WorldWideScience

Sample records for ambient fine particle

  1. Impact of fine particles in ambient air on lung cancer

    Institute of Scientific and Technical Information of China (English)

    Gerard Hoek; Ole Raaschou-Nielsen

    2014-01-01

    Recently, the International Agency for Research on Cancer (IARC) has classified outdoor air pol ution and the particulate matter component of outdoor air pollution as class I carcinogen. Air pollution is consistently associated with lung cancer in epidemiologic and experimental studies. The IARC assessment is specifical y designed as hazard identification, and it does not quantify the magnitude of the cancer risk. This article addresses the magnitude of the lung cancer risk in the population due to ambient air pol ution exposure.

  2. Mineralogical characterization of ambient fine/ultrafine particles emitted from Xuanwei C1 coal combustion

    Science.gov (United States)

    Lu, Senlin; Hao, Xiaojie; Liu, Dingyu; Wang, Qiangxiang; Zhang, Wenchao; Liu, Pinwei; Zhang, Rongci; Yu, Shang; Pan, Ruiqi; Wu, Minghong; Yonemochi, Shinich; Wang, Qingyue

    2016-03-01

    Nano-quartz in Xuanwei coal, the uppermost Permian (C1) coal deposited in the northwest of Yuanan, China, has been regarded as one of factors which caused high lung cancer incidence in the local residents. However, mineralogical characterization of the fine/ultrafine particles emitted from Xuanwei coal combustion has not previously been studied. In this study, PM1 and ultrafine particles emitted from Xuanwei coal combustion were sampled. Chemical elements in the ambient particles were analyzed by inductively coupled plasma mass spectrometry (ICP-MS), and mineralogical characterization of these ambient particles was investigated using scanning electronic microscopy (SEM/EDX) and transmission electronic microscopy, coupled with energy-dispersive spectroscopy (TEM/EDX). Our results showed that the size distribution of mineral particles from the coal combustion emissions ranged from 20 to 200 nm. Si-containing particles and Fe-containing particles accounted for 50.7% of the 150 individual particles measured, suggesting that these two types of particles were major minerals in the ambient particles generally. The nano-mineral particles were identified as quartz (SiO2) and gypsum (CaSO4) based on their crystal parameters and chemical elements. Additionally, there also existed unidentified nano-minerals. Armed with these data, toxicity assessments of the nano-minerals will be carried out in a future study.

  3. Ambient exposure to coarse and fine particle emissions from building demolition

    Science.gov (United States)

    Azarmi, Farhad; Kumar, Prashant

    2016-07-01

    Demolition of buildings produce large quantities of particulate matter (PM) that could be inhaled by on-site workers and people living in the neighbourhood, but studies assessing ambient exposure at the real-world demolition sites are limited. We measured concentrations of PM10 (≤10 μm), PM2.5 (≤2.5 μm) and PM1 (≤1 μm) along with local meteorology for 54 working hours over the demolition period. The measurements were carried out at (i) a fixed-site in the downwind of demolished building, (ii) around the site during demolition operation through mobile monitoring, (iii) different distances away from the demolition site through sequential monitoring, and (iv) inside an excavator vehicle cabin and on-site temporary office for engineers. Position of the PM instrument was continuously recorded using a Global Positioning System on a second basis during mobile measurements. Fraction of coarse particles (PM2.5-10) contributed 89 (with mean particle mass concentration, PMC ≈ 133 ± 17 μg m-3), 83 (100 ± 29 μg m-3), and 70% (59 ± 12 μg m-3) of total PMC during the fixed-site, mobile monitoring and sequential measurements, respectively, compared with only 50% (mean 12 ± 6 μg m-3) during the background measurements. The corresponding values for fine particles (PM2.5) were 11, 17 and 30% compared with 50% during background, showing a much greater release of coarse particles during demolition. The openair package in R and map source software (ArcGIS) were used to assess spatial variation of PMCs in downwind and upwind of the demolition site. A modified box model was developed to determine the emission factors, which were 210, 73 and 24 μg m-2 s-1 for PM10, PM2.5 and PM1, respectively. The average respiratory deposited doses to coarse (and fine) particles inside the excavator cabin and on-site temporary office increased by 57- (and 5-) and 13- (and 2-) times compared with the local background level, respectively. The monitoring stations in downwind direction

  4. 77 FR 65310 - Additional Air Quality Designations for the 2006 24-Hour Fine Particle National Ambient Air...

    Science.gov (United States)

    2012-10-26

    ... the 2006 24-hour Fine Particle (PM 2.5 ) National Ambient Air Quality Standards,'' 74 FR 58688... Federal Regulations DC District of Columbia EO Executive Order EPA Environmental Protection Agency FR... EPA finalized designations for the 2006 24-hour PM 2.5 NAAQS (74 FR 58688, November 13, 2009), the...

  5. Triggering of Transmural Infarctions, but Not Nontransmural Infarctions, by Ambient Fine Particles

    OpenAIRE

    Rich, David Q.; Kipen, Howard M.; Zhang, Junfeng; Kamat, Leena; Wilson, Alan C.; Kostis, John B; ,

    2010-01-01

    Background Previous studies have reported increased risk of myocardial infarction (MI) after increases in ambient particulate matter (PM) air pollution concentrations in the hours and days before MI onset. Objectives We hypothesized that acute increases in fine PM with aerodynamic diameter ≤ 2.5 μm (PM2.5) may be associated with increased risk of MI and that chronic obstructive pulmonary disease (COPD) and diabetes may increase susceptibility to PM2.5. We also explored whether both transmural...

  6. The chemical composition of fine ambient aerosol particles in the Beijing area

    Science.gov (United States)

    Nekat, Bettina; van Pinxteren, Dominik; Iinuma, Yoshiteru; Gnauk, Thomas; Müller, Konrad; Herrmann, Hartmut

    2010-05-01

    The strong economical growth in China during the last few decades led to heavy air pollution caused by significantly increased particle emissions. The aerosol particles affect not only the regional air quality and visibility, but can also influence cloud formation processes and the radiative balance of the atmosphere by their optical and microphysical properties. The ability to act as Cloud Condensation Nuclei (CCN) is related to microphysical properties like the hygroscopic growth or the cloud droplet activation. The chemical composition of CCN plays an important role on these properties and varies strongly with the particle size and the time of day. Hygroscopic or surface active substances can increase the hygroscopicity and lower the surface tension of the particle liquid phase, respectively. The presence of such compounds may result in faster cloud droplet activation by faster water uptake. The DFG project HaChi (Haze in China) aimed at studying physical and chemical parameters of urban aerosol particles in the Beijing area in order to associate the chemical composition of aerosol particles with their ability to act as CCN. To this end, two measurement campaigns were performed at the Wuqing National Ordinary Meteorological Observing Station, which is a background site near Beijing. The winter campaign was realized in March 2009 and the summer campaign took place from mid July 2009 to mid August 2009. Fine particles with an aerodynamic diameter smaller than or equal 1 μm were continuously sampled for 24h over the two campaigns using a DIGITEL high volume sampler (DHA-80). The present contribution presents and discusses the results of the chemical characterization of the DIGITEL filters samples. The filters were analyzed for the mass concentration, inorganic ions and carbon sum parameters like elemental (EC), organic (OC) and water soluble organic carbon (WSOC). The WSOC fraction was further characterized for hygroscopic substances like low molecular

  7. Diurnal and seasonal trends in the apparent density of ambient fine and coarse particles in Los Angeles

    International Nuclear Information System (INIS)

    Diurnal and seasonal variations in the apparent density of ambient fine and coarse particulate matter (PM2.5 and CPM [PM2.5–10], respectively) were investigated in a location near downtown Los Angeles. The apparent densities, determined by particle mass-to-volume ratios, showed strong diurnal and seasonal variations, with higher values during the warm phase (June to August 2013) compared to cold phase (November 2012 to February 2013). PM2.5 apparent density showed minima during the morning and afternoon rush hours of the cold phase (1.20 g cm−3), mainly due to the increased contribution of traffic-emitted soot particles, and highest values were found during the midday in the warm phase (2.38 g cm−3). The lowest CPM apparent density was observed during the morning rush hours of the cold phase (1.41 g cm−3), while highest in early afternoon during the warm phase (2.91 g cm−3), most likely due to the increased wind-induced resuspension of road dust. - Highlights: • Hourly apparent density of ambient fine and coarse PM was measured in Los Angeles. • Apparent densities were higher during the warm season. • PM2.5 apparent density showed minima during the traffic rush hours. • Coarse PM apparent density showed a similar diurnal trend with wind speed in summer. - The apparent density of ambient particles, a direct tracer of chemical composition and morphology, shows strong seasonal and diurnal variability

  8. Characterization of ambient fine particles in the northwestern area and Anchorage, Alaska.

    Science.gov (United States)

    Kim, Eugene; Hopke, Philip K

    2008-10-01

    Ambient PM2.5 (particulate matter less than 2.5 microm in aerodynamic diameter) in the northwestern United States and Alaska is dominated by carbonaceous compounds associated with wood burning and transportation sources. PM2.5 source characterization studies analyzing recent PM2.5 speciation data have not been previously reported for these areas. In this study, ambient PM2.5 speciation samples collected at two monitoring sites located in the northwestern area, Olympic Peninsula, WA, and Portland, OR, and one monitoring site located in Anchorage, AK, were characterized through source apportionments. Gasoline vehicle, secondary sulfate, and wood smoke were the largest sources of PM2.5 collected at the Anchorage, Olympic, and Portland monitoring sites, respectively. Secondary sulfates showed an April peak at Anchorage and a November peak at Portland that are likely related to the increased photochemical reaction and long-range transport in Anchorage and meteorological stagnation in Portland. Secondary nitrate at the Olympic site showed a weak summer high peak that could be caused by seasonal tourism in the national park. Backward trajectories suggested that the elevated aged sea salt concentrations at the Portland monitoring site could be regional transport of sea salt that passed through other contaminated air sheds along the coast. Oil combustion emissions that might originate from ships and ferries were observed at the Olympic monitoring site. PMID:18939780

  9. Ambient fine particles modify heart rate variability in young healthy adults.

    Science.gov (United States)

    Vallejo, Maite; Ruiz, Silvia; Hermosillo, Antonio G; Borja-Aburto, Víctor H; Cárdenas, Manuel

    2006-03-01

    Particulate air pollution has been related with cardiopulmonary morbidity and mortality. Recent studies have shown that an increase in particulate matter (PM)(2.5) ambient concentrations was associated with a decrease in heart rate variability (HRV) in the elderly with cardiovascular conditions, which could increase the risk of death. In order to assess if this association could also be observed in young adults, we studied 40 young healthy residents of the Mexico City Metropolitan Area (MCMA) who underwent 13 h Holter electrocardiographic and PM(2.5) personal monitoring. HRV was evaluated in time domain: the standard deviation of normal RR intervals (SDNN) and the percentage of differences between adjacent normal RR intervals larger than 50 ms (pNN50). In multivariate analysis with mixed effects models, a significant negative association of pNN50 with PM(2.5) accumulative exposure was found. An increase in 30 microg/m(3) of the average PM(2.5) personal exposure in the previous 2 h decreased the pNN50 in 0.08% (P=0.01). This observation revealed an acute effect related to environmental exposure to PM(2.5) with regard to HRV in normal youngsters. The long-term health consequences of this association in young healthy adults remain to be clarified. PMID:16151470

  10. The elemental composition and origin of fine ambient particles in the largest Polish conurbation: first results from the short-term winter campaign

    Science.gov (United States)

    Majewski, Grzegorz; Rogula-Kozłowska, Wioletta

    2016-07-01

    Diurnal (24-h) samples of fine particulate matter (PM2.5, ambient particles with an aerodynamic diameter not greater than 2.5 μm) and soil samples were collected in an urban area in Warsaw, in winter. The samples were analysed for 24 elements with an Epsilon 5 spectrometer (PANalytical). The results were then arranged and compared with the results of research conducted earlier in Poland and other parts of the world. Afterwards, sources of ambient PM2.5 were identified and the share of each in the concentration of PM2.5 was evaluated by means of enrichment factor (EF) analysis, principal component analysis (PCA) and multi-linear regression analysis (MLRA). The results were interpreted using a detailed analysis of correlations between diurnal concentrations of PM2.5, PM2.5-elements, and of changes in meteorological conditions. The winter average ambient concentration of PM2.5 in Warsaw, was 10.7 ± 7.5 μg/m3 and was much lower than in the other sites in Poland. In Warsaw, regardless of the concentration of PM2.5, the concentrations of certain PM2.5-bound elements, mainly toxic, were high, e.g. the average ambient concentrations of PM2.5-bound Se, As, Co, V, Cd and Ni were 12.7 ± 30.5, 10.6 ± 34.4, 9.4 ± 13.7, 15.1 ± 32.7, 9.6 ± 22.2 and 3.5 ± 5.0 ng/m3, respectively. The elemental composition and concentrations of PM2.5 appeared to be influenced mainly by the anthropogenic emissions (energy production based on coal and biomass combustion, whose mean contribution to the concentration of PM2.5 was 18.4 %, and energy production based on oil combustion with a contribution of 9.9 % in PM2.5). A mixture of soil matter and road dust was also identified in PM2.5 (8 %). The mean contribution of traffic (exhaust) emissions to the concentration of PM2.5 in an urban area, selected as representative of the Warsaw conurbation, was assessed at 15.4 %.

