic growth and the complicated behavior of natural aerosols. Furthermore, air quality in the big cities is worse in comparison with that in remote area because of the industries and auto mobiles. Then high resolved measurements of atmospheric aerosols in spatial- and temporal- scale are desired in Asian urban cities. NASA/Dragon-Asia practiced in the spring of 2012 is really meaningful accordingly. In recent years, heavy air pollutants as well as Asian dusts, i.e. yellow dust storm, transport to neighbor countries from the continent of China throughout year. These aerosol episodes, which mean dense concentrations of aerosols in the atmosphere, severely influence for the environment and human health. This work focuses on the aerosol remote sensing in the case of serious aerosol episodes detected by both satellite and ground measurements in East Asia. It is reasonable to consider for aerosol remote sensing that precise simulations of multiple light scattering processes ( cslled radiative transfer hereafter) in coupled Earth-atmosphere-surface model are necessary and need a long computational time especially for an optically thick atmosphere model such as an aerosol episode. Thus efficient and practical algorithms for radiative transfer are indispensable to retrieve aerosol properties from space. It is shown here that dense aerosol episodes can be well simulated by a semi-infinite radiation model composed of the proposed aerosol models, which are compiled from the accumulated measurements during more than ten years provided with the world wide aerosol monitoring network (NASA/AERONET). In addition the efficient procedure to solve the radiative transfer problem for semi-infinite medium named MSOS (Method of Successive Order of Scattering) is examined in practice around Beijing by using Aqua/MODIS data.

  12. Laboratory Experiments and Instrument Intercomparison Studies of Carbonaceous Aerosol Particles

    Energy Technology Data Exchange (ETDEWEB)

    Davidovits, Paul [Boston College, Chestnut Hill, MA (United States)

    2015-10-20

    ) two well-characterized source of soot particles and (b) a flow reactor for controlled OH and/or O3 oxidation of relevant gas phase species to produce well-characterized SOA particles. After formation, the aerosol particles are subjected to physical and chemical processes that simulate aerosol growth and aging. A suite of instruments in our laboratory is used to characterize the physical and chemical properties of aerosol particles before and after processing. The Time of Flight Aerosol Mass Spectrometer (ToF-AMS) together with a Scanning Mobility Particle Sizer (SMPS) measures particle mass, volume, density, composition (including black carbon content), dynamic shape factor, and fractal dimension. The–ToF-AMS was developed at ARI with Boston College participation. About 120 AMS instruments are now in service (including 5 built for DOE laboratories) performing field and laboratory studies world-wide. Other major instruments include a thermal denuder, two Differential Mobility Analyzers (DMA), a Cloud Condensation Nuclei Counter (CCN), a Thermal desorption Aerosol GC/MS (TAG) and the new Soot Particle Aerosol Mass Spectrometer (SP-AMS). Optical instrumentation required for the studies have been brought to our laboratory as part of ongoing and planned collaborative projects with colleagues from DOE, NOAA and university laboratories. Optical instruments that will be utilized include a Photoacoustic Spectrometer (PAS), a Cavity Ring Down Aerosol Extinction Spectrometer (CRD-AES), a Photo Thermal Interferometer (PTI), a new 7-wavelength Aethalometer and a Cavity Attenuated Phase Shift Extinction Monitor (CAPS). These instruments are providing aerosol absorption, extinction and scattering coefficients at a range of atmospherically relevant wavelengths. During the past two years our work has continued along the lines of our original proposal. We report on 12 completed and/or continuing projects conducted during the period 08/14 to 0814/2015. These projects are described in

  13. Atmospheric aerosol characterization combining multi-wavelength Raman lidar and MAX-DOAS measurements in Gwanjgu

    Science.gov (United States)

    Chong, Jihyo; Shin, Dong Ho; Kim, Kwang Chul; Lee, Kwon-Ho; Shin, Sungkyun; Noh, Young M.; Müller, Detlef; Kim, Young J.

    2011-11-01

    Integrated approach has been adopted at the ADvanced Environmental Research Center (ADEMRC), Gwangju Institute of Science and Technology (GIST), Korea for effective monitoring of atmospheric aerosol. Various active and passive optical remote sensing techniques such as multi-wavelength (3β+2α+1δ) Raman LIDAR, sun-photometry, MAX-DOAS, and satellite retrieval have been utilized. This integrated monitoring system approach combined with in-situ surface measurement is to allow better characterization of physical and optical properties of atmospheric aerosol. Information on the vertical distribution and microphysical properties of atmospheric aerosol is important for understanding its transport characteristics as well as radiative effect. The GIST multi-wavelength (3β + 2α+1δ) Raman lidar system can measure vertical profiles of optical properties of atmospheric aerosols such as extinction coefficients at 355 and 532nm, particle backscatter coefficients at 355, 532 and 1064 nm, and depolarization ratio at 532nm. The incomplete overlap between the telescope field-of-view and beam divergence of the transmitting laser significantly affects lidar measurement, resulting in higher uncertainty near the surface where atmospheric aerosols of interest are concentrated. Differential Optical Absorption Spectroscopy (DOAS) technique is applied as a complementary tool for the detection of atmospheric aerosols near the surface. The passive Multi-Axis DOAS (MAX-DOAS) technique uses scattered sunlight as a light source from several viewing directions. Recently developed aerosol retrieval algorithm based on O4 slant column densities (SCDs) measured at UV and visible wavelengths has been utilized to derive aerosol information (e.g., aerosol optical depth (AOD) and aerosol extinction coefficients (AECs)) in the lower troposphere. The aerosol extinction coefficient at 356 nm was retrieved for the 0-1 and 1-2 km layers based on the MAX-DOAS measurements using the retrieval algorithm

  14. The impacts of aerosol loading, composition, and water uptake on aerosol extinction variability in the Baltimore-Washington, D.C. region

    Science.gov (United States)

    Beyersdorf, A. J.; Ziemba, L. D.; Chen, G.; Corr, C. A.; Crawford, J. H.; Diskin, G. S.; Moore, R. H.; Thornhill, K. L.; Winstead, E. L.; Anderson, B. E.

    2016-01-01

    In order to utilize satellite-based aerosol measurements for the determination of air quality, the relationship between aerosol optical properties (wavelength-dependent, column-integrated extinction measured by satellites) and mass measurements of aerosol loading (PM2.5 used for air quality monitoring) must be understood. This connection varies with many factors including those specific to the aerosol type - such as composition, size, and hygroscopicity - and to the surrounding atmosphere, such as temperature, relative humidity (RH), and altitude, all of which can vary spatially and temporally. During the DISCOVER-AQ (Deriving Information on Surface conditions from Column and Vertically Resolved Observations Relevant to Air Quality) project, extensive in situ atmospheric profiling in the Baltimore, MD-Washington, D.C. region was performed during 14 flights in July 2011. Identical flight plans and profile locations throughout the project provide meaningful statistics for determining the variability in and correlations between aerosol loading, composition, optical properties, and meteorological conditions. Measured water-soluble aerosol mass was composed primarily of ammonium sulfate (campaign average of 32 %) and organics (57 %). A distinct difference in composition was observed, with high-loading days having a proportionally larger percentage of sulfate due to transport from the Ohio River Valley. This composition shift caused a change in the aerosol water-uptake potential (hygroscopicity) such that higher relative contributions of inorganics increased the bulk aerosol hygroscopicity. These days also tended to have higher relative humidity, causing an increase in the water content of the aerosol. Conversely, low-aerosol-loading days had lower sulfate and higher black carbon contributions, causing lower single-scattering albedos (SSAs). The average black carbon concentrations were 240 ng m-3 in the lowest 1 km, decreasing to 35 ng m-3 in the free troposphere (above

  15. Assimilation of POLDER aerosol optical thickness into the LMDz-INCA model: Implications for the Arctic aerosol burden

    International Nuclear Information System (INIS)

    The large spatial and temporal variability of atmospheric aerosol load makes it a challenge to quantify aerosol effect on climate. This study is one of the first attempts to apply data assimilation for the analysis of global aerosol distribution. Aerosol optical thickness (AOT) observed from the Polarization and Directionality of the Earth Reflectances (POLDER) space-borne instrument are assimilated into a three-dimensional chemistry model. POLDER capabilities to distinguish between fine and coarse AOT are used to constrain them separately in the model. Observation and model errors are a key component of such a system and are carefully estimated on a regional basis using some of the high-quality surface observations from the Aerosol Robotic Network (AERONET). Other AERONET data provide an independent evaluation of the a posteriori fields. Results for the fine mode show improvements, in terms of reduction of root-mean-square errors, in most regions with the largest improvements found in the Mediterranean Sea and Eurasia. We emphasize the results for the Arctic, where there is growing evidence of a strong aerosol impact on climate, but a lack of regional and continuous aerosol monitoring. The a posteriori fields noticeably well reproduce the winter-spring 'Arctic Haze' peak measured in Longyearbyen (15 degrees E, 78 degrees N) and typical seasonal variations in the Arctic region, where AOT increase by up to a factor of three between a posteriori and a priori. Enhanced AOT are found over a longer period in spring 2003 than in 1997, suggesting that the large Russian fires in 2003 have influenced the Arctic aerosol load. (authors)

  16. Note: Real time optical sensing of alpha-radiation emitting radioactive aerosols based on solid state nuclear track detector

    Energy Technology Data Exchange (ETDEWEB)

    Kulkarni, A.; Bak, M. S., E-mail: tkim@skku.edu, E-mail: moonsoo@skku.edu [School of Mechanical Engineering, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Ha, S. [SKKU Advanced Institute of Nano Technology (SAINT), Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Joshirao, P.; Manchanda, V. [Department of Energy Science, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Kim, T., E-mail: tkim@skku.edu, E-mail: moonsoo@skku.edu [School of Mechanical Engineering, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); SKKU Advanced Institute of Nano Technology (SAINT), Sungkyunkwan University, Suwon 440-746 (Korea, Republic of)

    2015-06-15

    A sensitive radioactive aerosols sensor has been designed and developed. Its design guidance is based on the need for a low operational cost and reliable measurements to provide daily aerosol monitoring. The exposure of diethylene-glycol bis (allylcarbonate) to radiation causes modification of its physico-chemical properties like surface roughness and reflectance. In the present study, optical sensor based on the reflectance measurement has been developed with an aim to monitor real time presence of alpha radioactive aerosols emitted from thorium nitrate hydrate. The results shows that the fabricated sensor can detect 0.0157 kBq to 0.1572 kBq of radio activity by radioactive aerosols generated from (Th(NO{sub 3}){sub 4} ⋅ 5H{sub 2}O) at 0.1 ml/min flow rate. The proposed instrument will be helpful to monitor radioactive aerosols in/around a nuclear facility, building construction sites, mines, and granite polishing factories.

  17. Note: Real time optical sensing of alpha-radiation emitting radioactive aerosols based on solid state nuclear track detector

    International Nuclear Information System (INIS)

    A sensitive radioactive aerosols sensor has been designed and developed. Its design guidance is based on the need for a low operational cost and reliable measurements to provide daily aerosol monitoring. The exposure of diethylene-glycol bis (allylcarbonate) to radiation causes modification of its physico-chemical properties like surface roughness and reflectance. In the present study, optical sensor based on the reflectance measurement has been developed with an aim to monitor real time presence of alpha radioactive aerosols emitted from thorium nitrate hydrate. The results shows that the fabricated sensor can detect 0.0157 kBq to 0.1572 kBq of radio activity by radioactive aerosols generated from (Th(NO3)4 ⋅ 5H2O) at 0.1 ml/min flow rate. The proposed instrument will be helpful to monitor radioactive aerosols in/around a nuclear facility, building construction sites, mines, and granite polishing factories

  18. Graphical aerosol classification method using aerosol relative optical depth

    Science.gov (United States)

    Chen, Qi-Xiang; Yuan, Yuan; Shuai, Yong; Tan, He-Ping

    2016-06-01

    A simple graphical method is presented to classify aerosol types based on a combination of aerosol optical thickness (AOT) and aerosol relative optical thickness (AROT). Six aerosol types, including maritime (MA), desert dust (DD), continental (CO), sub-continental (SC), urban industry (UI) and biomass burning (BB), are discriminated in a two dimensional space of AOT440 and AROT1020/440. Numerical calculations are performed using MIE theory based on a multi log-normal particle size distribution, and the AROT ranges for each aerosol type are determined. More than 5 years of daily observations from 8 representative aerosol sites are applied to the method to confirm spatial applicability. Finally, 3 individual cases are analyzed according to their specific aerosol status. The outcomes indicate that the new graphical method coordinates well with regional characteristics and is also able to distinguish aerosol variations in individual situations. This technique demonstrates a novel way to estimate different aerosol types and provide information on radiative forcing calculations and satellite data corrections.

  19. Aerosol samplers innovation possibilities

    International Nuclear Information System (INIS)

    The growing demand for an early detection of increased levels of the artificial radionuclides in the atmosphere resulted in the design and fabrication of an aerosol sampler with automated spectrometric unit providing online gamma spectrometry above the aerosol filter. Study was performed with two types of high volume samplers- SENYA JL-900 SnowWhite (900 m3/h) a SENYA JL-150 Hunter (150 m3/h). This work gives results of the design optimization with respect to the detector type, geometry of measurement, remote control and spectrometric evaluation 222Rn and 220Rn concentration fluctuations in the outdoor air are discussed with regard to the detection limit so the radionuclides expected after the NPP accident. (authors)

  20. An aerosol sampler

    International Nuclear Information System (INIS)

    That device is characterized in that, within a closed casing provided with a sealable opening, it comprises a storage rack for a plurality of stacked saucers, a sheath having a transverse slot for extracting said saucers separately from, or re-introducing same into, their respective sockets, a transfer gripping-member with its control mechanism for taking saucers from their respective sockets through said slot and moving them transversally, a sealing-plate mounted below the casing-opening, said plate being associated with a pushing mechanism, and a laterally retractable cover controlled by a separate mechanism for unsealing said casing opening and collecting aerosols on a saucer. That device can be used for taking samples of sodium aerosols

  1. Aerosol Observing System (AOS) Handbook

    Energy Technology Data Exchange (ETDEWEB)

    Jefferson, A

    2011-01-17

    The Aerosol Observing System (AOS) is a suite of in situ surface measurements of aerosol optical and cloud-forming properties. The instruments measure aerosol properties that influence the earth’s radiative balance. The primary optical measurements are those of the aerosol scattering and absorption coefficients as a function of particle size and radiation wavelength and cloud condensation nuclei (CCN) measurements as a function of percent supersaturation. Additional measurements include those of the particle number concentration and scattering hygroscopic growth. Aerosol optical measurements are useful for calculating parameters used in radiative forcing calculations such as the aerosol single-scattering albedo, asymmetry parameter, mass scattering efficiency, and hygroscopic growth. CCN measurements are important in cloud microphysical models to predict droplet formation.

  2. Aerosol characterization during project POLINAT

    Energy Technology Data Exchange (ETDEWEB)

    Hagen, D.E.; Hopkins, A.R.; Paladino, J.D.; Whitefield, P.D. [Missouri Univ., Rolla, MO (United States). Cloud and Aerosol Sciences Lab.; Lilenfeld, H.V. [McDonnell Douglas Aerospace-East, St. Louis, MO (United States)

    1997-12-31

    The objectives of the aerosol/particulate characterization measurements of project POLINAT (POLlution from aircraft emissions In the North ATlantic flight corridor) are: to search for aerosol/particulate signatures of air traffic emissions in the region of the North Atlantic Flight Corridor; to search for the aerosol/particulate component of large scale enhancement (`corridor effects`) of air traffic related species in the North Atlantic region; to determine the effective emission indices for the aerosol/particulate component of engine exhaust in both the near and far field of aircraft exhaust plumes; to measure the dispersion and transformation of the aerosol/particulate component of aircraft emissions as a function of ambient condition; to characterize background levels of aerosol/particulate concentrations in the North Atlantic Region; and to determine effective emission indices for engine exhaust particulates for regimes beyond the jet phase of plume expansion. (author) 10 refs.

  3. Dust and atmospheric aerosol

    International Nuclear Information System (INIS)

    The paper describes the types and characteristics of the various aerosol particles (by size effects, and origin) and goes on to discuss the composition of particulates and their variation in different places in Asia, and the origin of global particulate emissions from natural and anthropogenic sources. The effects of particulate matter on human health, visibility and climate are summarised. Techniques for control and abatement of particulate emissions are outlined. 10 refs., 4 figs., 11 tabs

  4. Photothermal spectroscopy of aerosols

    International Nuclear Information System (INIS)

    In situ aerosol absorption spectroscopy was performed using two novel photothermal detection schemes. The first, based on a photorefractive effect and coherent detection, called phase fluctuation optical heterodyne (PFLOH) spectroscopy, could, depending on the geometry employed, yield particle specific or particle and gas absorption data. Single particles of graphite as small as 1 μm were detected in the particle specific mode. In another geometrical configuration, the total absorption (both gas and particle) of submicron sized aerosols of ammonium sulfate particles in equilibrium with gaseous ammonia and water vapor were measured at varying CO2 laser frequencies. The specific absorption coefficient for the sulfate ion was measured to be 0.5 m2/g at 1087 cm-1. The absorption coefficient sensitivity of this scheme was less than or equal to 10-8 cm-1. The second scheme is a hybrid visible Mie scattering scheme incorporating photothermal modulation. Particle specific data on ammonium sulfate droplets were obtained. For chemically identical species, the relative absorption spectrum versus laser frequency can be obtained for polydisperse aerosol distributions directly from the data without the need for complex inverse scattering calculations

  5. Aerosol influence on radiative cooling

    OpenAIRE

    Grassl, Hartmut

    2011-01-01

    Aerosol particles have a complex index of refraction and therefore contribute to atmospheric emission and radiative cooling rates. In this paper calculations of the longwave flux divergence within the atmosphere at different heights are presented including water vapour and aerosol particles as emitters and absorbers. The spectral region covered is 5 to 100 microns divided into 23 spectral intervals. The relevant properties of the aerosol particles, the single scattering albedo and the extinct...

  6. Improvements to the OMI Near-uv Aerosol Algorithm Using A-train CALIOP and AIRS Observations

    Science.gov (United States)

    Torres, O.; Ahn, C.; Zhong, C.

    2014-01-01

    The height of desert dust and carbonaceous aerosols layers and, to a lesser extent, the difficulty in assessing the predominant size mode of these absorbing aerosol types, are sources of uncertainty in the retrieval of aerosol properties from near UV satellite observations. The availability of independent, near-simultaneous measurements of aerosol layer height, and aerosol-type related parameters derived from observations by other A-train sensors, makes possible the direct use of these parameters as input to the OMI (Ozone Monitoring Instrument) near UV retrieval algorithm. A monthly climatology of aerosol layer height derived from observations by the CALIOP (Cloud-Aerosol Lidar with Orthogonal Polarization) sensor, and real-time AIRS (Atmospheric Infrared Sounder) CO observations are used in an upgraded version of the OMI near UV aerosol algorithm. AIRS CO measurements are used as a reliable tracer of carbonaceous aerosols, which allows the identification of smoke layers in areas and times of the year where the dust-smoke differentiation is difficult in the near-UV. The use of CO measurements also enables the identification of elevated levels of boundary layer pollution undetectable by near UV observations alone. In this paper we discuss the combined use of OMI, CALIOP and AIRS observations for the characterization of aerosol properties, and show a significant improvement in OMI aerosol retrieval capabilities.

  7. Characterization and source apportionment of organic aerosol using offline aerosol mass spectrometry

    Directory of Open Access Journals (Sweden)

    K. R. Daellenbach

    2015-08-01

    Full Text Available Field deployments of the Aerodyne Aerosol Mass Spectrometer (AMS have significantly advanced real-time measurements and source apportionment of non-refractory particulate matter. However, the cost and complex maintenance requirements of the AMS make impractical its deployment at sufficient sites to determine regional characteristics. Furthermore, the negligible transmission efficiency of the AMS inlet for supermicron particles significantly limits the characterization of their chemical nature and contributing sources. In this study, we utilize the AMS to characterize the water-soluble organic fingerprint of ambient particles collected onto conventional quartz filters, which are routinely sampled at many air quality sites. The method was applied to 256 particulate matter (PM filter samples (PM1, PM2.5, PM10 collected at 16 urban and rural sites during summer and winter. We show that the results obtained by the present technique compare well with those from co-located online measurements, e.g. AMS or Aerosol Chemical Speciation Monitor (ACSM. The bulk recoveries of organic aerosol (60–91 % achieved using this technique, together with low detection limits (0.8 μg of organic aerosol on the analyzed filter fraction allow its application to environmental samples. We will discuss the recovery variability of individual hydrocarbon, oxygen containing and other ions. The performance of such data in source apportionment is assessed in comparison to ACSM data. Recoveries of organic components related to different sources as traffic, wood burning and secondary organic aerosol are presented. This technique, while subjected to the limitations inherent to filter-based measurements (e.g. filter artifacts and limited time resolution may be used to enhance the AMS capabilities in measuring size-fractionated, spatially-resolved long-term datasets.

  8. Characterization and source apportionment of organic aerosol using offline aerosol mass spectrometry

    Science.gov (United States)

    Daellenbach, K. R.; Bozzetti, C.; Křepelová, A.; Canonaco, F.; Wolf, R.; Zotter, P.; Fermo, P.; Crippa, M.; Slowik, J. G.; Sosedova, Y.; Zhang, Y.; Huang, R.-J.; Poulain, L.; Szidat, S.; Baltensperger, U.; El Haddad, I.; Prévôt, A. S. H.

    2016-01-01

    Field deployments of the Aerodyne Aerosol Mass Spectrometer (AMS) have significantly advanced real-time measurements and source apportionment of non-refractory particulate matter. However, the cost and complex maintenance requirements of the AMS make its deployment at sufficient sites to determine regional characteristics impractical. Furthermore, the negligible transmission efficiency of the AMS inlet for supermicron particles significantly limits the characterization of their chemical nature and contributing sources. In this study, we utilize the AMS to characterize the water-soluble organic fingerprint of ambient particles collected onto conventional quartz filters, which are routinely sampled at many air quality sites. The method was applied to 256 particulate matter (PM) filter samples (PM1, PM2.5, and PM10, i.e., PM with aerodynamic diameters smaller than 1, 2.5, and 10 µm, respectively), collected at 16 urban and rural sites during summer and winter. We show that the results obtained by the present technique compare well with those from co-located online measurements, e.g., AMS or Aerosol Chemical Speciation Monitor (ACSM). The bulk recoveries of organic aerosol (60-91 %) achieved using this technique, together with low detection limits (0.8 µg of organic aerosol on the analyzed filter fraction) allow its application to environmental samples. We will discuss the recovery variability of individual hydrocarbon ions, ions containing oxygen, and other ions. The performance of such data in source apportionment is assessed in comparison to ACSM data. Recoveries of organic components related to different sources as traffic, wood burning, and secondary organic aerosol are presented. This technique, while subjected to the limitations inherent to filter-based measurements (e.g., filter artifacts and limited time resolution) may be used to enhance the AMS capabilities in measuring size-fractionated, spatially resolved long-term data sets.

  9. Topics in current aerosol research

    CERN Document Server

    Hidy, G M

    1971-01-01

    Topics in Current Aerosol Research deals with the fundamental aspects of aerosol science, with emphasis on experiment and theory describing highly dispersed aerosols (HDAs) as well as the dynamics of charged suspensions. Topics covered range from the basic properties of HDAs to their formation and methods of generation; sources of electric charges; interactions between fluid and aerosol particles; and one-dimensional motion of charged cloud of particles. This volume is comprised of 13 chapters and begins with an introduction to the basic properties of HDAs, followed by a discussion on the form

  10. Variability of aerosol vertical distribution in the Sahel

    Directory of Open Access Journals (Sweden)

    O. Cavalieri

    2010-12-01

    continent by the monsoon flow.

    During summer months, the entire Sahelian region is under the influence of Saharan dust aerosols: the air masses in low levels arrive from West Africa crossing the Sahara desert or from the Southern Hemisphere crossing the Guinea Gulf while in the upper layers air masses still originate from North, North-East. The maximum of the desert dust activity is observed in this period which is characterized by large AOD (above 0.2 and backscattering values. It also corresponds to a maximum in the extension of the aerosol vertical distribution (up to 6 km of altitude. In correspondence, a progressive cleaning up of the lowermost layers of the atmosphere is occurring, especially evident in the Banizoumbou and Cinzana sites.

    Summer is in fact characterized by extensive and fast convective phenomena.

    Lidar profiles show at times large dust events loading the atmosphere with aerosol from the ground up to 6 km of altitude. These events are characterized by large total attenuated backscattering values, and alternate with very clear profiles, sometimes separated by only a few hours, indicative of fast removal processes occurring, likely due to intense convective and rain activity.

    The inter-annual variability in the three year monitoring period is not very significant. An analysis of the aerosol transport pathways, aiming at detecting the main source regions, revealed that air originated from the Saharan desert is present all year long and it is observed in the lower levels of the atmosphere at the beginning and at the end of the year. In the central part of the year it extends upward and the lower levels are less affected by air masses from Saharan desert when the monsoon flow carries air from the Guinea Gulf and the Southern Hemisphere inland.

  11. Growing up MODIS: Towards a mature aerosol climate data record

    Science.gov (United States)

    Levy, Robert C.

    2013-05-01

    . There are two orbiting MODIS sensors (on Terra and Aqua), and like human twins, they have had different life experiences; the result is a slightly different perspective on global aerosol distribution. To assess simple questions like "Is global aerosol increasing or decreasing?" requires detailed analyses into diverse subjects, such as instrument calibration, assumptions for gas correction, and aggregations of spatial sampling. With the recent launch of VIIRS on Suomi-NPP, there is a new addition to the aerosol monitoring "family." While preliminary indications are that it will produce a successful aerosol product, work on its position within the CDR is just beginning. In 1998, in addition to starting a new job, I joined a unique family composed of scientists around the world. I am grateful that the community has been supportive and nurturing. Of course, like in any family, there are many stories to tell. Here, at IRS-2012, I share some of my experiences of working within the collective MODIS aerosol project.

  12. Lessons learned from case studies of worker exposures to radioactive aerosols

    International Nuclear Information System (INIS)

    Considerable efforts in the aerosol science and health protection communities are devoted to developing a defensible technical basis for measuring, modeling, and mitigating toxic aerosols. These efforts involve understanding aerosol source terms, projecting potential aerosol releases, describing their behavior in the workplace and environment, developing instruments and techniques to measure the aerosols, designing ways to contain or control the aerosols, modeling and measuring uptake by workers and other people, estimating health effects, and planning appropriate responses. To help in this effort, we have compiled a data base of case studies involving releases of aerosols and worker exposures in a wide range of industries. Sources of information have included personal communications, limited distribution reports, open literature publications, and reports of abnormal occurrences in U.S. Department of Energy facilities and among licensees of the U.S. Nuclear Regulatory Commission. The data base currently includes more than 100 cases. The case studies have been organized according to the radionuclides involved and the circumstances and consequences of the release. This information has been used to address a number of important questions, such as the adequacy of current aerosol sampling and monitoring procedures, areas needing improvement, and strategies for planning for or responding to accidents. One area of particular interest is related to strategies for prospective or retrospective characterization of aerosol source terms. In some cases, worker exposures have involved aerosols that are similar in particle size distribution, composition, and solubility to aerosols routinely produced in the normal process activities. In such cases, prospective characterization of aerosol source terms has provided relevant and useful information

  13. Dust layer profiling using an aerosol dropsonde

    Science.gov (United States)

    Ulanowski, Zbigniew; Kaye, Paul Henry; Hirst, Edwin; Wieser, Andreas; Stanley, Warren

    2015-04-01

    Routine meteorological data is obtained in the atmosphere using disposable radiosondes, giving temperature, pressure, humidity and wind speed. Additional measurements are obtained from dropsondes, released from research aircraft. However, a crucial property not yet measured is the size and concentration of atmospheric particulates, including dust. Instead, indirect measurements are employed, relying on remote sensing, to meet the demands from areas such as climate research, air quality monitoring, civil emergencies etc. In addition, research aircraft can be used in situ, but airborne measurements are expensive, and aircraft use is restricted to near-horizontal profiling, which can be a limitation, as phenomena such as long-range transport depend on the vertical distribution of aerosol. The Centre for Atmospheric and Instrumentation Research at University of Hertfordshire develops light-scattering instruments for the characterization of aerosols and cloud particles. Recently a range of low-cost, miniature particle counters has been created, intended for use with systems such as disposable balloon-borne radiosondes, dropsondes, or in dense ground-based sensor networks. Versions for different particle size ranges exist. They have been used for vertical profiling of aerosols such as mineral dust or volcanic ash. A disadvantage of optical particle counters that sample through a narrow inlet is that they can become blocked, which can happen in cloud, for example. Hence, a different counter version has been developed, which can have open-path geometry, as the sensing zone is defined optically rather than being delimited by the flow system. This counter has been used for ground based air-quality monitoring around Heathrow airport. The counter has also been adapted for use with radiosondes or dropsondes. The dropsonde version has been successfully tested by launching it from research aircraft together with the so-called KITsonde, developed at the Karlsruhe Institute of

  14. Influence of aerosol concentration and multivariate processing on indication of radon progeny concentration in air

    International Nuclear Information System (INIS)

    Indication of concentration of radon progeny gauge in air is sensitive to aerosol concentration. Minimum detectable concentration and accuracy of the measurement is determined by random errors of the gauge. Multivariate data processing can be used to decrease random errors. To investigate influence of aerosol concentration on indication of radon progeny concentration in air, measurements of mining radiometer, operating on the principle of alpha radiation detection from radon progeny deposited on air filter, were carried out in radon chamber. Aerosol concentration and radon concentration in radon chamber were controlled and measurements of radon progeny concentration was measured by radon progeny monitor. Additionally count rate from the monitor detector originating from alpha activity deposited on air filter was measured in 1 min. intervals that were later used for three interval, and Principal Component Regression (PCR) data processing. It was found that for aerosol concentration in air from 40 p/cm3 to approx. 9 000 p/cm3 indications of the radon progeny monitor depends considerably on aerosol concentration. Radon daughters concentration normalized to radon concentration against aerosol concentration varied from 0.3-0.9. In mines where the aerosol concentration generally is high, this phenomenon has a little effect on the indication of the radon progeny monitor, but is has to be taken into account where aerosol concentration is low. Comparison of random errors when measured signal of the monitor (count rate against time) was processed employing three interval method and PCR data processing shows that PCR ensures 2-3 times lower random error than three interval data processing. (author)

  15. Research on measurement method of 220Rn progeny aerosol size distribution

    International Nuclear Information System (INIS)

    The method for measuring 220Rn progeny aerosol activity particle size distributions was introduced through ELPI system, α spectroscopy and the energy discrimination method. The different particle sizes of the 220Rn progeny aerosols were collected and the activity size distributions in the 220Rn laboratory of the University of South China were measured by this method. The experiment results show that the activity median aerodynamic diameter (AMAD) of ThB aerosol is 237 nm, and that of ThC is 245 nm. The simple and quick method can be used to monitor the particle size distributions of 220Rn progeny aerosol in real time, the aerosol activity size distributions of ThB and ThC can be obtained by this method at the same time, and the measurement accuracy of the energy spectrum is higher than that of custom method. (authors)

  16. Estimates of aerosol absorption over India using multi-satellite retrieval

    Energy Technology Data Exchange (ETDEWEB)

    Narasimhan, D.; Satheesh, S.K. [Indian Institute of Science, Bangalore (India). Centre for Atmospheric and Oceanic Sciences

    2013-11-01

    Aerosol absorption is poorly quantified because of the lack of adequate measurements. It has been shown that the Ozone Monitoring Instrument (OMI) aboard EOSAura and the Moderate Resolution Imaging Spectroradiometer (MODIS) aboard EOS-Aqua, which fly in formation as part of the A-train, provide an excellent opportunity to improve the accuracy of aerosol retrievals. Here, we follow a multi-satellite approach to estimate the regional distribution of aerosol absorption over continental India for the first time. Annually and regionally averaged aerosol singlescattering albedo over the Indian landmass is estimated as 0.94{+-}0.03. Our study demonstrates the potential of multisatellite data analysis to improve the accuracy of retrieval of aerosol absorption over land.

  17. Aerosol studies with Listeria innocua and Listeria monocytogenes.

    Science.gov (United States)

    Zhang, Guodong; Ma, Li; Oyarzabal, Omar A; Doyle, Michael P

    2007-08-01

    Aerosol studies of Listeria monocytogenes in food processing plants have been limited by lack of a suitable surrogate microorganism. The objective of this study was to investigate the potential of using green fluorescent protein-labeled strains of Listeria innocua as a surrogate for L. monocytogenes for aerosol studies. These studies were conducted in a laboratory bioaerosol chamber and a pilot food-processing facility. Four strains of L. innocua and five strains of L. monocytogenes were used. In the laboratory chamber study, Listeria cells were released into the environment at two different cell numbers and under two airflow conditions. Trypticase soy agar (TSA) plates and oven-roasted breasts of chicken and turkey were placed in the chamber to monitor Listeria cell numbers deposited from aerosols. A similar experimental design was used in the pilot plant study; however, only L. innocua was used. Results showed that L. monocytogenes and L. innocua survived equally well on chicken and turkey breast meats and TSA plates. No-fan and continuous fan applications, which affected airflow, had no significant effect on settling rates of aerosolized L. monocytogenes and L. innocua in the bioaerosol chamber or L. innocua in the pilot plant study. Listeriae cell numbers in the air decreased rapidly during the first 1.5 h following release, with few to no listeriae detected in the air at 3 h. Aerosol particles with diameters of 1 and 2 microM correlated directly with the number of Listeria cells in the aerosol but not with particles that were 0.3, 0.5, and 5 microM in diameter. Results indicate that L. innocua can be used as a surrogate for L. monocytogenes in an aerosol study. PMID:17803142

  18. Season - dependent and source-influenced aerosol in Northern Siberia

    Science.gov (United States)

    Popovicheva, Olga; Makshtas, Alexander; Bogorodsky, Peter; Eleftheriadis, Kostantinos; Diapouli, Evangelia; Shonia, Natalia; Uttal, Taneil

    2016-04-01

    Aerosol may serve as a tracer of arctic pollution, allowing a link to climate response if its major characteristics relating to natural and anthropogeneous sources are defined. It has been shown that BC and sulfates are the most important aerosol constituents measured in the Arctic boundary layer; these species demonstrate similar seasonal variations with a peak during winter to early spring and a minimum in summer. Long - time gap in consistent aerosol observations in the Russian Arctic strongly limits the assessment of air pollution and climate impacts. On-line monitoring, sampling, and analyses of atmospheric aerosols were carried out at the Tiksi Hydrometeorological Observatory, Northern Siberia, during one year from September 2014 to 2015. Physico-chemical characterization combining aethalometry, thermo-optical analysis, and analytical chemistry was used in order to identify the seasonal variability of aerosols and to link their composition to possible sources, as well as to characterize the differences in aerosol chemical composition between natural background conditions and BC-pollution episodes. The present study reports the first results from the Tiksi Observatory on season-dependent and source-influenced characteristics of aerosol species, such as carbon fractions (OC, EC), inorganic and organic functionalities of chemical compounds, sulfates, nitrates and other ion components, and elements. In addition, data obtained by individual particles analysis provide insight into micromarkers of combustion sources. Aerosol at the Tiksi Observatory is found to be originated from natural marine, biogenic, and continental sources as well as influenced by local residential activity and regional pollution. Characterization of aerosols during OC and BC-pollution episodes, combined with analysis of the wind direction, atmosphere stability, and air mass trajectories, allows for the identification of the sources which are responsible for the emission of hazardous compounds

  19. Connecting Water Quality With Air Quality Through Microbial Aerosols

    Science.gov (United States)

    Dueker, M. Elias

    Aerosol production from surface waters results in the transfer of aquatic materials (including nutrients and bacteria) to air. These materials can then be transported by onshore winds to land, representing a biogeochemical connection between aquatic and terrestrial systems not normally considered. In urban waterfront environments, this transfer could result in emissions of pathogenic bacteria from contaminated waters. Despite the potential importance of this link, sources, near-shore deposition, identity and viability of microbial aerosols are largely uncharacterized. This dissertation focuses on the environmental and biological mechanisms that define this water-air connection, as a means to build our understanding of the biogeochemical, biogeographical, and public health implications of the transfer of surface water materials to the near-shore environment in both urban and non-urban environments. The effects of tidal height, wind speed and fog on coastal aerosols and microbial content were first quantified on a non-urban coast of Maine, USA. Culture-based, culture-independent, and molecular methods were used to simultaneously sample microbial aerosols while monitoring meteorological parameters. Aerosols at this site displayed clear marine influence and high concentrations of ecologically-relevant nutrients. Coarse aerosol concentrations significantly increased with tidal height, onshore wind speed, and fog presence. Tidal height and fog presence did not significantly influence total microbial aerosol concentrations, but did have a significant effect on culturable microbial aerosol fallout. Molecular analyses of the microbes settling out of near-shore aerosols provided further evidence of local ocean to terrestrial transport of microbes. Aerosol and surface ocean bacterial communities shared species and in general were dominated by organisms previously sampled in marine environments. Fog presence strengthened the microbial connection between water and land through

  20. Aerosol extinction in coastal zone

    NARCIS (Netherlands)

    Piazzola, J.; Kaloshin, G.; Leeuw, G. de; Eijk, A.M.J. van

    2004-01-01

    The performance of electro-optical systems can be substantially affected by aerosol particles that scatter and absorb electromagnetic radiation. A few years ago, an empirical model was developed describing the aerosol size distributions in the Mediterranean coastal atmosphere near Toulon (France). T

  1. Aerosol therapy in young children

    NARCIS (Netherlands)

    H.M. Janssens (Hettie)

    2001-01-01

    textabstractInhalation of aerosolized drugs has become an established means for treatment of pulmonary diseases in the last fifiy years. The majoriry of aerosol therapy in childhood concerns inhaled corticosteroids and bronchodilators in the management of asthma. Administration of drugs via the inha

  2. Modeling of pollution aerosols in Ile-de-France

    International Nuclear Information System (INIS)

    The modeling of aerosols is a major stake in the understanding of the emission processes and evolution of particulates in the atmosphere. However, the parameterizations used in today's aerosol models still comprise many uncertainties. This work has been motivated by the need of better identifying the weaknesses of aerosols modeling tools and by the necessity of having new validation methods for a 3D evaluation of models. The studies have been carried out using the CHIMERE chemistry-transport model, which allows to simulate the concentrations and physico-chemical characteristics of pollution aerosols at the European scale and in Ile-de-France region. The validation approach used is based on the complementarity of the measurements performed on the ground by monitoring networks with those acquired during the ESQUIF campaign (study and simulation of air quality in Ile-de-France), with lidar and photometric measurements and with satellite observations. The comparison between the observations and the simulations has permitted to identify and reduce the modeling errors, and to characterize the aerosol properties in the vicinity of an urban area. (J.S.)