  11. Identification of potential sources and source regions of fine ambient particles measured at Gosan background site in Korea using advanced hybrid receptor model combined with positive matrix factorization

    Science.gov (United States)

    Han, J. S.; Moon, K. J.; Kim, Y. J.

    2006-11-01

    The size- and time-resolved measurement of particulate trace elements was made using an eight-stage Davis Rotating Unit for Monitoring sampler and synchrotron X-ray fluorescence system from 29 March to 29 May in 2002 at Gosan, Korea, which is one of the representative background sites in east Asia. As a result, continuous 3-hour average concentrations were obtained for 19 elements including S, Si, Al, Fe, Ca, Cl, Cu, Zn, Ti, K, Mn, Pb, Ni, V, Se, As, Rb, Cr, and Br. Positive matrix factorization (PMF) method was applied to the size-resolved aerosol data sets in order to identify the possible sources and to estimate their contribution to particulate matter mass in each size range. Twelve sources were then resolved in the fine size range (0.07 ˜ 1.15 μm), including continental aerosol, biomass burning, coal combustion, oil heating furnace, residual oil fired boiler, municipal incineration, nonferrous metal source, ferrous metal source, gasoline vehicle, diesel vehicle, copper smelter, and volcanic emission. A newly developed hybrid receptor model, concentration, retention time, and source emission weighted trajectory (CRSWT), was then applied to the source intensities derived from the PMF analysis by incorporating meteorological and source inventory information of the study region in order to suggest the regional information of long-range transported fine aerosol sources. The CRSWT model was able to resolve highly potential source areas and pathways for the fine ambient aerosol at the Gosan background site.

  12. Fine Particle Scrubbing: A Proceedings

    Science.gov (United States)

    Journal of the Air Pollution Control Association, 1974

    1974-01-01

    These articles deal with the proceedings of a 1974 symposium on the use of wet scrubbers for the control of fine particle air pollutants. Various wet scrubbers, their engineering, performance, efficiency, and future are discussed. Tables, formulas, and models are included. (TK)

  13. A hazard to health? Fine particles arouse worldwide interest

    Energy Technology Data Exchange (ETDEWEB)

    Karas, J.; Oesch, P.

    1998-07-01

    The most recent studies show that particles contained in the air that we breathe may have harmful effects on the health of asthmatics, children and old people in particular. Particle material found in ambient air is formed by emissions resulting from traffic, industry and other use of fuels. Nature`s own sources also have a significant effect on particle concentrations. The mechanisms by which fine particles may produce negative health effects are so far unknown. At present it is therefore impossible to assess the effects of emissions of fine particles resulting, for instance, from the use of fossil fuels

  14. Fractal aggregation and breakup of fine particles

    Directory of Open Access Journals (Sweden)

    Li Bingru

    2016-01-01

    Full Text Available Breakup may exert a controlling influence on particle size distributions and particles either are fractured or are eroded particle-by-particle through shear. The shear-induced breakage of fine particles in turbulent conditions is investigated using Taylor-expansion moment method. Their equations have been derived in continuous form in terms of the number density function with particle volume. It suitable for future implementation in computational fluid dynamics modeling.

  15. Relationship between Ambient Fine Particles and Ventricular Repolarization Changes and Heart Rate Variability of Elderly People with Heart Disease in Beijing, China

    Institute of Scientific and Technical Information of China (English)

    XU Mei Mei; JIA Yu Ping; LI Guo Xing; LIU Li Qun; MO Yun Zheng; JIN Xiao Bin; PAN Xiao Chuan

    2013-01-01

    Objective To explore the effects of particulate matters less than 2.5 μm in aerodynamic diameter (PM2.5) on heart repolarization/depolarization and heart rate variability (HRV). Methods We conducted a panel study for elderly subjects with heart disease in Beijing from 2007 to 2008. PM2.5 was measured at a fixed station for 20 h continuously each day while electrocardiogram (ECG) indexes of 42 subjects were also recorded repeatedly. Meteorological data was obtained from the China Meteorological Data Sharing Service System. A mixed linear regression model was used to estimate the associations between PM2.5 and the ECG indexes. The model was adjusted for age, body mass index, sex, day of the week and meteorology. Results Significant adverse effects of PM2.5 on ECG indexes reflecting HRV were observed statistically and the strongest effect of PM2.5 on HRV was on lag 1 day in our study. However, there were no associations between PM2.5 and ECG indexes reflecting heart repolarization/depolarization. Additionally, the effects of PM2.5 on subjects with hypertension were larger than on the subjects without hypertension. Conclusion This study showed ambient PM2.5 could affect cardiac autonomic function of the elderly people with heart disease, and subjects with hypertension appeared to be more susceptive to the autonomic dysfunction induced by PM2.5.

  16. ELECTROSTATICALLY SUPPORTED MIXING OF FINE GRAINED PARTICLES

    Institute of Scientific and Technical Information of China (English)

    K.-E.; Wirth; M.; Linsenbühler

    2005-01-01

    The processing of fine-grained particles with diameters between 1 and 10 microns is difficult due to strong van-der-Waals attraction forces. In order to improve the handling properties, the fine-grained particles, i.e. host-particles,are coated with various nanoparticles, i.e. guest-particles. The mixing of fine-grained powders is influenced by particle-particle interactions. If these forces are distinctively used, both interactive and ordered mixtures can be produced.These particle mixtures consist of composite-particles that have new physical properties. These modified properties d epend strongly on the coating process, the diameter- and mass-relationship of the guest- and the host-particles. The properties of the composite-particles can systematically be adjusted to the requirements of industrial applications. For example, a laboratory bubbling fluidized bed can be used to describe the conveying behavior of the functionalized host-particles. Applications for the functionalized particles are in the pharmaceutical and the powder coating industries,e.g. enhanced dry powder inhalers and thin lacquer films. The present research compares three different mixing/coating processes. The composite-particles are characterized by TEM, SEM and with their fluidization characteristics. The coating process itself is monitored by the electrostatic charge of the particles.

  17. Generation of Fine Particles with Specified Characteristics

    CERN Document Server

    Ishmatov, A N; Trubnikov, A A; Ogorodnikov, S P

    2013-01-01

    The research is devoted to the generation of fine particles and droplet flows with specified characteristics for a wide range of scientific problems. The aspects of aerodynamic fine atomization and the effects of atomizing gas density, gas velocity and mass flow rate, and liquid film thickness on the droplet formation are investigated. The hypothesis of highly efficient utilization of secondary droplets from a coarse polydisperse flow to produce fine particles is suggested and experimentally confirmed. A prototype device to implement the idea of separating the desired droplets fraction from a primary polydisperse flow was developed. In the case of fine liquid atomization, the developed spraying system enabled an increase in the gas-droplet flow concentration. The possibility of producing particles with different dispersiveness and morphology by employing the methods of spray separation and dilute solution atomization is demonstrated. The criteria of the system settings to generate the droplet flow with specif...

  18. Combustion generated fine carbonaceous particles

    OpenAIRE

    Bockhorn, Henning; D'Anna, Andrea; Sarofim, Adel F.; Wang, Hai

    2009-01-01

    Soot is of importance for its contribution to atmospheric particles with their adverse health impacts and for its contributions to heat transfer in furnaces and combustors, to luminosity from candles, and to smoke that hinders escape from buildings during fires and that impacts global warming or cooling. The different chapters of the book adress comprehensively the different aspects from fundamental approaches to applications in technical combustion devices.

  19. 40 CFR Table F-3 to Subpart F of... - Critical Parameters of Idealized Ambient Particle Size Distributions

    Science.gov (United States)

    2010-07-01

    ... Ambient Particle Size Distributions F Table F-3 to Subpart F of Part 53 Protection of Environment... Ambient Particle Size Distributions Idealized Distribution Fine Particle Mode MMD (µm) Geo. Std. Dev. Conc. (µg/m3) Coarse Particle Mode MMD (µm) Geo. Std. Dev. Conc. (µg/m3) PM2.5/PM10 Ratio FRM...

  20. Fine particle emissions from residential wood combustion

    Energy Technology Data Exchange (ETDEWEB)

    Tissari, J.

    2008-07-01

    Residential wood combustion (RWC) appliances have the high probability of incomplete combustion, producing e.g. fine particles and hazardous organic compounds. In this thesis, the fine particle number and mass emissions, particle composition and morphology, and gas emissions were investigated from the modern (MMH) and conventional masonry heaters (CMH), sauna stoves (SS) and pellet burner. The investigation was based on laboratory and field experiments applying extensive and unique particle sampling methods. The appliance type, fuel and operational practices were found to affect clearly the fine particle emissions. In good combustion conditions (e.g. in pellet combustion), the fine particle mass (PM{sub 1}) emission factors were low, typically below 0.3 g kg-1, and over 90% of the PM{sub 1} consisted of inorganic compounds (i.e fine ash). From the CMH the typical PM{sub 1} values were 1.6-1.8 g kg-1, and from the SS 2.7-5.0 g kg-1, but were strongly dependent on operational practices. The smouldering combustion in CMH increased PM{sub 1} emission up to 10 g kg-1. The good secondary combustion in the MMH reduced the particle organic matter (POM) and gaseous emissions, but not substantially the elemental carbon (EC, i.e. soot) emission, and the typical PM{sub 1} values were 0.7-0.8 g kg-1. The particle number emissions were high, and did not correspond with the completition of combustion. The particle number distributions were mainly dominated by ultrafine (<100 nm) particles, but varied dependent on combustion conditions. The electronmicroscopy analyses showed that ultrafine particles were composed mainly of K, S and Zn. From the smouldering combustion, particles were composed mainly of carbon compounds and they had a closed sinteredlike structure, due to organic matter on the particles. Controlling the gasification rate via the primary air supply, log and batch size, as well as fuel moisture content, is important for the reduction of emissions in batch combustion

  1. Chemical characterisation of fine particles from biomass burning

    Energy Technology Data Exchange (ETDEWEB)

    Saarnio, K.

    2013-10-15

    Biomass burning has lately started to attract attention because there is a need to decrease the carbon dioxide (CO{sub 2}) emissions from the combustion of fossil fuels. Biomass is considered as CO{sub 2} neutral fuel. However, the burning of biomass is one of the major sources of fine particles both at the local and global scale. In addition to the use of biomass as a fuel for heat energy production, biomass burning emissions can be caused, e.g. by slash-and-burn agriculture and wild open-land fires. Indeed, the emissions from biomass burning are crucially important for the assessment of the potential impacts on global climate and local air quality and hence on human health. The chemical composition of fine particles has a notable influence on these impacts. The overall object of this thesis was to gain knowledge on the chemistry of fine particles that originate from biomass burning as well as on the contribution of biomass burning emissions to the ambient fine particle concentrations. For this purpose novel analytical methods were developed and tested in this thesis. Moreover, the thesis is based on ambient aerosol measurements that were carried out in six European countries at 12 measurement sites during 2002-2011. Additionally, wood combustion experiments were conducted in a laboratory. The measurements included a wide range of techniques: filter and impactor samplings, offline chemical analyses (chromatographic and mass spectrometric techniques, thermal-optical method), and online measurements of particles' physical properties and chemical composition (incl. particle number and mass concentrations and size distributions, concentrations of carbonaceous components, water-soluble ions, and tracer compounds). This thesis presents main results of different studies aimed towards chemical characterisation of fine particle emissions from biomass burning. It was found that wood combustion had a significant influence on atmospheric fine particle concentrations in

  2. Simulation of Indoor Fine Suspension Particle Deposition

    Science.gov (United States)

    Li, K. Q.; Gong, G. C.; Zou, S. H.

    In this paper, the migration and deposition of particles are simulated using the Moment Dynamic Equation (MDE). Indoor fine suspension particle depositions and particle distribution function are obtained. Gas phase flow is simulated by v 2 - f model. The simulated results of particle concentration profiles show that a uniform concentration exists in the middle region of the room with a low supplying speed. At the same time, the total number of partciels deposited is also obtained using Gradient diffusion model. Through the comparison of velocity predictions among several CFD k-ɛ models and v 2 -f model and experimental data, it is concluded that the results obtained by v 2 -f model more accurately approximate the experimental data. So that the MDE combined v 2 -f model will gain in popularity amongst building engineers and it will gradually be adopted as an attractive alternative tool to predict contaminant particle dispersion and distribution.

  3. Computer Models Simulate Fine Particle Dispersion

    Science.gov (United States)

    2010-01-01

    Through a NASA Seed Fund partnership with DEM Solutions Inc., of Lebanon, New Hampshire, scientists at Kennedy Space Center refined existing software to study the electrostatic phenomena of granular and bulk materials as they apply to planetary surfaces. The software, EDEM, allows users to import particles and obtain accurate representations of their shapes for modeling purposes, such as simulating bulk solids behavior, and was enhanced to be able to more accurately model fine, abrasive, cohesive particles. These new EDEM capabilities can be applied in many industries unrelated to space exploration and have been adopted by several prominent U.S. companies, including John Deere, Pfizer, and Procter & Gamble.