  3. Hand calculations for transport of radioactive aerosols through sampling systems.

    Science.gov (United States)

    Hogue, Mark; Thompson, Martha; Farfan, Eduardo; Hadlock, Dennis

    2014-05-01

    Workplace air monitoring programs for sampling radioactive aerosols in nuclear facilities sometimes must rely on sampling systems to move the air to a sample filter in a safe and convenient location. These systems may consist of probes, straight tubing, bends, contractions and other components. Evaluation of these systems for potential loss of radioactive aerosols is important because significant losses can occur. However, it can be very difficult to find fully described equations to model a system manually for a single particle size and even more difficult to evaluate total system efficiency for a polydispersed particle distribution. Some software methods are available, but they may not be directly applicable to the components being evaluated and they may not be completely documented or validated per current software quality assurance requirements. This paper offers a method to model radioactive aerosol transport in sampling systems that is transparent and easily updated with the most applicable models. Calculations are shown with the R Programming Language, but the method is adaptable to other scripting languages. The method has the advantage of transparency and easy verifiability. This paper shows how a set of equations from published aerosol science models may be applied to aspiration and transport efficiency of aerosols in common air sampling system components. An example application using R calculation scripts is demonstrated. The R scripts are provided as electronic attachments. PMID:24667389

  4. Aerosol-cloud associations over Gangetic Basin during a typical monsoon depression event using WRF-Chem simulation

    Science.gov (United States)

    Sarangi, Chandan; Tripathi, S. N.; Tripathi, Shivam; Barth, Mary C.

    2015-10-01

    To study aerosol-cloud interactions over the Gangetic Basin of India, the Weather Research and Forecasting model coupled with chemistry (WRF-Chem) has been applied to a typical monsoon depression event prevalent between the 23 and 29 August 2009. This event was sampled during the Cloud Aerosol Interaction and Precipitation Enhancement EXperiment (CAIPEEX) aircraft campaign, providing measurements of aerosol and cloud microphysical properties from two sorties. Comparison of the simulated meteorological, thermodynamical, and aerosol fields against satellite and in situ aircraft measurements illustrated that the westward propagation of the monsoon depression and the cloud, aerosol, and rainfall spatial distribution was simulated reasonably well using anthropogenic emission rates from Monitoring Atmospheric Composition and Climate project along with cityZEN projects (MACCity)+Intercontinental Chemical Transport Experiment Phase B anthropogenic emission rates. However,the magnitude of aerosol optical depth was underestimated by up to 50%. A simulation with aerosol emissions increased by a factor of 6 over the CAIPEEX campaign domain increased the simulated aerosol concentrations to values close to the observations, mainly within boundary layer. Comparison of the low-aerosol simulation and high-aerosol simulation for the two sorties illustrated that more anthropogenic aerosols increased the cloud condensing nuclei (CCN) and cloud droplet mass concentrations. The number of simulated cloud droplets increased while the cloud droplet effective radii decreased, highlighting the importance of CCN-cloud feedbacks over this region. The increase in simulated anthropogenic aerosols (including absorbing aerosols) also increased the temperature of air parcels below clouds and thus the convective available potential energy (CAPE). The increase in CAPE intensified the updraft and invigorated the cloud, inducing formation of deeper clouds with more ice-phase hydrometeors for both cases

  5. Correlation for aerosol sedimentation

    International Nuclear Information System (INIS)

    The fission product source term from a postulated light water reactor (LWR) accident has several components. One of these components is the suspended aerosols present in the atmosphere during containment degradation and failure. Sedimentation, inertial impaction, and Stefan-Nusselt flows are the dominant natural removal mechanisms in the containment atmosphere for the majority of the postulated LWR severe accidents. The sedimentation correlation described was developed for conditions applicable to the primary coolant system and containment under severe accident conditions. The correlation exists as a result of a unique nondimensional mass concentration versus nondimensional particle volume

  6. Wide Area Wind Field Monitoring Status & Results

    Energy Technology Data Exchange (ETDEWEB)

    Alan Marchant; Jed Simmons

    2011-09-30

    Volume-scanning elastic has been investigated as a means to derive 3D dynamic wind fields for characterization and monitoring of wind energy sites. An eye-safe volume-scanning lidar system was adapted for volume imaging of aerosol concentrations out to a range of 300m. Reformatting of the lidar data as dynamic volume images was successfully demonstrated. A practical method for deriving 3D wind fields from dynamic volume imagery was identified and demonstrated. However, the natural phenomenology was found to provide insufficient aerosol features for reliable wind sensing. The results of this study may be applicable to wind field measurement using injected aerosol tracers.

  7. Aerosols indirectly warm the Arctic

    Directory of Open Access Journals (Sweden)

    T. Mauritsen

    2010-07-01

    Full Text Available On average, airborne aerosol particles cool the Earth's surface directly by absorbing and scattering sunlight and indirectly by influencing cloud reflectivity, life time, thickness or extent. Here we show that over the central Arctic Ocean, where there is frequently a lack of aerosol particles upon which clouds may form, a small increase in aerosol loading may enhance cloudiness thereby likely causing a climatologically significant warming at the ice-covered Arctic surface. Under these low concentration conditions cloud droplets grow to drizzle sizes and fall, even in the absence of collisions and coalescence, thereby diminishing cloud water. Evidence from a case study suggests that interactions between aerosol, clouds and precipitation could be responsible for attaining the observed low aerosol concentrations.

  8. An Indigenously Developed Insecticidal Aerosol

    Directory of Open Access Journals (Sweden)

    R. N. Varma

    1969-10-01

    Full Text Available A total of 6 "Test" insecticidal aerosols (TA-I to VI indigenously produced were tested during the years 1966-67 as suitable replacements for imported aerosols.TA-I produced deep yellow staining and a yellowish spray mist. Its capacity was only 120 ml fluid. TA-III types II and III containing modified aerosol formulation with "Esso solvent 3245" and mineral turpentine oil (Burmah Shelland Freon 12 11 (all indigenouswere comparable to he "SRA" in insecticidial efficacy. The container was also manufactured in the country and it compared well with the "SRA" in construction, resistance against rough usage and mechanical function. They were both finally approved for introduction in the services as replacement for imported aerosols. TA-IV performed well in inscticidial assessment, but the aerosols formulation. TA-V and VI were similar to TA-III types II and III respectively.

  9. Compact and portable system for evaluation of individual exposure at aerosol particle in urban area

    International Nuclear Information System (INIS)

    A compact and portable system for real-time acquisition of aerosol concentration data in urban and extra-urban area is presented. It is based on two optical type aerosol monitors integrated by aerosol particle separating and collecting devices, assembled into a carrying case together with temperature and relative humidity sensors and a programmable analog data logger; data output is addressed to a dedicated printer or personal computer. Further data about particle size, morphological aspect and particle mass concentration are obtainable by weighing supports used to concurrently collect aerosol particles and/or by means of microanalytical techniques. System performances are evaluated from the point of view of portability, possibility of use as stationary sampler for long-term monitoring purposes and coherence between optical response and ponderal mass. Some tests are finally carried out, to investigate the effect of relative humidity on the optical response of this type of instruments

  10. Characterization and source apportionment of aerosol light extinction with a coupled model of CMB-IMPROVE in Hangzhou, Yangtze River Delta of China

    Science.gov (United States)

    Wang, Jiao; Zhang, Yu-fen; Feng, Yin-chang; Zheng, Xian-jue; Jiao, Li; Hong, Sheng-mao; Shen, Jian-dong; Zhu, Tan; Ding, Jing; Zhang, Qi

    2016-09-01

    To investigate the characteristics and sources of aerosol light extinction in the Yangtze River Delta of China, a campaign was carried out in Hangzhou from December 2013 to November 2014. Hourly data for air pollutants including PM2.5, SO2, NO2, O3 and CO, and aerosol optical properties including aerosol scattering coefficient and aerosol absorbing coefficient was obtained in the environmental air quality automatic monitoring station. Meteorological parameters were measured synchronously in the automated meteorology monitoring station. Additionally, around seven sets of ambient PM2.5 samples per month were collected and analyzed during the campaign. The annual mean aerosol scattering coefficient, aerosol absorbing coefficient and aerosol single scattering albedo measured in this study was 514 ± 284 Mm- 1, 35 ± 20 Mm- 1 and 94% respectively. The aerosol extinction coefficient reconstructed using the modified IMPROVE (Interagency Monitoring of Protected Visual Environment) formula was compared to the measured extinction coefficient. Better correlations could be found between the measured and reconstructed extinction coefficient when RH was under 90%. A coupled model of CMB (chemical mass balance) and modified IMPROVE was used to apportion the sources of aerosol light extinction in Hangzhou. Vehicle exhaust, secondary nitrate and secondary sulfate were identified as the most significant sources for aerosol light extinction, accounted for 30.2%, 24.1% and 15.8% respectively.

  11. Modeling of pollution aerosols in Ile-de-France; Modelisation des aerosols de pollution en Ile-de-France

    Energy Technology Data Exchange (ETDEWEB)

    Hodzic, A

    2005-10-15

    The modeling of aerosols is a major stake in the understanding of the emission processes and evolution of particulates in the atmosphere. However, the parameterizations used in today's aerosol models still comprise many uncertainties. This work has been motivated by the need of better identifying the weaknesses of aerosols modeling tools and by the necessity of having new validation methods for a 3D evaluation of models. The studies have been carried out using the CHIMERE chemistry-transport model, which allows to simulate the concentrations and physico-chemical characteristics of pollution aerosols at the European scale and in Ile-de-France region. The validation approach used is based on the complementarity of the measurements performed on the ground by monitoring networks with those acquired during the ESQUIF campaign (study and simulation of air quality in Ile-de-France), with lidar and photometric measurements and with satellite observations. The comparison between the observations and the simulations has permitted to identify and reduce the modeling errors, and to characterize the aerosol properties in the vicinity of an urban area. (J.S.)

  12. Second organic aerosol formation from the ozonolysis of α-pinene in the presence of dry submicron ammonium sulfate aerosol

    Institute of Scientific and Technical Information of China (English)

    ZHAO Zhe; HAO Jiming; LI Junhua; WU Shan

    2008-01-01

    An indoor chamber facility is described for investigation of atmospheric aerosol chemistry. Two sets of α-pinene ozonolysisexperiments were conducted in the presence of dry ammonium sulfate seed particle: ozone limited experiments and α-pinene limitedexperiments. The concentration of gas phase and particle phase species was monitored continuously by on-line instruments andrecorded automatically by data sampling system. The evolution of size distribution was measured by a scanning mobility particlesizer (SMPS), and α-pinene consumed was measured using GC-FID. Secondary organic aerosol (SOA) produced for seed-free systemis 100% organic in content, resulting from a sufficient supersaturation of low volatility organics to produce homogeneous nucleationfollowed by condensation to the aerosol. Secondary organic aerosol produced in seeded system is a mixture of organic and inorganicconstituents, initially forms via condensation onto the inorganic particles, and subsequent growth occurs via absorption into the organicsurface coating the inorganic core. Although the formation process and the size distribution for seed-free system and seeded system isdifferent, the ultimate mass of SOA formed is equal, and SOA yield for the two system located in the same regression line when usingone-product model, suggesting that the presence of dry ammonium sulfate seed has no measurable effect on the total aerosol yield, and the dry seed particle acts solely as a site upon which organic deposition occurs.

  13. Retrieval of Aerosol Parameters from Continuous H24 Lidar-Ceilometer Measurements

    Science.gov (United States)

    Dionisi, D.; Barnaba, F.; Costabile, F.; Di Liberto, L.; Gobbi, G. P.; Wille, H.

    2016-06-01

    Ceilometer technology is increasingly applied to the monitoring and the characterization of tropospheric aerosols. In this work, a method to estimate some key aerosol parameters (extinction coefficient, surface area concentration and volume concentration) from ceilometer measurements is presented. A numerical model has been set up to derive a mean functional relationships between backscatter and the above mentioned parameters based on a large set of simulated aerosol optical properties. A good agreement was found between the modeled backscatter and extinction coefficients and the ones measured by the EARLINET Raman lidars. The developed methodology has then been applied to the measurements acquired by a prototype Polarization Lidar-Ceilometer (PLC). This PLC instrument was developed within the EC- LIFE+ project "DIAPASON" as an upgrade of the commercial, single-channel Jenoptik CHM15k system. The PLC run continuously (h24) close to Rome (Italy) for a whole year (2013-2014). Retrievals of the aerosol backscatter coefficient at 1064 nm and of the relevant aerosol properties were performed using the proposed methodology. This information, coupled to some key aerosol type identification made possible by the depolarization channel, allowed a year-round characterization of the aerosol field at this site. Examples are given to show how this technology coupled to appropriate data inversion methods is potentially useful in the operational monitoring of parameters of air quality and meteorological interest.

  14. Distinct impact of different types of aerosols on surface solar radiation in China

    Science.gov (United States)

    Yang, Xin; Zhao, Chuanfeng; Zhou, Lijing; Wang, Yang; Liu, Xiaohong

    2016-06-01

    Observations of surface direct solar radiation (DSR) and visibility, particulate matter with aerodynamic diameters less than 2.5 µm (PM2.5), together with the aerosol optical thickness (AOT) taken from Moderate-Resolution Imaging Spectroradiometer and Multiangle Imaging Spectroradiometer, were investigated to gain insight into the impact of aerosol pollution on surface solar radiation in China. The surface DSR decreased during 2004-2014 compared with 1993~2003 over eastern China, but no clear reduction was observed in remote regions with cleaner air. Significant correlations of visibility, PM2.5, and regionally averaged AOT with the surface DSR over eastern China indicate that aerosol pollution greatly affects the energy available at the surface. The net loss of surface solar radiation also reduces the surface ground temperature over eastern China. However, the slope of the linear variation of the radiation with respect to atmospheric visibility is distinctly different at different stations, implying that the main aerosol type varies regionally. The largest slope value occurs at Zhengzhou and indicates that the aerosol absorption in central China is the highest, and lower slope values suggest relatively weakly absorbing types of aerosols at other locations. The spatial distribution of the linear slopes agrees well with the geographical distribution of the absorbing aerosols derived from the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations and Ozone Monitoring Instrument over China. The regional correlation between a larger slope value and higher absorbance properties of aerosols indicates that the net effects of aerosols on the surface solar energy and corresponding climatic effects are dependent on both aerosol amount and optical properties.

  15. Evolution of aerosol loading in Santiago de Chile between 1997 and 2014

    Science.gov (United States)

    Pistone, Kristina; Gallardo, Laura

    2015-04-01

    While aerosols produced by major cities are a significant component of anthropogenic climate forcing as well as an important factor in public health, many South American cities have not been a major focus of aerosol studies due in part to relatively few long-term observations in the region. Here we present a synthesis of the available data for the emerging megacity of Santiago, Chile. We report new results from a recent NASA AERONET (AErosol RObotic NETwork) site in the Santiago basin, combining these with previous AERONET observations in Santiago as well as with a new assessment of the 11-station air quality monitoring network currently administered by the Chilean Environment Ministry (MMA, Ministerio del Medio Ambiente) to assess changes in aerosol composition since 1997. While the average surface concentration of pollution components (specifically PM2.5 and PM10) has decreased, no significant change in total aerosol optical depth was observed. However, changes in aerosol size and composition are suggested by the proxy measurements. Previous studies have revealed limitations in purely satellite-based studies over Santiago due to biases from high surface reflection in the region, particularly in summer months (e.g. Escribano et al 2014). To overcome this difficulty and certain limitations in the air quality data, we next incorporate analysis of aerosol products from the Multi-angle Imaging SpectroRadiometer (MISR) instrument along with those from the Moderate Resolution Imaging Spectroradiometer (MODIS) instrument, both on NASA's Terra satellite, to better quantify the high bias of MODIS. Thus incorporating these complementary datasets, we characterize the aerosol over Santiago over the period 1997 to 2014, including the evolution of aerosol properties over time and seasonal dependencies in the observed trends. References: Escribano et al (2014), "Satellite Retrievals of Aerosol Optical Depth over a Subtropical Urban Area: The Role of Stratification and Surface

  16. Simulation study of the aerosol information content in OMI spectral reflectance measurements

    Directory of Open Access Journals (Sweden)

    B. Veihelmann

    2007-06-01

    Full Text Available The Ozone Monitoring Instrument (OMI is an imaging UV-VIS solar backscatter spectrometer and is designed and used primarily to retrieve trace gases like O3 and NO2 from the measured Earth reflectance spectrum in the UV-visible (270–500 nm. However, also aerosols are an important science target of OMI. The multi-wavelength algorithm is used to retrieve aerosol parameters from OMI spectral reflectance measurements in up to 20 wavelength bands. A Principal Component Analysis (PCA is performed to quantify the information content of OMI reflectance measurements on aerosols and to assess the capability of the multi-wavelength algorithm to discern various aerosol types. This analysis is applied to synthetic reflectance measurements for desert dust, biomass burning aerosols, and weakly absorbing anthropogenic aerosol with a variety of aerosol optical thicknesses, aerosol layer altitudes, refractive indices and size distributions. The range of aerosol parameters considered covers the natural variability of tropospheric aerosols. This theoretical analysis is performed for a large number of scenarios with various geometries and surface albedo spectra for ocean, soil and vegetation. When the surface albedo spectrum is accurately known and clouds are absent, OMI reflectance measurements have 2 to 4 degrees of freedom that can be attributed to aerosol parameters. This information content depends on the observation geometry and the surface albedo spectrum. An additional wavelength band is evaluated, that comprises the O2-O2 absorption band at a wavelength of 477 nm. It is found that this wavelength band adds significantly more information than any other individual band.

  17. Determination of Aerosol Particle Diameter in Cementation Room of Radioactive Waste Management Instalation

    International Nuclear Information System (INIS)

    Determination of aerosol particle size distribution has been done using a low pressure cascade impactor with 8-stage metode. The aerosol was sampled with flow rate of 28.3 litre per minute during 4 hours. The counting and calculations result indicated that aerosol particle at compaction room have an aerodynamic median activity diameter (AMAD) between range (2.1 - 3.3) μm. This result could be used for detemine type of filter for contamination level monitoring and estimating the internal radiation level to workers from inhalation. (author)

  18. Atmospheric and aerosol chemistry

    International Nuclear Information System (INIS)

    This series presents critical reviews of the present position and future trends in modern chemical research. Short and concise reports on chemistry, each written by the world renowned experts. Still valid and useful after 5 or 10 years. More information as well as the electronic version of the whole content available at: springerlink.com. Christian George, Barbara D'Anna, Hartmut Herrmann, Christian Weller, Veronica Vaida, D. J. Donaldson, Thorsten Bartels-Rausch, Markus Ammann Emerging Areas in Atmospheric Photochemistry. Lisa Whalley, Daniel Stone, Dwayne Heard New Insights into the Tropospheric Oxidation of Isoprene: Combining Field Measurements, Laboratory Studies, Chemical Modelling and Quantum Theory. Neil M. Donahue, Allen L. Robinson, Erica R. Trump, Ilona Riipinen, Jesse H. Kroll Volatility and Aging of Atmospheric Organic Aerosol. P. A. Ariya, G. Kos, R. Mortazavi, E. D. Hudson, V. Kanthasamy, N. Eltouny, J. Sun, C. Wilde Bio-Organic Materials in the Atmosphere and Snow: Measurement and Characterization V. Faye McNeill, Neha Sareen, Allison N. Schwier Surface-Active Organics in Atmospheric Aerosols.

  19. Study on distribution of aerosol optical depth in Chongqing urban area

    Science.gov (United States)

    Yang, Shiqi; Liu, Can; Gao, Yanghua

    2015-12-01

    This paper selected 6S (second simulation of the satellite signal in the solar spectrum) model with dark pixel method to inversion aerosol optical depth by MODIS data, and got the spatial distribution and the temporal distribution of Chongqing urban area. By comparing with the sun photometer and API data, the result showed that the inversion method can be used in aerosol optical thickness monitoring in Chongqing urban area.

  20. Long-term trends in aerosol optical characteristics in the Po Valley, Italy

    OpenAIRE

    Putaud, J. P.; Cavalli, F; S. Martins dos Santos; A. Dell'Acqua

    2014-01-01

    Aerosol properties have been monitored by ground-based in situ and remote sensing measurements at the station for atmospheric research located in Ispra, on the edge of the Po Valley, for almost one decade. In situ measurements are performed according to Global Atmosphere Watch recommendations, and quality is assured through the participation in regular inter-laboratory comparisons. Sun-photometer data are produced by the Aerosol Robotic Network (AERONET). Data show significant dec...

  1. Temporal and spectral variation of desert dust and biomass burning aerosol scenes from 1995–2000 using GOME

    Directory of Open Access Journals (Sweden)

    I. Aben

    2006-02-01

    Full Text Available Global Ozone Monitoring Experiment (GOME Absorbing Aerosol Index (AAI and AAI-related residue data were used to investigate areas with UV-absorbing aerosols. Time series of regionally averaged residues show the seasonal variation and trends of aerosols and clouds in climatologically important parts of the globe. GOME spectra were used to study scenes containing specific types of aerosols. AAI data are specifically sensitive to biomass burning aerosols (BBA and desert dust aerosols (DDA. Areas where these aerosols are regularly found were analysed to find spectral fingerprints in the ultraviolet (UV, visible and near-infrared (near-IR, to establish an aerosol type classification of BBA and DDA. Spectral residues are different for BBA and DDA, but over deserts the surface albedo is dominant beyond the UV and spectral residues cannot be used over land. Over oceans, about half of the BBA scenes show a very high reflectance that is never observed for DDA scenes. However, in the case of low reflectance scenes BBA and DDA cannot be distinguished. This is in part due to the microphysical and optical properties of biomass burning aerosols, which are highly variable in time, making it difficult to specify them spectrally as one type. Because of their high hygroscopicity BBA are often found in the presence of clouds, which disturb the spectrum of the scenes. Desert dust aerosols are much less hygroscopic and behave spectrally more uniformly.

  2. Evaluation of cell sorting aerosols and containment by an optical airborne particle counter.

    Science.gov (United States)

    Xie, Mike; Waring, Michael T

    2015-08-01

    Understanding aerosols produced by cell sorting is critical to biosafety risk assessment and validation of containment efficiency. In this study an Optical Airborne Particle Counter was used to analyze aerosols produced by the BD FACSAria and to assess the effectiveness of its aerosol containment. The suitability of using this device to validate containment was directly compared to the Glo-Germ method put forth by the International Society for Advancement of Cytometry (ISAC) as a standard for testing. It was found that high concentrations of aerosols ranging from 0.3 µm to 10 µm can be detected in failure mode, with most less than 5 µm. In most cases, while numerous aerosols smaller than 5 µm were detected by the Optical Airborne Particle Counter, no Glo-Germ particles were detected, indicating that small aerosols are under-evaluated by the Glo-Germ method. The results demonstrate that the Optical Airborne Particle Counter offers a rapid, economic, and quantitative analysis of cell sorter aerosols and represents an improved method over Glo-Germ for the task of routine validation and monitoring of aerosol containment for cell sorting. PMID:26012776

  3. Relationship between aerosol characteristics and altitude based on multi-measurements and model simulations

    Science.gov (United States)

    Nakata, Makiko; Ohshima, Tsubasa; Fujito, Toshiyuki; Sano, Itaru; Mukai, Sonoyo

    2010-10-01

    The suspending particulate matter (PM2.5) is a typical indicator of small particles in the atmosphere. Accordingly in order to monitor the air quality, sampling of PM2.5 has been widely undertaken over the world, especially in the urban cities. On the other hand, it is known that the sun photometry provides us with the aerosol information, e.g. aerosol optical thickness (AOT), aerosol size information and so on. Simultaneous measurements of PM2.5 and the AOT have been performed at a NASA/AERONET (Aerosol Robotics Network) site in urban city of Higashi-Osaka in Japan since March 2004, and successfully provided a linear correlation between PM2.5 and AOT in separately considering with several cases, e.g. usual, anthropogenic aerosols, dust aerosols and so on. This fact suggests that the vertical distribution also should be taken into account separately for each aerosol type. In this work, vertical profiles of atmospheric aerosols are considered based on combination use of photometric data with AERONET, LIDAR (Light Detection and Ranging) measurements and model simulations.

  4. Evaluation and application of passive and active optical remote sensing methods for the measurement of atmospheric aerosol properties

    Energy Technology Data Exchange (ETDEWEB)

    Mielonen, T.

    2010-07-01

    Atmospheric aerosol particles affect the atmosphere's radiation balance by scattering and absorbing sunlight. Moreover, the particles act as condensation nuclei for clouds and affect their reflectivity. In addition, aerosols have negative health effects and they reduce visibility. Aerosols are emitted into the atmosphere from both natural and anthropogenic sources. Different types of aerosols have different effects on the radiation balance, thus global monitoring and typing of aerosols is of vital importance. In this thesis, several remote sensing methods used in the measurement of atmospheric aerosols are evaluated. Remote sensing of aerosols can be done with active and passive instruments. Passive instruments measure radiation emitted by the sun and the Earth while active instruments have their own radiation source, for example a black body radiator or laser. The instruments utilized in these studies were sun photometers (PFR, Cimel), lidars (POLLYXT, CALIOP), transmissiometer (OLAF) and a spectroradiometer (MODIS). Retrieval results from spaceborne instruments (MODIS, CALIOP) were evaluated with ground based measurements (PFR, Cimel). In addition, effects of indicative aerosol model assumptions on the calculated radiative transfer were studied. Finally, aerosol particle mass at the ground level was approximated from satellite measurements and vertical profiles of aerosols measured with a lidar were analyzed. For the evaluation part, these studies show that the calculation of aerosol induced attenuation of radiation based on aerosol size distribution measurements is not a trivial task. In addition to dry aerosol size distribution, the effect of ambient relative humidity on the size distribution and the optical properties of the aerosols need to be known in order to achieve correct results from the calculations. Furthermore, the results suggest that aerosol size parameters retrieved from passive spaceborne measurements depend heavily on surgace reflectance

  5. Aerosol composition and variability in the Baltimore-Washington, DC region

    Science.gov (United States)

    Beyersdorf, A. J.; Ziemba, L. D.; Chen, G.; Corr, C. A.; Crawford, J. H.; Diskin, G. S.; Moore, R. H.; Thornhill, K. L.; Winstead, E. L.; Anderson, B. E.

    2015-08-01

    In order to utilize satellite-based aerosol measurements for the determination of air quality, the relationship between aerosol optical properties (wavelength-dependent, column-integrated extinction measured by satellites) and mass measurements of aerosol loading (PM2.5 used for air quality monitoring) must be understood. This connection varies with many factors including those specific to the aerosol type, such as composition, size and hygroscopicity, and to the surrounding atmosphere, such as temperature, relative humidity (RH) and altitude, all of which can vary spatially and temporally. During the DISCOVER-AQ (Deriving Information on Surface conditions from Column and Vertically Resolved Observations Relevant to Air Quality) project, extensive in-situ atmospheric profiling in the Baltimore, MD-Washington, DC region was performed during fourteen flights in July 2011. Identical flight plans and profile locations throughout the project provide meaningful statistics for determining the variability in and correlations between aerosol loading, composition, optical properties and meteorological conditions. Measured water-soluble aerosol mass was composed primarily of ammonium sulfate (campaign average of 32 %) and organics (57 %). A distinct difference in composition was observed with high-loading days having a proportionally larger percentage of ammonium sulfate (up to 49 %) due to transport from the Ohio River Valley. This composition shift caused a change in the aerosol water-uptake potential (hygroscopicity) such that higher relative contributions of ammonium sulfate increased the bulk aerosol hygroscopicity. These days also tended to have higher relative humidity causing an increase in the water content of the aerosol. Conversely, low aerosol loading days had lower ammonium sulfate and higher black carbon contributions causing lower single scattering albedos (SSAs). The average black carbon concentrations were 240 ng m-3 in the lowest 1 km decreasing to 35 ng m-3

  6. Aerosol composition and variability in the Baltimore–Washington, DC region

    Directory of Open Access Journals (Sweden)

    A. J. Beyersdorf

    2015-08-01

    Full Text Available In order to utilize satellite-based aerosol measurements for the determination of air quality, the relationship between aerosol optical properties (wavelength-dependent, column-integrated extinction measured by satellites and mass measurements of aerosol loading (PM2.5 used for air quality monitoring must be understood. This connection varies with many factors including those specific to the aerosol type, such as composition, size and hygroscopicity, and to the surrounding atmosphere, such as temperature, relative humidity (RH and altitude, all of which can vary spatially and temporally. During the DISCOVER-AQ (Deriving Information on Surface conditions from Column and Vertically Resolved Observations Relevant to Air Quality project, extensive in-situ atmospheric profiling in the Baltimore, MD–Washington, DC region was performed during fourteen flights in July 2011. Identical flight plans and profile locations throughout the project provide meaningful statistics for determining the variability in and correlations between aerosol loading, composition, optical properties and meteorological conditions. Measured water-soluble aerosol mass was composed primarily of ammonium sulfate (campaign average of 32 % and organics (57 %. A distinct difference in composition was observed with high-loading days having a proportionally larger percentage of ammonium sulfate (up to 49 % due to transport from the Ohio River Valley. This composition shift caused a change in the aerosol water-uptake potential (hygroscopicity such that higher relative contributions of ammonium sulfate increased the bulk aerosol hygroscopicity. These days also tended to have higher relative humidity causing an increase in the water content of the aerosol. Conversely, low aerosol loading days had lower ammonium sulfate and higher black carbon contributions causing lower single scattering albedos (SSAs. The average black carbon concentrations were 240 ng m−3 in the lowest 1 km

  7. Two-Column Aerosol Project: Aerosol Light Extinction Measurements Field Campaign Report

    Energy Technology Data Exchange (ETDEWEB)

    Dubey, Manvendra [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Aiken, Allison [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Berg, Larry K. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Freedman, Andrew [Aerodyne Research, Inc., Billerica, MA (United States); Gorkowski, Kyle [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-09-01

    We deployed Aerodyne Research Inc.’s first Cavity Attenuated Phase Shift extinction (CAPS PMex) monitor (built by Aerodyne) that measures light extinction by using a visible-light-emitting diode (LED) as a light source, a sample cell incorporating two high-reflectivity mirrors centered at the wavelength of the LED, and a vacuum photodiode detector in Cape Cod in 2012/13 for the U.S. Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) Climate Research Facility’s Two-Column Aerosol Project (TCAP). The efficacy of this instrument is based on the fact that aerosols are broadband scatterers and absorbers of light. The input LED is square-wave modulated and passed through the sample cell that distorts it due to exponential decay by aerosol light absorption and scattering; this is measured at the detector. The amount of phase shift of the light at the detector is used to determine the light extinction. This extinction measurement provides an absolute value, requiring no calibration. The goal was to compare the CAPS performance with direct measurements of absorption with ARM’s baseline photoacoustic soot spectrometer (PASS-3) and nephelometer instruments to evaluate its performance.

  8. Aerosol quantification with the Aerodyne Aerosol Mass Spectrometer: detection limits and ionizer background effects

    Directory of Open Access Journals (Sweden)

    F. Drewnick

    2008-10-01

    Full Text Available Systematic laboratory experiments were performed to investigate quantification of various species with two versions of the Aerodyne Aerosol Mass Spectrometer, a Q-AMS and a c-ToF-AMS. Here we present a new method to continuously determine the detection limits of the AMS analyzers during regular measurements, yielding DL information under various measurement conditions. Minimum detection limits range from 0.03 μg m−3 (nitrate, sulfate, and chloride up to 0.5 μg m−3 (organics for the Q-AMS. Those of the c-ToF-AMS are found between 0.003 μg m−3 (nitrate, sulfate and 0.03 μg m−3 (ammonium, organics. The DL values found for the c-ToF-AMS were ~10 times lower than those of the Q-AMS, mainly due to differences in ion duty cycle. Effects causing an increase of the detection limits include long-term instrument contamination, measurement of high aerosol mass concentrations and short-term instrument history. The self-cleaning processes which reduce the instrument background after measurement of large aerosol concentrations as well as the influences of increased instrument background on mass concentration measurements are discussed. Finally, improvement of detection limits by extension of averaging time intervals, selected or reduced ion monitoring, and variation of particle-to-background measurement ratio are investigated.

  9. Aerosol light absorption and its measurement: A review

    International Nuclear Information System (INIS)

    Light absorption by aerosols contributes to solar radiative forcing through absorption of solar radiation and heating of the absorbing aerosol layer. Besides the direct radiative effect, the heating can evaporate clouds and change the atmospheric dynamics. Aerosol light absorption in the atmosphere is dominated by black carbon (BC) with additional, significant contributions from the still poorly understood brown carbon and from mineral dust. Sources of these absorbing aerosols include biomass burning and other combustion processes and dust entrainment. For particles much smaller than the wavelength of incident light, absorption is proportional to the particle volume and mass. Absorption can be calculated with Mie theory for spherical particles and with more complicated numerical methods for other particle shapes. The quantitative measurement of aerosol light absorption is still a challenge. Simple, commonly used filter measurements are prone to measurement artifacts due to particle concentration and modification of particle and filter morphology upon particle deposition, optical interaction of deposited particles and filter medium, and poor angular integration of light scattered by deposited particles. In situ methods measure particle absorption with the particles in their natural suspended state and therefore are not prone to effects related to particle deposition and concentration on filters. Photoacoustic and refractive index-based measurements rely on the heating of particles during light absorption, which, for power-modulated light sources, causes an acoustic signal and modulation of the refractive index in the air surrounding the particles that can be quantified with a microphone and an interferometer, respectively. These methods may suffer from some interference due to light-induced particle evaporation. Laser-induced incandescence also monitors particle heating upon absorption, but heats absorbing particles to much higher temperatures to quantify BC mass

  10. The GRAPE aerosol retrieval algorithm

    Directory of Open Access Journals (Sweden)

    G. E. Thomas

    2009-11-01

    Full Text Available The aerosol component of the Oxford-Rutherford Aerosol and Cloud (ORAC combined cloud and aerosol retrieval scheme is described and the theoretical performance of the algorithm is analysed. ORAC is an optimal estimation retrieval scheme for deriving cloud and aerosol properties from measurements made by imaging satellite radiometers and, when applied to cloud free radiances, provides estimates of aerosol optical depth at a wavelength of 550 nm, aerosol effective radius and surface reflectance at 550 nm. The aerosol retrieval component of ORAC has several incarnations – this paper addresses the version which operates in conjunction with the cloud retrieval component of ORAC (described by Watts et al., 1998, as applied in producing the Global Retrieval of ATSR Cloud Parameters and Evaluation (GRAPE data-set.

    The algorithm is described in detail and its performance examined. This includes a discussion of errors resulting from the formulation of the forward model, sensitivity of the retrieval to the measurements and a priori constraints, and errors resulting from assumptions made about the atmospheric/surface state.

  11. Research on aerosol formation, aerosol behaviour, aerosol filtration, aerosol measurement techniques and sodium fires at the Laboratory for Aerosol Physics and Filter Technology at the Nuclear Research Center Karlsruhe

    International Nuclear Information System (INIS)

    The behaviour of aerosols in LMFBR plant systems is of great importance for a number of problems, both normal operational and accident kind. This paper covers the following: aerosol modelling for LMFBR containment systems; aerosol size spectrometry by laser light scattering; experimental facilities and experimental results concerned with aerosol release under accident conditions; filtration of sodium oxide aerosols by multilayer sand bed filters

  12. Shipborne aerosol IR decoy modulated by laser

    Institute of Scientific and Technical Information of China (English)

    叶晓英; 吴刚; 邓盼; 范宁

    2004-01-01

    Working principles, features, current situation and future development of the aerosol IR decoys are summarized in this paper, and a new type aerosol IR decoy aerosol IR decoy modulated by laser is emphasized. The simulation results show that compared with the traditional IR decoys, the late-model aerosol IR decoy effectively enhances the capability of protecting targets and countermining IR guidance weapons. It is a new direction of aerosol IR decoys.

  13. Effect of aerosolization on subsequent bacterial survival.

    OpenAIRE

    Walter, M V; Marthi, B; Fieland, V P; Ganio, L M

    1990-01-01

    To determine whether aerosolization could impair bacterial survival, Pseudomonas syringae and Erwinia herbicola were aerosolized in a greenhouse, the aerosol was sampled at various distances from the site of release by using all-glass impingers, and bacterial survival was followed in the impingers for 6 h. Bacterial survival subsequent to aerosolization of P. syringae and E. herbicola was not impaired 1 m from the site of release. P. syringae aerosolized at 3 to 15 m from the site of release ...