  4. Applications of electroflotation for recovery fine and ultrafine particles

    OpenAIRE

    Zendelska, Afrodita; Golomeov, Blagoj; Krstev, Boris; Krstev, Aleksandar

    2010-01-01

    The problem of processing by flotation are fine and ultrafine particles. Particles have small kinetic energy and they can’t overcome hydrodynamic resistance of the fluid surrounding air bubbles, thus reducing the creating a complex of the air bubble - mineral. Electroflotation process is development and focused on recovery fine mineral particles (13-38 µm) and ultrafine mineral particles (

  5. Determination of OM/OC ratios and specific attenuation coefficients (SAC in ambient fine PM at a rural site in southern Ontario: implications for emission sources, particle aging, and radiative forcing

    Directory of Open Access Journals (Sweden)

    T. W. Chan

    2009-07-01

    Full Text Available Ambient particulate matter (PM samples were collected on quartz filters at a rural site in southern Ontario during intensive studies in 2005 and 2007. The concentrations of organic carbon (OC, pyrolysis organic carbon (POC, and elemental carbon (EC were determined by thermal analysis. These results were compared to the organic aerosol mass concentration (OM measured by an Aerodyne Aerosol Mass Spectrometer (AMS and to the particle absorption coefficient (b_asp obtained from a Radiance Research Particle Soot Absorption Photometer (PSAP. The total organic mass to organic carbon ratios (OM/OC and specific attenuation coefficients (SAC were also derived. According to the results, the POC mass is proportional to the approximated oxygen mass in the aerosols and OM/OC ratios can be estimated directly from thermal measurements. The study also suggests that the air masses from the south, with relatively low OC/EC ratios, high EC, sulphate contents and OM/OC ratios, were originated from urban and industrial emissions and subsequently experienced photo-oxidations in the atmosphere, implying that the oxygenated organics could come from both primary and secondary sources. Whereas the air masses from the north, with relatively high OC/EC ratios, low EC, sulphate contents and OM/OC ratios, were dominant by the background clean air with relatively larger contributions from biogenic emissions.

    The mean SAC derived from the 2005 and 2007 studies are 4.9 m2 g−1 and 3.8 m2 g−1, respectively. When POC mass approaching zero (i.e. the impact of atmospheric aging is minimized, the SAC for primary emitted soot is estimated to be 5.8 m2 g−1 and 6.3 m2 g−1 for the northern and southern air masses, respectively, supported by the corresponding values when particulate sulphate concentration approaches zero. A decreasing trend in the SAC value with atmospheric aging

  6. Typical household vacuum cleaners: the collection efficiency and emissions characteristics for fine particles.

    Science.gov (United States)

    Lioy, P J; Wainman, T; Zhang, J; Goldsmith, S

    1999-02-01

    The issue of fine particle (PM2.5) exposures and their potential health effects is a focus of scientific research because of the recently promulgated National Ambient Air Quality Standard for PM2.5. Before final implementation, the health and exposure basis for the standard will be reviewed by the U.S. Environmental Protection Agency within the next five years. As part of this process, it is necessary to understand total particle exposure issues and to determine the relative importance of the origin of PM2.5 exposure in various micro-environments. The results presented in this study examine emissions of fine particles from a previously uncharacterized indoor source: the residential vacuum cleaner. Eleven standard vacuum cleaners were tested for the emission rate of fine particles by their individual motors and for their efficiency in collecting laboratory-generated fine particles. An aerosol generator was used to introduce fine potassium chloride (KCl) particles into the vacuum cleaner inlet for the collection efficiency tests. Measurements of the motor emissions, which include carbon, and the KCl aerosol were made using a continuous HIAC/Royco 5130 A light-scattering particle detector. All tests were conducted in a metal chamber specifically designed to completely contain the vacuum cleaner and operate it in a stationary position. For the tested vacuum cleaners, fine particle motor emissions ranged from 9.6 x 10(4) to 3.34 x 10(8) particles/min, which were estimated to be 0.028 to 176 micrograms/min for mass emissions, respectively. The vast majority of particles released were in the range of 0.3-0.5 micron in diameter. The lowest particle emission rate was obtained for a vacuum cleaner that had a high efficiency (HEPA) filter placed after the vacuum cleaner bag and the motor within a sealed exhaust system. This vacuum cleaner removed the KCl particles that escaped the vacuum cleaner bag and the particles emitted by the motor. Results obtained for the KCl

  7. ENHANCED CHARACTERIZATION OF AMBIENT FINE PARTICULATE MATTER THROUGH COMPLEMENTARY DATA INTEGRATION AND IMPROVED MEASUREMENT INSTRUMENTATION

    Science.gov (United States)

    Improvements in fine particle characterization will allow for a more complete understanding of the processes particle in the atmosphere undergo. The integration of complementary measurements into a compact mathematical form, allows for ease of transfer from particle measureme...

  8. Fluidization and Spouting of Fine Particles: A Comparison

    OpenAIRE

    Pranati Sahoo; Abanti Sahoo

    2013-01-01

    The fluidization characteristics of fine particles have been studied in both the fluidized bed and spouted bed. The effect of different system parameters (viz. static bed height, particle size, particle density and superficial velocity of the fluidizing medium, rotational speed of stirrer, and spout diameter) on the fluidization characteristics such as bed expansion/fluctuation ratios, bed pressure drop, minimum fluidizing/spouting velocity, and fluidization index of fine particles (around 60...

  9. Effect of particle fineness on the finely disseminated iron ore for beneficiation

    Science.gov (United States)

    Qiu, T. S.; Zhang, W. X.; Fang, X. H.; Gao, G. K.

    2013-06-01

    This paper focused on Oolitic hematite ore which consists of extremely unequal disseminated particles that are fine-grained and easy to become muddy, It presents the effect of particle fineness, roasting temperature and roasting time and other variables on the beneficiation of this ore. The effect of particle fineness on the concentrate quality was also studied after magnetic roasting, the so-called process of "magnetic roasting-stage grinding-low intensity magnetic separation-cationic reverse flotation" was adopted to treat the raw ore under various experimental conditions including particle fineness, roasting temperature and roasting time, etc. it is found the concentrate grade of TFe of raw ore can be increased from 48.32%(original) to 61.30% at a recovery rate of 80.73%. Results show that the effect of particle fineness on mineral processing indexes is significant.

  10. IN SITU FIELD PORTABLE FINE PARTICLE MEASURING DEVICE

    Science.gov (United States)

    The report describes the design, development, and testing of an in situ fine particle measuring device--the Fine Particle Stack Spectrometer System (FPSSS). It is a laser-fed optical system with detection by near-forward light scattering. Sample volume is established by a high-re...

  11. A Modelling Approach on Fine Particle Spatial Distribution for Street Canyons in Asian Residential Community

    Science.gov (United States)

    Ling, Hong; Lung, Shih-Chun Candice; Uhrner, Ulrich

    2016-04-01

    Rapidly increasing urban pollution poses severe health risks.Especially fine particles pollution is considered to be closely related to respiratory and cardiovascular disease. In this work, ambient fine particles are studied in street canyons of a typical Asian residential community using a computational fluid dynamics (CFD) dispersion modelling approach. The community is characterised by an artery road with a busy traffic flow of about 4000 light vehicles (mainly cars and motorcycles) per hour at rush hours, three streets with hundreds light vehicles per hour at rush hours and several small lanes with less traffic. The objective is to study the spatial distribution of the ambient fine particle concentrations within micro-environments, in order to assess fine particle exposure of the people living in the community. The GRAL modelling system is used to simulate and assess the emission and dispersion of the traffic-related fine particles within the community. Traffic emission factors and traffic situation is assigned using both field observation and local emissions inventory data. High resolution digital elevation data (DEM) and building height data are used to resolve the topographical features. Air quality monitoring and mobile monitoring within the community is used to validate the simulation results. By using this modelling approach, the dispersion of fine particles in street canyons is simulated; the impact of wind condition and street orientation are investigated; the contributions of car and motorcycle emissions are quantified respectively; the residents' exposure level of fine particles is assessed. The study is funded by "Taiwan Megacity Environmental Research (II)-chemistry and environmental impacts of boundary layer aerosols (Year 2-3) (103-2111-M-001-001-); Spatial variability and organic markers of aerosols (Year 3)(104-2111-M-001 -005 -)"

  12. Origin-Oriented Elemental Profile of Fine Ambient Particulate Matter in Central European Suburban Conditions

    Science.gov (United States)

    Rogula-Kozłowska, Wioletta; Majewski, Grzegorz; Błaszczak, Barbara; Klejnowski, Krzysztof; Rogula-Kopiec, Patrycja

    2016-01-01

    Twenty-four-hour samples of fine ambient particulate matter (PM2.5; particles with aerodynamic diameters ≤2.5 µm) were collected in a suburban (quasi-rural) area in Racibórz (Poland) between 1 January 2011 and 26 December 2012. The samples were analyzed for the contents of 28 elements. Sources of PM2.5 were identified and the contribution of each source to the PM2.5 concentration was assessed using an enrichment factor (EF) analysis, a principal component analysis (PCA), and multi-linear regression analysis (MLRA). In the cold season (January–March and October–December 2011–2012), the mean ambient concentration of PM2.5 in Racibórz was 48.7 ± 39.4 µg·m−3, which was much higher than at other suburban or rural sites in Europe. Additionally the ambient concentrations of some toxic PM2.5-bound elements were also high, i.e., the mean ambient concentrations of PM2.5-bound As, Cd, and Pb were 11.3 ± 11.5, 5.2 ± 2.5, and 34.0 ± 34.2 ng·m−3, respectively. In the warm season (April–September 2011–2012), the PM2.5 and PM2.5-bound element concentrations in Racibórz were comparable to the concentrations noted at other suburban (or rural) sites in Europe. Our findings suggest that elemental composition and concentrations of PM2.5 in Racibórz are mainly influenced by anthropogenic emissions, i.e., the energy production based on coal and biomass combustion, traffic, and industry. PMID:27428988

  13. EDITORIAL: Cluster issue on fine particle magnetism

    Science.gov (United States)

    Fiorani, D.

    2008-07-01

    This Cluster issue of Journal of Physics D: Applied Physics arises from the 6th International Conference on Fine Particle Magnetism (ICFPM) held in Rome during 9-12 October 2007 at the headquarters of the National Research Council (NCR). It contains a collection of papers based on both invited and contributed presentations at the meeting. The ICFPM Conferences have previously been held in Rome, Italy (1991), Bangor, UK (1996), Barcelona, Spain (1999), Pittsburgh, USA (2002) and London, UK (2004). The aim of this series of Conferences is to bring together the experts in the field of nanoparticle magnetism at a single forum to discuss recent developments in both theoretical and experimental aspects, and technological applications. The Conference programme included sessions on: new materials, novel synthesis and processing techniques, with special emphasis on self-organized magnetic arrays; theory and modelling; surface and interface properties; transport properties; spin dynamics; magnetization reversal mechanisms; magnetic recording media and permanent magnets; biomedical applications and advanced investigation techniques. I would like to thank the European Physical Society and the Innovative Magnetic and Superconducting Materials and Devices Project of the Materials and Devices Department and the Institute of Structure of Matter (ISM) of CNR for their support. Thanks are also due to the members of the Programme Committee, to the local Organizing Committee, chaired by Elisabetta Agostinelli and to all the Conference participants. I am also indebted to the many scientists who contributed to assuring the high-quality of this Cluster by donating their time to reviewing the manuscripts contained herein. Finally, I'd like to dedicate this issue to the memories of Jean Louis Dormann, a great expert in nanoparticle magnetism, who was one of the promoters and first organizers of this series of Conferences, and of Grazia Ianni, the Conference secretary, who died before her

  14. Fine particle concentrations in buses and taxis in Florence, Italy

    Science.gov (United States)

    Fondelli, M. Cristina; Chellini, Elisabetta; Yli-Tuomi, Tarja; Cenni, Isabella; Gasparrini, Antonio; Nava, Silvia; Garcia-Orellana, Isabel; Lupi, Andrea; Grechi, Daniele; Mallone, Sandra; Jantunen, Matti

    On October 2004, a sampling survey was carried out in Florence to estimate urban fine particle exposure concentrations inside commuting vehicles during workdays characterized by heavy traffic. Portable samplers were positioned inside four regularly scheduled diesel-powered buses and four taxis during eight weekdays. Each sampler consisted of a 2.5 μm size pre-separator cyclone, a direct-reading data logging photometer (pDR-1200), and a 4 L min -1 filter sampler for the determination of PM 2.5 mass concentration. Based on reflectance analysis measurements, a PM 2.5 Black Smoke Index was determined for each filter, and the elemental composition of the PM 2.5 was analyzed by Particle Induced X-ray Emission (PIXE). PM 2.5 mass concentrations inside the vehicles correlated well with the urban ambient air PM 2.5 concentrations measured at the fixed-site monitoring stations. The PM 2.5 excess above the urban ambient level was on average 32 μg m -3 (range: 22-52 μg m -3) and 20 μg m -3 (range: 11-29 μg m -3) in buses and taxis, respectively. The PM 2.5-bound sulfur concentration was also higher in the buses than in the taxis. Based on daily Time-Microenvironment-Activity-Diary (TMAD) data, the Florentines spend on average 9.7% of their day in traffic, and the corresponding average exposure is approximately 12% of their daily PM 2.5 personal exposure. The obtained data could be used to plan interventions to minimize the PM 2.5 citizen exposures in commuting.