  14. Physico-chemical properties of aerosols in Sao Paulo, Brazil and mechanisms of secondary organic aerosol formation.

    Science.gov (United States)

    Artaxo, Paulo; Ferreira de Brito, Joel; Varanda Rizzo, Luciana; Luiza Godoy, Maria; Godoy, Jose Marcus

    2013-04-01

    Megacities emissions are increasingly becoming a global issue, where emissions from the transportation sector play an increasingly important role. Sao Paulo is a megacity with a population of about 18 million people, 7 million cars and large-scale industrial emissions. As a result of the vehicular and industrial emissions, the air quality in Sao Paulo is bellow WMO standards for aerosol particles and ozone. Many uncertainties are found on gas- and particulate matter vehicular emission factors and their following atmospheric processes, e.g. secondary organic aerosol formation. Due to the uniqueness of the vehicular fuel in Brazil, largely based on ethanol use, such characterization currently holds further uncertainties. To improve the understanding of the role of this unique emission characteristics, we are running a source apportionment study in Sao Paulo focused on the mechanisms of organic aerosol formation. One of the goals of this study is a quantitative aerosol source apportionment focused on vehicular emissions, including ethanol and gasohol (both fuels used by light-duty vehicles). This study comprises four sampling sites with continuous measurements for one year, where trace elements and organic aerosol are being measured for PM2.5 and PM10 along with real-time NOx, O3, PM10 and CO measurements. Aerosol optical properties and size distribution are being measured on a rotation basis between sampling stations. Furthermore, a Proton-Transfer-Reaction Mass Spectrometer (PTR-MS) and an Aerosol Chemical Speciation Monitor (ACSM) are used to measure in real time VOCs and aerosol composition, respectively. Trace elements were measured using XRF and OC/EC analysis was determined with a Sunset OC/EC instrument. A TSI Nephelometer with 3 wavelengths measure light scattering and a MAAP measure black carbon. Results show aerosol number concentrations ranging between 10,000 and 35,000 cm-3, mostly concentrated in the nucleation and Aitken modes, with a peak in size at 80

  15. A fixed frequency aerosol albedometer.

    Science.gov (United States)

    Thompson, Jonathan E; Barta, Nick; Policarpio, Danielle; Duvall, Richard

    2008-02-01

    A new method for the measurement of aerosol single scatter albedo (omega) at 532 nm was developed. The method employs cavity ring-down spectroscopy (CRDS) for measurement of aerosol extinction coefficient (b(ext)) and an integrating sphere nephelometer for determination of aerosol scattering coefficient (b(scat)). A unique feature of this method is that the extinction and scattering measurements are conducted simultaneously, on the exact same sample volume. Limits of detection (3s) for the extinction and scattering channel were 0.61 Mm(-1) and 2.7 Mm(-1) respectively. PMID:18542299

  16. eDPS Aerosol Collection

    Energy Technology Data Exchange (ETDEWEB)

    Venzie, J. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2015-10-13

    The eDPS Aerosol Collection project studies the fundamental physics of electrostatic aerosol collection for national security applications. The interpretation of aerosol data requires understanding and correcting for biases introduced from particle genesis through collection and analysis. The research and development undertaken in this project provides the basis for both the statistical correction of existing equipment and techniques; as well as, the development of new collectors and analytical techniques designed to minimize unwanted biases while improving the efficiency of locating and measuring individual particles of interest.

  17. Aerosol growth in Titan's ionosphere.

    Science.gov (United States)

    Lavvas, Panayotis; Yelle, Roger V; Koskinen, Tommi; Bazin, Axel; Vuitton, Véronique; Vigren, Erik; Galand, Marina; Wellbrock, Anne; Coates, Andrew J; Wahlund, Jan-Erik; Crary, Frank J; Snowden, Darci

    2013-02-19

    Photochemically produced aerosols are common among the atmospheres of our solar system and beyond. Observations and models have shown that photochemical aerosols have direct consequences on atmospheric properties as well as important astrobiological ramifications, but the mechanisms involved in their formation remain unclear. Here we show that the formation of aerosols in Titan's upper atmosphere is directly related to ion processes, and we provide a complete interpretation of observed mass spectra by the Cassini instruments from small to large masses. Because all planetary atmospheres possess ionospheres, we anticipate that the mechanisms identified here will be efficient in other environments as well, modulated by the chemical complexity of each atmosphere. PMID:23382231

  18. Comparison of Multi-angle Imaging SpectroRadiometer (MISR) joint aerosol product with high-resolution model output

    Science.gov (United States)

    Kalashnikova, O.; Lee, H.; Suzuki, K.; Braverman, A. J.

    2014-12-01

    The Multi-angle Imaging SpectroRadiometer (MISR) Level 3 Joint Aerosol product (JOINT_AS) provides global, descriptive summary of MISR Level 2 aerosol optical thickness (AOT) for eight different types of aerosols at 5 x 5 degrees of horizontal resolution in each month between March 2000 and present. Using Version 22 JOINT_AS, this study analyzed characteristics of the observed AOT distributions and compared various statistical moments of aerosol optical thickness derived from JOINT_AS with the results from Nonhydrostatic Icosahedral Atmospheric Model (NICAM) simulation. Overall, marginal distributions of AOT show highly positive skewness at many grid points. Some of the large skewness values are related to the problems in MISR's retrieval algorithm. For example, the positive skewness in AOT for strongly absorbing aerosols at mid- and high latitudes in winter results from few outlier values is due to cloud contamination over a wide area. Combined AOT for multiple MISR aerosol types is comparable to the AOT for carbonaceous, sulfate aerosols and dust particles from the NICAM simulation implemented with aerosol transport processes. NICAM's carbonaceous aerosols in the Southwest Africa show good agreement with MISR's strongly absorbing aerosols. The AOT of dust particles in MISR and NICAM exhibit similar spatial patterns over the Sahara desert. The AOT of nonabsorbing aerosols in MISR well represents spatial distributions of the sulfate aerosols originating from industrial complex over the Shandong Peninsula in China. Our results indicate that MISR's AOT for each aerosol type may be useful for monitoring biomass burning, dust storms and air pollution and evaluating chemistry climate models.

  19. Valuating report on radionuclide concentrations in aerosols in 1988

    International Nuclear Information System (INIS)

    Sample preparation - and measuring methods and results on aerosol samples from the Austrian Environment Radioactivity Monitoring Network are presented. Special emphasis is on Cs-134, Cs-137 (Chernobyl fallout) and I-131 from medical applications. Comparisons with 1987 are made. The lung doses for the population are estimated to be 0,5 - 5 nSv, i.e. very small. 8 refs., 15 figs., 11 tabs. (qui)

  20. Aerosol Transmission of Filoviruses

    Directory of Open Access Journals (Sweden)

    Berhanu Mekibib

    2016-05-01

    Full Text Available Filoviruses have become a worldwide public health concern because of their potential for introductions into non-endemic countries through international travel and the international transport of infected animals or animal products. Since it was first identified in 1976, in the Democratic Republic of Congo (formerly Zaire and Sudan, the 2013–2015 western African Ebola virus disease (EVD outbreak is the largest, both by number of cases and geographical extension, and deadliest, recorded so far in medical history. The source of ebolaviruses for human index case(s in most outbreaks is presumptively associated with handling of bush meat or contact with fruit bats. Transmission among humans occurs easily when a person comes in contact with contaminated body fluids of patients, but our understanding of other transmission routes is still fragmentary. This review deals with the controversial issue of aerosol transmission of filoviruses.

  1. Aerosol Transmission of Filoviruses.

    Science.gov (United States)

    Mekibib, Berhanu; Ariën, Kevin K

    2016-01-01

    Filoviruses have become a worldwide public health concern because of their potential for introductions into non-endemic countries through international travel and the international transport of infected animals or animal products. Since it was first identified in 1976, in the Democratic Republic of Congo (formerly Zaire) and Sudan, the 2013-2015 western African Ebola virus disease (EVD) outbreak is the largest, both by number of cases and geographical extension, and deadliest, recorded so far in medical history. The source of ebolaviruses for human index case(s) in most outbreaks is presumptively associated with handling of bush meat or contact with fruit bats. Transmission among humans occurs easily when a person comes in contact with contaminated body fluids of patients, but our understanding of other transmission routes is still fragmentary. This review deals with the controversial issue of aerosol transmission of filoviruses. PMID:27223296

  2. Stratospheric aerosol geoengineering

    International Nuclear Information System (INIS)

    The Geoengineering Model Intercomparison Project, conducting climate model experiments with standard stratospheric aerosol injection scenarios, has found that insolation reduction could keep the global average temperature constant, but global average precipitation would reduce, particularly in summer monsoon regions around the world. Temperature changes would also not be uniform; the tropics would cool, but high latitudes would warm, with continuing, but reduced sea ice and ice sheet melting. Temperature extremes would still increase, but not as much as without geoengineering. If geoengineering were halted all at once, there would be rapid temperature and precipitation increases at 5–10 times the rates from gradual global warming. The prospect of geoengineering working may reduce the current drive toward reducing greenhouse gas emissions, and there are concerns about commercial or military control. Because geoengineering cannot safely address climate change, global efforts to reduce greenhouse gas emissions and to adapt are crucial to address anthropogenic global warming

  3. Identification of secondary organic aerosols based on aerosol mass spectrometry

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Secondary organic aerosol (SOA) is one of the major components of aerosols in the atmosphere and has not been well understood so far.Due to the complex chemical composition of organic aerosols,the identification of SOA has been a hotspot and difficult issue in the field of aerosol study.This study attempts to quantitatively identify SOA in winter of Shenzhen based on positive matrix factorization (PMF) analysis.Major sources were resolved and SOA was identified subsequently according to the characteristic ion fragments measured by highly time-resolved aerosol mass spectrometer measurement.It showed that in the winter of Shenzhen the average SOA concentration was 9.41±6.33 g/m 3,accounting for 39.9±21.8% of the total organic mass.Compared with primary organic aerosol (POA),the SOA concentrations had no large variation,suggestive of characteristics of regional secondary pollutants.The ratio of SOA/BC had pronounced diurnal variation,similar to that of O x (O3+NO2),indicating SOA formation was significantly controlled by activity of photochemistry in the atmosphere.The most effective period for SOA formation was from 9 am~3 pm since the SOA/BC ratio increased by 122% during this period.This study provides a new technical method and a new idea for SOA investigation.

  4. The role of cloud contamination, aerosol layer height and aerosol model in the assessment of the OMI near-UV retrievals over the ocean

    Science.gov (United States)

    Gassó, Santiago; Torres, Omar

    2016-07-01

    Retrievals of aerosol optical depth (AOD) at 388 nm over the ocean from the Ozone Monitoring Instrument (OMI) two-channel near-UV algorithm (OMAERUV) have been compared with independent AOD measurements. The analysis was carried out over the open ocean (OMI and MODerate-resolution Imaging Spectrometer (MODIS) AOD comparisons) and over coastal and island sites (OMI and AERONET, the AErosol RObotic NETwork). Additionally, a research version of the retrieval algorithm (using MODIS and CALIOP (Cloud-Aerosol Lidar with Orthogonal Polarization) information as constraints) was utilized to evaluate the sensitivity of the retrieval to different assumed aerosol properties. Overall, the comparison resulted in differences (OMI minus independent measurements) within the expected levels of uncertainty for the OMI AOD retrievals (0.1 for AOD 0.3). Using examples from case studies with outliers, the reasons that led to the observed differences were examined with specific purpose to determine whether they are related to instrument limitations (i.e., pixel size, calibration) or algorithm assumptions (such as aerosol shape, aerosol height). The analysis confirms that OMAERUV does an adequate job at rejecting cloudy scenes within the instrument's capabilities. There is a residual cloud contamination in OMI pixels with quality flag 0 (the best conditions for aerosol retrieval according to the algorithm), resulting in a bias towards high AODs in OMAERUV. This bias is more pronounced at low concentrations of absorbing aerosols (AOD 388 nm ˜ < 0.5). For higher aerosol loadings, the bias remains within OMI's AOD uncertainties. In pixels where OMAERUV assigned a dust aerosol model, a fraction of them (< 20 %) had retrieved AODs significantly lower than AERONET and MODIS AODs. In a case study, a detailed examination of the aerosol height from CALIOP and the AODs from MODIS, along with sensitivity tests, was carried out by varying the different assumed parameters in the retrieval (imaginary

  5. Towards Optimal Aerosol Information for the Retrieval of Solar Surface Radiation Using Heliosat

    Directory of Open Access Journals (Sweden)

    Richard Mueller

    2015-06-01

    Full Text Available High quality data of surface radiation is a prerequisite for climate monitoring (Earth radiation budget and solar energy applications. A very common method to derive solar surface irradiance is the Heliosat method, a one channel approach for the retrieval of the effective cloud albedo (CAL. This information is then used to derive the solar surface irradiance by application of a clear sky model. The results of this study are based on radiative transfer modelling, visual inspection of satellite images and evaluation of satellite based solar surface radiation with ground measurements. The respective results provide evidence that variations in Aerosol Optical depth induced by desert storms and biomass burning events lead to a significant increase of the effective cloud albedo, thus, that certain aerosol events are interpreted as clouds by the method. For the estimation of the solar surface radiation aerosol information is needed as input for the clear sky model. As the aerosol effect is partly considered by CAL, there is a need to modify external aerosol information for the use within the clear sky model, e.g., by truncation of high aerosol loads. Indeed, it has been shown that a modified version of the Monitoring Atmospheric Composition and Climate (MACC aerosol information leads to better accuracy of the retrieved solar surface radiation than the original MACC data for the investigated 9 sites and time period (2006–2009. Further, the assumption of a constant aerosol optical depth of 0.18 provides also better accuracies of the estimated solar surface radiation than the original MACC data for the investigated sites and period. It is concluded that this is partly due to the consideration of scattering aerosols by the effective cloud albedo.

  6. Simulation of aerosol direct radiative forcing with RAMS-CMAQ in East Asia

    Science.gov (United States)

    Zhang, M.; Han, X.; Liu, X.

    2011-12-01

    The air quality modeling system RAMS-CMAQ is developed to assess aerosol direct radiative forcing by linking simulated meteorological parameters and aerosol mass concentration with the aerosol optical properties/radiative transfer module in this study. The module is capable of accounting for important factors that affect aerosol optical properties and radiative effect, such as incident wave length, aerosol size distribution, water uptake, and internal mixture. Subsequently, the modeling system is applied to simulate the temporal and spatial variations in mass burden, optical properties, and direct radiative forcing of diverse aerosols, including sulfate, nitrate, ammonium, black carbon, organic carbon, dust, and sea salt over East Asia throughout 2005. Model performance is fully evaluated using various observational data, including satellite monitoring of MODIS and surface measurements of EANET (Acid Deposition Monitoring Network), AERONET (Aerosol Robotic Network), and CSHNET (Chinese Sun Hazemeter Network). The correlation coefficients of the comparisons of daily average mass concentrations of sulfate, PM2.5, and PM10 between simulations and EANET measurements are 0.70, 0.61, and 0.64, respectively. It is also determined that the modeled aerosol optical depth (AOD) is in congruence with the observed results from the AERONET, the CSHNET, and the MODIS. The model results suggest that the high AOD values ranging from 0.8 to 1.2 are mainly distributed over the Sichuan Basin as well as over central and southeastern China, in East Asia. The aerosol direct radiative forcing patterns generally followed the AOD patterns. The strongest forcing effect ranging from -12 to -8 W/m2 was mainly distributed over the Sichuan Basin and the eastern China's coastal regions in the all-sky case at TOA, and the forcing effect ranging from -8 to -4 W/m2 could be found over entire eastern China, Korea, Japan, East China Sea, and the sea areas of Japan.

  7. Chemical characterization of submicron aerosol and particle growth events at a national background site (3295 m a.s.l.) on the Tibetan Plateau

    OpenAIRE

    Du, W.; Y. L. Sun; Xu, Y S; Jiang, Q.; Q. Q. Wang; Yang, W.; Wang, F.; Z. P. Bai; Zhao, X. D.; Yang, Y. C.

    2015-01-01

    Atmospheric aerosols exert highly uncertain impacts on radiative forcing and also have detrimental effects on human health. While aerosol particles are widely characterized in megacities in China, aerosol composition, sources and particle growth in rural areas in the Tibetan Plateau remain less understood. Here we present the results from an autumn study that was conducted from 5 September to 15 October 2013 at a national background monitoring station (3295 m a.s.l.) in the ...

  8. Chemical characterization of submicron aerosol and particle growth events at a national background site (3295 m a.s.l.) in the Tibetan Plateau

    OpenAIRE

    Du, W.; Y. L. Sun; Xu, Y S; Jiang, Q.; Q. Q. Wang; Yang, W.; Wang, F.; Z. P. Bai; Zhao, X. D.; Yang, Y. C.

    2015-01-01

    Atmospheric aerosols exert highly uncertain impacts on radiative forcing and also have detrimental effects on human health. While aerosol particles are widely characterized in megacities in China, aerosol composition, sources and particle growth in rural areas in the Tibetan Plateau remain less understood. Here we present the results from an autumn study that was conducted from 5 September to 15 October 2013 at a national background monitoring station (3295 ...

  9. Aerosol Characterisitics Over Alberta Using Modis and OMI Satellite Data

    Science.gov (United States)

    Marey, H. S.; Hashisho, Z., Sr.; Fu, L.; Gille, J. C.

    2015-12-01

    We present the first detailed analysis of optical aerosol characterization over Alberta based on satellite data analysis. Aerosol optical depth (AOD) at 550 nm for 11 years (2003-2013), derived from the Moderate Resolution Imaging Spectroradiometer (MODIS) sensor onboard NASA's Aqua satellite, was analyzed. Additionally, UV aerosol index (AI) data for 9 years (2005-2013) retrieved from the Ozone Monitoring Instrument (OMI) onboard NASA's Aura satellite was used to examine absorbing aerosols. Comparing AERONET to MODIS 3 km and 10 km products indicated a stronger correlation (r=0.9 for the latter vs 0.7 for the former) thus 10 km product has been utilized for this study. Overall, gridded seasonal maps (0.1 deg.) of the 11 yr averaged AOD illustrate the highest AOD during summer, followed by spring, with the lowest observed values during fall (there is no enough valid MODIS data in winter due to cloud cover). Aerosol optical properties exhibited large spatio-temporal heterogeneity in the summer with mean AOD of 0.25, followed by spring, while the fall had less variability with mean AOD below 0.1 for the entire region. However, the spatial analysis indicated hot spots around Edmonton and Calgary cities even in the fall when AODs are very low (close to background). All of the datasets showed interannual variability with no significant trend. The AI values ranged from 0.5 during winter to as high as 5 during summer suggesting mid- and long range transport of boreal fire emissions. Map correlation between AOD and UV AI showed large variability (0.2 to 0.7) indicating presence of different types of aerosols. These low correlations imply the presence of non-absorbing particles (e.g. sulfate) that comprise a relatively large mass fraction of AOD and/or low altitude particles.

  10. Radon and aerosol release from open-pit uranium mining

    International Nuclear Information System (INIS)

    The quantity of 222Rn (hereafter called radon) released per unit of uranium produced from open pit mining has been determined. A secondary objective was to determine the nature and quantity of airborne particles resulting from mine operations. To accomplish these objectives, a comprehensive study of the release rates of radon and aerosol material to the atmosphere was made over a one-year period from April 1979 to May 1980 at the Morton Ranch Mine which was operated by United Nuclear Corporation (UNC) in partnership with Tennessee Valley Authority (TVA). The mine is now operated for TVA by Silver King Mines. Morton Ranch Mine was one of five open pit uranium mines studied in central Wyoming. Corroborative measurements were made of radon flux and 226Ra (hereafter called radium) concentrations of various surfaces at three of the other mines in October 1980 and again at these three mines plus a fourth in April of 1981. Three of these mines are located in the Powder River Basin, about 80 kilometers east by northeast of Casper. One is located in the Shirley Basin, about 60 km south of Casper, and the remaining one is located in the Gas Hills, approximately 100 km west of Casper. The one-year intensive study included simultaneous measurement of several parameters: continuous measurement of atmospheric radon concentration near the ground at three locations, monthly 24-hour radon flux measurements from various surfaces, radium analyses of soil samples collected under each of the flux monitoring devices, monthly integrations of aerosols on dichotomous aerosol samplers, analysis of aerosol samplers for total dust loading, aerosol elemental and radiochemical composition, aerosol elemental composition by particle size, wind speed, wind direction, temperature, barometric pressure, and rainfall

  11. Influence of natural radioactive aerosols on artificial radioactivity detection in the Spanish surveillance networks

    International Nuclear Information System (INIS)

    The device used for continuous measurements of artificial α and β activity in Spanish radiological surveillance networks is the LB BAI 9850 monitor from the Berthold Company. The temporal variation of radon decay product equilibrium introduces a varying background signal in the artificial radioactivity in these monitors. This unwanted background signal can be significantly reduced by analyzing natural radioactive aerosols and their influence on the monitor

  12. Aerosol Size Distributions In Auckland.

    Czech Academy of Sciences Publication Activity Database

    Coulson, G.; Olivares, G.; Talbot, Nicholas

    2016-01-01

    Roč. 50, č. 1 (2016), s. 23-28. E-ISSN 1836-5876 Institutional support: RVO:67985858 Keywords : aerosol size distribution * particle number concentration * roadside Subject RIV: CF - Physical ; Theoretical Chemistry

  13. Aerosols Produced by Cosmic Rays

    DEFF Research Database (Denmark)

    Enghoff, Martin Andreas Bødker

    our investigation at the smallest scales, namely the role of cosmic ray produced ions on atmospheric aerosol nucleation and growth processes. Aerosol theory suggests that this is one of the most promising areas to search for an effect. However, guided by the nature of our initial results, it will be...... mechanism linking cosmic rays to clouds and climate is currently speculative, there have been various suggestions of the role atmospheric ions may play; these involve any one of a number of processes from the nucleation of aerosols up to the collection processes of cloud droplets. We have chosen to start...... applied to control the number of ions present. This will enable experiments to be performed both with and without the presence of ions, thus providing information as to the potential role of ions in aerosol processes....

  14. Highly Resolved Paleoclimatic Aerosol Records

    DEFF Research Database (Denmark)

    Kettner, Ernesto

    to paleotemperatures. Impurities in the matrix are comprised of particulate and soluble aerosols, each carrying information on its source’s activitiy and|or proximity. Opposed to gases and water isotopes, the seasonality of many aerosols is not smoothed out in the firn column so that large concentration gradients...... with frequently changing signs are preserved. Therefore, these aerosol records can be used for dating by annual layer counting. However, with increasing depth the annual layer thicknesses decreases due to pressure and ice flow and accurate dating is possible only as long as the rapid variations can be resolved...... experimentally. Over the last decades Continuous Flow Analysis (CFA) has become a well-established technique for aerosol quantification. In CFA, a piece of core is melted continuously and the melt water is analysed for an array of chemical impurities. When designing a CFA system, a trilemma between high sample...

  15. Survival of bacteria during aerosolization.

    OpenAIRE

    Marthi, B; Fieland, V P; Walter, M.; Seidler, R J

    1990-01-01

    One form of commercial application of microorganisms, including genetically engineered microorganisms is as an aerosol. To study the effect of aerosol-induced stress on bacterial survival, nonrecombinant spontaneous antibiotic-resistant mutants of four organisms, Enterobacter cloacae, Erwinia herbicola, Klebsiella planticola, and Pseudomonas syringae, were sprayed in separate experiments in a greenhouse. Samples were collected over a distance of 15 m from the spray site for enumeration. Spore...

  16. The influence of aerosol density upon the performance of centrifugal spectrometers

    International Nuclear Information System (INIS)

    Centrifugal instruments are valuable components for studying airborne particulate matter of health physics interest because a continuously graded aerodynamic diameter, Dae, spectrum is produced. Applications include the characterization of inhalation exposure aerosols, serving as particle monitors to measure respirable dose, and being the integral unit in a system to generate monodisperse aerosols. Some aerosols of health physics concern differ from the PSL aerosol used to calibrate centrifuges in two main respects: the particulate mass concentration, Cm, is large, and the aerosol gas is not air. The marked influence of these factors upon centrifuge performance is documented (T. B. Martonen, Ph.D. Thesis, University of Rochester, Rochester, NY, 1976). The phenomenon of cloud settling occurs when Cm is of sufficient magnitude. Aerosol gas effects can be defined in terms of the parameter K, the ratio of the aerosol gas to winnowing medium densities. Size classification is modified by diffusiophoretic forces when K1. In all cases, erroneous size distribution data results. Laboratory procedures are presented which permit accurate particle size assessment when aerosols of large Cm and/or K≠1 are sampled. An engineering analysis of centrifuge physics has been completed which allows optimum operating conditions, which may be quite different for different aerosols, to be computed. Cigarette smoke was used as a test aerosol to check the experimental and theoretical findings. Although it is shown to be subject to both cloud settling and dense gas subsidence, accurate size classification was obtained. The differential equation describing particle motion in centrifuges has been formulated and solved. Further, techniques of dimensional analysis were applied to the equations modelling flow in centrifuges; results indicate how operating conditions and instrument geometry influence particle size classification. These theoretical studies will lead to the development of improved

  17. Analysis of the origin of peak aerosol optical depth in springtime over the Gulf of Tonkin.

    Science.gov (United States)

    Shan, Xiaoli; Xu, Jun; Li, Yixue; Han, Feng; Du, Xiaohui; Mao, Jingying; Chen, Yunbo; He, Youjiang; Meng, Fan; Dai, Xuezhi

    2016-02-01

    By aggregating MODIS (moderate-resolution imaging spectroradiometer) AOD (aerosol optical depth) and OMI (ozone monitoring instrument) UVAI (ultra violet aerosol index) datasets over 2010-2014, it was found that peak aerosol loading in seasonal variation occurred annually in spring over the Gulf of Tonkin (17-23 °N, 105-110 °E). The vertical structure of the aerosol extinction coefficient retrieved from the spaceborne lidar CALIOP (cloud-aerosol lidar with orthogonal polarization) showed that the springtime peak AOD could be attributed to an abrupt increase in aerosol loading between altitudes of 2 and 5 km. In contrast, aerosol loading in the low atmosphere (below 1 km) was only half of that in winter. Wind fields in the low and high atmosphere exhibited opposite transportation patterns in spring over the Gulf of Tonkin, implying different sources for each level. By comparing the emission inventory of anthropogenic sources with biomass burning, and analyzing the seasonal variation of the vertical structure of aerosols over the Northern Indo-China Peninsula (NIC), it was concluded that biomass burning emissions contributed to high aerosol loading in spring. The relatively high topography and the high surface temperature in spring made planetary boundary layer height greater than 3 km over NIC. In addition, small-scale cumulus convection frequently occurred, facilitating pollutant rising to over 3 km, which was a height favoring long-range transport. Thus, pollutants emitted from biomass burning over NIC in spring were raised to the high atmosphere, then experienced long-range transport, leading to the increase in aerosol loading at high altitudes over the Gulf of Tonkin during spring. PMID:26969552

  18. Persistence of enhanced aerosol deposition in the lung after recovery from carbachol-induced airway obstruction.

    Science.gov (United States)

    Kim, C S; Garcia, L; Eldridge, M A; Wanner, A

    1990-12-01

    Time course recovery from induced airway obstruction by carbachol infusion (CI; 0.2 microgram.kg-1.min-1 for 40 min), carbachol aerosol (CA; 10 breaths of 2% solution), and histamine aerosol (HA; 25-50 breaths of 5% solution) challenge was investigated in conscious sheep (n = 6 each). Total lung aerosol deposition and airway caliber as assessed by pulmonary airflow resistance (RL) were measured every 20-30 min up to 4 h after the challenges. Aerosol deposition was measured by monitoring aerosol concentration continuously with a laser aerosol photometer while the sheep rebreathed 1.0-micron-diam inert oil droplets delivered by a 0.25-liter bag-in-box system driven by a respiratory pump at a breathing frequency of 30 breaths/min. Total accumulated deposition at the fifth breath (AD5) as percentage of the initial aerosol concentration was determined and used as an aerosol deposition index. Percent changes in AD5 from baseline were compared with corresponding changes in RL. Both RL and AD5 increased after Cl, CA, and HA: 192-477% for RL and 23-44% for AD5 (P less than 0.05). Mean RL return to baseline values 1 h after CI and HA and 2 h after CA. Mean AD5 returned to baseline at 1 h post-HA. In contrast, mean AD5 remained elevated for 2-4 h after CI and CA (P less than 0.05), and the increased AD5 could not be reversed by a bronchodilator aerosol. The persistence of enhanced aerosol deposition long after the return of RL to baseline suggests that complete recovery of airway conditions after CI and CA takes much longer than predicted by RL.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:2077007

  19. The removal of sodium aerosols

    International Nuclear Information System (INIS)

    This paper is concentrated on the removal of sodium combustion aerosol. The experimental results are presented in it. Besides, the output of the aerosol, the igniting point and combustion rate of sodium are also obtained. An experimental device for removing of the aerosol consists of a blower, sodium combustion container, water-spraying column, water storage tank and nitrogen bottle. In order to compare the concentrations at the outlet of the column before and after the water-spraying, the concentration distribution was measured in the process of sodium burning. It was found that similar concentration could be obtained from sixth to eighth minute after ignition of sodium in the container. During the interval the water-spraying was performed, the measurement of the aerosol concentrations at different water-spray height was proceeded. The removing efficiency of the aerosol at different water-spraying heights is different. The efficiency at the height of 1220 mm is near to maximum. The results show that further increasing water-spray height could not greatly reduce the concentration of the aerosol at the outlet. (author)

  20. Comparison of sodium aerosol codes

    International Nuclear Information System (INIS)

    Although hypothetical fast reactor accidents leading to severe core damage are very low probability events, their consequences are to be assessed. During such accidents, one can envisage the ejection of sodium, mixed with fuel and fission products, from the primary circuit into the secondary containment. Aerosols can be formed either by mechanical dispersion of the molten material or as a result of combustion of the sodium in the mixture. Therefore considerable effort has been devoted to study the different sodium aerosol phenomena. To ensure that the problems of describing the physical behaviour of sodium aerosols were adequately understood, a comparison of the codes being developed to describe their behaviour was undertaken. The comparison consists of two parts. The first is a comparative study of the computer codes used to predict aerosol behaviour during a hypothetical accident. It is a critical review of documentation available. The second part is an exercise in which code users have run their own codes with a pre-arranged input. For the critical comparative review of the computer models, documentation has been made available on the following codes: AEROSIM (UK), MAEROS (USA), HAARM-3 (USA), AEROSOLS/A2 (France), AEROSOLS/B1 (France), and PARDISEKO-IIIb (FRG)

  1. Aerosol generation and delivery in medical applications

    International Nuclear Information System (INIS)

    It is well established that radioaerosol lung technique by inhalation is a very versatile technique in the evaluation of health effects and medical diagnostic applications, especially to detect chronic obstructive pulmonary diseases, their defence mechanism permeability and many others. Most important part of aerosol technology is to generate reproducibly stable diagnostic radioaerosols of known characteristics. Many compressed air atomisers are commercially available for generating aerosols but they have limited utility in aerosol inhalation, either because of large droplet size, low aerosol output or high airflow rates. There is clearly a need for a versatile and economical aerosol generation/inhalation system that can produce dry labelled aerosol particles with high deep lung delivery efficiency suitable for clinical studies. BARC (Bhabha Atomic Research Centre) has developed a dry aerosol generation/delivery system which operates on compressed air and generates dry polydisperse aerosols. This system is described along with an assessment of the aerosol characteristics and efficiency for diagnosis of various respiratory disorders

  2. Devices and methods for generating an aerosol

    KAUST Repository

    Bisetti, Fabrizio

    2016-03-03

    Aerosol generators and methods of generating aerosols are provided. The aerosol can be generated at a stagnation interface between a hot, wet stream and a cold, dry stream. The aerosol has the benefit that the properties of the aerosol can be precisely controlled. The stagnation interface can be generated, for example, by the opposed flow of the hot stream and the cold stream. The aerosol generator and the aerosol generation methods are capable of producing aerosols with precise particle sizes and a narrow size distribution. The properties of the aerosol can be controlled by controlling one or more of the stream temperatures, the saturation level of the hot stream, and the flow times of the streams.

  3. Aerosol profile information from high resolution oxygen A-Band measurements from space

    Directory of Open Access Journals (Sweden)

    A. Geddes

    2014-06-01

    Full Text Available Aerosols are an important factor of the Earth climatic system and they play a key role for air quality and public health. Observations of the oxygen A-Band at 760 nm can provide information on the vertical distribution of aerosols from passive satellite sensors, that can be of great interest for operational monitoring applications with high coverage if the aerosol information is obtained with sufficient precision, accuracy and vertical resolution. To address this issue, retrieval simulations of the aerosol vertical profile retrieval from O2 A Band observations by GOSAT, the upcoming OCO-2 and Sentinel 5-P mission and the proposed CarbonSat mission have been carried out. Precise retrievals of AOD within the boundary layer were found to favour low resolution, high SNR instruments such as Sentinel-5 P, whereas higher resolution instruments such as OCO-2 showed greater performance at higher altitudes and in information content above the boundary layer. Accurate retrievals of the AOD in the 0–2 km range appears difficult from all studied instruments and the retrieval errors typically exceed a value of 0.05. Constraining the surface albedo is a promising and effective way of improving the retrieval of aerosol, but the required level of a priori knowledge is very high. Due to the limited information content of the aerosol profile retrieval, the use of a parameterised aerosol distribution has been assessed and we show that the AOD and height of an aerosol layer can be retrieved well if the aerosol layer is uplifted to the free troposphere but errors are often large for aerosol layers in the boundary layer. Additional errors will be introduced by incorrect assumptions on surface pressure and aerosol type which can both bias retrieved AOD and height by up to 40%. We conclude the aerosol profile retrievals from O2 A Band using existing or upcoming satellite sensors will only provide limited information on aerosols in the boundary layer but such

  4. How important is organic aerosol hygroscopicity to aerosol indirect forcing?

    International Nuclear Information System (INIS)

    Organics are among the most abundant aerosol components in the atmosphere. However, there are still large uncertainties with emissions of primary organic aerosol (POA) and volatile organic compounds (VOCs) (precursor gases of secondary organic aerosol, SOA), formation of SOA, and chemical and physical properties (e.g., hygroscopicity) of POA and SOA. All these may have significant impacts on aerosol direct and indirect forcing estimated from global models. In this study a modal aerosol module (MAM) in the NCAR community atmospheric model (CAM) is used to examine sensitivities of aerosol indirect forcing to hygroscopicity (represented by a single parameter 'κ' ) of POA and SOA. Our model simulation indicates that in the present-day (PD) condition changing the 'κ' value of POA from 0 to 0.1 increases the number concentration of cloud condensational nuclei (CCN) at supersaturation S = 0.1% by 40-80% over the POA source regions, while changing the 'κ' value of SOA by ± 50% (from 0.14 to 0.07 and 0.21) changes the CCN concentration within 40%. There are disproportionally larger changes in CCN concentration in the pre-industrial (PI) condition. Due to the stronger impact of organics hygroscopicity on CCN and cloud droplet number concentration at PI condition, global annual mean anthropogenic aerosol indirect forcing (AIF) between PD and PI conditions reduces with the increase of the hygroscopicity of organics. Global annual mean AIF varies by 0.4 W m-2 in the sensitivity runs with the control run of - 1.3 W m-2, highlighting the need for improved understanding of organics hygroscopicity and its representation in global models.

  5. Analysis of the Interaction and Transport of Aerosols with Cloud or Fog in East Asia from AERONET and Satellite Remote Sensing: 2012 DRAGON Campaigns and Climatological Data

    Science.gov (United States)

    Eck, T. F.; Holben, B. N.; Reid, J. S.; Lynch, P.; Schafer, J.; Giles, D. M.; Kim, J.; Kim, Y. J.; Sano, I.; Arola, A. T.; Munchak, L. A.; O'Neill, N. T.; Lyapustin, A.; Sayer, A. M.; Hsu, N. Y. C.; Randles, C. A.; da Silva, A. M., Jr.; Govindaraju, R.; Hyer, E. J.; Pickering, K. E.; Crawford, J. H.; Sinyuk, A.; Smirnov, A.

    2015-12-01

    Ground-based remote sensing observations from Aerosol Robotic Network (AERONET) sun-sky radiometers have recently shown several instances where cloud-aerosol interaction had resulted in modification of aerosol properties and/or in difficulty identifying some major pollution transport events due to aerosols being imbedded in cloud systems. Major Distributed Regional Aerosol Gridded Observation Networks (DRAGON) field campaigns involving multiple AERONET sites in Japan and South Korea during Spring of 2012 have yielded observations of aerosol transport associated with clouds and/or aerosol properties modification as a result of fog interaction. Analysis of data from the Korean and Japan DRAGON campaigns shows that major fine-mode aerosol transport events are sometimes associated with extensive cloud cover and that cloud-screening of observations often filter out significant pollution aerosol transport events. The Spectral De-convolution Algorithm (SDA) algorithm was utilized to isolate and analyze the fine-mode aerosol optical depth (AODf) signal from AERONET data for these cases of persistent and extensive cloud cover. Satellite retrievals of AOD from MODIS sensors (from Dark Target, Deep Blue and MAIAC algorithms) were also investigated to assess the issue of detectability of high AOD events associated with high cloud fraction. Underestimation of fine mode AOD by the Navy Aerosol Analysis and Prediction System (NAAPS) and by the NASA Modern-Era Retrospective Analysis For Research And Applications Aerosol Re-analysis (MERRAaero) models at very high AOD at sites in China and Korea was observed, especially for observations that are cloud screened by AERONET (Level 2 data). Additionally, multi-year monitoring at several AERONET sites are examined for climatological statistics of cloud screening of fine mode aerosol events. Aerosol that has been affected by clouds or the near-cloud environment may be more prevalent than AERONET data suggest due to inherent difficulty in

  6. Relative Contributions of Fossil and Contemporary Carbon sources to PM 2.5 Aerosols at Nine IMPROVE Network Sites

    Energy Technology Data Exchange (ETDEWEB)

    Bench, G; Fallon, S; Schichtel, B; Malm, W; McDade, C

    2006-06-26

    Particulate matter aerosols contribute to haze diminishing vistas and scenery at National Parks and Wilderness Areas within the United States. To increase understanding of the sources of carbonaceous aerosols at these settings, the total carbon loading and {sup 14}C/C ratio of PM 2.5 aerosols at nine IMPROVE (Interagency Monitoring for Protection Of Visual Environments) network sites were measured. Aerosols were collected weekly in the summer and winter at one rural site, two urban sites, five sites located in National Parks and one site located in a Wildlife Preserve. The carbon measurements together with the absence of {sup 14}C in fossil carbon materials and the known {sup 14}C/C levels in contemporary carbon materials were used to derive contemporary and fossil carbon contents of the particulate matter. Contemporary and fossil carbon aerosol loadings varied across the sites and suggest different percentages of carbon source inputs. The urban sites had the highest fossil carbon loadings that comprised around 50% of the total carbon aerosol loading. The Wildlife Preserve and National Park sites together with the rural site had much lower fossil carbon loading components. At these sites, variations in the total carbon aerosol loading were dominated by non-fossil carbon sources. This suggests that reduction of anthroprogenic sources of fossil carbon aerosols may result in little decrease in carbonaceous aerosol loading at many National Parks and rural areas.