  15. Fine Particle Matter (PM2.5) Design Value

    Data.gov (United States)

    U.S. Environmental Protection Agency — Fine particulate matter or PM2.5 (total mass of particles below 2.5 micron is diameter) is known to cause adverse health effects in humans.See the following...

  16. Simple model for fine particle (dust) clouds in plasmas

    Science.gov (United States)

    Totsuji, Hiroo

    2016-04-01

    In the cloud of fine particles (dusts) in plasmas, the charge neutrality can be much enhanced due to large charge numbers of fine particles. The required condition is not difficult to satisfy even when their charge density is substantially smaller than electrons or ions. Based on this fact, a simple model of fine particle clouds is proposed and the cloud radius is related to the half-width, the radius where the density of surrounding plasmas drops by half, in cylindrically and spherically symmetric cases under microgravity. When fine particles are gradually introduced with parameters of surrounding plasma especially the half-width being fixed, the size of clouds first increases and then saturates at the value determined by the plasma half-width, giving a possibility to control the size and density of clouds independently.

  17. The 2005 Study of Organic Aerosols at Riverside (SOAR-1): instrumental intercomparisons and fine particle composition

    OpenAIRE

    K. S. Docherty; A. C. Aiken; Huffman, J. A.; Ulbrich, I.M.; Decarlo, P. F.; D. Sueper; Worsnop, D. R.; Snyder, D. C.; Grover, B. D.; Eatough, D. J.; A. H. Goldstein; P. J. Ziemann; Jimenez, J. L.

    2011-01-01

    Multiple state-of-the-art instruments sampled ambient aerosol in Riverside, California during the 2005 Study of Organic Aerosols at Riverside (SOAR) to investigate sources and chemical composition of fine particles (PMf) in the inland region of Southern California. This paper briefly summarizes the spatial, meteorological and gas-phase conditions during SOAR-1 (15 July–15 August) and provides detailed intercomparisons of complementary measurements and average PM

  18. Characteristics of the fine particles generated in plasma process

    Energy Technology Data Exchange (ETDEWEB)

    Yamamoto, A.; Matsubayashi, K.; Susuki, M. [Tokyo Institute of Technology, Graduate School of Science and Engineering (Japan)

    2001-07-01

    Modeling of fine particles generation in plasma process under an atmospheric pressure is investigated. Our model consists of two physical phenomena, evaporation of metal and particle growth, were studied with computer simulation. Evaporation phenomenon is simulated by lattice Boltzmann method and evaporation rate of iron is estimated. Particle growth is simulated by using general dynamic equation. Agglomerate consisting of primary particles which is taken size distribution into account is represented by fractal dimension connecting number density of primary particles. Particle size and particle size distribution at various temperatures are obtained and discussed. (authors)

  19. 上海市两社区大气细颗粒物的污染状况%Status of Ambient Air Pollution of Fine Particle Matters at Two Communities in Shanghai

    Institute of Scientific and Technical Information of China (English)

    张莉君; 东春阳; 许慧慧; 施烨闻; 金奇昂; 刘立平; 沈先标

    2011-01-01

    [目的]了解上海市社区大气细颗粒物(PM2.5)的污染状况.[方法]于2008年1月至2009年12月在上海市大气污染程度不同的2个社区(A社区为中心城区、B社区位于郊区)设置监测点,每月10~16日连续监测PM2.5浓度,数据采集后采用Wilcoxon秩和检验进行统计分析.[结果]B社区的PM2.5浓度在4、6月份均高于A社区,差异有统计学意义(P第一阶段目标相比,除A社区2009年未超标外,两社区其余年份均超标.[结论]两社区PM2.5污染呈冬季严重,夏秋季减轻的特点,B社区PM2.5的污染问题较A社区严重,两社区的PM2.5的污染水平与美国EPA标准和WHO第一阶段目标相比均存在超标问题.%[Objective]To understand the situation of fine air particle matters (PM2.5) pollution at two communities in Shanghai.[Methods]From 2008 to 2009, air samples were collected at fixed sites in two communities (A district was a resident area and B district adjacent the industry area) for monitoring the PM2.5 concentration with membrane gravimetric method every month.Air samples were continuously collected for 7 d each time in order to calculating daily average concentration.Data were analyzed with Wilcoxon rank sum test in SPSS 11.5 software, and adopted median (M) and central quadruplets (P25 to P75) in presence.[Results]The monthly PM2.5 level in site B was higher than that in site A, the differences were significant in April and June (P < 0.05).The pollution was most serious in winter but least in summer and autumn.The quaternary level of PM2.5 in site B was higher significantly than that in site A in summer (P<0.01).In 2009, the PM2.5 level in site B was higher significantly than that in site A (P<0.001).The concentration values of PM2.5 in two sites were all beyo nd the Air Quality Planning and Standard of U.S Environmental Protection Agency (U.S.EPA) from 2008 to 2009.The exceeded proportions of PM2.5 concentration in site A were 54.76% and 35.71%, and the

  20. Particle formation in ambient MALDI plumes.

    Science.gov (United States)

    Musapelo, Thabiso; Murray, Kermit K

    2011-09-01

    The ablated particle count and size distribution of four solid matrix materials commonly used for matrix-assisted laser desorption ionization (MALDI) were measured with a scanning mobility particle sizer (SMPS) combined with a light scattering aerodynamic particle sizer (APS). The two particle sizing instruments allowed size measurements in the range from 10 nm to 20 μm. The four solid matrixes investigated were 2,5-dihydroxybenzoic acid (DHB), 4-nitroaniline (NA), α-cyano-4-hydroxycinnamic acid (CHCA), and sinapic acid (SA). A thin film of the matrix was deposited on a stainless steel target using the dried droplet method and was irradiated with a 337 nm nitrogen laser at atmospheric pressure. The target was rotated during the measurement. A large number of nanoparticles were produced, and average particle diameters ranged from 40 to 170 nm depending on the matrix and the laser fluence. These particles are attributed to agglomeration of smaller particles and clusters and/or hydrodynamic sputtering of melted matrix. A coarse particle component of the distribution was observed with diameters between 500 nm and 2 μm. The coarse particles were significantly lower in number but had a total mass that was comparable to that of the nanoparticles. The coarse particles are attributed to matrix melting and spallation. Two of the compounds, CHCA and SA, had a third particle size distribution component in the range of 10 to 30 nm, which is attributed to the direct ejection of clusters. PMID:21797202

  1. Detecting the ambient neutralino dark matter particles at accelerator

    OpenAIRE

    Feng, Tai-Fu; Li, Xue-Qian; Ma, Wen-Gan; Wang, Jian-Xiong; Zhao, Gong-bo

    2006-01-01

    In this work, we present a new strategy to investigate the possibility of direct detection of the ambient neutralino matter at accelerator. We calculate the cross sections for both elastic and inelastic scattering processes of the dark matter particles with the beam particles at $e^+e^-$ and hadron colliders.

  2. Glassy behavior in magnetic fine particles

    CERN Document Server

    Muro, M G D; Labarta, A

    2000-01-01

    A detailed study of the static and dynamic magnetic properties of nanocrystalline barium hexaferrite powder was done. Particles of about 10 nm diameter exhibit the main features attributed to glassy behavior. Different results make evident the presence of strong interactions in the studied system. This glassy state is mostly attributed to the frustration induced by magnetic interactions between randomly distributed particles, although the surface spins contribution cannot be discarded. The effective energy barrier distribution obtained from the analysis of the time dependence of the thermoremanence in terms of the T ln (t/tau sub 0) scaling shows a maximum located at energies higher than the mean anisotropy energy barrier. When doing the relaxation experiments after field cooling at increasing fields, the obtained effective energy distribution progressively resembles the anisotropy energy distribution. Therefore, we demonstrate how the glassy state can be erased by applying a magnetic field.

  3. Pressure characteristics of a hydrocyclone for fine particle separation

    Institute of Scientific and Technical Information of China (English)

    ZHAO Li-xin; JIANG Ming-hu; SUN De-zhi; BELAIDI A; THEW M

    2006-01-01

    Solid-liquid hydrocyclones are mainly used to separate large particles, such as the particles of drilling fluid in petroleum industry, and large mineral particles. Till now the hydrocyclonic separation for fine particles is still a big problem. Basic separation principle of hydrocyclones and experimental research facility are simply introduced. The difficulty of separating fine particle is analyzed. Based on a solid-liquid hydrocyclone used for separating fine particles, relationships of dimensionless pressure characteristic parameters, i.e. Euler number and pressure drop ratio, with several main dimensionless parameters, such as split ratio, swirl number and gas-liquid ratio, were experimentally studied in detail. The research was carried out by using the hydrocyclonic separation experimental rig at the University of Bradford. It is shown that the less the size of particle, the less the value of radius of the balance orbit occupied by the particle, and then the more difficult for the particle to be separated. Experiments indicate that Euler number of the tested hydrocyclone increases with the rise of Reynolds number, split ratio, swirl number and gas-liquid ratio respectively, and the pressure drop ratio falls with the increase of Reynolds number, split ratio and swirl number respectively. It is concluded that the most effective way to decrease the unit energy dissipation of hydrocyclone is to reduce swirl number or gas-liquid ratio of the mixed media.

  4. Fluidization and Spouting of Fine Particles: A Comparison

    Directory of Open Access Journals (Sweden)

    Pranati Sahoo

    2013-01-01

    Full Text Available The fluidization characteristics of fine particles have been studied in both the fluidized bed and spouted bed. The effect of different system parameters (viz. static bed height, particle size, particle density and superficial velocity of the fluidizing medium, rotational speed of stirrer, and spout diameter on the fluidization characteristics such as bed expansion/fluctuation ratios, bed pressure drop, minimum fluidizing/spouting velocity, and fluidization index of fine particles (around 60 micron particle size have been analyzed. A stirrer/rod promoter has been used in the bed to improve the bed fluidity for fluidization process and spout diameter has been varied for spouted bed. Mathematical expressions for these bed dynamics have been developed on the basis of dimensionless analysis. Finally calculated values of these bed dynamics are compared with the experimentally observed values thereby indicating the successful applications of these developed correlations over a wide range of parameters.

  5. Particle dispersion and fine scale eddies in wall turbulence

    International Nuclear Information System (INIS)

    To investigate a relation between fine scale eddies and particle dispersion in a near-wall turbulence, direct numerical simulations of turbulent channel flow laden particle are performed for Reτ=180. The motions of 0.8 million particles are calculated for several particle response times (tp) which is the particle response time based on stokes' friction law. The number density of particles has a tendency to increase with approaching the near-wall regions (y+p=0.02 and 15). Near the wall, the behavior and distribution of particles are deeply associated with the fine scale eddies, and are dependent on particle response times and a distance from the wall. The Stokes number that causes preferential distribution in turbulence is changed by a distance from the wall. The influential Stokes number based on the Burgers' vortex model is derived by using the time scale of the fine scale eddies. The influential Stokes number is also dependent on a distance from the wall and shows large value in the buffer layer

  6. Autonomous patterning of cells on microstructured fine particles

    Energy Technology Data Exchange (ETDEWEB)

    Takeda, Iwori, E-mail: takeda-iwori@ed.tmu.ac.jp; Kawanabe, Masato, E-mail: kawanabe-masato@ed.tmu.ac.jp; Kaneko, Arata, E-mail: kaneko-arata@tmu.ac.jp

    2015-05-01

    Regularly patterned cells can clarify cellular function and are required in some biochip applications. This study examines cell patterning along microstructures and the effect of microstructural geometry on selective cellular adhesion. Particles can be autonomously assembled on a soda-lime glass substrate that is chemically patterned by immersion in a suspension of fine particles. By adopting various sizes of fine particles, we can control the geometry of the microstructure. Cells adhere more readily to microstructured fine particles than to flat glass substrate. Silica particles hexagonally packed in 5–40 μm line and space microstructures provide an effective cell scaffold on the glass substrate. Cultured cells tend to attach and proliferate along the microstructured region while avoiding the flat region. The difference in cell adhesion is attributed to their geometries, as both of the silica particles and soda-lime glass are hydrophilic related with cell adhesiveness. After cell seeding, cells adhered to the flat region migrated toward the microstructured region. For most of the cells to assemble on the scaffold, the scaffolding microstructures must be spaced by at most 65 μm. - Highlights: • PS and SiO{sub 2} particles provide effective scaffolds for cells. • Cells that adhere to microstructured particles successfully proliferate and differentiate. • Selective adhesion and growth along the scaffold can be achieved by patterning the fine particle microstructure. • Cells adhered to flat regions migrate toward microstructured regions. • Selective adhesion by cells depends on the microstructural geometry; specifically, on the inter-line spacing.

  7. Deposition of fine and ultrafine particles on indoor surface materials

    DEFF Research Database (Denmark)

    Afshari, Alireza; Reinhold, Claus

    2008-01-01

    -scale test chamber. Experiments took place in a 32 m3 chamber with walls and ceiling made of glass. Prior to each experiment the chamber was flushed with outdoor air to reach an initial particle concentration typical of indoor air in buildings with natural ventilation. The decay of particle concentrations...... The aim of this study was the experimental determination of particle deposition for both different particle size fractions and different indoor surface materials. The selected surface materials were glass, gypsum board, carpet, and curtain. These materials were tested vertically in a full...... was monitored. Seven particle size fractions were studied. These comprised ultrafine and fine particles. Deposition was higher on carpet and curtain than on glass and gypsum board. Particles ranging from 0.3 to 0.5 µm had the lowest deposition. This fraction also has the highest penetration and its...

  8. Erosion control reduces fine particles in runoff to Lake Tahoe

    OpenAIRE

    Mark E. Grismer; Ellis, A. L.

    2006-01-01

    Sediment in hillslope runoff from disturbed soils in the Lake Tahoe Basin is the source of many fine suspended particles that transport nutrients and contribute to a loss in lake clarity. In previous studies, we used rainfall simulation to assess and quantify infiltration, runoff and erosion rates from hillslope soils. Building on this research, our current study evaluates the relationship between particle sizes in runoff sediments and slope, and compares the relationships between restored so...

  9. Modeling of Fine-Particle Formation in Turbulent Flames

    Science.gov (United States)

    Raman, Venkat; Fox, Rodney O.

    2016-01-01

    The generation of nanostructured particles in high-temperature flames is important both for the control of emissions from combustion devices and for the synthesis of high-value chemicals for a variety of applications. The physiochemical processes that lead to the production of fine particles in turbulent flames are highly sensitive to the flow physics and, in particular, the history of thermochemical compositions and turbulent features they encounter. Consequently, it is possible to change the characteristic size, structure, composition, and yield of the fine particles by altering the flow configuration. This review describes the complex multiscale interactions among turbulent fluid flow, gas-phase chemical reactions, and solid-phase particle evolution. The focus is on modeling the generation of soot particles, an unwanted pollutant from automobile and aircraft engines, as well as metal oxides, a class of high-value chemicals sought for specialized applications, including emissions control. Issues arising due to the numerical methods used to approximate the particle number density function, the modeling of turbulence-chemistry interactions, and model validation are also discussed.

  10. Sources of mutagenic activity in urban fine particles

    International Nuclear Information System (INIS)

    Samples were collected during the winter of 1984-1985 in the cities of Albuquerque, New Mexico and Raleigh, North Carolina as part of a US Environmental Agency study to evaluate methods to determine the emission sources contributing to the mutagenic properties of extractable organic matter (EOM) present in fine particles. Data derived from the analysis of the composition of these fine particles served as input to a multi-linear regression (MLR) model used to calculate the relative contribution of wood burning and motor vehicle sources to mutagenic activity observed in the extractable organic matter. At both sites the mutagenic potency of EOM was found to be greater (3-5 times) for mobile sources when compared to wood smoke extractable organics. Carbon-14 measurements which give a direct determination of the amount of EOM that originated from wood burning were in close agreement with the source apportionment results derived from the MLR model

  11. Sources of mutagenic activity in urban fine particles

    International Nuclear Information System (INIS)

    Samples were collected during the winter of 1984-1985 in the cities of Albuquerque, NM and Raleigh NC as part of a US Environmental Protection Agency study to evaluate methods to determine the emission sources contributing to the mutagenic properties of extractable organic matter (EOM) present in fine particles. Data derived from the analysis of the composition of these fine particles served as input to a multi-linear regression (MLR) model used to calculate the relative contribution of wood burning and motor vehicle sources to mutagenic activity observed in the extractable organic matter. At both sites the mutagenic potency of EOM was found to be greater (3-5 times) for mobile sources when compared to wood smoke extractable organics. Carbon-14 measurements which give a direct determination of the amount of EOM that originated from wood burning were in close agreement with the source apportionment results derived from the MLR model

  12. Concentrated ambient air particles induce vasoconstriction of small pulmonary arteries in rats.

    Science.gov (United States)

    Batalha, Joao R F; Saldiva, Paulo H N; Clarke, Robert W; Coull, Brent A; Stearns, Rebecca C; Lawrence, Joy; Murthy, G G Krishna; Koutrakis, Petros; Godleski, John J

    2002-01-01

    The objective of this study was to determine whether short-term exposures to concentrated ambient particles (CAPs) alter the morphology of small pulmonary arteries in normal rats and rats with chronic bronchitis (CB). Sprague-Dawley male rats were exposed to CAPs, using the Harvard Ambient Particle Concentrator, or to particle-free air (sham) under identical conditions during 3 consecutive days (5 hr/day) in six experimental sets. CB was induced by exposure to 276 +/- 9 ppm of sulfur dioxide (5 hr/day, 5 days/week, 6 weeks). Physicochemical characterization of CAPs included measurements of particle mass, size distribution, and composition. Rats were sacrificed 24 hr after the last CAPs exposure. Histologic slides were prepared from random sections of lung lobes and coded for blinded analysis. The lumen/wall area (L/W) ratio was determined morphometrically on transverse sections of small pulmonary arteries. When all animal data (normal and CB) were analyzed together, the L/W ratios decreased as concentrations of fine particle mass, silicon, lead, sulfate, elemental carbon, and organic carbon increased. In separate univariate analyses of animal data, the association for sulfate was significant only in normal rats, whereas silicon was significantly associated in both CB and normal rats. In multivariate analyses including all particle factors, the association with silicon remained significant. Our results indicate that short-term CAPs exposures (median, 182.75 micro g/m3; range, 73.50-733.00 micro g/m3) can induce vasoconstriction of small pulmonary arteries in normal and CB rats. This effect was correlated with specific particle components and suggests that the pulmonary vasculature might be an important target for ambient air particle toxicity. PMID:12460797

  13. Source appointment of fine particle number and volume concentration during severe haze pollution in Beijing in January 2013.

    Science.gov (United States)

    Liu, Zirui; Wang, Yuesi; Hu, Bo; Ji, Dongsheng; Zhang, Junke; Wu, Fangkun; Wan, Xin; Wang, Yonghong

    2016-04-01

    Extreme haze episodes repeatedly shrouded Beijing during the winter of 2012-2013, causing major environmental and health problems. To better understand these extreme events, particle number size distribution (PNSD) and particle chemical composition (PCC) data collected in an intensive winter campaign in an urban site of Beijing were used to investigate the sources of ambient fine particles. Positive matrix factorization (PMF) analysis resolved a total of eight factors: two traffic factors, combustion factors, secondary aerosol, two accumulation mode aerosol factors, road dust, and long-range transported (LRT) dust. Traffic emissions (54 %) and combustion aerosol (27 %) were found to be the most important sources for particle number concentration, whereas combustion aerosol (33 %) and accumulation mode aerosol (37 %) dominated particle volume concentrations. Chemical compositions and sources of fine particles changed dynamically in the haze episodes. An enhanced role of secondary inorganic species was observed in the formation of haze pollution. Regional transport played an important role for high particles, contribution of which was on average up to 24-49 % during the haze episodes. Secondary aerosols from urban background presented the largest contributions (45 %) for the rapid increase of fine particles in the severest haze episode. In addition, the invasion of LRT dust aerosols further elevated the fine particles during the extreme haze episode. Our results showed a clear impact of regional transport on the local air pollution, suggesting the importance of regional-scale emission control measures in the local air quality management of Beijing. PMID:26667647

  14. Characterization of ultrafine and fine particles from CHP Plants

    Energy Technology Data Exchange (ETDEWEB)

    2009-08-15

    Samples of particles collected at CHP plants in the project 'Survey of emissions from CHP Plants' have been analysed in this project to give information on the morphology and chemical composition of individual particle size classes. The objective of this project was to characterize ultrafine and fine particles emitted to the atmosphere from Danish CHP plants. Nine CHP plants were selected in the Emission Survey Project as being representative for the different types of CHP plants operating in Denmark: 1) Three Waste-to Energy (WTE) plants. 2) Three biomass fired (BM) plants (two straw fired, one wood/saw dust fired). 3) Two gas fired (GF) plants (one natural gas, one landfill gas fired). 4) One gasoil (GO) fired plant. At the WTE and BM plants, various types of emission control systems implemented. The results from these plants represent the composition and size distribution of combustion particles that are emitted from the plants emission control systems. The measured emissions of particles from the waste-to-energy plants WTE1-3 are generally very low. The number and mass concentrations of ultrafine particles (PM{sub 0.1}) were particularly low in the flue gas from WTE2 and WTE3, where bag filters are used for the reduction of particle emissions. The EDX analysis of particles from the WTE plants indicates that the PM{sub 0.1} that penetrates the ECS at WTE can contain high fractions of metals such as Fe, Mn and Cu. The SEM analysis of particles from WTE1-3 showed that the particles were generally porous and irregular in shape. The concentrations of particles in the flue gas from the biomass plants were generally higher than found for the WTE plants. The time series results showed that periodical, high concentration peaks of PM emissions occur from BM1 and BM2. The chemical composition of the particles emitted from the three biomass plants is generally dominated by C, O and S, and to some extend also Fe and Si. A high amount of Cu was found in selected

  15. Production of hydroxyl radicals from Fe-containing fine particles in Guangzhou, China

    Science.gov (United States)

    Ma, Shexia; Ren, Ke; Liu, Xiaowen; Chen, Laiguo; Li, Mei; Li, Xiaoying; Yang, Jian; Huang, Bo; Zheng, Mei; Xu, Zhencheng

    2015-12-01

    Reactive oxygen species (ROS) production from ambient fine particles has been correlated with the soluble transition metal content of PM2.5, which also has clear association with particle-mediated cardiopulmonary toxicity. Hydroxyl radical (rad OH) is the most harmful ROS species through chemical reactions of redox-active particle components. Atmospheric Fe, as the dominant species of the transition metals in the atmosphere, is associated with rad OH generation in ambient particle extracts. Our results revealed that Fe-containing particles (18,730 in total number) contributed approximately 3.7% on average to all detected particles throughout the summer and winter sampling period in Guangzhou, which was clustered into four distinct particle classes, including Fe-rich, Metal-rich, NaK-rich and Dust-rich. Fe-rich class was the dominant one with a fraction of 61%, followed by Dust-rich (14%), Metal-rich (13%). and NaK-rich (12%). The iron oxide was enriched in the Fe-rich class. rad OH generation induced by Fe-containing fine particles collected in Guangzhou (GZ) was quantified in a surrogate lung fluid (SLF), and it was found that Fe-containing fine particles were generally much reactive in generating rad OH in the presence of four antioxidants (200 μM ascorbate, 300 μM citrate, 100 μM reduced L-glutathione, and 100 μM uric acid). The annual average rad OH amount produced in our samples was 132.98 ± 27.43 nmol rad OH mg-1 PM2.5. rad OH production had a clear seasonal pattern with higher amount in summer and lower in winter. By measuring the amount of total and SLF-soluble metal in our PM2.5 samples using ICP-MS, we found that ROS activities were associated with the ionizable Fe through Fenton type reactions in the Guangzhou PM2.5. Expected burdens of PM2.5 derived rad OH in human lung lining fluid suggests that typical daily particulate matter exposure in Guangzhou is already a concern, and it could produce much higher levels of rad OH, leading to higher

  16. Thermodynamic instability and the critical point of fine particle (dusty) plasmas: enhancement of density fluctuations and experimental conditions for observation

    Energy Technology Data Exchange (ETDEWEB)

    Totsuji, Hiroo [Graduate School of Natural Science and Technology and Faculty of Engineering, Okayama University, Tsushimanaka 3-1-1, Okayama 700-8530 (Japan)], E-mail: totsuji@elec.okayama-u.ac.jp

    2009-05-29

    We analyze thermodynamics of fine particle (dusty) plasmas, regarding them as systems composed of charged particles with hard cores interacting via the repulsive Yukawa potential and the ambient plasma (of ions and electrons), taking the contribution of the latter properly into account. When the Coulomb coupling between fine particles becomes sufficiently strong, the isothermal compressibility of the whole system diverges and we have a phase separation and an associated critical point. The enhancement of long-wavelength density fluctuations near the critical point is shown. Experimental conditions of fine particle plasmas, densities and temperatures of components and the fine particle size are obtained corresponding to characteristic parameters around the critical point and the dependence on ion species and other factors is discussed. These phenomena will be observed in the bulk three-dimensional system which may be realized on the ground by somehow canceling the effect of gravity on fine particles. Experiments under the microgravity environment are naturally expected to provide a chance of observation.