  7. Determination of the broadband optical properties of biomass burning aerosol

    Science.gov (United States)

    Bluvshtein, Nir; Flores, J. Michel; Segev, Lior; Lin, Peng; Laskin, Alexander; Rudich, Yinon

    2016-04-01

    The direct and semi-direct effects of atmospheric aerosol on the Earth's energy balance are still the two of the largest uncertainties in our understanding of anthropogenic radiative forcing. In this study we developed a new approach for determining high sensitivity broadband UV-Vis spectrum (300-650 nm) of extinction, scattering and absorption coefficients, single scattering albedo and the complex refractive index for continuous, spectral and time dependent, monitoring of polydisperse aerosols population. This new approach was applied in a study of biomass burning aerosol. Extinction, scattering and absorption coefficients (αext, αsca, αabs, respectively) were continually monitored using photoacoustic spectrometer coupled to a cavity ring down spectrometer (PA-CRD-AS) at 404 nm, a dual-channel Broadband cavity-enhanced spectrometer (BBCES) at 315-345 nm and 390-420 nm and a three channel integrating nephelometer (IN) centered at 457, 525 and 637 nm. During the biomass burning event, the measured aerosol number concentration increased by more than an order of magnitude relative to other week nights and the mode of the aerosols size distribution increased from 40-50 nm to 110nm diameter. αext and αsca increased by a factor of about 5.5 and 4.5, respectively. The αabs increased by a factor over 20, indicating a significant change in the aerosol overall chemical composition. The imaginary part of the complex RI at 404nm increased from its background level at about 0.02 to a peak of about 0.08 and the SSA decreased from 0.9 to about 0.6. Significant change of the absorption spectral dependence indicates formation of visible-light absorbing compounds. The mass absorption cross section of the water soluble organic aerosol (MACWSOA) reached up to about 12% of the corresponding value for black carbon (BC) at 450 nm and up to 30% at 300 nm. These results demonstrate the importance of biomass burning in understanding global and regional radiative forcing.

  8. The Global Aerosol Synthesis and Science Project (GASSP)

    Science.gov (United States)

    Carslaw, Ken; Reddington, Carly; Lee, Lindsay; Johnson, Jill; Stier, Philip; Schutgens, Nick; Allan, James; Liu, Dantong; Coe, Hugh

    2016-04-01

    GASSP aims to improve the robustness of global aerosol models by assembling the largest ever dataset of global aerosol microphysics measurements and by developing statistical methodologies for using the data to constrain models. Although several measurement networks provide access to high quality well-documented data, like ACTRIS, a project like GASSP is still needed because vast amounts of data exist outside major measurement networks, mostly held by individual investigators. In collaboration with observation scientists, GASSP has assembled over 4000 datafiles going back to the 1990s. The datasets cover particle concentrations (CPC), size distributions, black carbon concentrations (SP2), CCN concentrations at several supersaturations, aerosol composition (AMS) and PM2.5. The data cover more than 100 field campaigns from ships, aircraft and ground stations plus data from more than 200 monitoring sites. All datasets have been processed from about ten different initial formats into a single well-documented NetCDF format that is easily used by modellers. The presentation shows the global extent of these highly valuable datasets and assesses the distribution of measurements in relation to key uncertainties in model processes. These comparisons reveal important gaps in available global data, most notably in remote regions, which limits our ability to evaluate natural aerosol processes in models. The presentation discusses the challenges of using extensive but spatially and temporally sparse situ measurements to evaluate global models and makes recommendations for improved progress in future.

  9. Characteristics and source of black carbon aerosol over Taklimakan Desert

    Institute of Scientific and Technical Information of China (English)

    FU; S.Joshua

    2010-01-01

    Black carbon(BC) and PM10 in the center of the Taklimakan Desert were online monitored in the whole year of 2007.In addi-tion,TSP samples were also synchronously daily collected by medium-volume samplers with Whatman41 filters in the spring of 2007.BC in the dust aerosol was up to 1.14%of the total mass of PM10.A remarkable seasonal variation of BC in the aerosol was observed in the order of winter>spring>autumn>summer.The peak value of BC appeared at midnight while the lowest one in the evening each day,which was just the reverse of that in the urban area.The contribution of BC to the total mass of PM10 on non-dust storm days was~11 times of that in dust storm.Through back trajectory and principal component analysis,it was found that BC in the dust aerosol over Taklimakan Desert might be attributed to the emission from the anthropogenic activities,including domestic heating,cooking,combustion of oil and natural gas,and the medium-range transport from those oases located in the margins of the desert.The total BC aerosol from the Taklimakan Desert to be transported to the eastward downstream was estimated to be 6.3×104 ton yr-1.

  10. Secondary Organic Aerosol Formation from Glyoxal: photochemical versus dark uptake and reversible versus irreversible SOA formation

    Science.gov (United States)

    Waxman, E.; Slowik, J.; Kampf, C.; Timkovsky, J.; Noziere, B.; Praplan, A.; Pffafenberger, L.; Holzinger, R.; Hoffmann, T.; Dommen, J.; Prevot, A.; Baltensperger, U.; Volkamer, R.

    2012-04-01

    Glyoxal forms secondary organic aerosol (SOA) by partitioning to the aerosol aqueous phase according to Henry's law. The subsequent processing by heterogeneous and multiphase reactions shifts the partitioning towards aerosols. Currently it is not well understood whether these reactions result in reversible or irreversible SOA formation, and what parameters influence the rate limiting step of multiphase processing. We conducted a series of simulation chamber experiments at PSI in April and May 2011 to investigate processing under dark conditions, UV and/or visible light irradiated conditions, and in the presence and absence of OH radicals. Experiments used ammonium sulfate or ammonium sulfate/fulvic acid mixtures as seed aerosols, and were conducted between 50% and 85% relative humidity at approximately constant RH over the course of any given experiment. Glyoxal was produced photochemically from acetylene, using HONO photolysis as the OH radical source. Gas-phase glyoxal was measured by the CU LED-Cavity Enhanced-DOAS. The Thermal-Desorption Proton-Transfer-Reaction Mass Spectrometer (TD-PTR-MS) and Ion Chromatography Mass Spectrometer (IC-MS) monitored both gas and aerosol-phase organic reaction products. Particle composition was monitored by High-Resolution Time-of-Flight Aerosol Mass Spectrometry (HR-ToF-AMS), and HPLC-ESI MS/MS and LC-MS analysis of filter samples.

  11. A new approach for retrieving the UV-vis optical properties of ambient aerosols

    Science.gov (United States)

    Bluvshtein, Nir; Flores, J. Michel; Segev, Lior; Rudich, Yinon

    2016-08-01

    Atmospheric aerosols play an important part in the Earth's energy budget by scattering and absorbing incoming solar and outgoing terrestrial radiation. To quantify the effective radiative forcing due to aerosol-radiation interactions, researchers must obtain a detailed understanding of the spectrally dependent intensive and extensive optical properties of different aerosol types. Our new approach retrieves the optical coefficients and the single-scattering albedo of the total aerosol population over 300 to 650 nm wavelength, using extinction measurements from a broadband cavity-enhanced spectrometer at 315 to 345 nm and 390 to 420 nm, extinction and absorption measurements at 404 nm from a photoacoustic cell coupled to a cavity ring-down spectrometer, and scattering measurements from a three-wavelength integrating nephelometer. By combining these measurements with aerosol size distribution data, we retrieved the time- and wavelength-dependent effective complex refractive index of the aerosols. Retrieval simulations and laboratory measurements of brown carbon proxies showed low absolute errors and good agreement with expected and reported values. Finally, we implemented this new broadband method to achieve continuous spectral- and time-dependent monitoring of ambient aerosol population, including, for the first time, extinction measurements using cavity-enhanced spectrometry in the 315 to 345 nm UV range, in which significant light absorption may occur.

  12. Urban surface models for better aerosol retrieval with MODIS and Landsat

    Science.gov (United States)

    Hernandez, Eduardo H.

    Aerosols are notoriously hard to measure on a global scale since they do not have unique spectral signatures like trace green house gases. Accurate global characterization of Aerosol Optical Depth (AOD) is essential because aerosols are the most uncertain mechanism in climate forecast models, and have known impact on human health. In particular, fine mode particulates (PM2.5) can penetrate deep into the lung tissue contributing to lung damage and cardiac distress. Because of these effects on human health, the Environmental Protection Agency has strict monitoring standards for PM2.5. Aerosols measurements over urban areas are critical because extended urban centers can have significant aerosol loadings with air quality levels that are above EPA standards. For global studies, satellite measurements are the only realistic approach. Making this monitoring possible from space is the observation that column AOD is quite remarkably related to PM2.5. Dark vegetative surfaces make such correlations strongest and more accurate aerosols retrieval. However, over urban scenes, it is particularly complicated due to the confusion between the ground signal and the aerosol signal. The satellite sensors cannot distinguish if the incoming photons come from the surface or from atmosphere scattering. For global retrieval of aerosols, the MODIS sensor is perhaps the most suited for global observations, because it can cover almost the entire planet in less than 2 days. The general approach is to use the Long Wave Channel (2130nm) as a good estimate of the surface albedo, since the aerosols contribution in this channel is almost always negligible (especially urban aerosols). Then, the surface albedos in the visible channels, where aerosols are important, can be inferred from empirical relations. However, it has become more apparent that the relations used by MODIS algorithms are not optimized for urban areas and tend to overestimate the AOD. This thesis provides a more extensive study of

  13. Techniques for Measuring Aerosol Attenuation using the Central Laser Facility at the Pierre Auger Observatory

    CERN Document Server

    ,

    2013-01-01

    The Pierre Auger Observatory in Malarg\\"ue, Argentina, is designed to study the properties of ultra-high energy cosmic rays with energies above 1018 eV. It is a hybrid facility that employs a Fluorescence Detector to perform nearly calorimetric measurements of Extensive Air Shower energies. To obtain reliable calorimetric information from the FD, the atmospheric conditions at the observatory need to be continuously monitored during data acquisition. In particular, light attenuation due to aerosols is an important atmospheric correction. The aerosol concentration is highly variable, so that the aerosol attenuation needs to be evaluated hourly. We use light from the Central Laser Facility, located near the center of the observatory site, having an optical signature comparable to that of the highest energy showers detected by the FD. This paper presents two procedures developed to retrieve the aerosol attenuation of fluorescence light from CLF laser shots. Cross checks between the two methods demonstrate that re...

  14. Calibration of a Polytec HC-15 optical particle analyser with water-droplet aerosols

    International Nuclear Information System (INIS)

    Water-droplet aerosols are of interest in many industrial processes, and their efficient removal from any gaseous effluent requires quantification of droplet concentrations and size distributions. Optical aerosol analysers such as the Polytech HC-15 can be used to monitor the number concentration and size distribution of such aerosols. However, the intensity of the scattered light detected is dependent on the refractive index of the aerosol droplets. A method has been developed to calibrate the Polytech HC-15 with water droplets that have been transported through a single-stage impactor whose characteristic 50% cut-off diameter (D50) can be varied over the size range 3 to 18 μm aerodynamic diameter. The D50 of a particular assembly can be related to the appropriate size channel of the Polytech by comparing the measured droplet-size distributions with and without the removable collection stage in position. (author)

  15. MELCOR 1.8.1 assessment: LACE aerosol experiment LA4

    International Nuclear Information System (INIS)

    The MELCOR code has been used to simulate LACE aerosol experiment LA4. In this test, the behavior of single- and double-component, hygroscopic and nonhygroscopic, aerosols in a condensing environment was monitored. Results are compared to experimental data, and to CONTAIN calculations. Sensitivity studies have been done on time step effects and machine dependencies; thermal/hydraulic parameters such as condensation on heat structures and on pool surface, and radiation heat transfer; and aerosol parameters such as number of MAEROS components and sections assumed, the degree to which plated aerosols are washed off heat structures by condensate film draining, and the effect of non-default values for shape factors and diameter limits. 9 refs., 50 figs., 13 tabs

  16. Effect of aerosol sub-grid variability on aerosol optical depth and cloud condensation nuclei: Implications for global aerosol modelling

    OpenAIRE

    Weigum, N; Schutgens, N.; Stier, P.

    2016-01-01

    A fundamental limitation of grid-based models is their inability to resolve variability on scales smaller than a grid box. Past research has shown that significant aerosol variability exists on scales smaller than these grid-boxes, which can lead to discrepancies in simulated aerosol climate effects between high and low resolution models. This study investigates the impact of neglecting sub-grid variability in present-day global microphysical aerosol models on aerosol optical depth (AOD) and ...

  17. Global aerosol modeling with the online NMMB/BSC Chemical Transport Model: sensitivity to fire injection height prescription and secondary organic aerosol schemes

    Science.gov (United States)

    Spada, Michele; Jorba, Oriol; Pérez García-Pando, Carlos; Tsigaridis, Kostas; Soares, Joana; Obiso, Vincenzo; Janjic, Zavisa; Baldasano, Jose M.

    2015-04-01

    We develop and evaluate a fully online-coupled model simulating the life-cycle of the most relevant global aerosols (i.e. mineral dust, sea-salt, black carbon, primary and secondary organic aerosols, and sulfate) and their feedbacks upon atmospheric chemistry and radiative balance. Following the capabilities of its meteorological core, the model has been designed to simulate both global and regional scales with unvaried parameterizations: this allows detailed investigation on the aerosol processes bridging the gap between global and regional models. Since the strong uncertainties affecting aerosol models are often unresponsive to model complexity, we choose to introduce complexity only when it clearly improves results and leads to a better understanding of the simulated aerosol processes. We test two important sources of uncertainty - the fires injection height and secondary organic aerosol (SOA) production - by comparing a baseline simulation with experiments using more advanced approaches. First, injection heights prescribed by Dentener et al. (2006, ACP) are compared with climatological injection heights derived from satellite measurements and produced through the Integrated Monitoring and Modeling System For Wildland Fires (IS4FIRES). Also global patterns of SOA produced by the yield conversion of terpenes as prescribed by Dentener et al. (2006, ACP) are compared with those simulated by the two-product approach of Tsigaridis et al. (2003, ACP). We evaluate our simulations using a variety of observations and measurement techniques. Additionally, we discuss our results in comparison to other global models within AEROCOM and ACCMIP.

  18. Application of Spectral Analysis Techniques in the Intercomparison of Aerosol Data: Part III. Using Combined PCA to Compare Spatiotemporal Variability of MODIS, MISR and OMI Aerosol Optical Depth

    Science.gov (United States)

    Li, Jing; Carlson, Barbara E.; Lacis, Andrew A.

    2014-01-01

    Satellite measurements of global aerosol properties are very useful in constraining aerosol parameterization in climate models. The reliability of different data sets in representing global and regional aerosol variability becomes an essential question. In this study, we present the results of a comparison using combined principal component analysis (CPCA), applied to monthly mean, mapped (Level 3) aerosol optical depth (AOD) product from Moderate Resolution Imaging Spectroradiometer (MODIS), Multiangle Imaging Spectroradiometer (MISR), and Ozone Monitoring Instrument (OMI). This technique effectively finds the common space-time variability in the multiple data sets by decomposing the combined AOD field. The results suggest that all of the sensors capture the globally important aerosol regimes, including dust, biomass burning, pollution, and mixed aerosol types. Nonetheless, differences are also noted. Specifically, compared with MISR and OMI, MODIS variability is significantly higher over South America, India, and the Sahel. MODIS deep blue AOD has a lower seasonal variability in North Africa, accompanied by a decreasing trend that is not found in either MISR or OMI AOD data. The narrow swath of MISR results in an underestimation of dust variability over the Taklamakan Desert. The MISR AOD data also exhibit overall lower variability in South America and the Sahel. OMI does not capture the Russian wild fire in 2010 nor the phase shift in biomass burning over East South America compared to Central South America, likely due to cloud contamination and the OMI row anomaly. OMI also indicates a much stronger (boreal) winter peak in South Africa compared with MODIS and MISR.

  19. Factors Affecting Aerosol Radiative Forcing

    Science.gov (United States)

    Wang, Jingxu; Lin, Jintai; Ni, Ruijing

    2016-04-01

    Rapid industrial and economic growth has meant a large amount of aerosols in the atmosphere with strong radiative forcing (RF) upon the climate system. Over parts of the globe, the negative forcing of aerosols has overcompensated for the positive forcing of greenhouse gases. Aerosol RF is determined by emissions and various chemical-transport-radiative processes in the atmosphere, a multi-factor problem whose individual contributors have not been well quantified. In this study, we analyze the major factors affecting RF of secondary inorganic aerosols (SIOAs, including sulfate, nitrate and ammonium), primary organic aerosol (POA), and black carbon (BC). We analyze the RF of aerosols produced by 11 major regions across the globe, including but not limited to East Asia, Southeast Asia, South Asia, North America, and Western Europe. Factors analyzed include population size, per capita gross domestic production (GDP), emission intensity (i.e., emissions per unit GDP), chemical efficiency (i.e., mass per unit emissions) and radiative efficiency (i.e., RF per unit mass). We find that among the 11 regions, East Asia produces the largest emissions and aerosol RF, due to relatively high emission intensity and a tremendous population size. South Asia produce the second largest RF of SIOA and BC and the highest RF of POA, in part due to its highest chemical efficiency among all regions. Although Southeast Asia also has large emissions, its aerosol RF is alleviated by its lowest chemical efficiency. The chemical efficiency and radiative efficiency of BC produced by the Middle East-North Africa are the highest across the regions, whereas its RF is lowered by a small per capita GDP. Both North America and Western Europe have low emission intensity, compensating for the effects on RF of large population sizes and per capita GDP. There has been a momentum to transfer industries to Southeast Asia and South Asia, and such transition is expected to continue in the coming years. The

  20. Global Monitoring

    OpenAIRE

    Victor Ya. Tsvetkov

    2012-01-01

    The article describes the technology and classification of global monitoring, shows the relationship between the global monitoring and geographic information monitoring, presents the cause-and-effect diagram of global monitoring. The paper discloses the value of the time series for global monitoring, offers a functional diagram of the global monitoring system, gives the main characteristics of global monitoring.

  1. Miniature Sensor for Aerosol Mass Measurements Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This SBIR project seeks to develop a miniature sensor for mass measurement of size-classified aerosols. A cascade impactor will be used to classify aerosol sample...

  2. MISR Aerosol Climatology Product V001

    Data.gov (United States)

    National Aeronautics and Space Administration — This product is 1)the microphysical and scattering characteristics of pure aerosol upon which routine retrievals are based;2)mixtures of pure aerosol to be compared...

  3. Bio-aerosols in indoor environment: Composition, health effects and analysis

    Directory of Open Access Journals (Sweden)

    Srikanth Padma

    2008-01-01

    Full Text Available Bio-aerosols are airborne particles that are living (bacteria, viruses and fungi or originate from living organisms. Their presence in air is the result of dispersal from a site of colonization or growth. The health effects of bio-aerosols including infectious diseases, acute toxic effects, allergies and cancer coupled with the threat of bioterrorism and SARS have led to increased awareness on the importance of bio-aerosols. The evaluation of bio-aerosols includes use of variety of methods for sampling depending on the concentration of microorganisms expected. There have been problems in developing standard sampling methods, in proving a causal relationship and in establishing threshold limit values for exposures due to the complexity of composition of bio-aerosols, variations in human response to their exposure and difficulties in recovering microorganisms. Currently bio-aerosol monitoring in hospitals is carried out for epidemiological investigation of nosocomial infectious diseases, research into airborne microorganism spread and control, monitoring biohazardous procedures and use as a quality control measure. In India there is little awareness regarding the quality of indoor air, mould contamination in indoor environments, potential source for transmission of nosocomial infections in health care facilities. There is an urgent need to undertake study of indoor air, to generate baseline data and explore the link to nosocomial infections. This article is a review on composition, sources, modes of transmission, health effects and sampling methods used for evaluation of bio-aerosols, and also suggests control measures to reduce the loads of bio-aerosols.

  4. Bio-aerosols in indoor environment: composition, health effects and analysis.

    Science.gov (United States)

    Srikanth, Padma; Sudharsanam, Suchithra; Steinberg, Ralf

    2008-01-01

    Bio-aerosols are airborne particles that are living (bacteria, viruses and fungi) or originate from living organisms. Their presence in air is the result of dispersal from a site of colonization or growth. The health effects of bio-aerosols including infectious diseases, acute toxic effects, allergies and cancer coupled with the threat of bioterrorism and SARS have led to increased awareness on the importance of bio-aerosols. The evaluation of bio-aerosols includes use of variety of methods for sampling depending on the concentration of microorganisms expected. There have been problems in developing standard sampling methods, in proving a causal relationship and in establishing threshold limit values for exposures due to the complexity of composition of bio-aerosols, variations in human response to their exposure and difficulties in recovering microorganisms. Currently bio-aerosol monitoring in hospitals is carried out for epidemiological investigation of nosocomial infectious diseases, research into airborne microorganism spread and control, monitoring biohazardous procedures and use as a quality control measure. In India there is little awareness regarding the quality of indoor air, mould contamination in indoor environments, potential source for transmission of nosocomial infections in health care facilities. There is an urgent need to undertake study of indoor air, to generate baseline data and explore the link to nosocomial infections. This article is a review on composition, sources, modes of transmission, health effects and sampling methods used for evaluation of bio-aerosols, and also suggests control measures to reduce the loads of bio-aerosols. PMID:18974481

  5. Aerosol Climate Time Series in ESA Aerosol_cci

    Science.gov (United States)

    Popp, Thomas; de Leeuw, Gerrit; Pinnock, Simon

    2016-04-01

    Within the ESA Climate Change Initiative (CCI) Aerosol_cci (2010 - 2017) conducts intensive work to improve algorithms for the retrieval of aerosol information from European sensors. Meanwhile, full mission time series of 2 GCOS-required aerosol parameters are completely validated and released: Aerosol Optical Depth (AOD) from dual view ATSR-2 / AATSR radiometers (3 algorithms, 1995 - 2012), and stratospheric extinction profiles from star occultation GOMOS spectrometer (2002 - 2012). Additionally, a 35-year multi-sensor time series of the qualitative Absorbing Aerosol Index (AAI) together with sensitivity information and an AAI model simulator is available. Complementary aerosol properties requested by GCOS are in a "round robin" phase, where various algorithms are inter-compared: fine mode AOD, mineral dust AOD (from the thermal IASI spectrometer, but also from ATSR instruments and the POLDER sensor), absorption information and aerosol layer height. As a quasi-reference for validation in few selected regions with sparse ground-based observations the multi-pixel GRASP algorithm for the POLDER instrument is used. Validation of first dataset versions (vs. AERONET, MAN) and inter-comparison to other satellite datasets (MODIS, MISR, SeaWIFS) proved the high quality of the available datasets comparable to other satellite retrievals and revealed needs for algorithm improvement (for example for higher AOD values) which were taken into account for a reprocessing. The datasets contain pixel level uncertainty estimates which were also validated and improved in the reprocessing. For the three ATSR algorithms the use of an ensemble method was tested. The paper will summarize and discuss the status of dataset reprocessing and validation. The focus will be on the ATSR, GOMOS and IASI datasets. Pixel level uncertainties validation will be summarized and discussed including unknown components and their potential usefulness and limitations. Opportunities for time series extension

  6. Aerosol MALDI mass spectrometry for bioaerosol analysis

    OpenAIRE

    Kleefsman, W.A.

    2008-01-01

    In the thesis Aerosol MALDI mass spectrometry for bioaerosol analysis is described how the aerosol mass spectrometer of the TU Delft has been further developed for the on-line analysis of bioaerosols. Due to the implemented improvements mass spectra with high resolution and a high mass range can be obtained from single protein containing aerosol particles. Fluorescence is used to select the biological fraction of an aerosol: when a particle emits fluorescence when irradiated with UV-laser lig...

  7. Origins of atmospheric aerosols. Basic concepts on aerosol main physical properties; L`aerosol atmospherique: ses origines quelques notions sur les principales proprietes physiques des aerosols

    Energy Technology Data Exchange (ETDEWEB)

    Renoux, A. [Paris-12 Univ., 94 - Creteil (France). Laboratoire de Physique des aerosols et de transferts des contaminations

    1996-12-31

    Natural and anthropogenic sources of atmospheric aerosols are reviewed and indications of their concentrations and granulometry are given. Calculation of the lifetime of an atmospheric aerosol of a certain size is presented and the various modes of aerosol granulometry and their relations with photochemical and physico-chemical processes in the atmosphere are discussed. The main physical, electrical and optical properties of aerosols are also presented: diffusion coefficient, dynamic mobility and relaxation time, Stokes number, limit rate of fall, electrical mobility, optical diffraction

  8. Natural aerosol direct and indirect radiative effects

    OpenAIRE

    Rap, Alexandru; Scott, Catherine E.; Spracklen, Dominick V; Bellouin, Nicolas; Forster, Piers M.; Carslaw, Kenneth S.; Schmidt, Anja; Mann, Graham

    2013-01-01

    Natural aerosol plays a significant role in the Earth's system due to its ability to alter the radiative balance of the Earth. Here we use a global aerosol microphysics model together with a radiative transfer model to estimate radiative effects for five natural aerosol sources in the present-day atmosphere: dimethyl sulfide (DMS), sea-salt, volcanoes, monoterpenes, and wildfires. We calculate large annual global mean aerosol direct and cloud albedo effects especially for DMS-derived sulfate ...

  9. Aerosol filtration with metallic fibrous filters

    International Nuclear Information System (INIS)

    The filtration efficiency of stainless steel fibrous filters (BEKIPOR porous mats and sintered webs) is determined using submicronic monodisperse polystyrene aerosols. Lasers spectrometers are used for the aerosol measurements. The parameters varied are the fiber diameter, the number of layers, the aerosol diameter and the superficial velocity. Two selected types of filters are tested with polydisperse methylene blue aerosols to determine the effect of bed loading on the filter performance and to test washing techniques for the regeneration of the filter

  10. Classification of Dust Days by Satellite Remotely Sensed Aerosol Products

    Science.gov (United States)

    Sorek-Hammer, M.; Cohen, A.; Levy, Robert C.; Ziv, B.; Broday, D. M.

    2013-01-01

    Considerable progress in satellite remote sensing (SRS) of dust particles has been seen in the last decade. From an environmental health perspective, such an event detection, after linking it to ground particulate matter (PM) concentrations, can proxy acute exposure to respirable particles of certain properties (i.e. size, composition, and toxicity). Being affected considerably by atmospheric dust, previous studies in the Eastern Mediterranean, and in Israel in particular, have focused on mechanistic and synoptic prediction, classification, and characterization of dust events. In particular, a scheme for identifying dust days (DD) in Israel based on ground PM10 (particulate matter of size smaller than 10 nm) measurements has been suggested, which has been validated by compositional analysis. This scheme requires information regarding ground PM10 levels, which is naturally limited in places with sparse ground-monitoring coverage. In such cases, SRS may be an efficient and cost-effective alternative to ground measurements. This work demonstrates a new model for identifying DD and non-DD (NDD) over Israel based on an integration of aerosol products from different satellite platforms (Moderate Resolution Imaging Spectroradiometer (MODIS) and Ozone Monitoring Instrument (OMI)). Analysis of ground-monitoring data from 2007 to 2008 in southern Israel revealed 67 DD, with more than 88 percent occurring during winter and spring. A Classification and Regression Tree (CART) model that was applied to a database containing ground monitoring (the dependent variable) and SRS aerosol product (the independent variables) records revealed an optimal set of binary variables for the identification of DD. These variables are combinations of the following primary variables: the calendar month, ground-level relative humidity (RH), the aerosol optical depth (AOD) from MODIS, and the aerosol absorbing index (AAI) from OMI. A logistic regression that uses these variables, coded as binary

  11. Long-term trends in aerosol optical characteristics in the Po Valley, Italy

    Science.gov (United States)

    Putaud, J. P.; Cavalli, F.; Martins dos Santos, S.; Dell'Acqua, A.

    2014-09-01

    Aerosol properties have been monitored by ground-based in situ and remote sensing measurements at the station for atmospheric research located in Ispra, on the edge of the Po Valley, for almost one decade. In situ measurements are performed according to Global Atmosphere Watch recommendations, and quality is assured through the participation in regular inter-laboratory comparisons. Sun-photometer data are produced by the Aerosol Robotic Network (AERONET). Data show significant decreasing trends over the 2004-2010 period for a number of variables, including particulate matter (PM) mass concentration, aerosol scattering, backscattering and absorption coefficients, and aerosol optical thickness (AOT). In situ measurement data show no significant trends in the aerosol backscatter ratio, but they do show a significant decreasing trend of about -0.7 ± 0.3% yr-1 in the aerosol single scattering albedo (SSA) in the visible light range. Similar trends are observed in the SSA retrieved from sun-photometer measurements. Correlations appear between in situ PM mass concentration and aerosol scattering coefficient, on the one hand, and elemental carbon (EC) concentration and aerosol absorption coefficient, on the other hand. However, no increase in the EC / PM ratio was observed, which could have explained the decrease in SSA. The application of a simple approximation to calculate the direct radiative forcing by aerosols suggests a significant diminution in their cooling effect, mainly due to the decrease in AOT. Applying the methodology we present to those sites, where the necessary suite of measurements is available, would provide important information to inform future policies for air-quality enhancement and fast climate change mitigation.

  12. Aerosol climatology over Nile Delta based on MODIS, MISR and OMI satellite data

    Science.gov (United States)

    Marey, H. S.; Gille, J. C.; El-Askary, H. M.; Shalaby, E. A.; El-Raey, M. E.

    2011-10-01

    Since 1999 Cairo and the Nile delta region have suffered from air pollution episodes called the "black cloud" during the fall season. These have been attributed to either burning of agriculture waste or long-range transport of desert dust. Here we present a detailed analysis of the optical and microphysical aerosol properties, based on satellite data. Monthly mean values of Moderate Resolution Imaging Spectroradiometer (MODIS) aerosol optical depth (AOD) at 550 nm were examined for the 10 yr period from 2000-2009. Significant monthly variability is observed in the AOD with maxima in April or May (~0.5) and October (~0.45), and a minimum in December and January (~0.2). Monthly mean values of UV Aerosol Index (UVAI) retrieved by the Ozone Monitoring Instrument (OMI) for 4 yr (2005-2008) exhibit the same AOD pattern. The carbonaceous aerosols during the black cloud periods are confined to the planetary boundary layer (PBL), while dust aerosols exist over a wider range of altitudes, as shown by Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) aerosol profiles. The monthly climatology of Multi-angle Imaging SpectroRadiometer (MISR) data show that the aerosols during the black cloud periods are spherical with a higher percentage of small and medium size particles, whereas the spring aerosols are mostly large non-spherical particles. All of the results show that the air quality in Cairo and the Nile delta region is subject to a complex mixture of air pollution types, especially in the fall season, when biomass burning contributes to a background of urban pollution and desert dust.

  13. Aerosol climatology over Nile Delta based on MODIS, MISR and OMI satellite data

    Directory of Open Access Journals (Sweden)

    H. S. Marey

    2011-10-01

    Full Text Available Since 1999 Cairo and the Nile delta region have suffered from air pollution episodes called the "black cloud" during the fall season. These have been attributed to either burning of agriculture waste or long-range transport of desert dust. Here we present a detailed analysis of the optical and microphysical aerosol properties, based on satellite data. Monthly mean values of Moderate Resolution Imaging Spectroradiometer (MODIS aerosol optical depth (AOD at 550 nm were examined for the 10 yr period from 2000–2009. Significant monthly variability is observed in the AOD with maxima in April or May (~0.5 and October (~0.45, and a minimum in December and January (~0.2. Monthly mean values of UV Aerosol Index (UVAI retrieved by the Ozone Monitoring Instrument (OMI for 4 yr (2005–2008 exhibit the same AOD pattern. The carbonaceous aerosols during the black cloud periods are confined to the planetary boundary layer (PBL, while dust aerosols exist over a wider range of altitudes, as shown by Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO aerosol profiles. The monthly climatology of Multi-angle Imaging SpectroRadiometer (MISR data show that the aerosols during the black cloud periods are spherical with a higher percentage of small and medium size particles, whereas the spring aerosols are mostly large non-spherical particles. All of the results show that the air quality in Cairo and the Nile delta region is subject to a complex mixture of air pollution types, especially in the fall season, when biomass burning contributes to a background of urban pollution and desert dust.

  14. Aerosol Climatology over Nile Delta based on MODIS, MISR and OMI satellite data

    Directory of Open Access Journals (Sweden)

    H. S. Marey

    2011-04-01

    Full Text Available Since 1999 Cairo and the Nile delta region have suffered from air pollution episodes called the "black cloud" during the fall season. These have been attributed to either burning of agriculture waste or long-range transport of desert dust. Here we present a detailed analysis of the optical and microphysical aerosol properties, based on satellite data. Monthly mean values of Moderate Resolution Imaging Spectroradiometer (MODIS aerosol optical depth (AOD at 550 nm were examined for the 10 yr 2000–2009. Significant monthly variability is observed with maxima in April or May (~0.5 and October (~0.45, and a minimum in December and January (~0.2. Monthly mean values of UV Aerosol Index (UVAI retrieved by the Ozone Monitoring Instrument (OMI for 4 yr (2005–2008 exhibit the same AOD pattern. The carbonaceous aerosols during the black cloud periods are confined to the planetary boundary layer (PBL, while dust aerosols exist over a wider range of altitudes, as shown by Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO aerosol profiles. The monthly climatology of Multi-angle Imaging SpectroRadiometer (MISR data show that the aerosols during the black cloud periods are spherical with a higher percentage of small and medium size particles, whereas the spring aerosols are mostly large non-spherical particles. All of the results show that the air quality in Cairo and the Nile delta region is subject to a complex mixture of air pollution types, especially in the fall season, when biomass burning contributes to a background of urban pollution and desert dust.

  15. Aerosol retrieval experiments in the ESA Aerosol_cci project

    Directory of Open Access Journals (Sweden)

    T. Holzer-Popp

    2013-08-01

    Full Text Available Within the ESA Climate Change Initiative (CCI project Aerosol_cci (2010–2013, algorithms for the production of long-term total column aerosol optical depth (AOD datasets from European Earth Observation sensors are developed. Starting with eight existing pre-cursor algorithms three analysis steps are conducted to improve and qualify the algorithms: (1 a series of experiments applied to one month of global data to understand several major sensitivities to assumptions needed due to the ill-posed nature of the underlying inversion problem, (2 a round robin exercise of "best" versions of each of these algorithms (defined using the step 1 outcome applied to four months of global data to identify mature algorithms, and (3 a comprehensive validation exercise applied to one complete year of global data produced by the algorithms selected as mature based on the round robin exercise. The algorithms tested included four using AATSR, three using MERIS and one using PARASOL. This paper summarizes the first step. Three experiments were conducted to assess the potential impact of major assumptions in the various aerosol retrieval algorithms. In the first experiment a common set of four aerosol components was used to provide all algorithms with the same assumptions. The second experiment introduced an aerosol property climatology, derived from a combination of model and sun photometer observations, as a priori information in the retrievals on the occurrence of the common aerosol components. The third experiment assessed the impact of using a common nadir cloud mask for AATSR and MERIS algorithms in order to characterize the sensitivity to remaining cloud contamination in the retrievals against the baseline dataset versions. The impact of the algorithm changes was assessed for one month (September 2008 of data: qualitatively by inspection of monthly mean AOD maps and quantitatively by comparing daily gridded satellite data against daily averaged AERONET sun

  16. Utilization of O4 slant column density to derive aerosol layer height from a space-borne UV-visible hyperspectral sensor: sensitivity and case study

    Science.gov (United States)

    Park, Sang Seo; Kim, Jhoon; Lee, Hanlim; Torres, Omar; Lee, Kwang-Mog; Lee, Sang Deok

    2016-02-01

    The sensitivities of oxygen-dimer (O4) slant column densities (SCDs) to changes in aerosol layer height are investigated using the simulated radiances by a radiative transfer model, the linearized pseudo-spherical vector discrete ordinate radiative transfer (VLIDORT), and the differential optical absorption spectroscopy (DOAS) technique. The sensitivities of the O4 index (O4I), which is defined as dividing O4 SCD by 1040 molecules2 cm-5, to aerosol types and optical properties are also evaluated and compared. Among the O4 absorption bands at 340, 360, 380, and 477 nm, the O4 absorption band at 477 nm is found to be the most suitable to retrieve the aerosol effective height. However, the O4I at 477 nm is significantly influenced not only by the aerosol layer effective height but also by aerosol vertical profiles, optical properties including single scattering albedo (SSA), aerosol optical depth (AOD), particle size, and surface albedo. Overall, the error of the retrieved aerosol effective height is estimated to be 1276, 846, and 739 m for dust, non-absorbing, and absorbing aerosol, respectively, assuming knowledge on the aerosol vertical distribution shape. Using radiance data from the Ozone Monitoring Instrument (OMI), a new algorithm is developed to derive the aerosol effective height over East Asia after the determination of the aerosol type and AOD from the MODerate resolution Imaging Spectroradiometer (MODIS). About 80 % of retrieved aerosol effective heights are within the error range of 1 km compared to those obtained from the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) measurements on thick aerosol layer cases.

  17. Utilization of O4 Slant Column Density to Derive Aerosol Layer Height from a Space-Borne UV-Visible Hyperspectral Sensor: Sensitivity and Case Study

    Science.gov (United States)

    Park, Sang Seo; Kim, Jhoon; Lee, Hanlim; Torres, Omar; Lee, Kwang-Mog; Lee, Sang Deok

    2016-01-01

    The sensitivities of oxygen-dimer (O4) slant column densities (SCDs) to changes in aerosol layer height are investigated using the simulated radiances by a radiative transfer model, the linearized pseudo-spherical vector discrete ordinate radiative transfer (VLIDORT), and the differential optical absorption spectroscopy (DOAS) technique. The sensitivities of the O4 index (O4I), which is defined as dividing O4 SCD by 10(sup 40) molecules (sup 2) per centimeters(sup -5), to aerosol types and optical properties are also evaluated and compared. Among the O4 absorption bands at 340, 360, 380, and 477 nanometers, the O4 absorption band at 477 nanometers is found to be the most suitable to retrieve the aerosol effective height. However, the O4I at 477 nanometers is significantly influenced not only by the aerosol layer effective height but also by aerosol vertical profiles, optical properties including single scattering albedo (SSA), aerosol optical depth (AOD), particle size, and surface albedo. Overall, the error of the retrieved aerosol effective height is estimated to be 1276, 846, and 739 meters for dust, non-absorbing, and absorbing aerosol, respectively, assuming knowledge on the aerosol vertical distribution shape. Using radiance data from the Ozone Monitoring Instrument (OMI), a new algorithm is developed to derive the aerosol effective height over East Asia after the determination of the aerosol type and AOD from the MODerate resolution Imaging Spectroradiometer (MODIS). About 80 percent of retrieved aerosol effective heights are within the error range of 1 kilometer compared to those obtained from the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) measurements on thick aerosol layer cases.