  17. Fullerene fine particles adhere to pollen grains and affect their autofluorescence and germination.

    Science.gov (United States)

    Aoyagi, Hideki; Ugwu, Charles U

    2011-01-01

    Adhesion of commercially produced fullerene fine particles to Cryptomeria japonica, Chamaecyparis obtusa and Camellia japonica pollen grains was investigated. The autofluorescence of pollen grains was affected by the adhesion of fullerene fine particles to the pollen grains. The degree of adhesion of fullerene fine particles to the pollen grains varied depending on the type of fullerene. Furthermore, germination of Camellia japonica pollen grains was inhibited by the adhesion of fullerene fine particles. PMID:24198486

  18. Controlled human exposures to ambient pollutant particles in susceptible populations

    Directory of Open Access Journals (Sweden)

    Ghio Andrew J

    2009-07-01

    Full Text Available Abstract Epidemiologic studies have established an association between exposures to air pollution particles and human mortality and morbidity at concentrations of particles currently found in major metropolitan areas. The adverse effects of pollution particles are most prominent in susceptible subjects, including the elderly and patients with cardiopulmonary diseases. Controlled human exposure studies have been used to confirm the causal relationship between pollution particle exposure and adverse health effects. Earlier studies enrolled mostly young healthy subjects and have largely confirmed the capability of particles to cause adverse health effects shown in epidemiological studies. In the last few years, more studies involving susceptible populations have been published. These recent studies in susceptible populations, however, have shown that the adverse responses to particles appear diminished in these susceptible subjects compared to those in healthy subjects. The present paper reviewed and compared control human exposure studies to particles and sought to explain the "unexpected" response to particle exposure in these susceptible populations and make recommendations for future studies. We found that the causes for the discrepant results are likely multifactorial. Factors such as medications, the disease itself, genetic susceptibility, subject selection bias that is intrinsic to many controlled exposure studies and nonspecificity of study endpoints may explain part of the results. Future controlled exposure studies should select endpoints that are more closely related to the pathogenesis of the disease and reflect the severity of particle-induced health effects in the specific populations under investigation. Future studies should also attempt to control for medications and genetic susceptibility. Using a different study design, such as exposing subjects to filtered air and ambient levels of particles, and assessing the improvement in

  19. Preparation of cefpodoxime proxetil fine particles using supercritical fluids.

    Science.gov (United States)

    Chu, Junho; Li, Guanghua; Row, Kyung Ho; Kim, Hwayong; Lee, Youn-Woo

    2009-03-18

    Fine particles of cefpodoxime proxetil (CPD) were prepared using an Aerosol Solvent Extraction System (ASES) with supercritical CO(2). The resulting primary particles were approximately 0.1-0.2microm in size and were almost spherical in shape. The secondary particles were approximately 0.2-0.6microm in size and had irregular shapes. The larger particle size and irregular shapes were due to the agglomeration of the primary particles. The effects of solvent type, CO(2)-to-CPD solution weight ratio, and CPD solution concentration on the extent of agglomeration were investigated. As a result, the use of ethyl acetate and acetone as solvents also reduced the degree of agglomeration. The degree of agglomeration was reduced with the use of a high CO(2)-to-solution weight ratio, and a low solution concentration. In particular, spherical particles, approximately 0.1-0.4microm in size, were obtained when a 10.0wt% CPD solution was used. As a result of dissolution study, almost 90% of the processed CPD had dissolved within 10min. The recovery yield of the CPD powder reached approximately 80% using a membrane filter. PMID:19041383

  20. Fullerene fine particles adhere to pollen grains and affect their autofluorescence and germination

    Directory of Open Access Journals (Sweden)

    Aoyagi H

    2011-05-01

    Full Text Available Hideki Aoyagi, Charles U UgwuLife Science and Bioengineering, Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, JapanAbstract: Adhesion of commercially produced fullerene fine particles to Cryptomeria japonica, Chamaecyparis obtusa and Camellia japonica pollen grains was investigated. The autofluorescence of pollen grains was affected by the adhesion of fullerene fine particles to the pollen grains. The degree of adhesion of fullerene fine particles to the pollen grains varied depending on the type of fullerene. Furthermore, germination of Camellia japonica pollen grains was inhibited by the adhesion of fullerene fine particles.Keywords: Cryptomeria japonica, Chamaecyparis obtusa, Camellia japonica, autofluorescence, pollen grains, fullerene fine particle

  1. Cardiopulmonary Toxicity Induced by Ambient Particulate Matter (BI City Concentrated Ambient Particle Study)

    Energy Technology Data Exchange (ETDEWEB)

    Annette Rohr; James Wagner Masako Morishita; Gerald Keeler; Jack Harkema

    2010-06-30

    Alterations in heart rate variability (HRV) have been reported in rodents exposed to concentrated ambient particles (CAPs) from different regions of the United States. The goal of this study was to compare alterations in cardiac function induced by CAPs in two distinct regional atmospheres. AirCARE 1, a mobile laboratory with an EPA/Harvard fine particle (particulate matter <2.5 {micro}m; PM{sub 2.5}) concentrator was located in urban Detroit, MI, where the PM mixture is heavily influenced by motor vehicles, and in Steubenville, OH, where PM is derived primarily from long-range transport and transformation of power plant emissions, as well as from local industrial operations. Each city was studied during both winter and summer months, for a total of four sampling periods. Spontaneously hypertensive rats instrumented for electrocardiogram (ECG) telemetry were exposed to CAPs 8 h/day for 13 consecutive days during each sampling period. Heart rate (HR), and indices of HRV (standard deviation of the average normal-to-normal intervals [SDNN]; square root of the mean squared difference of successive normal-to-normal intervals [rMSSD]), were calculated for 30-minute intervals during exposures. A large suite of PM components, including nitrate, sulfate, elemental and organic carbon, and trace elements, were monitored in CAPs and ambient air. In addition, a unique sampler, the Semi-Continuous Elements in Air Sampler (SEAS) was employed to obtain every-30-minute measurements of trace elements. Positive matrix factorization (PMF) methods were applied to estimate source contributions to PM{sub 2.5}. Mixed modeling techniques were employed to determine associations between pollutants/CAPs components and HR and HRV metrics. Mean CAPs concentrations in Detroit were 518 and 357 {micro}g/m{sup 3} (summer and winter, respectively) and 487 and 252 {micro}g/m{sup 3} in Steubenville. In Detroit, significant reductions in SDNN were observed in the summer in association with cement

  2. Cardiopulmonary Toxicity Induced by Ambient Particulate Matter (BI City Concentrated Ambient Particle Study)

    Energy Technology Data Exchange (ETDEWEB)

    Annette Rohr; James Wagner Masako Morishita; Gerald Keeler; Jack Harkema

    2010-06-30

    Alterations in heart rate variability (HRV) have been reported in rodents exposed to concentrated ambient particles (CAPs) from different regions of the United States. The goal of this study was to compare alterations in cardiac function induced by CAPs in two distinct regional atmospheres. AirCARE 1, a mobile laboratory with an EPA/Harvard fine particle (particulate matter <2.5 {micro}m; PM{sub 2.5}) concentrator was located in urban Detroit, MI, where the PM mixture is heavily influenced by motor vehicles, and in Steubenville, OH, where PM is derived primarily from long-range transport and transformation of power plant emissions, as well as from local industrial operations. Each city was studied during both winter and summer months, for a total of four sampling periods. Spontaneously hypertensive rats instrumented for electrocardiogram (ECG) telemetry were exposed to CAPs 8 h/day for 13 consecutive days during each sampling period. Heart rate (HR), and indices of HRV (standard deviation of the average normal-to-normal intervals [SDNN]; square root of the mean squared difference of successive normal-to-normal intervals [rMSSD]), were calculated for 30-minute intervals during exposures. A large suite of PM components, including nitrate, sulfate, elemental and organic carbon, and trace elements, were monitored in CAPs and ambient air. In addition, a unique sampler, the Semi-Continuous Elements in Air Sampler (SEAS) was employed to obtain every-30-minute measurements of trace elements. Positive matrix factorization (PMF) methods were applied to estimate source contributions to PM{sub 2.5}. Mixed modeling techniques were employed to determine associations between pollutants/CAPs components and HR and HRV metrics. Mean CAPs concentrations in Detroit were 518 and 357 {micro}g/m{sup 3} (summer and winter, respectively) and 487 and 252 {micro}g/m{sup 3} in Steubenville. In Detroit, significant reductions in SDNN were observed in the summer in association with cement

  3. Deviation from the superparamagnetic behaviour of fine-particle systems

    CERN Document Server

    Malaescu, I

    2000-01-01

    Studies concerning superparamagnetic behaviour of fine magnetic particle systems were performed using static and radiofrequency measurements, in the range 1-60 MHz. The samples were: a ferrofluid with magnetite particles dispersed in kerosene (sample A), magnetite powder (sample B) and the same magnetite powder dispersed in a polymer (sample C). Radiofrequency measurements indicated a maximum in the imaginary part of the complex magnetic susceptibility, for each of the samples, at frequencies with the magnitude order of tens of MHz, the origin of which was assigned to Neel-type relaxation processes. The static measurements showed a Langevin-type dependence of magnetisation M and of susceptibility chi, on the magnetic field for sample A. For samples B and C deviations from this type of dependence were found. These deviations were analysed qualitatively and explained in terms of the interparticle interactions, dispersion medium influence and surface effects.

  4. Identification of persons with cardiorespiratory conditions who are at risk of dying from the acute effects of ambient air particles.

    OpenAIRE

    Goldberg, M S; Burnett, R.T.; Bailar, J C; Tamblyn, R.; Ernst, P.; Flegel, K.; J. Brook; Bonvalot, Y; Singh, R.; Valois, M F; Vincent, R

    2001-01-01

    This study was undertaken to identify subgroups of the population susceptible to the effects of ambient air particles. Fixed-site air pollution monitors in Montreal, Quebec, Canada, provided daily mean levels of various measures of particulates and gaseous pollutants. Total sulfates were also measured daily (1986-1993) at a monitoring station 150 km southeast of the city (Sutton, Quebec, Canada). We used coefficient of haze (COH), extinction coefficient, and Sutton sulfates to predict fine pa...

  5. Fine and ultrafine particle emissions from microwave popcorn.

    Science.gov (United States)

    Zhang, Q; Avalos, J; Zhu, Y

    2014-04-01

    This study characterized fine (PM2.5 ) and ultrafine particle (UFP, diameter popcorn and analyzed influential factors. Each pre-packed popcorn bag was cooked in a microwave oven enclosed in a stainless steel chamber for 3 min. The number concentration and size distribution of UFPs and PM2.5 mass concentration were measured inside the chamber repeatedly for five different flavors under four increasing power settings using either the foil-lined original package or a brown paper bag. UFPs and PM2.5 generated by microwaving popcorn were 150-560 and 350-800 times higher than the emissions from microwaving water, respectively. About 90% of the total particles emitted were in the ultrafine size range. The emitted PM concentrations varied significantly with flavor. Replacing the foil-lined original package with a brown paper bag significantly reduced the peak concentration by 24-87% for total particle number and 36-70% for PM2.5 . A positive relationship was observed between both UFP number and PM2.5 mass and power setting. The emission rates of microwave popcorn ranged from 1.9 × 10(10) to 8.0 × 10(10) No./min for total particle number and from 134 to 249 μg/min for PM2.5 . PMID:24106981

  6. PREFACE: Fifth International Conference on Fine Particle Magnetism

    Science.gov (United States)

    Pankhurst, Quentin

    2005-01-01

    In September 2004, the UK Nanomagnetism Network and the London Centre for Nanotechnology hosted the 5th International Conference on Fine Particle Magnetism. The objective of the meeting, as in Rome (1991), Bangor (1996), Barcelona (1999) and Pittsburgh (2002), was to explore latest developments in the fundamentals and applications of nanoscale magnetic clusters, particles and grains. This particular conference had a very broad remit, and encompassed the interdisciplinary breadth of much of today's innovative work on nanoscale magnetic materials. In recognition of this, symposia were organised around the themes of biomagnetism and Earth and the environment, alongside the familiar themes of fundamental properties, applications, and imaging and characterisation. The aim was that this wide-ranging scope would provide the participants with new insights into how researchers from other disciplines approach similar problems to their own, which would help in their own work. This seemed to be borne out by the lively and good-natured discussion that the talks and posters generated. In keeping with this goal of combining cutting edge research with educating ourselves across traditional disciplinary boundaries, we are very pleased to have received such excellent support from the contributing authors for this proceedings volume. The papers contained herein are an accurate reflection of the topics covered, and include several review style papers. We hope that these proceedings will provide the reader with an understanding of the current vibrancy of research into fine particle magnetism. Furthermore, we hope that this volume sets the scene for the continuing cross-border work between physical scientists, life scientists, social scientists, clinicians and engineers that promises to make this field a very lively one in the years to come.

  7. Ambient Carbon Monoxide and Fine Particulate Matter in Relation to Preeclampsia and Preterm Delivery in Western Washington State

    OpenAIRE

    Rudra, Carole B.; Williams, Michelle A.; Sheppard, Lianne; Koenig, Jane Q.; Schiff, Melissa A.

    2011-01-01

    Background Preterm delivery and preeclampsia are common adverse pregnancy outcomes that have been inconsistently associated with ambient air pollutant exposures. Objectives We aimed to prospectively examine relations between exposures to ambient carbon monoxide (CO) and fine particulate matter [≤ 2.5 μm in aerodynamic diameter (PM2.5)] and risks of preeclampsia and preterm delivery. Methods We used data from 3,509 western Washington women who delivered infants between 1996 and 2006. We predic...

  8. Aerosol dynamics and the synthesis of fine solid particles

    Energy Technology Data Exchange (ETDEWEB)

    Bandyopadhyaya, R.; Lall, A.A.; Friedlander, S.K. [University of California in Los Angeles, Los Angeles, CA (USA). Dept. of Chemical Engineering

    2004-01-26

    Aerosol dynamics (AD) is the discipline that deals with changes in particle size distributions in space and time. AD is based on (1) certain fundamental principles embodied in a set of equations, (2) experimental methods and instrumentation and (3) numerical and computational methods. Over the last few decades, AD has emerged as an enabling discipline in the design of aerosol reactors employed in the gas phase synthesis of fine powders, the characterization of particle emissions from sources such as coal-fired power plants and the atmospheric aerosol. The development of basic AD concepts since early in the 20th century is traced to the present. Major gaps that remain in the field and likely advances over the next few years are discussed. Although accurate predictions of particle size from first principles are difficult to make in practical applications, AD principles can be used to explain trends in product properties for flame and laser ablation reactors that operate under very different temperatures and quench rates.