  18. Aerosols and fission product transport

    International Nuclear Information System (INIS)

    A survey is presented of current knowledge of the possible role of aerosols in the consequences of in- and out-of-core LOCAs and of end fitting failures in CANDU reactors. An extensive literature search has been made of research on the behaviour of aerosols in possible accidents in water moderated and cooled reactors and the results of various studies compared. It is recommended that further work should be undertaken on the formation of aerosols during these possible accidents and to study their subsequent behaviour. It is also recommended that the fission products behaviour computer code FISSCON II should be re-examined to determine whether it reflects the advances incorporated in other codes developed for light water reactors which have been extensively compared. 47 refs

  19. Air ions and aerosol science

    Science.gov (United States)

    Tammet, Hannes

    1996-03-01

    Collaboration between Gas Discharge and Plasma Physics, Atmospheric Electricity, and Aerosol Science is a factor of success in the research of air ions. The concept of air ion as of any carrier of electrical current through the air is inherent to Atmospheric Electricity under which a considerable statistical information about the air ion mobility spectrum is collected. A new model of air ion size-mobility correlation has been developed proceeding from Aerosol Science and joining the methods of neighboring research fields. The predicted temperature variation of the mobility disagrees with the commonly used Langevin rule for the reduction of air ion mobilities to the standard conditions. Concurrent errors are too big to be neglected in applications. The critical diameter distinguishing cluster ions and charged aerosol particles has been estimated to be 1.4-1.8 nm.

  20. Air ions and aerosol science

    Energy Technology Data Exchange (ETDEWEB)

    Tammet, H. [Department of Environmental Physics, Tartu University, Tartu, Estonia (Estonia) 2400

    1996-03-01

    Collaboration between Gas Discharge and Plasma Physics, Atmospheric Electricity, and Aerosol Science is a factor of success in the research of air ions. The concept of air ion as of any carrier of electrical current through the air is inherent to Atmospheric Electricity under which a considerable statistical information about the air ion mobility spectrum is collected. A new model of air ion size-mobility correlation has been developed proceeding from Aerosol Science and joining the methods of neighboring research fields. The predicted temperature variation of the mobility disagrees with the commonly used Langevin rule for the reduction of air ion mobilities to the standard conditions. Concurrent errors are too big to be neglected in applications. The critical diameter distinguishing cluster ions and charged aerosol particles has been estimated to be 1.4{endash}1.8 nm. {copyright} {ital 1996 American Institute of Physics.}

  1. Characterization of Florida red tide aerosol and the temporal profile of aerosol concentration

    OpenAIRE

    Cheng, Yung Sung; Zhou, Yue; Pierce, Richard H.; Henry, Mike; Baden, Daniel G.

    2009-01-01

    Red tide aerosols containing aerosolized brevetoxins are produced during the red tide bloom and transported by wind to coastal areas of Florida. This study reports the characterization of Florida red tide aerosols in human volunteer studies, in which an asthma cohort spent 1 h on Siesta Beach (Sarasota, Florida) during aerosolized red tide events and non-exposure periods. Aerosol concentrations, brevetoxin levels, and particle size distribution were measured. Hourly filter samples were taken ...

  2. The relationship between aerosol and cloud drop number concentrations in a global aerosol microphysics model

    OpenAIRE

    Pringle, K. J.; Carslaw, K. S.; D. V. Spracklen; Mann, G. M.; M. P. Chipperfield

    2009-01-01

    Empirical relationships that link cloud droplet number (CDN) to aerosol number or mass are commonly used to calculate global fields of CDN for climate forcing assessments. In this work we use a sectional global model of sulfate and sea-salt aerosol coupled to a mechanistic aerosol activation scheme to explore the limitations of this approach. We find that a given aerosol number concentration produces a wide range of CDN concentrations due to variations in the shape of the aerosol size distrib...

  3. ATI TDA 5A aerosol generator evaluation

    International Nuclear Information System (INIS)

    Oil based aerosol ''Smoke'' commonly used for testing the efficiency and penetration of High Efficiency Particulate Air filters (HEPA) and HEPA systems can produce flammability hazards that may not have been previously considered. A combustion incident involving an aerosol generator has caused an investigation into the hazards of the aerosol used to test HEPA systems at Hanford

  4. Autonomous Ozone and Aerosol Lidar Platform: Preliminary Results

    Science.gov (United States)

    Strawbridge, K. B.

    2014-12-01

    Environment Canada is developing an autonomous tropospheric ozone and aerosol lidar system for deployment in support of short-term field studies. Tropospheric ozone and aerosols (PM10 and PM2.5) are important atmospheric constituents in low altitude pollution affecting human health and vegetation. Ozone is photo-chemically active with nitrogen oxides and can have a distinct diurnal variability. Aerosols contribute to the radiative budget, are a tracer for pollution transport, undergo complex mixing, and contribute to visibility and cloud formation. This particular instrument will employ two separate lidar transmitter and receiver assemblies. The tropospheric ozone lidar, based on the differential absorption lidar (DIAL) technique, uses the fourth harmonics of a Nd:YAG laser directed into a CO2 Raman cell to produce 276 nm, 287nm and 299 nm (first to third Stokes lines) output wavelengths. The aerosol lidar is based on the 3+2 design using a tripled Nd:YAG to output 355 nm, 532 nm and 1064nm wavelengths. Both lidars will be housed in a modified cargo trailer allowing for easy deployment to remote areas. The unit can be operated and monitored 24 hours a day via an internet link and requires an external power source. Simultaneous ozone and aerosol lidar measurements will provide the vertical context necessary to understand the complex mixing and transformation of pollutants - particularly when deployed near other ground-based in-situ sensors. Preliminary results will be shown from a summer field study at the Centre For Atmospheric Research Experiments (CARE).

  5. 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

  6. Significant Atmospheric Aerosol Pollution Caused by World Food Cultivation

    Science.gov (United States)

    Bauer, Susanne E.; Tsigaridis, Kostas; Miller, Ron

    2016-01-01

    Particulate matter is a major concern for public health, causing cancer and cardiopulmonary mortality. Therefore, governments in most industrialized countries monitor and set limits for particulate matter. To assist policy makers, it is important to connect the chemical composition and severity of particulate pollution to its sources. Here we show how agricultural practices, livestock production, and the use of nitrogen fertilizers impact near-surface air quality. In many densely populated areas, aerosols formed from gases that are released by fertilizer application and animal husbandry dominate over the combined contributions from all other anthropogenic pollution. Here we test reduction scenarios of combustion-based and agricultural emissions that could lower air pollution. For a future scenario, we find opposite trends, decreasing nitrate aerosol formation near the surface while total tropospheric loads increase. This suggests that food production could be increased to match the growing global population without sacrificing air quality if combustion emission is decreased.

  7. Significant atmospheric aerosol pollution caused by world food cultivation

    Science.gov (United States)

    Bauer, Susanne E.; Tsigaridis, Kostas; Miller, Ron

    2016-05-01

    Particulate matter is a major concern for public health, causing cancer and cardiopulmonary mortality. Therefore, governments in most industrialized countries monitor and set limits for particulate matter. To assist policy makers, it is important to connect the chemical composition and severity of particulate pollution to its sources. Here we show how agricultural practices, livestock production, and the use of nitrogen fertilizers impact near-surface air quality. In many densely populated areas, aerosols formed from gases that are released by fertilizer application and animal husbandry dominate over the combined contributions from all other anthropogenic pollution. Here we test reduction scenarios of combustion-based and agricultural emissions that could lower air pollution. For a future scenario, we find opposite trends, decreasing nitrate aerosol formation near the surface while total tropospheric loads increase. This suggests that food production could be increased to match the growing global population without sacrificing air quality if combustion emission is decreased.

  8. The coagulation of radioactive aerosols

    International Nuclear Information System (INIS)

    Radioactive aerosols can become charged by emitting charges during the decay process, and the resulting electrostatic forces will modify coagulation rates. For Brownian coagulation, calculations for nuclear containment aerosols show that rates averaged over charge distributions can be strongly reduced between particles of the same size, but that increases in average rates can occur for particles of different sizes. The increases arise from small, but significant, negative charging of non-radioactive and small-sized radioactive particles, and are sensitive to the asymmetry between the positive and negative ion mobilities. (Author)

  9. Volcanic aerosol layer formed in the tropical upper troposphere by the eruption of Mt. Merapi, Java, in November 2010 observed by the spaceborne lidar CALIOP

    Science.gov (United States)

    Shibata, Takashi; Kinoshita, Taro

    2016-02-01

    Mt. Merapi in Java, Indonesia, erupted in November 2010. The eruption was proved to be the source of the aerosol layer observed by a ground-based lidar at Biak, Indonesia, in January 2011 using data on the global distribution of aerosols observed by the spaceborne cloud-aerosol lidar with orthogonal polarization (CALIOP). These data were used to describe how the volcanic aerosols produced by the volcanic eruption diffused throughout the tropical tropopause layer (TTL). The equivalent maximum total amount of volcanic SO2 estimated from the spatially integrated total amount of aerosols was 0.09 Tg, which is one-third to half that of gaseous SO2 after the eruption was observed by the ozone monitoring instrument satellite. The obtained cirrus-cloud-appearance frequency data exhibit a seasonal cycle having its maximum in winter and no detectable variations that are synchronized with the increase in TTL volcanic aerosols.

  10. Whole-body monitor, hand-feet monitor, gaseous effluent, area monitor

    International Nuclear Information System (INIS)

    The following gaseous (iodine, noble gases and aerosols) effluents monitoring equipment developed by INVAP may be installed in any nuclear facility with a ventilation system that expels air through a chimney. Should the facility fail to have such a ventilation system - hence the extraction chimney - INVAP can offer an alternative system: a portable gaseous-effluent measuring equipment which can be installed, for example, in the hall of the reactor. Basically, the system consists of forcing, by means of an aspiration pump, a known and fixed air flow fraction from the chimney (or the hall) and to retain the aerosols continuously in a glass microfiber filter. Aerosols are thus measured according to a specially-designed geometry which confronts the filter with the plastic scintillator. The gas thus obtained is free from aerosols. It then passes through a carbon-activated filter which retains iodine. This filter has a coaxial geometry, lodging inside an INa (Tl) gamma radiation-sensitive scintillator. Both scintillators are optically coupled to their respective photomultipliers. Their pulses are processed with a load preamplifier and a discriminating amplifier in order to store them in counters to be periodically read by the intelligent controller. Actual monitoring will be carried out by means of independent measuring channels for iodine and aerosols, with each channel featuring remote reading and alarms (for instance, at the Control Room). Data thus acquired will be processed by an intelligent controller (INVAP Mod. SAPP-09) which will perform the following functions: - Calculation and unit conversion in order to inform in a TRC total and incremental activity released by the installation during a pre-set period established by the operator. - Calculation, including statistical errors, to determine whether incremental alarm values and pre-set totals are adequate or whether they have been exceeded, providing the results. - Process-control operations (counting failure

  11. O-MIF signature in sulfate aerosols from Mexico City

    Science.gov (United States)

    Erwann, Legendre; Erwan, Martin; Slimane, Bekki; Armando, Retama; Pierre, Cartigny; Becky, Alexander; Aurora, Armienta Maria; Claus, Siebe

    2016-04-01

    Since the discovery of mass independent fractionation of sulfur and oxygen isotopes (S- and O-MIF) on Earth, the study of sulfate isotopic composition opened a new and wide field of investigation on the evolution of the atmospheric composition and its consequences for the climate. Sulfate aerosols that have a negative forcing on the climate can therefore be studied via their isotopic composition and leads to better constraints on their formation, fate and sinks, which is essential for our understanding of the sulfur cycle on Earth. In this study we focus on the interaction between anthropogenic and volcanic emissions that is necessary to figure out the climatic impact of volcanoes in large urban area. For the first time the O- composition of sulfate aerosols was monitored over the past 25 years in one of the world's largest megacities: Mexico City (MC). Sulfate aerosols from the megalopolis were sampled from 1989 to 2013 in different stations by high volume pumps and collected on glass filters. Additionally, fresh volcanic ash samples were collected during recent eruptions (from 1997 to 2013) of the Popocatepetl, which is only 70km from MC. After extraction and purification of sulfate from filters and volcanic ash, the isotopic composition is measured. The sulfate aerosols from MC show O-MIF composition with Δ17O of about 0.7‰ during the wet season and around 1.2‰ during the dry season and δ18O from -0.4‰ to 17.5‰. However, the volcanic sulfate aerosols from the Popocatepetl do not show O-MIF and δ18O vary from 7.0‰ to 12.2‰. The dataset allows us to discuss the seasonal variations in the SO2 oxidation pathways that lead to sulfate aerosol formation in the troposphere above MC during the last 25 years. Furthermore, since 1997 we are able to trace and quantify the influence of volcanic sulfate aerosols on the megalopolis, which is important for the sulfur budget in the region.

  12. Retrieval of aerosol absorption properties using the AATSR satellite instrument: a case study of wildfires over Russia 2010

    Directory of Open Access Journals (Sweden)

    E. Rodríguez

    2014-09-01

    Full Text Available The retrieval of aerosol properties from satellite data is based on the optimized fit of simulated and measured radiances at the top of the atmosphere (TOA. The simulations are made using a radiative transfer model with a variety of representative aerosol properties.The optimum fit is obtained for a certain combination of aerosol components, which are externally mixed to provide the aerosol model which in turn is used to calculate the aerosol optical depth (AOD. However, other aerosol properties could be provided. In the aerosol retrieval algorithm (ADV applied to data from the Advanced Along Track Scanning Radiometer (AATSR, four aerosol components are used, each of which is defined by their (lognormal size distribution and a complex refractive index. The fine mode fraction is a continuous mixture of weakly and strongly absorbing components which allows for the definition of any absorbing aerosol model within the specified limits. Hence, assuming that the correct aerosol model is selected during the retrieval process, also the single scattering albedo (SSA should correctly be retrieved. In this paper we present the SSA retrieval using the ADV algorithm by application to wildfires over Russia in the summer of 2010. Together with the AOD, the SSA provides the aerosol absorbing optical depth (AAOD. The results are compared with AERONET data, i.e. AOD level 2.0 and SSA and AAOD inversion products. The RMSE is 0.03 for SSA and 0.02 for AAOD. The SSA is further evaluated by comparison with the SSA retrieved from the Ozone Monitoring Instrument (OMI. The SSA retrieved from both instruments show similar features, but the AATSR-retrieved SSA values over areas affected by wildfires are lower.

  13. Aerosols of Mongolian arid area

    Science.gov (United States)

    Golobokova, L.; Marinayte, I.; Zhamsueva, G.

    2012-04-01

    Sampling was performed in July-August 2005-2010 at Station Sain Shand (44°54'N, 110°07'E) in the Gobi desert (1000 m a.s.l.), West Mongolia. Aerosol samples were collected with a high volume sampler PM 10 (Andersen Instruments Inc., USA) onto Whatman-41 filters. The substance was extracted from the filters by de-ionized water. The solution was screened through an acetate-cellulose filter with 0.2 micron pore size. Ions of ammonium, sodium, potassium, magnesium, and calcium, as well as sulphate ions, nitrate ions, hydrocarbonate, chloride ions were determined in the filtrate by means of an atomic adsorption spectrometer Carl Zeiss Jena (Germany), a high performance liquid chromatographer «Milichrome A-02» (Russia), and an ionic chromatographer ICS-3000 (Dionex, USA). The PAH fraction was separated from aerosol samples using hexane extraction at room temperature under UV environment. The extract was concentrated to 0.1-0.2 ml and analysed by a mass-spectrometer "Agilent, GC 6890, MSD 5973 Network". Analysis of concentrations of aerosols components, their correlation ratios, and meteorological modeling show that the main factor affecting chemical composition of aerosols is a flow of contaminants transferred by air masses to the sampling area mainly from the south and south-east, as well as wind conditions of the area, dust storms in particular. Sulphate, nitrate, and ammonium are major ions in aerosol particles at Station Sain Shand. Dust-borne aerosol is known to be a sorbent for both mineral and organic admixtures. Polycyclic aromatic hydrocarbons (PAH) being among superecotoxicants play an important role among resistant organic substances. PAH concentrations were determined in the samples collected in 2010. All aerosol samples contained dominant PAHs with 5-6 benzene rings ( (benze(k)fluoranthen, benze(b)flouranthen, benze(a)pyren, benze(?)pyren, perylene, benze(g,h,i)perylene, and indene(1,2,3-c,d)pyrene). Their total quantity varied between 42 and 90

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

    OpenAIRE

    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

    2016-01-01

    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 multilinea...

  15. New Approach for Near-Real-Time Measurement of Elemental Composition of Aerosol Using Laser-Induced Breakdown Spectroscopy

    OpenAIRE

    Diwakar, Prasoon; Kulkarni, Pramod; Birch, M. Eileen

    2011-01-01

    A new approach has been developed for making near-real-time measurement of elemental composition of aerosols using plasma spectroscopy. The method allows preconcentration of miniscule particle mass (pg to ng) directly from the sampled aerosol stream through electrostatic deposition of charged particles (30–900 nm) onto a flat-tip microneedle electrode. The collected material is subsequently ablated from the electrode and monitored by laser-induced breakdown spectroscopy. Atomic emission spect...

  16. Impacts of the direct radiative effect of aerosols in numerical weather prediction over Europe using the ALADIN-HIRLAM NWP system

    Science.gov (United States)

    Toll, V.; Gleeson, E.; Nielsen, K. P.; Männik, A.; Mašek, J.; Rontu, L.; Post, P.

    2016-05-01

    Aerosol feedbacks are becoming more accepted as physical mechanisms that should be included in numerical weather prediction models in order to improve the accuracy of the weather forecasts. The default set-up in the Aire Limitee Adaptation dynamique Developpement INternational (ALADIN) - High Resolution Limited Area Model (HIRLAM) numerical weather prediction system includes monthly aerosol climatologies to account for the average direct radiative effect of aerosols. This effect was studied using the default aerosol climatology in the system and compared to experiments run using the more up-to-date Max-Planck-Institute Aerosol Climatology version 1 (MACv1), and time-varying aerosol data from the Monitoring Atmospheric Composition and Climate (MACC) reanalysis aerosol dataset. Accounting for the direct radiative effect using monthly aerosol climatologies or near real-time aerosol distributions improved the accuracy of the simulated radiative fluxes and temperature and humidity forecasts in the lower troposphere. However, the dependency of forecast meteorological conditions on the aerosol dataset itself was found to be weak.

  17. Dissolution of LMFBR fuel-sodium aerosols

    International Nuclear Information System (INIS)

    Aerosols of either LMFBR fuel or PuO2 are essentially insoluble in water or biological fluids. If either of these aerosols is exposed to sodium metal vapor, the resulting aerosol is much more soluble in aqueous solutions. Preferential dissolution of uranium from mixed sodium-fuel aerosols makes the plutonium more readily soluble than for sodium-PuO2 aerosol. Ultrafiltration of the dissolution test solvent revealed the plutonium to be associated with particles between 2 nm and 10 nm in diameter, in both cases

  18. Contribution of methane to aerosol carbon mass

    Science.gov (United States)

    Bianchi, F.; Barmet, P.; Stirnweis, L.; El Haddad, I.; Platt, S. M.; Saurer, M.; Lötscher, C.; Siegwolf, R.; Bigi, A.; Hoyle, C. R.; DeCarlo, P. F.; Slowik, J. G.; Prévôt, A. S. H.; Baltensperger, U.; Dommen, J.

    2016-09-01

    Small volatile organic compounds (VOC) such as methane (CH4) have long been considered non-relevant to aerosol formation due to the high volatility of their oxidation products. However, even low aerosol yields from CH4, the most abundant VOC in the atmosphere, would contribute significantly to the total particulate carbon budget. In this study, organic aerosol (OA) mass yields from CH4 oxidation were evaluated at the Paul Scherrer Institute (PSI) smog chamber in the presence of inorganic and organic seed aerosols. Using labeled 13C methane, we could detect its oxidation products in the aerosol phase, with yields up to 0.09

  19. The Cloud-Aerosol Transport System (CATS): A New Lidar for Aerosol and Cloud Profiling from the International Space Station

    Science.gov (United States)

    Welton, Ellsworth J.; McGill, Mathew J.; Yorks. John E.; Hlavka, Dennis L.; Hart, William D.; Palm, Stephen P.; Colarco, Peter R.

    2012-01-01

    Spaceborne lidar profiling of aerosol and cloud layers has been successfully implemented during a number of prior missions, including LITE, ICESat, and CALIPSO. Each successive mission has added increased capability and further expanded the role of these unique measurements in wide variety of applications ranging from climate, to air quality, to special event monitoring (ie, volcanic plumes). Many researchers have come to rely on the availability of profile data from CALIPSO, especially data coincident with measurements from other A-Train sensors. The CALIOP lidar on CALIPSO continues to operate well as it enters its fifth year of operations. However, active instruments have more limited lifetimes than their passive counterparts, and we are faced with a potential gap in lidar profiling from space if the CALIOP lidar fails before a new mission is operational. The ATLID lidar on EarthCARE is not expected to launch until 2015 or later, and the lidar component of NASA's proposed Aerosols, Clouds, and Ecosystems (ACE) mission would not be until after 2020. Here we present a new aerosol and cloud lidar that was recently selected to provide profiling data from the International Space Station (ISS) starting in 2013. The Cloud-Aerosol Transport System (CATS) is a three wavelength (1064,532,355 nm) elastic backscatter lidar with HSRL capability at 532 nm. Depolarization measurements will be made at all wavelengths. The primary objective of CATS is to continue the CALIPSO aerosol and cloud profile data record, ideally with overlap between both missions and EarthCARE. In addition, the near real time (NRT) data capability ofthe ISS will enable CATS to support operational applications such as aerosol and air quality forecasting and special event monitoring. The HSRL channel will provide a demonstration of technology and a data testbed for direct extinction retrievals in support of ACE mission development. An overview of the instrument and mission will be provided, along with a

  20. Charge distributions and coagulation of radioactive aerosols

    International Nuclear Information System (INIS)

    The self-charging of radioactive aerosols will be reduced by background ions, such as those produced by radioactive gases. The sources of these background ions and their production rates are specified for a reactor containment atmosphere during a possible nuclear accident. Previous theory is extended to calculate the charging of a polydisperse radioactive aerosol. Gaussian approximations to charge distributions on an aerosol of a given size, and are shown to give a good representation of the exact numerical charge distributions of a Cs aerosol at normal temperatures, and also for highly radioactive aerosol containing 131I in a containment atmosphere. Extensive calculations are performed for charged-induced modifications to Brownian coagulation rates between steady-state size distribution of these radioactive aerosols, and also between small-sized radioactive aerosol and larger (non-radioactive) aerosol. The results show considerable enhancements of the coagulation rates between large and small-sized aerosol, but also a strong suppression of coagulation between large particles. Rate modifications calculated using the Gaussian approximations are generally close to the exact values. Time-dependent calculations for a monodisperse α-decaying aerosol reveal enhancements in coagulation rates even when the average charge on the aerosol is positive. Our results are relevant to behaviour in a dusty plasma. (author)

  1. 6.7 Continuous Aerosol Number Size Distributions Measurement at Košetice Observatory

    Czech Academy of Sciences Publication Activity Database

    Zíková, Naděžda; Ondráček, Jakub; Schwarz, Jaroslav; Ždímal, Vladimír

    Vol. 1. Prague : Czech Hydrometeorological Institute, 2014 - (Holubová Šmejkalová, A.), s. 69-73 ISBN 978-80-87577-40-0 R&D Projects: GA ČR GAP209/11/1342 Institutional support: RVO:67985858 Keywords : atmospheric aerosols * backround station * monitoring Subject RIV: CF - Physic al ; Theoretical Chemistry http://hdl.handle.net/11104/0245199

  2. Retrieval of aerosol optical properties from OMI radiances using a multiwavelength algorithm : Application to Western Europe

    NARCIS (Netherlands)

    Curier, R.L.; Veefkind, J.P.; Braak, R.; Veihelmann, B.; Torres, O.; Leeuw, G. de

    2008-01-01

    The Ozone Monitoring Instrument (OMI) multiwavelength algorithm has been developed to retrieve aerosol optical depth using OMI-measured reflectance at the top of the atmosphere. This algorithm was further developed by using surface reflectance data from a field campaign in Cabauw (The Netherlands),

  3. Aerosol optical thickness and spatial variability along coastal and offshore waters of the eastern Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Menon, H.B.; Sangekar, N.; Lotliker, A.; Moorthy, K.K.; Vethamony, P.

    Data from the ocean-colour monitor (OCM) on board the Indian Remote Sensing Satellite P4 were used to analyse the spatial and temporal distribution of aerosol optical thickness (AOT) over the coastal and offshore waters of the eastern Arabian Sea...

  4. The effects of aerosols on climate

    International Nuclear Information System (INIS)

    Atmospheric aerosols (fine particles suspended in the atmosphere) can play two roles in the Earth’s radiation budget. In cloud-free air, aerosols scatter sunlight, some of which is reflected back to space (direct effect). Aerosols also determine the microphysical and optical properties of clouds (indirect effect). Whereas changes in natural aerosols are probably small during the last 100 years, there has been a large increase in the concentration of anthropogenic aerosols. The magnitude of their radiative effects is still very uncertain but seems to be sufficient to mask part of the global warming expected to stem from anthropogenic greenhouse gases. This paper presents the physical mechanisms of aerosol influence on climate. We then estimate the anthropogenic aerosol radiative effects and assess the climate response to these perturbations. (author)

  5. A statistical-numerical aerosol parameterization scheme

    Directory of Open Access Journals (Sweden)

    J.-P. Chen

    2013-05-01

    Full Text Available A new modal aerosol parameterization scheme, Statistical-Numerical Aerosol Parameterization (SNAP, was developed for studying aerosol processes and aerosol-cloud interactions in regional or global models. SNAP applies statistical fitting on numerical results to generate accurate parameterization formulas without sacrificing details of the growth kernel. Processes considered in SNAP include fundamental aerosol processes, as well as processes related to aerosol-cloud interactions. Comparison of SNAP with numerical solutions, analytical solutions, and binned aerosol model simulations showed that the new method performs well, with accuracy higher than that of the high-order numerical quadrature technique, at much less computation time. The SNAP scheme has been implemented in regional air quality models, producing results very close to those using binned-size schemes or numerical quadrature schemes.

  6. Review of models applicable to accident aerosols

    International Nuclear Information System (INIS)

    Estimations of potential airborne-particle releases are essential in safety assessments of nuclear-fuel facilities. This report is a review of aerosol behavior models that have potential applications for predicting aerosol characteristics in compartments containing accident-generated aerosol sources. Such characterization of the accident-generated aerosols is a necessary step toward estimating their eventual release in any accident scenario. Existing aerosol models can predict the size distribution, concentration, and composition of aerosols as they are acted on by ventilation, diffusion, gravity, coagulation, and other phenomena. Models developed in the fields of fluid mechanics, indoor air pollution, and nuclear-reactor accidents are reviewed with this nuclear fuel facility application in mind. The various capabilities of modeling aerosol behavior are tabulated and discussed, and recommendations are made for applying the models to problems of differing complexity

  7. Optical trapping of gold aerosols

    DEFF Research Database (Denmark)

    Schmitt, Regina K.; Pedersen, Liselotte Jauffred; Taheri, S. M.;

    2015-01-01

    Aerosol trapping has proven challenging and was only recently demonstrated.1 This was accomplished by utilizing an air chamber designed to have a minimum of turbulence and a laser beam with a minimum of aberration. Individual gold nano-particles with diameters between 80 nm and 200 nm were trappe...

  8. Saving Joint with Aerosol physics

    International Nuclear Information System (INIS)

    Full text: Using electro spray method to analyze wear debris from artificial joints. Well known aerosol techniques have been applied to determine the size distribution and concentration of wear particles found in joint fluids. The organic fraction (cells and large molecules) are removed by digestion. Knowing these data the risk of clogging of blood vessels can be medicinally reduced. (author)

  9. Immunization by a bacterial aerosol.

    Science.gov (United States)

    Garcia-Contreras, Lucila; Wong, Yun-Ling; Muttil, Pavan; Padilla, Danielle; Sadoff, Jerry; Derousse, Jessica; Germishuizen, Willem Andreas; Goonesekera, Sunali; Elbert, Katharina; Bloom, Barry R; Miller, Rich; Fourie, P Bernard; Hickey, Anthony; Edwards, David

    2008-03-25

    By manufacturing a single-particle system in two particulate forms (i.e., micrometer size and nanometer size), we have designed a bacterial vaccine form that exhibits improved efficacy of immunization. Microstructural properties are adapted to alter dispersive and aerosol properties independently. Dried "nanomicroparticle" vaccines possess two axes of nanoscale dimensions and a third axis of micrometer dimension; the last one permits effective micrometer-like physical dispersion, and the former provides alignment of the principal nanodimension particle axes with the direction of airflow. Particles formed with this combination of nano- and micrometer-scale dimensions possess a greater ability to aerosolize than particles of standard spherical isotropic shape and of similar geometric diameter. Here, we demonstrate effective application of this biomaterial by using the live attenuated tuberculosis vaccine bacille Calmette-Guérin (BCG). Prepared as a spray-dried nanomicroparticle aerosol, BCG vaccine exhibited high-efficiency delivery and peripheral lung targeting capacity from a low-cost and technically simple delivery system. Aerosol delivery of the BCG nanomicroparticle to normal guinea pigs subsequently challenged with virulent Mycobacterium tuberculosis significantly reduced bacterial burden and lung pathology both relative to untreated animals and to control animals immunized with the standard parenteral BCG. PMID:18344320

  10. Climatic impacts of anthropogenic aerosols

    Energy Technology Data Exchange (ETDEWEB)

    Iversen, T. [Oslo Univ. (Norway)

    1996-03-01

    This paper was read at the workshop ``The Norwegian Climate and Ozone Research Programme`` held on 11-12 March 1996. Anthropogenic production of aerosols is mainly connected with combustion of fossil fuel. Measured by particulate mass, the anthropogenic sulphate production is the dominating source of aerosols in the Northern Hemisphere. Particles emitted in mechanical processes, fly ash etc. are less important because of their shorter atmospheric residence time. Possible climatological effects of anthropogenic aerosols are usually classified in two groups: direct and indirect. Direct effects are alterations of the radiative heating budget due to the aerosol particles in clear air. Indirect effects involve the interaction between particles and cloud processes. A simplified one-layer radiation model gave cooling in the most polluted mid-latitude areas and heating due to soot absorption in the Arctic. This differential trend in heating rates may have significant effects on atmospheric meridional circulations, which is important for the atmosphere as a thermodynamic system. Recently the description of sulphur chemistry in the hemispheric scale dispersion model has been improved and will be used in a model for Mie scattering and absorption

  11. Uncertainty quantification in aerosol dynamics

    International Nuclear Information System (INIS)

    The influence of uncertainty in coagulation and depositions mechanisms, as well as in the initial conditions, on the solution of the aerosol dynamic equation have been assessed using polynomial chaos theory. In this way, large uncertainties can be incorporated into the equations and their propagation as a function of space and time studied. We base our calculations on the simplified point model dynamic equation which includes coagulation and deposition removal mechanisms. Results are given for the stochastic mean aerosol density as a function of time as well as its variance. The stochastic mean and deterministic mean are shown to differ and the associated uncertainty, in the form of a sensitivity coefficient, is obtained as a function of time. In addition, we obtain the probability density function of the aerosol density and show how this varies with time. In view of the generally uncertain nature of an accidental aerosol release in a nuclear reactor accident, the polynomial chaos method is a particularly useful technique as it allows one to deal with a very large spread of input data and examine the effect this has on the quantities of interest. Convergence matters are studied and numerical values given.

  12. PIXE Analysis of Indoor Aerosols

    Science.gov (United States)

    Johnson, Christopher; Turley, Colin; Moore, Robert; Battaglia, Maria; Labrake, Scott; Vineyard, Michael

    2011-10-01

    We have performed a proton-induced X-ray emission (PIXE) analysis of aerosol samples collected in academic buildings at Union College to investigate the air quality in these buildings and the effectiveness of their air filtration systems. This is also the commissioning experiment for a new scattering chamber in the Union College Ion-Beam Analysis Laboratory. The aerosol samples were collected on Kapton foils using a nine-stage cascade impactor that separates particles according to their aerodynamic size. The foils were bombarded with beams of 2.2-MeV protons from the Union College 1.1-MV Pelletron Accelerator and the X-ray products were detected with an Amptek silicon drift detector. After subtracting the contribution from the Kapton foils, the X-ray energy spectra of the aerosol samples were analyzed using GUPIX software to determine the elemental concentrations of the samples. We will describe the collection of the aerosol samples, discuss the PIXE analysis, and present the results.

  13. Aerosol behaviour modeling and measurements

    International Nuclear Information System (INIS)

    Aerosol behavior within Liquid Metal Fast Breeder Reactor (LMFBR) containments is of critical importance since most of the radioactive species are expected to be associated with particulate forms and the mass of radiologically significant material leaked to the ambient atmosphere is directly related to the aerosol concentration airborne within the containment. Mathematical models describing the behavior of aerosols in closed environments, besides providing a direct means of assessing the importance of specific assumptions regarding accident sequences, will also serve as the basic tool with which to predict the consequences of various postulated accident situations. Consequently, considerable efforts have been recently directed toward the development of accurate and physically realistic theoretical aerosol behavior models. These models have accounted for various mechanisms affecting agglomeration rates of airborne particulate matter as well as particle removal rates from closed systems. In all cases, spatial variations within containments have been neglected and a well-mixed control volume has been assumed. Examples of existing computer codes formulated from the mathematical aerosol behavior models are the Brookhaven National Laboratory TRAP code, the PARDISEKO-II and PARDISEKO-III codes developed at Karlsruhe Nuclear Research Center, and the HAA-2, HAA-3, and HAA-3B codes developed by Atomics International. Because of their attractive short computation times, the HAA-3 and HAA-3B codes have been used extensively for safety analyses and are attractive candidates with which to demonstrate order of magnitude estimates of the effects of various physical assumptions. Therefore, the HAA-3B code was used as the nucleus upon which changes have been made to account for various physical mechanisms which are expected to be present in postulated accident situations and the latest of the resulting codes has been termed the HAARM-2 code. It is the primary purpose of the HAARM

  14. Aerosol Absorption Measurements in MILAGRO.

    Science.gov (United States)

    Gaffney, J. S.; Marley, N. A.; Arnott, W. P.; Paredes-Miranda, L.; Barnard, J. C.

    2007-12-01

    During the month of March 2006, a number of instruments were used to determine the absorption characteristics of aerosols found in the Mexico City Megacity and nearby Valley of Mexico. These measurements were taken as part of the Department of Energy's Megacity Aerosol Experiment - Mexico City (MAX-Mex) that was carried out in collaboration with the Megacity Interactions: Local and Global Research Observations (MILAGRO) campaign. MILAGRO was a joint effort between the DOE, NSF, NASA, and Mexican agencies aimed at understanding the impacts of a megacity on the urban and regional scale. A super-site was operated at the Instituto Mexicano de Petroleo in Mexico City (designated T-0) and at the Universidad Technologica de Tecamac (designated T-1) that was located about 35 km to the north east of the T-0 site in the State of Mexico. A third site was located at a private rancho in the State of Hidalgo approximately another 35 km to the northeast (designated T-2). Aerosol absorption measurements were taken in real time using a number of instruments at the T-0 and T-1 sites. These included a seven wavelength aethalometer, a multi-angle absorption photometer (MAAP), and a photo-acoustic spectrometer. Aerosol absorption was also derived from spectral radiometers including a multi-filter rotating band spectral radiometer (MFRSR). The results clearly indicate that there is significant aerosol absorption by the aerosols in the Mexico City megacity region. The absorption can lead to single scattering albedo reduction leading to values below 0.5 under some circumstances. The absorption is also found to deviate from that expected for a "well-behaved" soot anticipated from diesel engine emissions, i.e. from a simple 1/lambda wavelength dependence for absorption. Indeed, enhanced absorption is seen in the region of 300-450 nm in many cases, particularly in the afternoon periods indicating that secondary organic aerosols are contributing to the aerosol absorption. This is likely due

  15. Impact of the modal aerosol scheme GLOMAP-mode on aerosol forcing in the Hadley Centre Global Environmental Model

    OpenAIRE

    Bellouin, N; Mann, G.W.; Woodhouse, M.T.; Johnson, C.; Carslaw, K. S.; Dalvi, M.

    2012-01-01

    The Hadley Centre Global Environmental Model (HadGEM) includes two aerosol schemes: the Coupled Large-scale Aerosol Simulator for Studies in Climate (CLASSIC), and the new Global Model of Aerosol Processes (GLOMAP-mode). GLOMAP-mode is a modal aerosol microphysics scheme that simulates not only aerosol mass but also aerosol number, represents internally-mixed particles, and includes aerosol microphysical processes such as nucleation. In this study, both schemes provide hindcast simulations of...

  16. Composition and physical properties of the Asian Tropopause Aerosol Layer and the North American Tropospheric Aerosol Layer

    OpenAIRE

    Yu, P.; Toon, OB; Neely, RR; Martinsson, BG; Brenninkmeijer, CAM

    2015-01-01

    Recent studies revealed layers of enhanced aerosol scattering in the upper troposphere and lower stratosphere over Asia (Asian Tropopause Aerosol Layer (ATAL)) and North America (North American Tropospheric Aerosol Layer (NATAL)). We use a sectional aerosol model (Community Aerosol and Radiation Model for Atmospheres (CARMA)) coupled with the Community Earth System Model version 1 (CESM1) to explore the composition and optical properties of these aerosol layers. The observed aerosol extinctio...

  17. Tracking of urban aerosols using combined lidar-based remote sensing and ground-based measurements

    Directory of Open Access Journals (Sweden)

    T.-Y. He

    2011-10-01

    Full Text Available A measuring campaign was performed over the neighboring towns of Nova Gorica in Slovenia and Gorizia in Italy on 24 and 25 May 2010, to investigate the concentration and distribution of urban aerosols. Tracking of two-dimensional spatial and temporal aerosol distributions was performed using scanning elastic lidar operating at 1064 nm. In addition, PM10 concentrations of particles, NOx and meteorological data were continuously monitored within the lidar scanning region. Based on the collected data, we investigated the flow dynamics and the aerosol concentrations within the lower troposphere and an evidence for daily aerosol cycles. We observed a number of cases with spatially localized increased lidar returns, which were found to be due to the presence of point sources of particulate matter. Daily aerosol concentration cycles were also clearly visible with a peak in aerosol concentration during the morning rush hours and daily maximum at around 17:00 Central European Time. We also found that the averaged horizontal atmospheric extinction within the scanning region 200 m above the ground is correlated to the PM10 concentration at the ground level with a correlation coefficient of 0.64, which may be due to relatively quiet meteorological conditions and basin-like terrain configuration.

  18. Apportionment of urban aerosol sources in Chongqing (China) using synergistic on-line techniques

    Science.gov (United States)

    Chen, Yang; Yang, Fumo

    2016-04-01

    The sources of ambient fine particulate matter (PM2.5) during wintertime at a background urban location in Chongqing (southwestern China) have been determined. Aerosol chemical composition analyses were performed using multiple on-line techniques, such as single particle aerosol mass spectrometer (SPAMS) for single particle chemical composition, on-line elemental carbon-organic carbon analyzer (on-line OC-EC), on-line X-ray fluorescence (XRF) for elements, and in-situ Gas and Aerosol Compositions monitor (IGAC) for water-soluble ions in PM2.5. All the datasets from these techniques have been adjusted to a 1-h time resolution for receptor model input. Positive matrix factorization (PMF) has been used for resolving aerosol sources. At least six sources, including domestic coal burning, biomass burning, dust, traffic, industrial and secondary/aged factors have been resolved and interpreted. The synergistic on-line techniques were helpful for identifying aerosol sources more clearly than when only employing the results from the individual techniques. This results are useful for better understanding of aerosol sources and atmospheric processes.

  19. Real-time measurement of aerosol particle concentration at high temperatures; Hiukkaspitoisuuden reaaliaikainen mittaaminen korkeassa laempoetilassa

    Energy Technology Data Exchange (ETDEWEB)

    Keskinen, J.; Hautanen, J.; Laitinen, A. [Tampere Univ. of Technology (Finland). Physics

    1997-10-01

    The aim of this project is to develop a new method for continuous aerosol particle concentration measurement at elevated temperatures (up to 800-1000 deg C). The measured property of the aerosol particles is the so called Fuchs surface area. This quantity is relevant for diffusion limited mass transfer to particles. The principle of the method is as follows. First, aerosol particles are charged electrically by diffusion charging process. The charging takes place at high temperature. After the charging, aerosol is diluted and cooled. Finally, aerosol particles are collected and the total charge carried by the aerosol particles is measured. Particle collection and charge measurement take place at low temperature. Benefits of this measurement method are: particles are charged in-situ, charge of the particles is not affected by the temperature and pressure changes after sampling, particle collection and charge measurement are carried out outside the process conditions, and the measured quantity is well defined. The results of this study can be used when the formation of the fly ash particles is studied. Another field of applications is the study and the development of gasification processes. Possibly, the method can also be used for the monitoring the operation of the high temperature particle collection devices. (orig.)

  20. Development of a radon-aerosol system for testing radon and radon decay products measuring instruments

    International Nuclear Information System (INIS)

    Exposures to radon and its decay products may arise from NORM-related work activities. Employers are responsible for monitoring radon in their workplaces, and the methods and instruments used must be subjected to adequate quality assurance. A radon chamber is an important component of a quality assurance programme. In this study we developed a radon-aerosol chamber and used it to characterise the prototype version of a newly developed radon decay product measuring instrument. The system comprises a small radon chamber with dry radon source, aerosol chamber, monodisperse aerosol generator, and TSI aerodynamic particle sizer with its accessories. Radon-laden air mixed with aerosols is pumped from the radon-aerosol system through the radon decay product measuring instrument. The instrument's response is obtained continuously from alpha spectrometric analyses of the radon decay products, 218Po and 214Po, deposited on a membrane filter (0.8 - m pore sizes and 25 mm diameter) held close to a silicon surface barrier detector. A second couple of filter and detector is inserted downstream to check the efficiency and eventual leakage of the membrane filter. The results show that alpha activity on the filter nearer to the inlet was significantly higher than the activity on the second filter. There were also significant losses of aerosols to the inner wall of the instrument as air flows through. The implications of these observations on the response of the instrument are discussed. (author)

  1. Atmospheric aerosol particle analysis at the Debrecen Nuclear Microprobe

    International Nuclear Information System (INIS)

    Complete text of publication follows. Characterisation of atmospheric aerosol is in the focus of several national and international research programs due to their health impact and effects on the radiative balance of Earth. Bulk elemental analytical techniques, like macro-PIXE, are extensively used for analysing atmospheric aerosol. However more detailed and reliable data can be obtained if individual aerosol particles are analysed. Nuclear microscopy is a powerful tool which enables the quantitative determination of trace element distribution in complex samples with a sensitivity of μg/g on micrometer scale. In the frame of an OTKA and a Coordinated Research Project of the IAEA, an experimental setup based on the simultaneous use of different ion beam analytical techniques was developed at the Debrecen scanning nuclear microprobe facility, which enables the total quantitative analysis of microparticles. This measurement, data collection and evaluation setup was already applied successfully in various studies: (1) ion beam microanalysis of desert dust particles originating from Saharan dust intrusions, (2) characterization of urban aerosol sources by single particle analysis, (3) characterization of indoor aerosols. As an example, nuclear microprobe study of indoor aerosol particles containing toxic metals is presented. Aerosol samples were collected in the IBA Lab of ATOMKI in the frame of a laboratory practice for undergraduate students. At the same time mechanical repair work was carried out on the heating system in the corridor outside the Laboratory. In order to demonstrate the monitoring of air pollution for the students, aerosol samples were collected with a 2-stage filter unit on Nuclepore polycarbonate filters. The samples were analysed by bulk-PIXE. Concentration of Zn, Cd and Pb were found to be exceeding the national air quality limit. Therefore single particle analysis was carried out on the coarse mode samples to find out the origin of the toxic

  2. Aerosol classification by airborne high spectral resolution lidar observations

    Directory of Open Access Journals (Sweden)

    S. Groß

    2012-10-01

    Full Text Available During four aircraft field experiments with the DLR research aircraft Falcon in 1998 (LACE, 2006 (SAMUM-1 and 2008 (SAMUM-2 and EUCAARI, airborne High Spectral Resolution Lidar (HSRL and in situ measurements of aerosol microphysical and optical properties were performed. Altogether, the properties of six different aerosol types and aerosol mixtures – Saharan mineral dust, Saharan dust mixtures, Canadian biomass burning aerosol, African biomass burning aerosol, anthropogenic pollution aerosol, and marine aerosol have been studied. On the basis of this extensive HSRL data set, we present an aerosol classification scheme which is also capable to identify mixtures of different aerosol types. We calculated mixing lines that allowed us to determine the contributing aerosol types. The aerosol classification scheme was validated with in-situ measurements and backward trajectory analyses. Our results demonstrate that the developed aerosol mask is capable to identify complex stratifications with different aerosol types throughout the atmosphere.

  3. Status on contamination monitoring in China

    Energy Technology Data Exchange (ETDEWEB)

    Gou Quanlu [China Institute for Radiation Protection, Taiyuan (China)

    1997-06-01

    The air contaminated by radioactive materials in nuclear enterprises and radioactive workplaces and forming radioactive aerosol and the leakage of radioactive materials in operation cause internal exposure damage in workers. It is necessary and important to monitor air and surface contaminations for the health of public and workers, and for protecting environment. At present, many institutes engage in the studies on surface contamination monitoring in China, and the government has formulated the control limits of surface contamination in the Regulations of Radiation Protection. The monitors for surface contamination monitoring are almost home-made. The methods being used often are smear test and placing surface sample test. Scintillation counters, semiconductor detectors and G-M counters have been used for detecting alpha surface contamination. Plastic scintillator meters and thin wall/window G-M counters are used for beta surface contamination. Special detectors have been designed for monitoring low energy nuclides. The status of airborne contamination monitoring in China is reported. As the studies for future, the development of the surface contamination monitor for low energy beta nuclides, especially H-3, the monitoring methods for the special shapes of surfaces, the technology of decontamination and the calibration method and device for on-line radioactive aerosol continuous monitors are taken up. (K.I.)

  4. Aerosol characterization over the North China Plain: Haze life cycle and biomass burning impacts in summer

    Science.gov (United States)

    Sun, Yele; Jiang, Qi; Xu, Yisheng; Ma, Yan; Zhang, Yingjie; Liu, Xingang; Li, Weijun; Wang, Fei; Li, Jie; Wang, Pucai; Li, Zhanqing

    2016-03-01

    The North China Plain experiences frequent severe haze pollution during all seasons. Here we present the results from a summer campaign that was conducted at Xianghe, a suburban site located between the megacities of Beijing and Tianjin. Aerosol particle composition was measured in situ by an Aerosol Chemical Speciation Monitor along with a suite of collocated measurements during 1-30 June 2013. Our results showed that aerosol composition at the suburban site was overall similar to that observed in Beijing, which was mainly composed of organics (39%), nitrate (20%), and sulfate (18%). Positive matrix factorization of organic aerosol (OA) identified four OA factors with different sources and processes. While secondary organic aerosol dominated OA, on average accounting for 70%, biomass burning OA (BBOA) was also observed to have a considerable contribution (11%) for the entire study period. The contribution of BBOA was increased to 21% during the BB period in late June, indicating a large impact of agricultural burning on air pollution in summer. Biomass burning also exerted a significant impact on aerosol optical properties. It was estimated that ~60% enhancement of absorption at the ultraviolet spectral region was caused by the organic compounds from biomass burning. The formation mechanisms and sources of severe haze pollution episodes were investigated in a case study. The results highlighted two different mechanisms, i.e., regional transport and local sources, driving the haze life cycles differently in summer in the North China Plain. While secondary aerosol species dominated aerosol composition in the episode from regional transport, organics and black carbon comprised the major fraction in the locally formed haze episode.

  5. Incremental Reactivity Effects on Secondary Organic Aerosol Formation in Urban Atmospheres with and without Biogenic Influence

    Science.gov (United States)

    Kacarab, Mary; Li, Lijie; Carter, William P. L.; Cocker, David R., III

    2016-04-01

    Two different surrogate mixtures of anthropogenic and biogenic volatile organic compounds (VOCs) were developed to study secondary organic aerosol (SOA) formation at atmospheric reactivities similar to urban regions with varying biogenic influence levels. Environmental chamber simulations were designed to enable the study of the incremental aerosol formation from select anthropogenic (m‑Xylene, 1,2,4-Trimethylbenzene, and 1-Methylnaphthalene) and biogenic (α-pinene) precursors under the chemical reactivity set by the two different surrogate mixtures. The surrogate reactive organic gas (ROG) mixtures were based on that used to develop the maximum incremental reactivity (MIR) factors for evaluation of O3 forming potential. Multiple incremental aerosol formation experiments were performed in the University of California Riverside (UCR) College of Engineering Center for Environmental Research and Technology (CE-CERT) dual 90m3 environmental chambers. Incremental aerosol yields were determined for each of the VOCs studied and compared to yields found from single precursor studies. Aerosol physical properties of density, volatility, and hygroscopicity were monitored throughout experiments. Bulk elemental chemical composition from high-resolution time of flight aerosol mass spectrometer (HR-ToF-AMS) data will also be presented. Incremental yields and SOA chemical and physical characteristics will be compared with data from previous single VOC studies conducted for these aerosol precursors following traditional VOC/NOx chamber experiments. Evaluation of the incremental effects of VOCs on SOA formation and properties are paramount in evaluating how to best extrapolate environmental chamber observations to the ambient atmosphere and provides useful insights into current SOA formation models. Further, the comparison of incremental SOA from VOCs in varying surrogate urban atmospheres (with and without strong biogenic influence) allows for a unique perspective on the impacts

  6. Assessment of OMI near-UV aerosol optical depth over Central and East Asia

    Science.gov (United States)

    Zhang, Wenhao; Gu, Xingfa; Xu, Hui; Yu, Tao; Zheng, Fengjie

    2016-01-01

    Several essential improvements have been made in recent Ozone Monitoring Instrument (OMI) near-ultraviolet (UV) aerosol retrieval algorithm version (OMAERUV version 1.4.2), but few regional validations for its aerosol optical depth (AOD) product are conducted. This paper assessed the OMAERUV AOD product over Central and East Asia. The OMAERUV Level 2.0 AOD product was compared with Aerosol Robotic Network (AERONET) Level 2.0 direct Sun AOD measurement over 10 years (2005-2014) at 27 selected AERONET sites. A combined comparison of OMAERUV-AERONET AOD at 25 (2) sites was carried out and yielded correlation coefficient (ρ) of 0.63 (0.77), slope of 0.53 (0.57), y intercept of 0.18 (0.13), and 50.71% (57.24%) OMAERUV AOD fall within the expected uncertainty boundary (larger by 0.1 or ±30%) at 380 nm (440 nm). The more accurate (ρ > 0.70) OMAERUV retrievals are reported over eastern and northern China and South Korea. The two primary reasons for the underestimation of OMAERUV AOD over China are as follows: (1) the use of single-channel (388 nm) retrieval method retrieves scattering AOD and not total AOD, and (2) the spectral dependence of the imaginary part of the refractive index in the near-UV region assumed in the algorithm may not be representative of aerosols found over China. The comparisons for three predominant aerosol types indicate that smoke aerosol exhibits the best performance, followed by dust and nonabsorbing aerosol. It is consistent with the characteristic of near-UV wavelength that it is more sensitive to absorbent particles. The comprehensive yearly (2005-2014) comparison at 25 sites and comparison between two periods (2005-2006 and 2009-2014) at selected four sites show no discernible decrease of temporal trend, which indicates that the OMAERUV algorithm successfully maintains its quality of aerosol product despite post-2008 row anomaly instrument problem.

  7. 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

  8. 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

    2010-11-01

    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 2 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 fresh wildfire smoke. These ratios suggest minimal precipitation scavenging and removal of

  9. Toxicity of atmospheric aerosols on marine phytoplankton

    Science.gov (United States)

    Paytan, A.; Mackey, K.R.M.; Chen, Y.; Lima, I.D.; Doney, S.C.; Mahowald, N.; Labiosa, R.; Post, A.F.

    2009-01-01

    Atmospheric aerosol deposition is an important source of nutrients and trace metals to the open ocean that can enhance ocean productivity and carbon sequestration and thus influence atmospheric carbon dioxide concentrations and climate. Using aerosol samples from different back trajectories in incubation experiments with natural communities, we demonstrate that the response of phytoplankton growth to aerosol additions depends on specific components in aerosols and differs across phytoplankton species. Aerosol additions enhanced growth by releasing nitrogen and phosphorus, but not all aerosols stimulated growth. Toxic effects were observed with some aerosols, where the toxicity affected picoeukaryotes and Synechococcus but not Prochlorococcus.We suggest that the toxicity could be due to high copper concentrations in these aerosols and support this by laboratory copper toxicity tests preformed with Synechococcus cultures. However, it is possible that other elements present in the aerosols or unknown synergistic effects between these elements could have also contributed to the toxic effect. Anthropogenic emissions are increasing atmospheric copper deposition sharply, and based on coupled atmosphere-ocean calculations, we show that this deposition can potentially alter patterns of marine primary production and community structure in high aerosol, low chlorophyll areas, particularly in the Bay of Bengal and downwind of South and East Asia.

  10. A case study on long-range transported aerosols of biomass burning: effects on aerosol optical properties and surface radiation levels

    Directory of Open Access Journals (Sweden)

    A. Arola

    2007-05-01

    Full Text Available In spring 2006, biomass burning aerosols from eastern Europe were transported extensively to Finland, and to other parts of northern Europe. They were observed as far as in the European Arctic. In the first part of this paper, temporal and spatial evolution and transport of these biomass burning aerosols are monitored with MODIS retrieved aerosol optical depth (AOD imagery at visible wavelengths (0.55 μm. Comparison of MODIS and AERONET AOD is conducted at Tõravere, Estonia. Then trajectory analyses, as well as MODIS Fire Mapper products are used to better understand the type and origin of the air masses. During the studied four-week period AOD values ranged from near zero up to 1.2 at 0.55 μm and the linear correlation between MODIS and AERONET was very high (~0.97. Temporal variability observed within this four-week period was also rather well explained by the trajectory analysis in conjunction with the fire detections produced by the MODIS Rapid Response System. In the second part of our study, the surface measurements of global and UV radiation at Jokioinen, Finland are used to study the effect of this haze episode on the levels of surface radiation. We found reductions up to 35% in surface UV irradiance (at 340 nm as compared to typical aerosol conditions. For global (total solar radiation, the reduction was always smaller, in line with the expected wavelength dependence of the aerosol effect.

  11. MODIS Aerosol Optical Depth Bias Adjustment Using Machine Learning Algorithms

    Science.gov (United States)

    Albayrak, Arif; Wei, Jennifer; Petrenko, Maksym; Lary, David; Leptoukh, Gregory

    2011-01-01

    To monitor the earth atmosphere and its surface changes, satellite based instruments collect continuous data. While some of the data is directly used, some others such as aerosol properties are indirectly retrieved from the observation data. While retrieved variables (RV) form very powerful products, they don't come without obstacles. Different satellite viewing geometries, calibration issues, dynamically changing atmospheric and earth surface conditions, together with complex interactions between observed entities and their environment affect them greatly. This results in random and systematic errors in the final products.

  12. Surface Chemistry at Size-Selected Nano-Aerosol Particles

    Science.gov (United States)

    Roberts, Jeffrey

    2005-03-01

    A method has been developed to conduct surface chemistry and extract surface kinetic rates from size-selected aerosol nanoparticles. The measurements encompass broad ranges of particle size, phase, and composition. Results will be presented on the uptake of water by aerosolized soot nanoparticles of radius between 10 and 40 nm. Water uptake was monitored by tandem differential mobility analysis (T-DMA), which is capable of measuring changes in particle diameter as little as 0.2 nm. Soot particles were produced in an ethene diffusion flame and extracted into an atmospheric pressure aerosol flow tube reactor. The particles were subjected to various thermal and oxidative treatments, and the effects of these treatments on the ability of soot to adsorb monolayer quantities of water was determined. The results are important because soot nucleates atmospheric cloud particles. More generally, the results represent one of the first kinetic and mechanistic studies of gas-phase nanoparticle reactivity. Co-author: Henry Ajo, University of Minnesota

  13. OH-initiated heterogeneous aging of highly oxidized organic aerosol

    Energy Technology Data Exchange (ETDEWEB)

    Kessler, Sean H.; Nah, Theodora; Daumit, Kelly E.; Smith, Jared D.; Leone, Stephen R.; Kolb, Charles E.; Worsnop, Douglas R.; Wilson, Kevin R.; Kroll, Jesse H.

    2011-12-05

    The oxidative evolution (“aging”) of organic species in the atmosphere is thought to have a major influence on the composition and properties of organic particulate matter, but remains poorly understood, particularly for the most oxidized fraction of the aerosol. Here we measure the kinetics and products of the heterogeneous oxidation of highly oxidized organic aerosol, with an aim of better constraining such atmospheric aging processes. Submicron particles composed of model oxidized organics—1,2,3,4-butanetetracarboxylic acid (C{sub 8}H{sub 10}O{sub 8}), citric acid (C{sub 6}H{sub 8}O{sub 7}), tartaric acid (C{sub 4}H{sub 6}O{sub 6}), and Suwannee River fulvic acid—were oxidized by gas-phase OH in a flow reactor, and the masses and elemental composition of the particles were monitored as a function of OH exposure. In contrast to our previous studies of less-oxidized model systems (squalane, erythritol, and levoglucosan), particle mass did not decrease significantly with heterogeneous oxidation. Carbon content of the aerosol always decreased somewhat, but this mass loss was approximately balanced by an increase in oxygen content. The estimated reactive uptake coefficients of the reactions range from 0.37 to 0.51 and indicate that such transformations occur at rates corresponding to 1-2 weeks in the atmosphere, suggesting their importance in the atmospheric lifecycle of organic particulate matter.

  14. Remote sensing of aerosol characteristics and radiative forcing in Pakistan

    International Nuclear Information System (INIS)

    This thesis investigates the aerosol characteristics over different cities of Pakistan through satellite borne sensors, namely the Total Ozone Mapping Spectrometer (TOMS), the Moderate Resolution Imaging Spectroradiometer (MODIS), and the Multi-angle Imaging Spectroradiometer (MISR), and ground-based instruments such as Aerosol Robotic Network (AERONET) and GRIMM 1.109 dust monitor. A Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) model was used for trajectory analysis in order to visualize the origins of air masses and understand the spatio-temporal variability of aerosol concentrations. An assessment of seasonal variability in aerosol optical depth (AOD) for industrial, urban, semi-urban, rural, and semi-arid areas revealed maximum AOD values during summer over all the areas under investigation. The correlation between AERONET and MODIS/MISR AODs during 2007 was also analyzed for Karachi and Lahore. The correlation coefficient for Karachi was found to be relatively high between AERONET and MISR and lower between AERONET and MODIS. In contrast, the correlation coefficient for Lahore was higher between AERONET and MODIS than between AERONET and MISR. The results suggest that the MISR sensor provides better AOD estimates near the ocean while AOD estimates from the MODIS sensor are better over terrestrial regions (especially over vegetated surfaces). The assessment of aerosol optical properties and aerosol radiative forcing (ARF) through the ground-based Aerosol Robotic Network (AERONET) over Lahore and Karachi has also been investigated in this study. The monthly mean of AOD at 500 nm over Lahore and Karachi ranges from 0.39 to 0.76, and the monthly mean Angstrom Exponent ranges from 0.29 to 1.22. The relationship between the Absorption Angstrom Exponent and the Extinction Angstrom Exponent provided an indication of relative proportions of urban-industrial and mineral dust aerosols over both sites. The single scattering albedo (SSA) ranged from 0

  15. CCN activity of aliphatic amine secondary aerosol

    Directory of Open Access Journals (Sweden)

    X. Tang

    2014-01-01

    Full Text Available Aliphatic amines can form secondary aerosol via oxidation with atmospheric radicals (e.g. hydroxyl radical and nitrate radical. The particle composition can contain both secondary organic aerosol (SOA and inorganic salts. The fraction of organic to inorganic materials in the particulate phase influences aerosol hygroscopicity and cloud condensation nuclei (CCN activity. SOA formed from trimethylamine (TMA and butylamine (BA reactions with hydroxyl radical (OH is composed of organic material of low hygroscopicity (single hygroscopicity parameter, κ ≤ 0.25. Secondary aerosol formed from the tertiary aliphatic amine (TMA with N2O5 (source of nitrate radical, NO3, contains less volatile compounds than the primary aliphatic amine (BA aerosol. TMA + N2O5 form semi-volatile organics in low RH conditions that have κ ~ 0.20, indicative of slightly soluble organic material. As RH increases, several inorganic amine salts are formed as a result of acid-base reactions. The CCN activity of the humid TMA-N2O5 aerosol obeys Zdanovskii, Stokes, and Robinson (ZSR ideal mixing rules. Higher CCN activity (κ > 0.3 was also observed for humid BA+N2O5 aerosols compared with dry aerosol (κ ~ 0.2, as a result of the formation of inorganic salts such as NH4NO3 and butylamine nitrate (C4H11N · HNO3. Compared with TMA, BA+N2O5 reactions produce more volatile aerosols. The BA+N2O5 aerosol products under humid experiments were found to be very sensitive to the temperature within the stream-wise continuous flow thermal gradient CCN counter. The CCN counter, when set above a 21 °C temperature difference, evaporates BA+N2O5 aerosol formed at RH ≥ 30%; κ ranges from 0.4 to 0.7 and is dependent on the instrument supersaturation (ss settings. The aerosol behaves non-ideally, hence simple ZSR rules cannot be applied to the CCN results from the primary aliphatic amine system. Overall, aliphatic amine aerosol systems κ ranges from 0.2 < κ < 0.7. This work indicates that

  16. How We Can Constrain Aerosol Type Globally

    Science.gov (United States)

    Kahn, Ralph

    2016-01-01

    In addition to aerosol number concentration, aerosol size and composition are essential attributes needed to adequately represent aerosol-cloud interactions (ACI) in models. As the nature of ACI varies enormously with environmental conditions, global-scale constraints on particle properties are indicated. And although advanced satellite remote-sensing instruments can provide categorical aerosol-type classification globally, detailed particle microphysical properties are unobtainable from space with currently available or planned technologies. For the foreseeable future, only in situ measurements can constrain particle properties at the level-of-detail required for ACI, as well as to reduce uncertainties in regional-to-global-scale direct aerosol radiative forcing (DARF). The limitation of in situ measurements for this application is sampling. However, there is a simplifying factor: for a given aerosol source, in a given season, particle microphysical properties tend to be repeatable, even if the amount varies from day-to-day and year-to-year, because the physical nature of the particles is determined primarily by the regional environment. So, if the PDFs of particle properties from major aerosol sources can be adequately characterized, they can be used to add the missing microphysical detail the better sampled satellite aerosol-type maps. This calls for Systematic Aircraft Measurements to Characterize Aerosol Air Masses (SAM-CAAM). We are defining a relatively modest and readily deployable, operational aircraft payload capable of measuring key aerosol absorption, scattering, and chemical properties in situ, and a program for characterizing statistically these properties for the major aerosol air mass types, at a level-of-detail unobtainable from space. It is aimed at: (1) enhancing satellite aerosol-type retrieval products with better aerosol climatology assumptions, and (2) improving the translation between satellite-retrieved aerosol optical properties and

  17. Beschrijving van een verdampings-condensatie aerosol generator voor de produktie van submicron aerosol

    NARCIS (Netherlands)

    Feijt; A.*; Meulen; A.van der

    1985-01-01

    Dit rapport is een handleiding voor een bedrijfszeker, routinematig gebruik van een zgn. Evaporation-Condensation aerosol Conditioner. Met deze aerosol generatie apparatuur kunnen op stabiele, reproduceerbare manier zeer hoge concentraties (tot 1 miljoen deeltjes per cc) monodispers submicron ae

  18. Determination of 129I/127I in aerosol samples in Seville (Spain)

    International Nuclear Information System (INIS)

    In this work we present results of the 129I/127I ratio in aerosols of Seville, Southwest of Spain (37.4 deg. N,6 deg. W). A radiochemical method is applied to extract the iodine from the aerosols and prepare samples to be measured by accelerator mass spectrometry (AMS) at the ETH facility in Zuerich. We have found the possibility of monitoring the 129I/127I isotopic ratio on a two-days basis with sensitivities in the order of 104-105 atoms 129I/m3, and values of 10-8-10-9 for the isotopic ratio

  19. Measurement of Fukushima Aerosol Debris in Sequim and Richland, WA and Ketchikan, AK

    Energy Technology Data Exchange (ETDEWEB)

    Miley, Harry S.; Bowyer, Ted W.; Engelmann, Mark D.; Eslinger, Paul W.; Friese, Judah I.; Greenwood, Lawrence R.; Haas, Derek A.; Hayes, James C.; Keillor, Martin E.; Kiddy, Robert A.; Kirkham, Randy R.; Landen, Jonathan W.; Lepel, Elwood A.; Lidey, Lance S.; Litke, Kevin E.; Morris, Scott J.; Olsen, Khris B.; Thompson, Robert C.; Valenzuela, Blandina R.; Woods, Vincent T.; Biegalski, Steven R.

    2013-05-01

    Aerosol collections were initiated at several locations by PNNL shortly after the Great East Japan Earthquake of May 2011. Aerosol samples were transferred to laboratory high-resolution gamma spectrometers for analysis. Similar to treaty monitoring stations operating across the Northern hemisphere, iodine and other isotopes which could be volatilized at high temperature were detected. Though these locations are not far apart, they have significant variations with respect to water, mountain-range placement, and local topography. Variation in computed source terms will be shown to bound the variability of this approach to source estimation.

  20. Periodicities in Aerosol Optical Depths

    CERN Document Server

    Ramachandran, S; Verma, Amit; Panigrahi, Prasanta K

    2011-01-01

    We investigate the temporal and spatial variability in aerosol optical depth (AOD) over different geographic locations in India due to their important role in the earth-atmosphere radiation budget. The use of continuous wavelet transform pinpoints the spatio-temporal non-stationarity of the periodic variations in the AOD depending on local factors. The optimal time-frequency localization ability of Morlet wavelet accurately isolates the periodic features in the different frequency domains, to study the variations in the dominant periods due to local effects. The origin of the effects on the periodic modulations is then related to physical phenomena of regional nature, which throws considerable light on the observed variations in aerosol optical depths. We also find the phase relationship between different locations and to identify the possible correlations between different geographic locations and related environmental variations.

  1. Photostimulated Aggregation of Metal Aerosols

    CERN Document Server

    Karpov, Sergei V

    2010-01-01

    The effect of optical radiation on the rate of aggregation of nanoscopic particles is studied in metal aerosols. It has been shown that under light exposure, polydisperse metal aerosols can aggregate up to two orders faster due to the size dependent photoelectron effect from nanoparticles. Different size nanoparticles undergo mutual heteropolar charging when exchanging photoelectrons through the interparticle medium to result in an increased rate of aggregation. It is shown that long-range electrostatic attractive forces drive the particles into closer distances where the short-range Van-der-Waals forces become dominating. Attention is drawn to the fact that this effect may occur in various types of dispersed systems as well as in natural heteroaerosols.

  2. A mathematical model of aerosol holding chambers

    DEFF Research Database (Denmark)

    Zak, M; Madsen, J; Berg, E;

    1999-01-01

    A mathematical model of aerosol delivery from holding chambers (spacers) was developed incorporating tidal volume (VT), chamber volume (Vch), apparatus dead space (VD), effect of valve insufficiency and other leaks, loss of aerosol by immediate impact on the chamber wall, and fallout of aerosol...... in the chamber with time. Four different spacers were connected via filters to a mechanical lung model, and aerosol delivery during "breathing" was determined from drug recovery from the filters. The formula correctly predicted the delivery of budesonide aerosol from the AeroChamber (Trudell Medical, London......-mentioned factors, initial loss of aerosol by impact on the chamber wall is most important for the efficiency of a spacer. With a VT of 195 mL, the AeroChamber and Babyhaler were emptied in two breaths, the NebuChamber in four breaths, and the Nebuhaler in six breaths. Insufficiencies of the expiratory valves were...

  3. Immunization by a bacterial aerosol

    OpenAIRE

    Garcia-Contreras, Lucila; Wong, Yun-Ling; Muttil, Pavan; Padilla, Danielle; Sadoff, Jerry; DeRousse, Jessica; Germishuizen, Willem Andreas; Goonesekera, Sunali; Elbert, Katharina; Bloom, Barry R.; Miller, Rich; Fourie, P. Bernard; Hickey, Anthony; Edwards, David

    2008-01-01

    By manufacturing a single-particle system in two particulate forms (i.e., micrometer size and nanometer size), we have designed a bacterial vaccine form that exhibits improved efficacy of immunization. Microstructural properties are adapted to alter dispersive and aerosol properties independently. Dried “nanomicroparticle” vaccines possess two axes of nanoscale dimensions and a third axis of micrometer dimension; the last one permits effective micrometer-like physical dispersion, and the form...

  4. Aerosol-cloud interaction inferred from MODIS satellite data and global aerosol models

    OpenAIRE

    G. Myhre; F. Stordal; M. Johnsrud; Y. J. Kaufman; D. Rosenfeld; Storelvmo, T.; Kristjansson, J. E.; Berntsen, T. K.; Myhre, A.; I. S. A. Isaksen

    2007-01-01

    We have used the MODIS satellite data and two global aerosol models to investigate the relationships between aerosol optical depth (AOD) and cloud parameters that may be affected by the aerosol concentration. The relationships that are studied are mainly between AOD, on the one hand, and cloud cover, cloud liquid water path, and water vapour, on the other. Additionally, cloud droplet effective radius, cloud optical depth, cloud top pressure and aerosol Ångström exponent, have been a...

  5. High resolution aerosol optical thickness retrieval over the Pearl River Delta region with improved aerosol modelling

    Institute of Scientific and Technical Information of China (English)

    WONG ManSing; NICHOL Janet; LEE Kwon Ho; LI ZhanQing

    2009-01-01

    Aerosol retrieval algorithms for the MODerate Resolution Imaging Spectroradiometer (MODIS) have been developed to estimate aerosol and microphysical properties of the atmosphere, which help to address aerosol climatic issues at global scale. However, higher spatial resolution aerosol products for urban areas have not been well researched mainly due to the difficulty of differentiating aerosols from bright surfaces in urban areas. Here, a new aerosol retrieval algorithm using the MODIS 500 m resolu-tion images is described, to retrieve aerosol properties over Hong Kong and the Pearl River Delta re-gion. The rationale of our technique is to first estimate the aerosol reflectance by decomposing the top-of-atmosphere reflectance from surface reflectance and Rayleigh path reflectance. For the deter-mination of surface reflectance, a modified Minimum Reflectance Technique (MRT) is used, and MRT images are computed for different seasons. A strong correlation is shown between the surface reflec-tance of MRT images and MODIS land surface reflectance products (MOD09), with a value of 0.9. For conversion of aerosol reflectance to Aerosol Optical Thickness (AOT), comprehensive Look Up Tables (LUT) are constructed, in which aerosol properties and sun-viewing geometry in the radiative transfer calculations are taken into account. Four aerosol types, namely mixed urban, polluted urban, dust, and heavy pollution, were derived using cluster analysis on three years of AERONET measurements in Hong Kong. Their aerosol properties were input for LUT calculation. The resulting 500 m AOT images are highly correlated (r=0.89) with AERONET sunphotometer observations in Hong Kong. This study demonstrates the applicability of aerosol retrieval at fine resolution scale in urban areas, which can assist the study of aerosol loading distribution and the impact of localized and transient pollution on urban air quality. In addition, the MODIS 500 m AOT images can be used to study cross

  6. High resolution aerosol optical thickness retrieval over the Pearl River Delta region with improved aerosol modelling

    Institute of Scientific and Technical Information of China (English)

    WONG; ManSing; NICHOL; Janet; LEE; Kwon; Ho

    2009-01-01

    Aerosol retrieval algorithms for the MODerate Resolution Imaging Spectroradiometer (MODIS) have been developed to estimate aerosol and microphysical properties of the atmosphere, which help to address aerosol climatic issues at global scale. However, higher spatial resolution aerosol products for urban areas have not been well researched mainly due to the difficulty of differentiating aerosols from bright surfaces in urban areas. Here, a new aerosol retrieval algorithm using the MODIS 500 m resolution images is described, to retrieve aerosol properties over Hong Kong and the Pearl River Delta region. The rationale of our technique is to first estimate the aerosol reflectance by decomposing the top-of-atmosphere reflectance from surface reflectance and Rayleigh path reflectance. For the determination of surface reflectance, a modified Minimum Reflectance Technique (MRT) is used, and MRT images are computed for different seasons. A strong correlation is shown between the surface reflectance of MRT images and MODIS land surface reflectance products (MOD09), with a value of 0.9. For conversion of aerosol reflectance to Aerosol Optical Thickness (AOT), comprehensive Look Up Tables (LUT) are constructed, in which aerosol properties and sun-viewing geometry in the radiative transfer calculations are taken into account. Four aerosol types, namely mixed urban, polluted urban, dust, and heavy pollution, were derived using cluster analysis on three years of AERONET measurements in Hong Kong. Their aerosol properties were input for LUT calculation. The resulting 500 m AOT images are highly correlated (r = 0.89) with AERONET sunphotometer observations in Hong Kong. This study demonstrates the applicability of aerosol retrieval at fine resolution scale in urban areas, which can assist the study of aerosol loading distribution and the impact of localized and transient pollution on urban air quality. In addition, the MODIS 500 m AOT images can be used to study cross

  7. Beschrijving van een verdampings-condensatie aerosol generator voor de produktie van submicron aerosol

    OpenAIRE

    Feijt; Meulen, van der, A.; De, A.

    1985-01-01

    Dit rapport is een handleiding voor een bedrijfszeker, routinematig gebruik van een zgn. Evaporation-Condensation aerosol Conditioner. Met deze aerosol generatie apparatuur kunnen op stabiele, reproduceerbare manier zeer hoge concentraties (tot 1 miljoen deeltjes per cc) monodispers submicron aerosol geproduceerd worden. De aerosol afmetingen kunnen gevarieerd worden tussen 0.3 en 1.2 mu-m in diameter de geometrische standaardafwijking bedraagt circa 1.25-1.4.

  8. Characterization of aerosol particles at the forested site in Lithuania

    Science.gov (United States)

    Rimselyte, I.; Garbaras, A.; Kvietkus, K.; Remeikis, V.