  9. Comprehensive characterization of ambient nanoparticles collected near an industrial science park: Particle size distributions and relationships with environmental factors

    Institute of Scientific and Technical Information of China (English)

    Yuhjeen Huang; Lingyen Hsu; Yunghsun Chang

    2011-01-01

    We investigated the characteristics of ambient particles and their relationships with various environmental factors,including gaseous pollutants (CH4,non-methane hydrocarbons (NMHC),total hydrocarbons (THC),NOx,CO,SO2),meteorological parameters (humidity,temperature),and time (day/night,workday/weekend).We used an electrical low-pressure cascade impactor to measure the number and size distributions of ambient particles (0.007-10 μm) that were collected approximately 1 km northwest of Hsinchu Science Park in Talwan between February and May 2007.The number concentrations of particles were enhanced through photochemical reactions during the day.In addition,high traffic flow during workdays increased the formation of particulates.Except for SO2,all of the gaseous pollutants we studied (CH4,NMHC,THC,NOx,CO) correlated positively with the total number concentrations of ambient particles during daytime,indicating that they might contribute to the particulate burden.The poorer relationship between the SO2 level and the total number concentration of particles suggests that SO2 might participate indirectly in the nucleation process during particle formation,The high enrichment factors for Zn,Pb,Cu,and Mn,which mostly comprised the ultrafine particles (diameter:< 0.1 μm) and fine particles (diameter:0.1-1 μm),presumably arose from emissions from traffic and high technology factories.Heterogeneous reactions on solid particles might play a role in the removal of SOx and NOx from the atmosphere.Sulfides and nitrides can further react with these local pollutants,forming specific Cu-containing compounds:CuO (39%),CuSO4 (34%),and Cu(NO3)2 (27%),within the ambient particles in this industrial area.

  10. Sources of fine particle composition in New York city

    Science.gov (United States)

    Li, Zheng; Hopke, Philip K.; Husain, Liaquat; Qureshi, Sumizah; Dutkiewicz, Vincent A.; Schwab, James J.; Drewnick, Frank; Demerjian, Kenneth L.

    Fine particle composition data from samples collected at Queens College during July 2001 were studied using positive matrix factorization (PMF). The sampling systems are an integrated filter sampler with a 6-h sampling time interval, an aerosol mass spectrometer (AMS) with a 10-min sampling time interval and a particle-into-liquid sampler with ion chromatography (PILS-IC) with 15-min sampling time interval. The data from the AMS and the PILS-IC were aggregated to 6-h average values for the PMF calculation. Sulfate, ammonium, and nitrate data were compared among the different instruments. The PMF method uses the estimated errors in the data to provide optimal point-by-point weighting and permits efficient treatment of missing and below detection limit values. Six source categories were resolved from the data. They are: secondary sulfate with high concentration SO 42-; secondary nitrate with the presence of high concentration NO 3-; motor vehicle emissions with high concentration of OC and Zn; road dust represented by Al, Ca, Fe, and K; sea salt with high concentration of Cl and Na; and oil combustion marked by the presence of Ni and V.

  11. Fullerene fine particles adhere to pollen grains and affect their autofluorescence and germination

    OpenAIRE

    Aoyagi H; Ugwu CU

    2011-01-01

    Hideki Aoyagi, Charles U UgwuLife Science and Bioengineering, Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, JapanAbstract: Adhesion of commercially produced fullerene fine particles to Cryptomeria japonica, Chamaecyparis obtusa and Camellia japonica pollen grains was investigated. The autofluorescence of pollen grains was affected by the adhesion of fullerene fine particles to the pollen grains. The degree of adhesion of fullerene fine particles to the po...

  12. AP的安全制备%Safe Preparations of Fine Ammonium Perchlorate Particles

    Institute of Scientific and Technical Information of China (English)

    Makoto Kohga

    2006-01-01

    Fine AP particles are required to manufacture the AP-based composite propellants with a wide burning rate range for various applications,especially high burning rate propellants. However,it is difficult to prepare a fine AP safely. Some safe methods for preparing the fine AP particles are reported such as the spray-dry method and freeze-dry method. It is shown that the crystal habit modified AP particle is an effective oxidizer to enhance the burning rate.

  13. Spatial variability of fine particle concentrations in three European areas

    Science.gov (United States)

    Hoek, Gerard; Meliefste, Kees; Cyrys, Josef; Lewné, Marie; Bellander, Tom; Brauer, Mike; Fischer, Paul; Gehring, Ulrike; Heinrich, Joachim; van Vliet, Patricia; Brunekreef, Bert

    Epidemiological studies of long-term air pollution effects have been hampered by difficulties in characterizing the spatial variation in air pollution. We conducted a study to assess the risk of long-term exposure to traffic-related air pollution for the development of inhalant allergy and asthma in children in Stockholm county, Munich and the Netherlands. Exposure to traffic-related air pollution was assessed through a 1-year monitoring program and regression modeling using exposure indicators. This paper documents the performance of the exposure monitoring strategy and the spatial variation of ambient particle concentrations. We measured the ambient concentration of PM2.5 and the reflectance of PM2.5 filters ('soot') at 40-42 sites representative of different exposure conditions of the three study populations. Each site was measured during four 14-day average sampling periods spread over one year (spring 1999 to summer 2000). In each study area, a continuous measurement site was operated to remove potential bias due to temporal variation. The selected approach was an efficient method to characterize spatial differences in annual average concentration between a large number of sites in each study area. Adjustment with data from the continuous measurement site improved the precision of the calculated annual averages, especially for PM2.5. Annual average PM2.5 concentrations ranged from 11 to 20 μg/m 3 in Munich, from 8 to 16 μg/m 3 in Stockholm and from 14 to 26 μg/m 3 in the Netherlands. Larger spatial contrasts were found for the absorption coefficient of PM2.5. PM2.5 concentrations were on average 17-18% higher at traffic sites than at urban background sites, but PM2.5 absorption coefficients at traffic sites were between 31% and 55% increased above background. This suggests that spatial variation of traffic-related air pollution may be underestimated if PM2.5 only is measured.

  14. Ambient Fine Particulate Matter and Mortality among Survivors of Myocardial Infarction: Population-Based Cohort Study

    Science.gov (United States)

    Chen, Hong; Burnett, Richard T.; Copes, Ray; Kwong, Jeffrey C.; Villeneuve, Paul J.; Goldberg, Mark S.; Brook, Robert D.; van Donkelaar, Aaron; Jerrett, Michael; Martin, Randall V.; Brook, Jeffrey R.; Kopp, Alexander; Tu, Jack V.

    2016-01-01

    Background: Survivors of acute myocardial infarction (AMI) are at increased risk of dying within several hours to days following exposure to elevated levels of ambient air pollution. Little is known, however, about the influence of long-term (months to years) air pollution exposure on survival after AMI. Objective: We conducted a population-based cohort study to determine the impact of long-term exposure to fine particulate matter ≤ 2.5 μm in diameter (PM2.5) on post-AMI survival. Methods: We assembled a cohort of 8,873 AMI patients who were admitted to 1 of 86 hospital corporations across Ontario, Canada in 1999–2001. Mortality follow-up for this cohort extended through 2011. Cumulative time-weighted exposures to PM2.5 were derived from satellite observations based on participants’ annual residences during follow-up. We used standard and multilevel spatial random-effects Cox proportional hazards models and adjusted for potential confounders. Results: Between 1999 and 2011, we identified 4,016 nonaccidental deaths, of which 2,147 were from any cardiovascular disease, 1,650 from ischemic heart disease, and 675 from AMI. For each 10-μg/m3 increase in PM2.5, the adjusted hazard ratio (HR10) of nonaccidental mortality was 1.22 [95% confidence interval (CI): 1.03, 1.45]. The association with PM2.5 was robust to sensitivity analyses and appeared stronger for cardiovascular-related mortality: ischemic heart (HR10 = 1.43; 95% CI: 1.12, 1.83) and AMI (HR10 = 1.64; 95% CI: 1.13, 2.40). We estimated that 12.4% of nonaccidental deaths (or 497 deaths) could have been averted if the lowest measured concentration in an urban area (4 μg/m3) had been achieved at all locations over the course of the study. Conclusions: Long-term air pollution exposure adversely affects the survival of AMI patients. Citation: Chen H, Burnett RT, Copes R, Kwong JC, Villeneuve PJ, Goldberg MS, Brook RD, van Donkelaar A, Jerrett M, Martin RV, Brook JR, Kopp A, Tu JV. 2016. Ambient fine

  15. Characterisation of particle emissions from the driving car fleet and the contribution to ambient and indoor particle concentrations

    Science.gov (United States)

    Palmgren, Finn; Wåhlin, Peter; Kildesø, Jan; Afshari, Alireza; Fogh, Christian L.

    The population is mainly exposed to high air pollution concentrations in the urban environment, where motor vehicle emissions constitute the main source of fine and ultrafine particles. These particles can penetrate deep into the respiratory system, and studies indicate that the smaller the particle, the larger the health impacts. The chemical composition, surface reactivity and physical properties are also important. However, the knowledge about chemical and physical properties of particles and the temporal and spatial variability of the smallest particles is still very limited. The present study summarises the first results of a larger project with the aims to improve the knowledge. The concentration and the emissions of ultrafine particles from petrol and diesel vehicles, respectively, have been quantified using Scanning Mobility Particle Sizer of ultrafine particles in the size range 6-700 nm and routine monitoring data from urban streets and urban background in Denmark. The quantification was carried out using receptor modelling. The number size distributions of petrol and diesel emissions showed a maximum at 20-30 nm and non-traffic at ≈100 nm. The contribution of ultrafine particles from diesel vehicles is dominating in streets. The same technique has been applied on PM 10, and ≈50% contribution from non-traffic. The technique has also been introduced in relation to elemental and organic carbon, and the first data showed strong correlation between traffic pollution and elemental carbon. The outdoor air quality has a significant effect on indoor pollution levels, and we spend most of the time indoors. Knowledge about the influence of ambient air pollution on the concentrations in the indoor environment is therefore crucial for assessment of human health effects of traffic pollution. The results of our studies will be included in air quality models for calculation of human exposure. Preliminary results from our first campaign showed, that the deposition

  16. Organic Components and Elemental Carbon in Soils and Ambient Particles near Phoenix, AZ

    Science.gov (United States)

    Fraser, M. P.; Jia, Y.; Clements, A.

    2008-12-01

    In the desert southwest, fugitive dust emissions contribute significantly to ambient aerosol concentrations. Wind erosion from the arid land is a primary contributor to ambient particulate matter (PM) concentrations but, in regions including Central Arizona, desert lands have been converted for agriculture use and thus agriculture processes constitute another contributor. As the metropolitan Phoenix region expands into these agricultural lands, urban sources and construction also contributes to the ambient PM load. In an effort to identify and access relative contribution of these and other major PM sources in the region, a series of ambient PM samples and soil samples were collected near Higley, AZ, a suburb of Phoenix which has seen rapid urbanization onto agricultural lands between January and May 2008. The soil samples collected were resuspended and samples of resuspended dust were collected to represent particles smaller than 2.5 microns and 10 microns in aerodynamic diameter (PM2.5 and PM10 respectively). The size segregated soil and ambient PM samples were analyzed for bulk mass, elemental and organic carbon content, and a number of specific compounds including ions, metals, alkanes, organic acids, polycyclic aromatic hydrocarbons, and saccharides. The saccharide contribution to soil organic carbon has been studied to elucidate key factors in the soil carbon balance and markers have been developed for tracing fungal metabolites, plant growth and budding and organic matter decay. Using organic markers, the contribution of various sources to PM10 and PM2.5 levels have been determined by positive matrix factorization (PMF) of the ambient aerosol marker concentrations quantified from PM samples. Subsequently, samples of local soil from native and agricultural fields and local roadways wers size- segregated and analyzed in an effort to create a source profile for the dust in the area. A chemical mass balance model has been used to compare with the PMF results

  17. Individual aerosol particles in ambient and updraft conditions below convective cloud bases in the Oman mountain region

    Science.gov (United States)

    Semeniuk, T. A.; Bruintjes, R. T.; Salazar, V.; Breed, D. W.; Jensen, T. L.; Buseck, P. R.