    2009-04-01

    monitoring station (55˚ 26'26"N; 26˚ 03'60"E) in the eastern part of Lithuania in the Aukštaitija national park during 2-24 July, 2008. The Rugšteliškis station is located in a remote relatively clean forested area. An aerosol mass spectrometer (AMS), developed at Aerodyne Research, was used to obtain real-time quantitative information on particle size-resolved mass loadings for volatile and semi-volatile chemical components present in/on ambient aerosol. The AMS inlet system allows 100 % transmission efficiency for particles with size diameter between 60 to 600 nm and partial transmission down to 20 nm and up to 2000 nm. The aerosol sampling was also carried out using a Micro-Orifice Uniform Deposit Impactor (MOUDI) model 110. The flow rate was 30 l/min, and the 50% aerodynamic cutoff diameters of the 10 stages were 18, 10, 5.6, 3.2, 1.8, 1.0, 0.56, 0.32, 0.18, 0.10 and 0.056 m. Aluminum foil was used as the impaction surface. The aerosol samples were analyzed for total carbon using the elemental analyzer (Flash EA1112). Besides, samples were analyzed for ^13C/12C ratio by the isotopic ratio mass spectrometer (Thermo Finnigan Delta Plus Advantage) (Norman et al., 1999; Garbaras et al., 2008). During campaign the dynamic behavior of aerosols was measured and quantitatively compared with meteorological conditions and air mass transport. The submicron aerosol was predominately sulphate and organic material. The AMS was able to discriminate and quantify mixed organic/inorganic accumulation mode particles (300 - 400 nm), which appeared to be dominated by regional sources and were of the origin similar to those seen in the more remote areas. The particulate organic fraction was also investigated in detail using the mass spectral data. By combining the organic matter size distribution (measured with AMS) with the total carbon (TC) size distribution (measured with MOUDI) we were able to report organic carbon to total carbon (OC/TC) ratio in different size particles

  9. Optical and microphysical properties of atmospheric aerosols in Moldova

    Science.gov (United States)

    Aculinin, Alexandr; Smicov, Vladimir

    2010-05-01

    Measurements of aerosol properties in Kishinev, Moldova are being carried out within the framework of the international AERONET program managed by NASA/GSFC since 1999. Direct solar and sky diffuse radiances are measured by using of sunphotometer Cimel-318. Aerosol optical properties are retrieved from measured radiances by using of smart computational procedures developed by the AERONET's team. The instrument is situated at the ground-based solar radiation monitoring station giving the opportunity to make simultaneous spectral (win sunphotometer) and broadband (with the set of sensors from radiometric complex) solar radiation. Detailed description of the station and investigations in progress can be found at the http://arg.phys.asm.md. Ground station is placed in an urban environment of Kishinev city (47.00N; 28.56E; 205 m a.s.l). Summary of aerosol optical and microphysical properties retrieved from direct solar and diffuse sky radiance observations at Moldova site from September 1999 to June 2009 are presented below. Number of measurements (total): 1695 Number of measurements (for ?o, n, k): 223 Range of aerosol optical depth (AOD) @440 nm: 0.03 =0.25 Range of Ångström parameter : 0.14 (440/670/870/1020): 0.93/0.92/0.90/0.89 ±0.04 Parameters of volume particle size distribution function: (fine mode) volume median radius r v,f , μm: 0.17 ± 0.06 particle volume concentration Cv,f, μm3/μm2: 0.04 ± 0.03 (coarse mode) volume median radius rv,c , μm: 3.08 ± 0.64 particle volume concentration Cv,c, μm3/μm2: 0.03 ± 0.03 Climatic norms of AOD@500 nm and Ångström parameter at the site of observation are equal to 0.21 ± 0.06 and 1.45 ± 0.14, respectively. The aerosol type in Moldova may be considered as 'urban-industrial and mixed' in accordance with the classification of aerosol type models systematized and developed by AERONET team (O.Dubovik et al., 2002, J. Atmosph. Sci., 59, 590-608) on the basis of datasets acquired from worldwide observations at the

  10. Ice-condenser aerosol tests

    International Nuclear Information System (INIS)

    This report presents the results of an experimental investigation of aerosol particle transport and capture using a full-scale height and reduced-scale cross section test facility based on the design of the ice compartment of a pressurized water reactor (PWR) ice-condenser containment system. Results of 38 tests included thermal-hydraulic as well as aerosol particle data. Particle retention in the test section was greatly influenced by thermal-hydraulic and aerosol test parameters. Test-average decontamination factor (DF) ranged between 1.0 and 36 (retentions between ∼0 and 97.2%). The measured test-average particle retentions for tests without and with ice and steam ranged between DF = 1.0 and 2.2 and DF = 2.4 and 36, respectively. In order to apparent importance, parameters that caused particle retention in the test section in the presence of ice were steam mole fraction (SMF), noncondensible gas flow rate (residence time), particle solubility, and inlet particle size. Ice-basket section noncondensible flows greater than 0.1 m3/s resulted in stable thermal stratification whereas flows less than 0.1 m3/s resulted in thermal behavior termed meandering with frequent temperature crossovers between flow channels. 10 refs., 66 figs., 16 tabs

  11. Characterization of Aerosols Containing Microcystin

    Directory of Open Access Journals (Sweden)

    Lorraine C. Backer

    2007-10-01

    Full Text Available Toxic blooms of cyanobacteria are ubiquitous in both freshwater and brackishwater sources throughout the world. One class of cyanobacterial toxins, calledmicrocystins, is cyclic peptides. In addition to ingestion and dermal, inhalation is a likelyroute of human exposure. A significant increase in reporting of minor symptoms,particularly respiratory symptoms was associated with exposure to higher levels ofcyanobacteria during recreational activities. Algae cells, bacteria, and waterborne toxinscan be aerosolized by a bubble-bursting process with a wind-driven white-capped wavemechanism. The purposes of this study were to: evaluate sampling and analysis techniquesfor microcystin aerosol, produce aerosol droplets containing microcystin in the laboratory,and deploy the sampling instruments in field studies. A high-volume impactor and an IOMfilter sampler were tried first in the laboratory to collect droplets containing microcystins.Samples were extracted and analyzed for microcystin using an ELISA method. Thelaboratory study showed that cyanotoxins in water could be transferred to air via a bubble-bursting process. The droplets containing microcystins showed a bimodal size distributionwith the mass median aerodynamic diameter (MMAD of 1.4 and 27.8 μm. The samplingand analysis methods were successfully used in a pilot field study to measure microcystinaerosol in situ.

  12. Chromism of Model Organic Aerosol

    Science.gov (United States)

    Rincon, Angela; Guzman, Marcelo; Hoffmann, Michael; Colussi, Agustin

    2008-03-01

    The optical properties of the atmospheric aerosol play a fundamental role in the Earth's radiative balance. Since more than half of the aerosol mass consists of complex organic matter that absorbs in the ultraviolet and visible regions of the spectrum, it is important to establish the identity of the organic chromophores. Here we report studies on the chromism vs. chemical composition of photolyzed (lambda longer than 305 nm) solutions of pyruvic acid, a widespread aerosol component, under a variety of experimental conditions that include substrate concentration, temperature and the presence of relevant spectator solutes, such ammonium sulfate. We use high resolution mass- and 13C NMR-spectrometries to track chemical speciation in photolyzed solutions as they undergo thermochromic and photobleaching cycles. Since the chemical identity of the components of these mixtures does not change in these cycles, in which photobleached solutions gradually recover their yellow color in the dark with non-conventional kinetics typical of aggregation processes, we infer that visible absorptions likely involve the intermolecular coupling of carbonyl chromophores in supramolecular assemblies made possible by the polyfunctional nature of the products of pyruvic acid photolysis.

  13. Ice-condenser aerosol tests

    Energy Technology Data Exchange (ETDEWEB)

    Ligotke, M.W.; Eschbach, E.J.; Winegardner, W.K. (Pacific Northwest Lab., Richland, WA (United States))

    1991-09-01

    This report presents the results of an experimental investigation of aerosol particle transport and capture using a full-scale height and reduced-scale cross section test facility based on the design of the ice compartment of a pressurized water reactor (PWR) ice-condenser containment system. Results of 38 tests included thermal-hydraulic as well as aerosol particle data. Particle retention in the test section was greatly influenced by thermal-hydraulic and aerosol test parameters. Test-average decontamination factor (DF) ranged between 1.0 and 36 (retentions between {approximately}0 and 97.2%). The measured test-average particle retentions for tests without and with ice and steam ranged between DF = 1.0 and 2.2 and DF = 2.4 and 36, respectively. In order to apparent importance, parameters that caused particle retention in the test section in the presence of ice were steam mole fraction (SMF), noncondensible gas flow rate (residence time), particle solubility, and inlet particle size. Ice-basket section noncondensible flows greater than 0.1 m{sup 3}/s resulted in stable thermal stratification whereas flows less than 0.1 m{sup 3}/s resulted in thermal behavior termed meandering with frequent temperature crossovers between flow channels. 10 refs., 66 figs., 16 tabs.

  14. Initial steps of aerosol growth

    Directory of Open Access Journals (Sweden)

    O. Kulmala

    2004-09-01

    Full Text Available The formation and growth of atmospheric aerosols depend on several steps, namely nucleation, initial steps of growth and subsequent – mainly condensational – growth. This work focuses on the initial steps of growth, meaning the growth right after nucleation, where the interplay of curvature effects and thermodynamics has a significant role on the growth kinetics. More specifically, we investigate how ion clusters and aerosol particles grow from 1.5 nm to 20 nm in atmospheric conditions using experimental data obtained by air ion and aerosol spectrometers. The measurements have been performed at a boreal forest site in Finland. The observed trend that the growth rate seems to increase as a function of size can be used to investigate possible growth mechanisms. Such a growth rate is consistent with a recently suggested nano-Köhler mechanism, in which growth is activated at a certain size with respect to condensation of organic vapors. The results also imply that charge-enhance growth associated with ion-mediated nucleation plays only a minor role in the initial steps of growth, since it would imply a clear decrease of the growth rate with size. Finally, further evidence was obtained on the earlier suggestion that atmospheric nucleation and the subsequent growth of fresh nuclei are likely to be uncoupled phenomena via different participating vapors.

  15. Initial steps of aerosol growth

    Directory of Open Access Journals (Sweden)

    M. Kulmala

    2004-01-01

    Full Text Available The formation and growth of atmospheric aerosols depend on several steps, namely nucleation, initial steps of growth and subsequent – mainly condensational – growth. This work focuses on the initial steps of growth, meaning the growth right after nucleation, where the interplay of curvature effects and thermodynamics has a significant role on the growth kinetics. More specifically, we investigate how ion clusters and aerosol particles grow from 1.5 nm to 20 nm (diameter in atmospheric conditions using experimental data obtained by air ion and aerosol spectrometers. The measurements have been performed at a boreal forest site in Finland. The observed trend that the growth rate seems to increase as a function of size can be used to investigate possible growth mechanisms. Such a growth rate is consistent with a recently suggested nano-Köhler mechanism, in which growth is activated at a certain size with respect to condensation of organic vapors. The results also imply that charge-enhanced growth associated with ion-mediated nucleation plays only a minor role in the initial steps of growth, since it would imply a clear decrease of the growth rate with size. Finally, further evidence was obtained on the earlier suggestion that atmospheric nucleation and the subsequent growth of fresh nuclei are likely to be uncoupled phenomena via different participating vapors.

  16. Initial steps of aerosol growth

    Science.gov (United States)

    Kulmala, M.; Laakso, L.; Lehtinen, K. E. J.; Riipinen, I.; Dal Maso, M.; Anttila, T.; Kerminen, V.-M.; Hõrrak, U.; Vana, M.; Tammet, H.

    2004-12-01

    The formation and growth of atmospheric aerosols depend on several steps, namely nucleation, initial steps of growth and subsequent - mainly condensational - growth. This work focuses on the initial steps of growth, meaning the growth right after nucleation, where the interplay of curvature effects and thermodynamics has a significant role on the growth kinetics. More specifically, we investigate how ion clusters and aerosol particles grow from 1.5 nm to 20 nm (diameter) in atmospheric conditions using experimental data obtained by air ion and aerosol spectrometers. The measurements have been performed at a boreal forest site in Finland. The observed trend that the growth rate seems to increase as a function of size can be used to investigate possible growth mechanisms. Such a growth rate is consistent with a recently suggested nano-Köhler mechanism, in which growth is activated at a certain size with respect to condensation of organic vapors. The results also imply that charge-enhanced growth associated with ion-mediated nucleation plays only a minor role in the initial steps of growth, since it would imply a clear decrease of the growth rate with size. Finally, further evidence was obtained on the earlier suggestion that atmospheric nucleation and the subsequent growth of fresh nuclei are likely to be uncoupled phenomena via different participating vapors.

  17. Characterization of Sodium Spray Aerosols

    International Nuclear Information System (INIS)

    The consequences of pool and spray fires require evaluation in the safety analysis of liquid metal-cooled fast breeder reactors. Sodium spray fires are characterized by high temperature and pressure, produced during the rapid combustion of sodium in air. Following the initial energy release, some fraction of the reaction products are available as aerosols which follow the normal laws of agglomeration, growth, settling, and plating. An experimental study is underway at Atomics International to study the characteristics of high concentration sprays of liquid sodium in reduced oxygen atmospheres and in air. The experiments are conducted in a 31.5 ft3 (2 ft diam. by 10 ft high) vessel, certified for a pressure of 100 lb/in2 (gauge). The spray injection apparatus consists of a heated sodium supply pot and a spray nozzle through which liquid sodium is driven by nitrogen pressure. Spray rate and droplet size can be varied by the injection velocity (nozzle size, nitrogen pressure, and sodium temperature). Aerosols produced in 0, 4, and 10 vol. % oxygen environments have been studied. The concentration and particle size distribution of the material remaining in the air after the spray injection and reaction period are measured. Fallout rates are found to be proportional to the concentration of aerosol which remains airborne following the spray period. (author)

  18. New apparatus of single particle trap system for aerosol visualization

    Science.gov (United States)

    Higashi, Hidenori; Fujioka, Tomomi; Endo, Tetsuo; Kitayama, Chiho; Seto, Takafumi; Otani, Yoshio

    2014-08-01

    Control of transport and deposition of charged aerosol particles is important in various manufacturing processes. Aerosol visualization is an effective method to directly observe light scattering signal from laser-irradiated single aerosol particle trapped in a visualization cell. New single particle trap system triggered by light scattering pulse signal was developed in this study. The performance of the device was evaluated experimentally. Experimental setup consisted of an aerosol generator, a differential mobility analyzer (DMA), an optical particle counter (OPC) and the single particle trap system. Polystylene latex standard (PSL) particles (0.5, 1.0 and 2.0 μm) were generated and classified according to the charge by the DMA. Singly charged 0.5 and 1.0 μm particles and doubly charged 2.0 μm particles were used as test particles. The single particle trap system was composed of a light scattering signal detector and a visualization cell. When the particle passed through the detector, trigger signal with a given delay time sent to the solenoid valves upstream and downstream of the visualization cell for trapping the particle in the visualization cell. The motion of particle in the visualization cell was monitored by CCD camera and the gravitational settling velocity and the electrostatic migration velocity were measured from the video image. The aerodynamic diameter obtained from the settling velocity was in good agreement with Stokes diameter calculated from the electrostatic migration velocity for individual particles. It was also found that the aerodynamic diameter obtained from the settling velocity was a one-to-one function of the scattered light intensity of individual particles. The applicability of this system will be discussed.

  19. Uptake of Ambient Organic Gases to Acidic Sulfate Aerosols

    Science.gov (United States)

    Liggio, J.; Li, S.

    2009-05-01

    The formation of secondary organic aerosols (SOA) in the atmosphere has been an area of significant interest due to its climatic relevance, its effects on air quality and human health. Due largely to the underestimation of SOA by regional and global models, there has been an increasing number of studies focusing on alternate pathways leading to SOA. In this regard, recent work has shown that heterogeneous and liquid phase reactions, often leading to oligomeric material, may be a route to SOA via products of biogenic and anthropogenic origin. Although oligomer formation in chamber studies has been frequently observed, the applicability of these experiments to ambient conditions, and thus the overall importance of oligomerization reactions remain unclear. In the present study, ambient air is drawn into a Teflon smog chamber and exposed to acidic sulfate aerosols which have been formed in situ via the reaction of SO3 with water vapor. The aerosol composition is measured with a High Resolution Aerodyne Aerosol Mass Spectrometer (HR-ToF-AMS), and particle size distributions are monitored with a scanning mobility particle sizer (SMPS). The use of ambient air and relatively low inorganic particle loading potentially provides clearer insight into the importance of heterogeneous reactions. Results of experiments, with a range of sulfate loadings show that there are several competing processes occurring on different timescales. A significant uptake of ambient organic gases to the particles is observed immediately followed by a slow shift towards higher m/z over a period of several hours indicating that higher molecular weight products (possibly oligomers) are being formed through a reactive process. The results suggest that heterogeneous reactions can occur with ambient organic gases, even in the presence of ammonia, which may have significant implications to the ambient atmosphere where particles may be neutralized after their formation.

  20. Aerosol climatology and discrimination of aerosol types retrieved from MODIS, MISR and OMI over Durban (29.88°S, 31.02°E), South Africa

    Science.gov (United States)

    Kumar, K. Raghavendra; Yin, Yan; Sivakumar, V.; Kang, Na; Yu, Xingna; Diao, Yiwei; Adesina, A. Joseph; Reddy, R. R.

    2015-09-01

    The present study represents the characteristics of aerosol optical depth (AOD) retrieved from multiple satellite sensors (MODerate resolution Imaging Spectroradiometer (MODIS), Multi-angle Imaging SpectroRadiometer (MISR), and Ozone Monitoring Instrument (OMI)) during 2003-2013 over an urban-coastal region, Durban (DBN; 29.88°S, 31.02°E, 46 m°asl), situated on the east coast of South Africa. An intercomparison and validation of AOD is performed against the AOD measurements from ground-based AErosol RObotic NETwork (AERONET) Sunphotometer. The results revealed that MISR-AERONET comparison indicated strong correlation compared to MODIS-AERONET comparison. Also, the comparison between MODIS and MISR AODs noticed significant positive correlation over DBN with the overestimation of latter by former. Highest AOD characterizes during the spring (September-November) followed by summer (December-February) and autumn (March-May) with the lowest AOD observed during the winter (June-August) season. The Angstrom exponent (AE470-600) indicates predominance of fine-mode aerosols during spring and summer and dominance of coarse-mode aerosols in winter. A HYbrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) model is used to locate the origin of airmass transport and understand the variability of aerosol source regions. Finally, the relationship between AOD and AE has been examined to classify different aerosol types and showed seasonal heterogeneity in their contribution depending upon variability in sources. This is the first ever attempt to classify aerosols over this environment.

  1. Survival of virulent Legionella pneumophila in aerosols.

    OpenAIRE

    Hambleton, P.; Broster, M G; Dennis, P J; Henstridge, R.; Fitzgeorge, R.; Conlan, J W

    1983-01-01

    Aqueous suspensions of virulent Legionella pneumophila grown on solid medium retained virulence and aerosol survival characteristics for several months. Significant numbers of viable organisms were recovered from aerosols held at various relative humidities (r.h.) for up to 2 h. The organisms survived best at 65% r.h. and were least stable at 55% r.h. Exponential phase broth-grown organisms survived poorly in aerosols in comparison with stationary phase broth cultures or organisms grown on so...

  2. Atmospheric Aerosols at the MAGIC Site

    CERN Document Server

    Garrido, Daniel; Doro, Michele; Font, Lluís; López-Oramas, Alicia; Moralejo, Abelardo

    2013-01-01

    We investigate the performance of the MAGIC telescopes under three simulated atmospheric conditions: an increased aerosol content in the lower part of the troposphere, the presence of thin aerosol over-densities at different heights, and an extremely clean atmosphere. Weshow how the effective area of the telescope system is gradually reduced in the presence of varying concentrations of aerosols whereas the energy threshold rises. Clouds at different heights produce energy and altitude-dependent effects on the performance of the system.

  3. Inverse Modeling of Cloud – Aerosol Interactions

    OpenAIRE

    Partridge, Daniel

    2011-01-01

    The role of aerosols and clouds is one of the largest sources of uncertainty in understanding climate change. The primary scientific goal of this thesis is to improve the understanding of cloud-aerosol interactions by applying inverse modeling using Markov Chain Monte Carlo (MCMC) simulation. Through a set of synthetic tests using a pseudo-adiabatic cloud parcel model, it is shown that a self adaptive MCMC algorithm can efficiently find the correct optimal values of meteorological and aerosol...

  4. Microphysical Characterization of Aerosol Signatures over Greece

    OpenAIRE

    Akshath Sharma; Sampann Arora; Pranav Chandramouli; Costas Varotsos; Sat Ghosh; Archit Verma; Ishan Saini

    2016-01-01

    A detailed microphysical characterization is presented for aerosol spectra over three major areas over Greece, namely- the Area West of Crete (AWC), the Greater Thessaloniki area (GTA) and the Greater Athens Area (GAA) based on measurements made by Varotsos (2005). Aerosol size distributions along with cloud droplet concentrations were gathered from data collected from the Forward Scattering Spectrometer Probe (FSSP)-300 and Passive Cavity Aerosol Spectrometer Probe (PCASP)-100X flown on a Fa...

  5. Monodisperse Aerosol Particles in an Apartment

    Czech Academy of Sciences Publication Activity Database

    Ondráček, Jakub; Ondráčková, Lucie; Stavová, P.; Ždímal, Vladimír; Barták, M.; Smolík, Jiří

    Thessaloniki : Hellenic Association for Aerosol Research, 2008, T10A012P. [European Aerosol Conference 2008. Thessaloniki (GR), 24.08.2008-29.08.2008] R&D Projects: GA ČR GA101/07/1361 Institutional research plan: CEZ:AV0Z40720504 Keywords : indoor aerosols * dynamic characteristics * number size distribution Subject RIV: CF - Physical ; Theoretical Chemistry www.eac2008.org

  6. Nanoscale Polymeric Particles via Aerosol-Photopolymerization

    OpenAIRE

    Akgün, Ertan

    2015-01-01

    This PhD thesis focuses on the process of aerosol-photopolymerization for the generation of various polymeric particles. Such structures are most often prepared by liquid-based methods via the well-established thermal initiation step, and aerosol-photopolymerization is presented as an alternative, aerosol-based technique which employs photoinitiated polymerization. Discussed within this thesis are the advantages and broad aspects of the process.

  7. Aerosol from Organic Nitrogen in the Southeast United States

    Science.gov (United States)

    Biogenic volatile organic compounds (BVOCs) contribute significantly to organic aerosol in the southeastern United States. During the Southern Oxidant and Aerosol Study (SOAS), a portion of ambient organic aerosol was attributed to isoprene oxidation and organic nitrogen from BVO...

  8. Carbonaceous aerosols in the Western Mediterranean during summertime and their contribution to the aerosol optical properties at ground level: First results of the ChArMEx-ADRIMED 2013 intensive campaign in Corsica

    Science.gov (United States)

    Sciare, Jean; Dulac, Francois; Feron, Anais; Crenn, Vincent; Sarda Esteve, Roland; Baisnee, Dominique; Bonnaire, Nicolas; Hamonou, Eric; Mallet, Marc; Lambert, Dominique; Nicolas, Jose B.; Bourrianne, Thierry; Petit, Jean-Eudes; Favez, Olivier; Canonaco, Francesco; Prevot, Andre; Mocnik, Grisa; Drinovec, Luka; Marpillat, Alexandre; Serrie, Wilfrid

    2014-05-01

    As part of the Chemistry-Aerosol Mediterranean Experiment (ChArMEx, http://charmex.lsce.ipsl.fr/), the CORSiCA (http://www.obs-mip.fr/corsica) and the ANR-ADRIMED programs, a large set of real-time measurements of carbonaceous aerosols was deployed in June 2013 at the Cape Corsica atmospheric supersite (http://gaw.empa.ch/gawsis/reports.asp?StationID=2076203042). Submicron organic aerosols (OA) were monitored every 30 min using an Aerosol Chemical Speciation Monitor (ACSM; Aerodyne Res. Inc. MA, USA); Fine (PM2.5) Organic Carbon (OC) and Elemental Carbon (EC) were measured every 2h using an OCEC Sunset Field Instrument (Sunset Lab, OR, USA) and every 12h using a low-vol (Leckel) filter sampler running at 2.3m3/h. Equivalent Black Carbon (BC) was monitored using two Aethalometers (models AE31 and AE33, Magee Scientific, US & Aerosol d.o.o., Slovenia) and a MAAP instrument (Thermo). Quality control of this large dataset was performed through chemical mass closure studies (using co-located SMPS and TEOM-FDMS) and direct comparisons with other real-time instruments running in parallel (Particle-Into-Liquid-Sampler-Ion-Chromatograph for ions, filter sampling, ...). Source apportionment of OA was then performed using the SourceFinder software (SoFi v4.5, http://www.psi.ch/acsm-stations/me-2) allowing the distinction between hydrogen- and oxygen-like organic aerosols (HOA and OOA, respectively) and highlighting the major contribution of secondary OA in the Western Mediterranean during summer. Using this time-resolved chemical information, reconstruction of the optical aerosol properties were performed and compared with integrating nephelometer (Model 3563, TSI, US) and photoacoustic extinctiometer (PAX, DMT, US) measurements performed in parallel. Results of these different closure studies (chemical/physical/optical) are presented and discussed here in details. They highlight the central role of carbonaceous aerosols on the optical properties of aerosols at ground level

  9. The fifth Finnish national aerosol symposium

    International Nuclear Information System (INIS)

    The Fifth Finnish Aerosol Symposium was held June 1-3, 1993. Symposium is jointly organized by FAAR, Aerosol Technology Group of Technical Research Centre of Finland and Helsinki University, Department of Physics. Aerosols, the suspensions of solid and liquid particles and gases, are receiving increasing importance in many areas of science and technology. These include industrial hygiene, ambient and indoor air pollution, pollution control technologies, cloud physics, nuclear safety engineering, combustion science and engineering, clean manufacturing technologies and material processing. The importance of aerosol issues during the development of advanced fuel conversion and material processing technologies can be realized when looking at the numerous papers presented on these topics at the Symposium

  10. The boiling point of stratospheric aerosols.

    Science.gov (United States)

    Rosen, J. M.

    1971-01-01

    A photoelectric particle counter was used for the measurement of aerosol boiling points. The operational principle involves raising the temperature of the aerosol by vigorously heating a portion of the intake tube. At or above the boiling point, the particles disintegrate rather quickly, and a noticeable effect on the size distribution and concentration is observed. Stratospheric aerosols appear to have the same volatility as a solution of 75% sulfuric acid. Chemical analysis of the aerosols indicates that there are other substances present, but that the sulfate radical is apparently the major constituent.

  11. SPM analysis of single aerosol particles

    International Nuclear Information System (INIS)

    Aerosol samples were collected using Anderson cascade impact samplers and the dispersed single aerosol particles were embedded in thin PVDF films. A group of single aerosol particles distributed in an area of 180 μm x 150 μm was analyzed by the scanning proton microprobe (SPM). The distributions of 12 elements in the group were mapped with the three dimensional contour technique. Air pollution sources were then analyzed in some details. It is shown that analysis of the group of single aerosol particles by SPM may become a new approach to the study of air pollution

  12. A mathematical model of aerosol holding chambers

    DEFF Research Database (Denmark)

    Zak, M; Madsen, J; Berg, E;

    1999-01-01

    A mathematical model of aerosol delivery from holding chambers (spacers) was developed incorporating tidal volume (VT), chamber volume (Vch), apparatus dead space (VD), effect of valve insufficiency and other leaks, loss of aerosol by immediate impact on the chamber wall, and fallout of aerosol......-mentioned factors, initial loss of aerosol by impact on the chamber wall is most important for the efficiency of a spacer. With a VT of 195 mL, the AeroChamber and Babyhaler were emptied in two breaths, the NebuChamber in four breaths, and the Nebuhaler in six breaths. Insufficiencies of the expiratory valves were...

  13. The Aerosol/Cloud/Ecosystems Mission (ACE)

    Science.gov (United States)

    Schoeberl, Mark

    2008-01-01

    The goals and measurement strategy of the Aerosol/Cloud/Ecosystems Mission (ACE) are described. ACE will help to answer fundamental science questions associated with aerosols, clouds, air quality and global ocean ecosystems. Specifically, the goals of ACE are: 1) to quantify aerosol-cloud interactions and to assess the impact of aerosols on the hydrological cycle and 2) determine Ocean Carbon Cycling and other ocean biological processes. It is expected that ACE will: narrow the uncertainty in aerosol-cloud-precipitation interaction and quantify the role of aerosols in climate change; measure the ocean ecosystem changes and precisely quantify ocean carbon uptake; and, improve air quality forecasting by determining the height and type of aerosols being transported long distances. Overviews are provided of the aerosol-cloud community measurement strategy, aerosol and cloud observations over South Asia, and ocean biology research goals. Instruments used in the measurement strategy of the ACE mission are also highlighted, including: multi-beam lidar, multiwavelength high spectra resolution lidar, the ocean color instrument (ORCA)--a spectroradiometer for ocean remote sensing, dual frequency cloud radar and high- and low-frequency micron-wave radiometer. Future steps for the ACE mission include refining measurement requirements and carrying out additional instrument and payload studies.

  14. Topics in current aerosol research (part2)

    CERN Document Server

    Hidy, G M

    1972-01-01

    Topics in Current Aerosol Research, Part 2 contains some selected articles in the field of aerosol study. The chosen topics deal extensively with the theory of diffusiophoresis and thermophoresis. Also covered in the book is the mathematical treatment of integrodifferential equations originating from the theory of aerosol coagulation. The book is the third volume of the series entitled International Reviews in Aerosol Physics and Chemistry. The text offers significant understanding of the methods employed to develop a theory for thermophoretic and diffusiophoretic forces acting on spheres in t

  15. Is aerosol formation in cirrus clouds possible?

    Directory of Open Access Journals (Sweden)

    J. Kazil

    2007-01-01

    Full Text Available The recent observation of ultrafine aerosol particles in cirrus clouds has raised the question whether aerosol formation within cirrus clouds is possible, and if so, what mechanisms are involved. We have developed an aerosol parcel model of neutral and charged H2SO4/H2O aerosol processes, including nucleation from the gas phase and loss onto cirrus ice particles. Laboratory thermodynamic data for sulfuric acid uptake and loss by small neutral and charged clusters are used, allowing for a reliable description of both neutral and charged nucleation down to the very low temperatures occurring in the upper troposphere and lower stratosphere. The model implements a first order scheme for resolving the aerosol size distribution within its geometric size sections, which efficiently suppresses numerical diffusion. We operate the model offline on trajectories generated with a detailed 1D cirrus model which describes ice crystal nucleation, deposition growth, vertical advection of ice crystals and water vapor, and ice crystal sedimentation. In this paper we explore the possibility of aerosol formation within non-convective cirrus clouds and draw conclusions for aerosol formation in anvil cirrus. We find that sulfate aerosol formation within cirrus clouds can proceed even at high ice surface area concentrations, and depends strongly on the size of the cirrus ice crystals and on the surface area concentration of preexisting aerosol particles.

  16. SMEX02 Atmospheric Aerosol Optical Properties Data

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set consists of observations of atmospheric parameters including spectral aerosol optical depths, precipitable water, sky radiance distributions and...

  17. Detailed Aerosol Characterization using Polarimetric Measurements

    Science.gov (United States)

    Hasekamp, Otto; di Noia, Antonio; Stap, Arjen; Rietjens, Jeroen; Smit, Martijn; van Harten, Gerard; Snik, Frans

    2016-04-01

    Anthropogenic aerosols are believed to cause the second most important anthropogenic forcing of climate change after greenhouse gases. In contrast to the climate effect of greenhouse gases, which is understood relatively well, the negative forcing (cooling effect) caused by aerosols represents the largest reported uncertainty in the most recent assessment of the International Panel on Climate Change (IPCC). To reduce the large uncertainty on the aerosol effects on cloud formation and climate, accurate satellite measurements of aerosol optical properties (optical thickness, single scattering albedo, phase function) and microphysical properties (size distribution, refractive index, shape) are essential. There is growing consensus in the aerosol remote sensing community that multi-angle measurements of intensity and polarization are essential to unambiguously determine all relevant aerosol properties. This presentations adresses the different aspects of polarimetric remote sensing of atmospheric aerosols, including retrieval algorithm development, validation, and data needs for climate and air quality applications. During past years, at SRON-Netherlands Instite for Space Research retrieval algorithms have been developed that make full use of the capabilities of polarimetric measurements. We will show results of detailed aerosol properties from ground-based- (groundSPEX), airborne- (NASA Research Scanning Polarimeter), and satellite (POLDER) measurements. Also we will discuss observational needs for future instrumentation in order to improve our understanding of the role of aerosols in climate change and air quality.

  18. Multi-Sensor Aerosol Products Sampling System

    Science.gov (United States)

    Petrenko, M.; Ichoku, C.; Leptoukh, G.

    2011-01-01

    Global and local properties of atmospheric aerosols have been extensively observed and measured using both spaceborne and ground-based instruments, especially during the last decade. Unique properties retrieved by the different instruments contribute to an unprecedented availability of the most complete set of complimentary aerosol measurements ever acquired. However, some of these measurements remain underutilized, largely due to the complexities involved in analyzing them synergistically. To characterize the inconsistencies and bridge the gap that exists between the sensors, we have established a Multi-sensor Aerosol Products Sampling System (MAPSS), which consistently samples and generates the spatial statistics (mean, standard deviation, direction and rate of spatial variation, and spatial correlation coefficient) of aerosol products from multiple spacebome sensors, including MODIS (on Terra and Aqua), MISR, OMI, POLDER, CALIOP, and SeaWiFS. Samples of satellite aerosol products are extracted over Aerosol Robotic Network (AERONET) locations as well as over other locations of interest such as those with available ground-based aerosol observations. In this way, MAPSS enables a direct cross-characterization and data integration between Level-2 aerosol observations from multiple sensors. In addition, the available well-characterized co-located ground-based data provides the basis for the integrated validation of these products. This paper explains the sampling methodology and concepts used in MAPSS, and demonstrates specific examples of using MAPSS for an integrated analysis of multiple aerosol products.

  19. Simplified aerosol modeling for variational data assimilation

    Directory of Open Access Journals (Sweden)

    F. Chevallier

    2009-06-01

    Full Text Available We have developed a simplified aerosol model together with its tangent linear and adjoint versions for variational assimilation of aerosol optical depth with the aim to optimize aerosol emissions over the globe. The model was derived from the general circulation model LMDz; it groups together the 24 aerosol species simulated in LMDz into 4 species, namely gaseous precursors, fine mode aerosols, coarse mode desert dust and coarse mode sea salt. The emissions have been kept as in the original model. Modifications, however, were introduced in the computation of aerosol optical depth and in the processes of sedimentation, dry and wet deposition and sulfur chemistry to ensure consistency with the new set of species and their composition.

    The simplified model successfully manages to reproduce the main features of the aerosol distribution in LMDz. Differences between the original and simplified models are mainly associated to the new deposition and sedimentation velocities consistent with the definition of species in the simplified model and the simplification of the sulfur chemistry. Furthermore, simulated aerosol optical depth remains within the variability of AERONET observations for all aerosol types and all sites throughout most of the year.

    Sensitivity analyses with the tangent linear version show that the simplified sulfur chemistry is the dominant process responsible for the strong non-linearity of the model.

  20. Reactive processing of formaldehyde and acetaldehyde in aqueous aerosol mimics: surface tension depression and secondary organic products

    Directory of Open Access Journals (Sweden)

    Z. Li

    2011-07-01

    Full Text Available The reactive uptake of carbonyl-containing volatile organic compounds (cVOCs by aqueous atmospheric aerosols is a likely source of particulate organic material. The aqueous-phase secondary organic products of some cVOCs are surface-active. Therefore, cVOC uptake can lead to organic film formation at the gas-aerosol interface and changes in aerosol surface tension. We examined the chemical reactions of two abundant cVOCs, formaldehyde and acetaldehyde, in water and aqueous ammonium sulfate (AS solutions mimicking tropospheric aerosols. Secondary organic products were identified using Aerosol Chemical Ionization Mass Spectrometry (Aerosol-CIMS, and changes in surface tension were monitored using pendant drop tensiometry. Hemiacetal oligomers and aldol condensation products were identified using Aerosol-CIMS. A hemiacetal sulfate ester was tentatively identified in the formaldehyde-AS system. Acetaldehyde depresses surface tension to 65(±2 dyn cm−1 in pure water and 62(±1 dyn cm−1 in AS solutions. Surface tension depression by formaldehyde in pure water is negligible; in AS solutions, a 9 % reduction in surface tension is observed. Mixtures of these species were also studied in combination with methylglyoxal in order to evaluate the influence of cross-reactions on surface tension depression and product formation in these systems. We find that surface tension depression in the solutions containing mixed cVOCs exceeds that predicted by an additive model based on the single-species isotherms.

  1. Reactive processing of formaldehyde and acetaldehyde in aqueous aerosol mimics: surface tension depression and secondary organic products

    Science.gov (United States)

    Li, Z.; Schwier, A. N.; Sareen, N.; McNeill, V. F.

    2011-11-01

    The reactive uptake of carbonyl-containing volatile organic compounds (cVOCs) by aqueous atmospheric aerosols is a likely source of particulate organic material. The aqueous-phase secondary organic products of some cVOCs are surface-active. Therefore, cVOC uptake can lead to organic film formation at the gas-aerosol interface and changes in aerosol surface tension. We examined the chemical reactions of two abundant cVOCs, formaldehyde and acetaldehyde, in water and aqueous ammonium sulfate (AS) solutions mimicking tropospheric aerosols. Secondary organic products were identified using Aerosol Chemical Ionization Mass Spectrometry (Aerosol-CIMS), and changes in surface tension were monitored using pendant drop tensiometry. Hemiacetal oligomers and aldol condensation products were identified using Aerosol-CIMS. Acetaldehyde depresses surface tension to 65(±2) dyn cm-1 in pure water (a 10% surface tension reduction from that of pure water) and 62(±1) dyn cm-1 in AS solutions (a 20.6% reduction from that of a 3.1 M AS solution). Surface tension depression by formaldehyde in pure water is negligible; in AS solutions, a 9% reduction in surface tension is observed. Mixtures of these species were also studied in combination with methylglyoxal in order to evaluate the influence of cross-reactions on surface tension depression and product formation in these systems. We find that surface tension depression in the solutions containing mixed cVOCs exceeds that predicted by an additive model based on the single-species isotherms.

  2. Reactive processing of formaldehyde and acetaldehyde in aqueous aerosol mimics: Surface tension depression and secondary organic products

    CERN Document Server

    Li, Zhi; Sareen, Neha; McNeill, V Faye

    2011-01-01

    The reactive uptake of carbonyl-containing volatile organic compounds (cVOCs) by aqueous atmospheric aerosols is a likely source of particulate organic material. The aqueous-phase secondary organic products of some cVOCs are surface-active. Therefore, cVOC uptake can lead to organic film formation at the gas-aerosol interface and changes in aerosol surface tension. We examined the chemical reactions of two abundant cVOCs, formaldehyde and acetaldehyde, in water and aqueous ammonium sulfate (AS) solutions mimicking tropospheric aerosols. Secondary organic products were identified using Aerosol Chemical Ionization Mass Spectrometry (Aerosol-CIMS), and changes in surface tension were monitored using pendant drop tensiometry. Hemiacetal oligomers and aldol condensation products were identified using Aerosol-CIMS. A hemiacetal sulfate ester was tentatively identified in the formaldehyde-AS system. Acetaldehyde depresses surface tension to 65(\\pm2) dyn/cm in pure water and 62(\\pm1) dyn/cm in AS solutions. Surface t...

  3. Monitoring the source monitoring.

    Science.gov (United States)

    Luna, Karlos; Martín-Luengo, Beatriz

    2013-11-01

    The hypothesis that the retrieval of correct source memory cues, those leading to a correct source attribution, increases confidence, whereas the retrieval of incorrect source memory cues, those leading to a source misattribution, decreases confidence was tested. Four predictions were derived from this hypothesis: (1) confidence should be higher for correct than incorrect source attribution except; (2) when no source cues are retrieved; (3) only the source misattributions inferred from the retrieval of incorrect source cues will be rated with low confidence; and (4) the number of source cues retrieved, either correct or incorrect, will affect the confidence in the source attributions. To test these predictions, participants read two narratives from two witnesses to a bank robbery, a customer and a teller. Then, participants completed a source monitoring test with four alternatives, customer, teller, both, or neither, and rated their confidence in their source attribution. Results supported the first three predictions, but they also suggested that the number of correct source monitoring cues retrieved did not play a role in the monitoring of the accuracy of the source attributions. Attributions made from the recovery of incorrect source cues could be tagged as dubious or uncertain, thus leading to lowered confidence irrespective of the number of incorrect source cues or whether another correct source cue was also recovered. This research has potential applications for eyewitness memory because it shows that confidence can be an indicator of the accuracy of a source attribution. PMID:23553316

  4. New Approach to Monitor Transboundary Particulate Pollution over Northeast Asia

    Science.gov (United States)

    Park, M. E.; Song, C. H.; Park, R. S.; Lee, Jaehwa; Kim, J.; Lee, S.; Woo, J. H.; Carmichael, G. R.; Eck, Thomas F.; Holben, Brent N.; Lee, S. S.; Song, C. K.; Hong, Y. D.

    2014-01-01

    A new approach to more accurately monitor and evaluate transboundary particulate matter (PM) pollution is introduced based on aerosol optical products from Korea's Geostationary Ocean Color Imager (GOCI). The area studied is Northeast Asia (including eastern parts of China, the Korean peninsula and Japan), where GOCI has been monitoring since June 2010. The hourly multi-spectral aerosol optical data that were retrieved from GOCI sensor onboard geostationary satellite COMS (Communication, Ocean, and Meteorology Satellite) through the Yonsei aerosol retrieval algorithm were first presented and used in this study. The GOCI-retrieved aerosol optical data are integrated with estimated aerosol distributions from US EPA Models-3/CMAQ (Community Multi-scale Air Quality) v4.5.1 model simulations via data assimilation technique, thereby making the aerosol data spatially continuous and available even for cloud contamination cells. The assimilated aerosol optical data are utilized to provide quantitative estimates of transboundary PM pollution from China to the Korean peninsula and Japan. For the period of 1 April to 31 May, 2011 this analysis yields estimates that AOD as a proxy for PM2.5 or PM10 during long-range transport events increased by 117-265% compared to background average AOD (aerosol optical depth) at the four AERONET sites in Korea, and average AOD increases of 121% were found when averaged over the entire Korean peninsula. This paper demonstrates that the use of multi-spectral AOD retrievals from geostationary satellites can improve estimates of transboundary PM pollution. Such data will become more widely available later this decade when new sensors such as the GEMS (Geostationary Environment Monitoring Spectrometer) and GOCI-2 are scheduled to be launched.

  5. A perspective on SOA generated in aerosol water from glyoxal and methylglyoxal and its impacts on climate-relevant aerosol properties

    Science.gov (United States)

    Sareen, N.; McNeill, V. F.

    2011-12-01

    . These compounds included (hemi)acetals, aldol condensation products, and oligomeric species up to 759 amu. Since these products are vulnerable to oxidants such as O3 and OH in the atmosphere, kinetic studies were conducted to study their affect upon exposure to O3 and OH. Custom-designed flow tube reactors were coupled with the Aerosol-CIMS to monitor aerosol composition, and consequently this data was used to determine reactive uptake coefficients (γO3~10-8 and γOH~ 10-6). Additionally, the lifetime of these SOA species in the atmosphere can be estimated and if these time scales are sufficiently long, they may affect aerosol optical properties. The effect of oxidation on the optical properties is also currently being tested by collecting aerosol particles before and after oxidation on a quartz window and testing changes in absorption using the UV-Vis spectrophotometer. The results of all these studies will be integrated to understand the role of methylglyoxal as a SOA precursor and the effect on various aerosol properties, and this will be used as a model system to predict the fate of similar organics in the atmosphere.

  6. Vertical profiles of aerosol optical properties over central Illinois and comparison with surface and satellite measurements

    Directory of Open Access Journals (Sweden)

    P. J. Sheridan

    2012-12-01

    Full Text Available Between June 2006 and September 2009, an instrumented light aircraft measured over 400 vertical profiles of aerosol and trace gas properties over eastern and central Illinois. The primary objectives of this program were to (1 measure the in situ aerosol properties and determine their vertical and temporal variability and (2 relate these aircraft measurements to concurrent surface and satellite measurements. The primary profile location was within 15 km of the NOAA/ESRL surface aerosol monitoring station near Bondville, Illinois. Identical instruments at the surface and on the aircraft ensured that the data from both platforms would be directly comparable and permitted a determination of how representative surface aerosol properties were of the lower column. Aircraft profiles were also conducted occasionally at two other nearby locations to increase the frequency of A-Train satellite underflights for the purpose of comparing in situ and satellite-retrieved aerosol data. Measurements of aerosol properties conducted at low relative humidity over the Bondville site compare well with the analogous surface aerosol data and do not indicate any major sampling issues or that the aerosol is radically different at the surface compared with the lowest flyby altitude of ~ 240 m above ground level. Statistical analyses of the in situ vertical profile data indicate that aerosol light scattering and absorption (related to aerosol amount decreases substantially with increasing altitude. Parameters related to the nature of the aerosol (e.g., single-scattering albedo, Ångström exponent, etc., however, are relatively constant throughout the mixed layer, and do not vary as much as the aerosol amount throughout the profile. While individual profiles often showed more variability, the median in situ single-scattering albedo was 0.93–0.95 for all sampled altitudes. Several parameters (e.g., submicrometer scattering fraction, hemispheric backscattering fraction, and

  7. The relationship between aerosol and cloud drop number concentrations in a global aerosol microphysics model

    Directory of Open Access Journals (Sweden)

    K. J. Pringle

    2009-06-01

    Full Text Available Empirical relationships that link cloud droplet number (CDN to aerosol number or mass are commonly used to calculate global fields of CDN for climate forcing assessments. In this work we use a sectional global model of sulfate and sea-salt aerosol coupled to a mechanistic aerosol activation scheme to explore the limitations of this approach. We find that a given aerosol number concentration produces a wide range of CDN concentrations due to variations in the shape of the aerosol size distribution. On a global scale, the dependence of CDN on the size distribution results in regional biases in predicted CDN (for a given aerosol number. Empirical relationships between aerosol number and CDN are often derived from regional data but applied to the entire globe. In an analogous process, we derive regional "correlation-relations" between aerosol number and CDN and apply these regional relations to calculations of CDN on the global scale. The global mean percentage error in CDN caused by using regionally derived CDN-aerosol relations is 20 to 26%, which is about half the global mean percentage change in CDN caused by doubling the updraft velocity. However, the error is as much as 25–75% in the Southern Ocean, the Arctic and regions of persistent stratocumulus when an aerosol-CDN correlation relation from the North Atlantic is used. These regions produce much higher CDN concentrations (for a given aerosol number than predicted by the globally uniform empirical relations. CDN-aerosol number relations from different regions also show very different sensitivity to changing aerosol. The magnitude of the rate of change of CDN with particle number, a measure of the aerosol efficacy, varies by a factor 4. CDN in cloud processed regions of persistent stratocumulus is particularly sensitive to changing aerosol number. It is therefore likely that the indirect effect will be underestimated in these important regions.

  8. The relationship between aerosol and cloud drop number concentrations in a global aerosol microphysics model

    Directory of Open Access Journals (Sweden)

    K. J. Pringle

    2009-01-01

    Full Text Available Empirical relationships that link cloud droplet number (CDN to aerosol number or mass are commonly used to calculate global fields of CDN for climate forcing assessments. In this work we use a sectional global model of sulfate and sea-salt aerosol coupled to a mechanistic aerosol activation scheme to explore the limitations of this approach. We find that a given aerosol number concentration produces a wide range of CDN concentrations due to variations in the shape of the aerosol size distribution. On a global scale, the dependence of CDN on the size distribution results in regional biases in predicted CDN (for a given aerosol number. Empirical relationships between aerosol number and CDN are often derived from regional data but applied to the entire globe. In an analogous process, we derive regional "correlation-relations" between aerosol number and CDN and apply these regional relations to calculations of CDN on the global scale. The global mean percentage error in CDN caused by using regionally derived CDN-aerosol relations is 20 to 26%, which is about half the global mean percentage change in CDN caused by doubling the updraft velocity. However, the error is as much as 25–75% in the Southern Ocean, the Arctic and regions of persistent stratocumulus when an aerosol-CDN correlation relation from the North Atlantic is used. These regions produce much higher CDN concentrations (for a given aerosol number than predicted by the globally uniform empirical relations. CDN-aerosol number relations from different regions also show very different sensitivity to changing aerosol. The magnitude of the rate of change of CDN with particle number, a measure of the aerosol efficacy, varies by a factor 4. CDN in cloud processed regions of persistent stratocumulus is particularly sensitive to changing aerosol number. It is therefore likely that the indirect effect will be underestimated in these important regions.

  9. The correlative method of industrial aerosol express-diagnostic

    International Nuclear Information System (INIS)

    The main difficulty of industrial aerosol control is absence of real-time data analysis methods for measurement quantities of a specific aerosol (for example, radioactive particles, beryllium aerosols, etc. This report is an attempt to establish a new experimental method for control of industrial aerosol pollution. The main idea of the method is to determine correlation dependences among the aerosol particle size distributions and quantities of specific aerosol particles in industrial pollutions, for which real-time control is very difficult. The possibility of specific aerosol control is suggested by means of aerosol size control. (author)

  10. Observation of attachment ratio of fission products on solution aerosol

    International Nuclear Information System (INIS)

    Attachment behavior of fission products to solution aerosols has been observed to elucidate the role of chemical effects in the generation mechanism of fissionproduct aerosols. Primary aerosols generated from aqueous solution of sodium chloride or ammonium sulfate were passed through a fission-product chamber, and radioactive aerosols were generated by attaching fission products to the primary aerosol particles. Attachment ratios of the fission products on aerosols were estimated from activity measurements. It was found that the attachment ratio of the sodium chloride solution aerosol is larger than that of the ammonium sulfate solution aerosol. (author)

  11. Improved global aerosol datasets for 2008 from Aerosol_cci

    Science.gov (United States)

    Holzer-Popp, Thomas; de Leeuw, Gerrit

    2013-04-01

    Within the ESA Climate Change Initiative (CCI) the Aerosol_cci project has meanwhile produced and validated global datasets from AATSR, PARASOL, MERIS, OMI and GOMOS for the complete year 2008. Whereas OMI and GOMOS were used to derive absorbing aerosol index and stratospheric extinction profiles, respectively, Aerosol Optical Depth (AOD) and Angstrom coefficient were retrieved from the three nadir sensors. For AATSR three algorithms were applied. AOD validation was conducted against AERONET sun photometer observations also in comparison to MODIS and MISR datasets. Validation included level2 (pixel level) and level3 (gridded daily) datasets. Several validation metrices were used and in some cases developed further in order to comprehensively evaluate the capabilities and limitations of the datasets. The metrices include standard statistical quantities (bias, rmse, Pearson correlation, linear regression) as well as scoring approaches to quantitatively assess the spatial and temporal correlations against AERONET. Over open ocean also MAN data were used to better constrain the aerosol background, but in 2008 had limited coverage. The validation showed that the PARASOL (ocean only) and AATSR (land and ocean) datasets have improved significantly and now reach the quality level and sometimes even go beyond the level of MODIS and MISR. However, the coverage of these European datasets is weaker than the one of the NASA datasets due to smaller instrument swath width. The MERIS dataset provides better coverage but has lower quality then the other datasets. A detailed regional and seasonal analysis revealed the strengths and weaknesses of each algorithm. Also, Angstrom coefficient was validated and showed encouraging results (more detailed aerosol type information provided in particular from PARASOL was not yet evaluated further). Additionally, pixel uncertainties contained in each dataset were statistically assessed which showed some remaining issues but also the added value

  12. Laboratory Studies of Processing of Carbonaceous Aerosols by Atmospheric Oxidants/Hygroscopicity and CCN Activity of Secondary & Processed Primary Organic Aerosols

    Energy Technology Data Exchange (ETDEWEB)

    Ziemann, P.J.; Arey, J.; Atkinson, R.; Kreidenweis, S.M.; Petters, M.D.

    2012-06-13

    to carry out reactions of representative anthropogenic and biogenic VOCs and organic particles with ozone (O3), and hydroxyl (OH), nitrate (NO3), and chlorine (Cl) radicals, which are the major atmospheric oxidants, under simulated atmospheric conditions in large-volume environmental chambers. A combination of on-line and off-line analytical techniques were used to monitor the chemical and physical properties of the particles including their hygroscopicity and CCN activity. The results of the studies were used to (1) improve scientific understanding of the relationships between the chemical composition of organic particles and their hygroscopicity and CCN activity, (2) develop an improved molecular level theoretical framework for describing these relationships, and (3) establish a large database that is being used to develop parameterizations relating organic aerosol chemical properties and SOA sources to particle hygroscopicity and CCN activity for use in regional and global atmospheric air quality and climate models.

  13. Onsite aerosol measurements for various engineered nanomaterials at industrial manufacturing plants

    International Nuclear Information System (INIS)

    Evaluation of the health impact of and control over exposure to airborne engineered nanomaterials (ENMs) requires information, inter alia, the magnitude of environmental release during various industrial processes, as well as the size distribution and morphology of the airborne ENM particles. In this study, we performed onsite aerosol measurements for various ENMs at industrial manufacturing plants. The industrial processes investigated were the collection of SiC from synthesis reactors, synthesis and bagging of LiFePO4, and bagging of ZnO. Real-time aerosol monitoring using condensation particle counters, optical particle counters, and an electrical low-pressure impactor revealed frequent increases in the number concentrations of submicron- and micron-sized aerosol particles, but few increases in the number concentrations of nanoparticles. In the SEM observations, a large number of submicron- and micron-sized agglomerated ENM particles were observed.

  14. Cosmic ray-induced stratospheric aerosols: a possible connection to polar ozone depletions

    International Nuclear Information System (INIS)

    The model calculations of altitude distribution of CN (condensation nuclei), plausible centers of sulfate aerosol formation after the occurrence of GLE, are presented. Events with relativistic solar protons (i.e. protons with energies >450 MeV) are observed at ground level by neutron monitors and called ground-level events (GLEs) (Shea and Smart, 2001). Analysis of experimental data and model calculations permits us to explain some distinctions observed in ozone total content (OTC) variations during several GLEs. For example, model simulations show a significant CN concentration enhancement during the May 1990 GLEs of relatively 'moderate' magnitude, when polar ozone 'miniholes' (OTC depletions up to 20%) have been observed, while not OTC variations and considerable aerosol enhancements were seen during more powerful GLEs (4 August 1972, 2 May 1998, 14 July 2000) (Reagan et al., 1981; Shumilov et al., 1995, 2003). Our results demonstrate that 'moderate' GLEs may increase aerosol content significantly and cause ozone 'mini-hole' creation. (orig.)

  15. [The research on remote sensing dust aerosol by using split window emissivity].

    Science.gov (United States)

    Xu, Hui; Yu, Tao; Gu, Xing-Fa; Cheng, Tian-Hai; Xie, Dong-Hai; Liu, Qian

    2013-05-01

    Dust aerosol can cause the change in the land surface emissivity in split window by radiative forcing (RF). Firstly, the present paper explained from the microscopic point of view the extinction properties of dust aerosols in the 11 and 12 microm channels, and their influence on the land surface emissivity. Secondly, on April 29, 2011, in the northern region of Inner Mongolia a strong sandstorm outbroke, and based on the analysis of the changes in land surface emissivity, this paper proposed a dust identification method by using the variation of emissivity. At last, the dust identification result was evaluated by the dust monitoring product provided by the National Satellite Meteorological Center. The result shows that under the assumption that the 12 microm emissivity equals to 1, using 11 microm relative emissivity could identify dust cover region effectively, and the 11 microm relative emissivity to a certain extent represented the intensity information of dust aerosol. PMID:23905316

  16. Aerosol sampler with remote air flow control and online radioactivity measurement above the filter

    International Nuclear Information System (INIS)

    The Czech national Radiation Monitoring Network is equipped with JL-150 aerosol samplers 150 m3/h air flow rate. An upgraded design of this system is proposed. The features of the upgraded aerosol sampler include remote air flow rate control via pump power, maintaining the adjusted flow rate constant, sending status information either on demand or automatically on any change, online gamma spectra acquisition above the aerosol filter and their automatic evaluation, comparison of selected regions of a spectrum with the reference levels and automatic signalling when they are exceeded. The minimum detectable activities of 131I and 137Cs, which may be present in the air in case of NPP accident, are at tenths of Bq/m3 for 1 hour measuring time. (orig.)

  17. Personal exposure to aerosolized red tide toxins (brevetoxins).

    Science.gov (United States)

    Cheng, Yung Sung; Zhou, Yue; Naar, Jerome; Irvin, C Mitch; Su, Wei-Chung; Fleming, Lora E; Kirkpatrick, Barbara; Pierce, Richard H; Backer, Lorraine C; Baden, Daniel G

    2010-06-01

    Florida red tides occur annually in the Gulf of Mexico from blooms of the marine dinoflagellate, Karenia brevis, which produces highly potent natural polyether toxins, brevetoxins. Several epidemiologic studies have demonstrated that human exposure to red tide aerosol could result in increased respiratory symptoms. Environmental monitoring of aerosolized brevetoxins was performed using a high-volume sampler taken hourly at fixed locations on Siesta Beach, Florida. Personal exposure was monitored using personal air samplers and taking nasal swab samples from the subjects who were instructed to spend 1 hr on Sarasota Beach during two sampling periods of an active Florida red tide event in March 2005, and in May 2008 when there was no red tide. Results showed that the aerosolized brevetoxins from the personal sampler were in modest agreement with the environmental concentration taken from a high-volume sampler. Analysis of nasal swab samples for brevetoxins demonstrated 68% positive samples in the March 2005 sampling period when air concentrations of brevetoxins were between 50 to 120 ng/m(3) measured with the high-volume sampler. No swab samples showed detectable levels of brevetoxins in the May 2008 study, when all personal samples were below the limit of detection. However, there were no statistical correlations between the amounts of brevetoxins detected in the swab samples with either the environmental or personal concentration. Results showed that the personal sample might provide an estimate of individual exposure level. Nasal swab samples showed that brevetoxins indeed were inhaled and deposited in the nasal passage during the March 2005 red tide event. PMID:20379895

  18. Characterization of aerosols produced by surgical procedures

    Energy Technology Data Exchange (ETDEWEB)

    Yeh, H.C.; Muggenburg, B.A.; Lundgren, D.L.; Guilmette, R.A.; Snipes, M.B.; Jones, R.K. [Inhalation Toxicology Research Institute, Albuquerque, NM (United States); Turner, R.S. [Lovelace Health Systems, Albuquerque, NM (United States)

    1994-07-01

    In many surgeries, especially orthopedic procedures, power tools such as saws and drills are used. These tools may produce aerosolized blood and other biological material from bone and soft tissues. Surgical lasers and electrocautery tools can also produce aerosols when tissues are vaporized and condensed. Studies have been reported in the literature concerning production of aerosols during surgery, and some of these aerosols may contain infectious material. Garden et al. (1988) reported the presence of papilloma virus DNA in the fumes produced from laser surgery, but the infectivity of the aerosol was not assessed. Moon and Nininger (1989) measured the size distribution and production rate of emissions from laser surgery and found that particles were generally less than 0.5 {mu}m diameter. More recently there has been concern expressed over the production of aerosolized blood during surgical procedures that require power tools. In an in vitro study, the production of an aerosol containing the human immunodeficiency virus (HIV) was reported when power tools were used to cut tissues with blood infected with HIV. Another study measured the size distribution of blood aerosols produced by surgical power tools and found blood-containing particles in a number of size ranges. Health care workers are anxious and concerned about whether surgically produced aerosols are inspirable and can contain viable pathogens such as HIV. Other pathogens such as hepatitis B virus (HBV) are also of concern. The Occupational Safety and Health funded a project at the National Institute for Inhalation Toxicology Research Institute to assess the extent of aerosolization of blood and other tissues during surgical procedures. This document reports details of the experimental and sampling approach, methods, analyses, and results on potential production of blood-associated aerosols from surgical procedures in the laboratory and in the hospital surgical suite.

  19. Potential climatic effects of anthropogenic aerosols

    International Nuclear Information System (INIS)

    Aerosols act as part of the climate system through their influence on solar and terrestrial radiation. The effect of anthropogenic aerosols on the reduction of visibility is explored in this chapter. Elemental carbon has been identified as the most effective visibility-reducing species. Most of the visibility reduction is due to particles with diameter smaller than 2.5 μm. Studies indicate that sulfate is also a very important aerosol species that results in low visibility and high turbidity. Radiative properties such as aerosol single-scattering albedo values and absorption-to-backscatter ratios purported to produce warming or cooling effects of aerosols are discussed. It is concluded that aerosol clouds have a tendency to cool when they are over a low-albedo surface and have a tendency to warm when they are over high-albedo surfaces such as snow. Anthropogenic aerosols have a tendency to warm the earth's atmospheric system, based on calculations and assumed aerosol optical properties. However, this effect is somewhat offset by the absorption and re-emission into space of infrared terrestrial radiation. The net effect depends on the ratio of the absorption coefficients in the visible and infrared and also on the surface albedo. The effects on infrared radiation are documented for two anthropogenic aerosol sources in the United States, the Denver metropolitan area and power plant plumes in New Mexico, through calculations and measurements. Measured cooling rates within an aerosol plume are not sufficient to offset the warming rate due to absorption of short-wave radiation. Research indicates that anthropogenic aerosols can possibly cause local-scale warming of the atmosphere, but global-scale climatic effects remain an open question

  20. Environmental monitoring using lasers

    International Nuclear Information System (INIS)

    Activities of human beings are creating slow and long term changes in the Earth's atmosphere. As the sun provides the driving force for earth's ecosystem, therefore earth's radiation budget is an important parameter. Composition of the atmosphere is of basic importance in determining this radiation budget. Out of the atmospheric species, ozone is of special importance because it filters out much of the solar UV, while certain other molecular species, such as SO/sub 2/ , NO/sub 2/, benzene, toluene and aerosols have very harmful effects on life. Depletion of ozone layer over Antarctic and addition of chemical species to atmosphere and oceans have disturbed our ecosystem seriously. Thorough monitoring of distribution and dynamics of these species is essential for devising any countermeasure for their control. Conventional method of atmospheric monitoring (balloon, rocket or satellite borne sensors) are limited either in range or type of measurement apart from being complex and somewhat expensive. LASER based 'light detection and ranging (LIDAR) technique, on the other hand, enjoys a number of advantages over others. Due to recent developments in LASER technique, on the other hand, enjoys a number of advantages over other. Due to recent developments in LASER technology, LIDARS are economical and very flexible in range and type of measurement. This paper presents an overview of the technique. It includes principle of LIDAR, highlights its applications to the monitoring of atmosphere, biosphere and hydrosphere. (author)

  1. Remote sensing of aerosol in the terrestrial atmosphere from space: "AEROSOL-UA" mission

    Science.gov (United States)

    Yatskiv, Yaroslav; Milinevsky, Gennadi; Degtyarev, Alexander

    2016-07-01

    The distribution and properties of atmospheric aerosols on a global scale are not well known in terms of determination of their effects on climate. This mostly is due to extreme variability of aerosol concentrations, properties, sources, and types. Aerosol climate impact is comparable to the effect of greenhouse gases, but its influence is more difficult to measure, especially with respect to aerosol microphysical properties and the evaluation of anthropogenic aerosol effect. There are many satellite missions studying aerosol distribution in the terrestrial atmosphere, such as MISR/Terra, OMI/Aura, AVHHR, MODIS/Terra and Aqua, CALIOP/CALIPSO. To improve the quality of data and climate models, and to reduce aerosol climate forcing uncertainties, several new missions are planned. The gap in orbital instruments for studying aerosol microphysics has arisen after the Glory mission failed during launch in 2011. In this review paper, we describe several planned aerosol space missions, including the Ukrainian project AEROSOL-UA that will obtain the data using a multi-channel scanning polarimeter and wide-angle polarimetric camera. The mission is designed for remote sensing of the aerosol microphysics and cloud properties on a global scale.

  2. Aerosol retrieval algorithm for the characterization of local aerosol using MODIS L1B data

    International Nuclear Information System (INIS)

    Atmospheric aerosol plays an important role in radiation budget, climate change, hydrology and visibility. However, it has immense effect on the air quality, especially in densely populated areas where high concentration of aerosol is associated with premature death and the decrease of life expectancy. Therefore, an accurate estimation of aerosol with spatial distribution is essential, and satellite data has increasingly been used to estimate aerosol optical depth (AOD). Aerosol product (AOD) from Moderate Resolution Imaging Spectroradiometer (MODIS) data is available at global scale but problems arise due to low spatial resolution, time-lag availability of AOD product as well as the use of generalized aerosol models in retrieval algorithm instead of local aerosol models. This study focuses on the aerosol retrieval algorithm for the characterization of local aerosol in Hong Kong for a long period of time (2006-2011) using high spatial resolution MODIS level 1B data (500 m resolution) and taking into account the local aerosol models. Two methods (dark dense vegetation and MODIS land surface reflectance product) were used for the estimation of the surface reflectance over land and Santa Barbara DISORT Radiative Transfer (SBDART) code was used to construct LUTs for calculating the aerosol reflectance as a function of AOD. Results indicate that AOD can be estimated at the local scale from high resolution MODIS data, and the obtained accuracy (ca. 87%) is very much comparable with the accuracy obtained from other studies (80%-95%) for AOD estimation

  3. Ceilometer aerosol profiling vs. Raman lidar in the frame of INTERACT campaign of ACTRIS

    Directory of Open Access Journals (Sweden)

    F. Madonna

    2014-12-01

    Full Text Available Despite their differences from more advanced and more powerful lidars, the low construction and operation cost of ceilometers, originally designed for cloud base height monitoring, has fostered their use for the quantitative study of aerosol properties. The large number of ceilometers available worldwide represents a strong motivation to investigate both the extent to which they can be used to fill in the geographical gaps between advanced lidar stations and also how their continuous data flow can be linked to existing networks of the more advanced lidars, like EARLINET (European Aerosol Research LIdar NETwork. In this paper, multi-wavelength Raman lidar measurements are used to investigate the capability of ceilometers to provide reliable information about atmospheric aerosol content through the INTERACT (INTERcomparison of Aerosol and Cloud Tracking campaign carried out at the CNR-IMAA Atmospheric Observatory (760 m a.s.l., 40.60° N, 15.72° E, in the framework of ACTRIS (Aerosol Clouds Trace gases Research InfraStructure FP7 project. This work is the first time that three different commercial ceilometers with an advanced Raman lidar are compared over a period of six months. The comparison of the attenuated backscatter profiles from a multi-wavelength Raman lidar and three ceilometers (CHM15k, CS135s, CT25K reveals differences due to the expected discrepancy in the SNR but also due to effect of changes in the ambient temperature on the short and mid-term stability of ceilometer calibration. A large instability of ceilometers in the incomplete overlap region has also been observed, making the use of a single overlap correction function for the whole duration of the campaign critical. Therefore, technological improvements of ceilometers towards their operational use in the monitoring of the atmospheric aerosol in the low and free troposphere are needed.

  4. The Stratospheric Aerosol and Gas Experiment (SAGE III) on the International Space Station (ISS) Mission

    Science.gov (United States)

    Cisewski, Michael; Zawodny, Joseph; Gasbarre, Joseph; Eckman, Richard; Topiwala, Nandkishore; Rodriquez-Alvarez, Otilia; Cheek, Dianne; Hall, Steve

    2014-01-01

    The Stratospheric Aerosol and Gas Experiment III on the International Space Station (SAGE III/ISS) mission will provide the science community with high-vertical resolution and nearly global observations of ozone, aerosols, water vapor, nitrogen dioxide, and other trace gas species in the stratosphere and upper-troposphere. SAGE III/ISS measurements will extend the long-term Stratospheric Aerosol Measurement (SAM) and SAGE data record begun in the 1970s. The multi-decadal SAGE ozone and aerosol data sets have undergone intense scrutiny and are considered the international standard for accuracy and stability. SAGE data have been used to monitor the effectiveness of the Montreal Protocol. Key objectives of the mission are to assess the state of the recovery in the distribution of ozone, to re-establish the aerosol measurements needed by both climate and ozone models, and to gain further insight into key processes contributing to ozone and aerosol variability. The space station mid-inclination orbit allows for a large range in latitude sampling and nearly continuous communications with payloads. The SAGE III instrument is the fifth in a series of instruments developed for monitoring atmospheric constituents with high vertical resolution. The SAGE III instrument is a moderate resolution spectrometer covering wavelengths from 290 nm to 1550 nm. Science data is collected in solar occultation mode, lunar occultation mode, and limb scatter measurement mode. A SpaceX Falcon 9 launch vehicle will provide access to space. Mounted in the unpressurized section of the Dragon trunk, SAGE III will be robotically removed from the Dragon and installed on the space station. SAGE III/ISS will be mounted to the ExPRESS Logistics Carrier-4 (ELC-4) location on the starboard side of the station. To facilitate a nadir view from this location, a Nadir Viewing Platform (NVP) payload was developed which mounts between the carrier and the SAGE III Instrument Payload (IP).

  5. Development and Testing of the New Surface LER Climatology for OMI UV Aerosol Retrievals

    Science.gov (United States)

    Gupta, Pawan; Torres, Omar; Jethva, Hiren; Ahn, Changwoo

    2014-01-01

    Ozone Monitoring Instrument (OMI) onboard Aura satellite retrieved aerosols properties using UV part of solar spectrum. The OMI near UV aerosol algorithm (OMAERUV) is a global inversion scheme which retrieves aerosol properties both over ocean and land. The current version of the algorithm makes use of TOMS derived Lambertian Equivalent Reflectance (LER) climatology. A new monthly climatology of surface LER at 354 and 388 nm have been developed. This will replace TOMS LER (380 nm and 354nm) climatology in OMI near UV aerosol retrieval algorithm. The main objectives of this study is to produce high resolution (quarter degree) surface LER sets as compared to existing one degree TOMS surface LERs, to product instrument and wavelength consistent surface climatology. Nine years of OMI observations have been used to derive monthly climatology of surface LER. MODIS derived aerosol optical depth (AOD) have been used to make aerosol corrections on OMI wavelengths. MODIS derived BRDF adjusted reflectance product has been also used to capture seasonal changes in the surface characteristics. Finally spatial and temporal averaging techniques have been used to fill the gaps around the globes, especially in the regions with consistent cloud cover such as Amazon. After implementation of new surface data in the research version of algorithm, comparisons of AOD and single scattering albedo (SSA) have been performed over global AERONET sites for year 2007. Preliminary results shows improvements in AOD retrievals globally but more significance improvement were observed over desert and bright locations. We will present methodology of deriving surface data sets and will discuss the observed changes in retrieved aerosol properties with respect to reference AERONET measurements.

  6. Satellite Characterization of Fire Emissions of Aerosols and Gases Relevant to Air-Quality Modeling

    Science.gov (United States)

    Ichoku, C. M.; Ellison, L.; Yue, Y.; Wang, J.

    2015-12-01

    Because of the transient and widespread nature of wildfires and other types of open biomass burning, satellite remote sensing has become an indispensable technique for characterizing their smoke emissions for modeling applications, especially at regional to global scales. Fire radiative energy (FRE), whose instantaneous rate of release or fire radiative power (FRP) is measurable from space, has been found to be proportional to both the biomass consumption and emission of aerosol particulate matter. We have leveraged this relationship to generate a global, gridded smoke-aerosol emission coefficients (Ce) dataset based on FRP and aerosol optical thickness (AOT) measurements from the MODIS sensors aboard the Terra and Aqua satellites. Ce is a simple coefficient to convert FRE to smoke aerosol emissions, in the same manner as traditional emission factors are used to convert burned biomass to emissions. The first version of this Fire Energetics and Emissions Research (FEER.v1) global gridded Ce product at 1°x1° resolution is available at http://feer.gsfc.nasa.gov/. Based on published emission ratios, the FEER.v1 Ce product for total smoke aerosol has also been used to generate similar products for specific fire-emitted aerosols and gases, including those that are regulated as 'criteria pollutants' under the US Environmental Protection Agency's National Ambient Air Quality Standards (NAAQS), such as particulate matter (PM) and carbon monoxide (CO). These gridded Ce products were used in conjunction with satellite measurements of FRP to derive emissions of several smoke constituents, which were applied to WRF-Chem fully coupled meteorology-chemistry-aerosol model simulations, with promising results. In this presentation, we analyze WRF-Chem simulations of surface-level concentrations of various pollutants based on FEER.v1 emission products to illustrate their value for air-quality modeling, particularly in parts of Africa and southeast Asia where ground-based air

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

    Science.gov (United States)

    Schlag, Patrick; Kiendler-Scharr, Astrid; Blom, Marcus Johannes; Canonaco, Francesco; Sebastiaan Henzing, Jeroen; Moerman, Marcel; Prévôt, André Stephan Henry; Holzinger, Rupert

    2016-07-01

    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.

  8. Aerosol Sampling System for Collection of Capstone Depleted Uranium Particles in a High-Energy Environment

    International Nuclear Information System (INIS)

    The Capstone Depleted Uranium Aerosol Study was undertaken to obtain aerosol samples resulting from a kinetic-energy cartridge with a large-caliber depleted uranium (DU) penetrator striking an Abrams or Bradley test vehicle. The sampling strategy was designed to (1) optimize the performance of the samplers and maintain their integrity in the extreme environment created during perforation of an armored vehicle by a DU penetrator, (2) collect aerosols as a function of time post-impact, and (3) obtain size-classified samples for analysis of chemical composition, particle morphology, and solubility in lung fluid. This paper describes the experimental setup and sampling methodologies used to achieve these objectives. Custom-designed arrays of sampling heads were secured to the inside of the target in locations approximating the breathing zones of the vehicle commander, loader, gunner, and driver. Each array was designed to support nine filter cassettes and nine cascade impactors mounted with quick-disconnect fittings. Shielding and sampler placement strategies were used to minimize sampler loss caused by the penetrator impact and the resulting fragments of eroded penetrator and perforated armor. A cyclone train was used to collect larger quantities of DU aerosol for chemical composition and solubility. A moving filter sample was used to obtain semicontinuous samples for depleted uranium concentration determination. Control for the air samplers was provided by five remotely located valve control and pressure monitoring units located inside and around the test vehicle. These units were connected to a computer interface chassis and controlled using a customized LabVIEW engineering computer control program. The aerosol sampling arrays and control systems for the Capstone study provided the needed aerosol samples for physicochemical analysis, and the resultant data were used for risk assessment of exposure to DU aerosol

  9. Aerosol sampling system for collection of Capstone depleted uranium particles in a high-energy environment.

    Science.gov (United States)

    Holmes, Thomas D; Guilmette, Raymond A; Cheng, Yung Sung; Parkhurst, Mary Ann; Hoover, Mark D

    2009-03-01

    The Capstone Depleted Uranium (DU) Aerosol Study was undertaken to obtain aerosol samples resulting from a large-caliber DU penetrator striking an Abrams or Bradley test vehicle. The sampling strategy was designed to (1) optimize the performance of the samplers and maintain their integrity in the extreme environment created during perforation of an armored vehicle by a DU penetrator, (2) collect aerosols as a function of time post perforation, and (3) obtain size-classified samples for analysis of chemical composition, particle morphology, and solubility in lung fluid. This paper describes the experimental setup and sampling methodologies used to achieve these objectives. Custom-designed arrays of sampling heads were secured to the inside of the target in locations approximating the breathing zones of the crew locations in the test vehicles. Each array was designed to support nine filter cassettes and nine cascade impactors mounted with quick-disconnect fittings. Shielding and sampler placement strategies were used to minimize sampler loss caused by the penetrator impact and the resulting fragments of eroded penetrator and perforated armor. A cyclone train was used to collect larger quantities of DU aerosol for measurement of chemical composition and solubility. A moving filter sample was used to obtain semicontinuous samples for DU concentration determination. Control for the air samplers was provided by five remotely located valve control and pressure monitoring units located inside and around the test vehicle. These units were connected to a computer interface chassis and controlled using a customized LabVIEW engineering computer control program. The aerosol sampling arrays and control systems for the Capstone study provided the needed aerosol samples for physicochemical analysis, and the resultant data were used for risk assessment of exposure to DU aerosol. PMID:19204482

  10. Aerosol radiative forcing efficiency in the UV-B region over central Argentina

    Science.gov (United States)

    Palancar, Gustavo G.; Olcese, Luis E.; Lanzaco, Bethania L.; Achad, Mariana; López, María Laura; Toselli, Beatriz M.

    2016-07-01

    AEROSOL Robotic Network (AERONET), Moderate Resolution Imaging Spectroradiometer (MODIS) and global UV-B (280-315 nm) irradiance measurements and calculations were combined to investigate the effects of aerosol loading on the ultraviolet B radiation (UV-B) reaching the su