    2014-03-01

    An airborne study of cloud microphysics provided an opportunity to collect aerosol particles in ambient and updraft conditions of natural convection systems for transmission electron microscopy (TEM). Particles were collected simultaneously on lacey carbon and calcium-coated carbon (Ca-C) TEM grids, providing information on particle morphology and chemistry and a unique record of the particle's physical state on impact. In total, 22 particle categories were identified, including single, coated, aggregate, and droplet types. The fine fraction comprised up to 90% mixed cation sulfate (MCS) droplets, while the coarse fraction comprised up to 80% mineral-containing aggregates. Insoluble (dry), partially soluble (wet), and fully soluble particles (droplets) were recorded on Ca-C grids. Dry particles were typically silicate grains; wet particles were mineral aggregates with chloride, nitrate, or sulfate components; and droplets were mainly aqueous NaCl and MCS. Higher numbers of droplets were present in updrafts (80% relative humidity (RH)) compared with ambient conditions (60% RH), and almost all particles activated at cloud base (100% RH). Greatest changes in size and shape were observed in NaCl-containing aggregates (>0.3 µm diameter) along updraft trajectories. Their abundance was associated with high numbers of cloud condensation nuclei (CCN) and cloud droplets, as well as large droplet sizes in updrafts. Thus, compositional dependence was observed in activation behavior recorded for coarse and fine fractions. Soluble salts from local pollution and natural sources clearly affected aerosol-cloud interactions, enhancing the spectrum of particles forming CCN and by forming giant CCN from aggregates, thus, making cloud seeding with hygroscopic flares ineffective in this region.

  18. Quantifying spatiotemporal variability of fine particles in an urban environment using combined fixed and mobile measurements

    Science.gov (United States)

    Sullivan, R. C.; Pryor, S. C.

    2014-06-01

    Spatiotemporal variability of fine particle concentrations in Indianapolis, Indiana is quantified using a combination of high temporal resolution measurements at four fixed sites and mobile measurements with instruments attached to bicycles during transects of the city. Average urban PM2.5 concentrations are an average of ˜3.9-5.1 μg m-3 above the regional background. The influence of atmospheric conditions on ambient PM2.5 concentrations is evident with the greatest temporal variability occurring at periods of one day and 5-10 days corresponding to diurnal and synoptic meteorological processes, and lower mean wind speeds are associated with episodes of high PM2.5 concentrations. An anthropogenic signal is also evident. Higher PM2.5 concentrations coincide with morning rush hour, the frequencies of PM2.5 variability co-occur with those for carbon monoxide, and higher extreme concentrations were observed mid-week compared to weekends. On shorter time scales (sites) was within ±3.6 μg m-3 of the stationary measurements (once the temporal variability is removed). Localized extreme values of PM2.5 concentrations ranged in the spatial dimension from a few hundred meters up to 2 km, and contributed an average of 4.4 μg m-3 to ambient concentrations.

  19. Element determination of fine particles in environmental aerosols using PIXE

    International Nuclear Information System (INIS)

    The Mexico city is classified as one of the more populated cities of the world which presents a decrease in the air quality and that gives place to a severe problematic in atmospheric pollution. To cooperate in the solution of this problem it is necessary to carry out studies that allow a better knowledge of the atmosphere of the city. This study presents the results of a monitoring campaign of fine particle carried out from September 21 to December 12, 2001 in three sites of the Mexico City center area. The samples were collected every third day with a collector type unit of heaped filters (Gent). The analysis of these samples was carried out in the 2 MV accelerator of the National Institute of Nuclear Research (ININ) applying the PIXE technique and with this analysis its were identified in the samples approximately 15 elements in each one of the 3 sites and was calculated the concentration in that its were present. With these results a database was created and by means of it mathematical treatment the Enrichment factor (FE), the time series of each element and the multiple correlation matrix were evaluated. The obtained results showed that the Civil Registration site (Salto del Agua) it was the more polluted coinciding that to a bigger concentration of activities a bigger increase in the pollution is generated. (Author)

  20. Using monosaccharide anhydrides to estimate the impact of wood combustion on fine particles in the Helsinki Metropolitan Area

    Energy Technology Data Exchange (ETDEWEB)

    Saarnio, K.; Saarikoski, S. [Finnish Meteorological Institute, Helsinki (Finland); Niemi, J.V. [HSY Helsinki Region Environmental Services Authority, Helsinki (Finland)

    2012-11-01

    The spatiotemporal variation of ambient particles under the influence of biomass burning emissions was studied in the Helsinki Metropolitan Area (HMA) in selected periods during 2005-2009. Monosaccharide anhydrides (MAs; levoglucosan, mannosan and galactosan), commonly known biomass burning tracers, were used to estimate the wood combustion contribution to local particulate matter (PM) concentration levels at three urban background sites close to the city centre, and at three suburban sites influenced by local small-scale wood combustion. In the cold season (October-March), the mean MAs concentrations were 115-225 ng m{sup -3} and 83-98 ng m{sup -} {sup 3}at the suburban and urban sites, respectively. In the warm season, the mean MAs concentrations were low (19-78 ng m{sup -3}), excluding open land fire smoke episodes (222-378 ng m{sup -}3{sup )}. Regionally distributed wood combustion particles raised the levels over the whole HMA while particles from local wood combustion sources raised the level at suburban sites only. The estimated average contribution of wood combustion to fine particles (PM{sub 2.5}) ranged from 18% to 29% at the urban sites and from 31% to 66% at the suburban sites in the cold season. The PM measurements from ambient air and combustion experiments showed that the proportions of the three MAs can be utilised to separate the wildfire particles from residential wood combustion particles. (orig.)

  1. Characteristics of fine and coarse particles of natural and urban aerosols of Brazil

    International Nuclear Information System (INIS)

    Fine and coarse particles have been sampled from 1982 to 1985 in one natural forest seacoast site (Jureia) and five urban-industrial cities (Vitoria, Salvador, Porto Alegre, Sao Paulo, and Belo Horizonte). The time variations of concentrations in air and the relative elemental compositions of fine and coarse particle fractions, sampled by Nuclepore stacked filter units (SFU), have been determined gravimetrically and by PIXE analysis, respectively. Enrichment factors and correlation coefficients of the trace elements measured lead to unambiguous characterization of soil dust and sea salt, both major aerosol sources that emit coarse particles, and soil dust is also a significant source of fine particles. (Author)

  2. Measurement adhesion force between fine particle and effect of humidity: An study with Atomic Force Microscopy

    International Nuclear Information System (INIS)

    Adhesion force is interaction between particle- particle and particle surface. First Hertz in 1882 calculated adhesion force between spherical particle and planar surface. Adhesion force in interested for scientist and different industries such as paint, foot, pharmaceutical, etc. In this study we measured adhesion force between fine particle such as silica and silicon and mica surface, with Atomic Force Microscopy. The adhesion force measured between particle-planar surfaces with Atomic Force Microscopy on different humidity and simulated results.

  3. Concentrated ambient air particles induce vasoconstriction of small pulmonary arteries in rats.

    OpenAIRE

    Batalha, Joao R F; Saldiva, Paulo H N; Clarke, Robert W.; Coull, Brent A.; Stearns, Rebecca C; Lawrence, Joy; Murthy, G G Krishna; Koutrakis, Petros; Godleski, John J.

    2002-01-01

    The objective of this study was to determine whether short-term exposures to concentrated ambient particles (CAPs) alter the morphology of small pulmonary arteries in normal rats and rats with chronic bronchitis (CB). Sprague-Dawley male rats were exposed to CAPs, using the Harvard Ambient Particle Concentrator, or to particle-free air (sham) under identical conditions during 3 consecutive days (5 hr/day) in six experimental sets. CB was induced by exposure to 276 +/- 9 ppm of sulfur dioxide ...

  4. Stochastic modeling of fine particle deposition, resuspension, and hyporheic exchange in rivers

    Science.gov (United States)

    Packman, Aaron; Drummond, Jennifer; Aubeneau, Antoine

    2013-04-01

    Fine suspended particles are responsible for substantial flux of organic matter and contaminants in rivers. Further, microorganisms delivered from the terrestrial system or resuspended from benthic and hyporheic biofilms also propagate downstream in rivers, providing connectivity in the river microbial community. Because fine particle concentrations are often similar along the length of rivers, there has been a tendency to think that their dynamics are simple. Historically, fine suspended particles have been considered to show little interaction with streambed sediments. This is a fallacy. Recent observations have demonstrated that fine particles show complex dynamics in rivers, including ongoing deposition and resuspension. This provides substantial opportunity for interaction with benthic and hyporheic sediments and biofilms, which can lead to enhanced processing of fine particulate organic carbon, accumulation of pathogens in riverbeds, and mixing of particle-bound contaminants into bed sediments. Here I will briefly review current understanding of fine particle deposition, resuspension, and hyporheic exchange processes, develop a conceptual model for fine particle dynamics in rivers, and present a stochastic modeling framework that can represent most of these processes. I will close by discussing the limits of current modeling capability and prospects for future development of more general models.

  5. Regulation of cytokine production in human alveolar macrophages and airway epithelial cells in response to ambient air pollution particles: Further mechanistic studies

    International Nuclear Information System (INIS)

    In order to better understand how ambient air particulate matter (PM) affect lung health, the two main airway cell types likely to interact with inhaled particles, alveolar macrophages (AM) and airway epithelial cells have been exposed to particles in vitro and followed for endpoints of inflammation, and oxidant stress. Separation of Chapel Hill PM 10 into fine and coarse size particles revealed that the main proinflammatory response (TNF, IL-6, COX-2) in AM was driven by material present in the coarse PM, containing 90-95% of the stimulatory material in PM10. The particles did not affect expression of hemoxygenase-1 (HO-1), a sensitive marker of oxidant stress. Primary cultures of normal human bronchial epithelial cells (NHBE) also responded to the coarse fraction with higher levels of IL-8 and COX-2, than induced by fine or ultrafine PM. All size PM induced oxidant stress in NHBE, while fine PM induced the highest levels of HO-1 expression. The production of cytokines in AM by both coarse and fine particles was blocked by the toll like receptor 4 (TLR4) antagonist E5531 involved in the recognition of LPS and Gram negative bacteria. The NHBE were found to recognize coarse and fine PM through TLR2, a receptor with preference for recognition of Gram positive bacteria. Compared to ambient PM, diesel PM induced only a minimal cytokine response in both AM and NHBE. Instead, diesel suppressed LPS-induced TNF and IL-8 release in AM. Both coarse and fine ambient air PM were also found to inhibit LPS-induced TNF release while silica, volcanic ash or carbon black had no inhibitory effect. Diesel particles did not affect cytokine mRNA induction nor protein accumulation but interfered with the release of cytokine from the cells. Ambient coarse and fine PM, on the other hand, inhibited both mRNA induction and protein production. Exposure to coarse and fine PM decreased the expression of TLR4 in the macrophages. Particle-induced decrease in TLR4 and hyporesponsiveness to LPS

  6. Plasma etching of single fine particle trapped in Ar plasma by optical tweezers

    International Nuclear Information System (INIS)

    Physical and chemical interactions between plasmas and nano-featured surfaces are one important issue in the plasma processing. Here we optically trap single fine particle levitated at plasma/sheath boundary with an infrared laser to realize in-situ analysis of such interactions. We have measured time evolution of the diameter of the single fine particle in Ar plasma. The trapped particle was etched at an etching rate of 1 nm/min in Ar plasma. We also obtained a Raman peak at around 2950 cm−1 corresponding to C-H bonds in the single fine particle in Ar plasma. The results open a new possibility to observe directly interactions between plasma and single fine particle

  7. 77 FR 65346 - Determination of Attainment for the Sacramento Nonattainment Area for the 2006 Fine Particle...

    Science.gov (United States)

    2012-10-26

    ... AGENCY 40 CFR Part 52 Determination of Attainment for the Sacramento Nonattainment Area for the 2006 Fine... primary and secondary \\1\\ annual and 24-hour standards for PM 2.5 (62 FR 38652). The annual standard was... presence of such air pollutant in the ambient air. See CAA section 109(b). On October 17, 2006 (71 FR...

  8. 77 FR 65656 - Determination of Attainment for the Nogales Nonattainment Area for the 2006 Fine Particle...

    Science.gov (United States)

    2012-10-30

    ... AGENCY 40 CFR Part 52 Determination of Attainment for the Nogales Nonattainment Area for the 2006 Fine... secondary\\1\\ annual and 24-hour standards for PM 2.5 (62 FR 38652). The annual standard was set at 15.0... air pollutant in the ambient air. See CAA section 109(b). On October 17, 2006 (71 FR 61144),...

  9. 78 FR 42018 - Determination of Attainment for the Sacramento Nonattainment Area for the 2006 Fine Particle...

    Science.gov (United States)

    2013-07-15

    ... remanded to EPA the ``Final Clean Air Fine Particle Implementation Rule'' (72 FR 20586, April 25, 2007) and... AGENCY 40 CFR Part 52 Determination of Attainment for the Sacramento Nonattainment Area for the 2006 Fine..., 2012 (77 FR 65346), EPA proposed to determine that the Sacramento nonattainment area in California...

  10. Fine particle deposition at Vainguinim tourist beach, Goa, India

    Digital Repository Service at National Institute of Oceanography (India)

    Chandramohan, P.; Jayakumar, S.; SanilKumar, V.; Ilangovan, D.

    . The beach sediments consist primarily shell fragments and quartz, with heavy mineral composed of ilmenits, magnetite and manganese. The black stain of the fine-grained heavy minerals deposited on the beach face reduces the aesthetics of the beach. This paper...

  11. Health impact of exposure to fine particles. Epidemiology of short-term effects

    International Nuclear Information System (INIS)

    Epidemiological studies on short-term effects of fine particles are investigating whether morbidity or mortality increase on days with high particle concentrations. Multi-center studies have shown on a daily basis that there is an increase in morbidity and/or mortality in association with particle concentrations. Studies on the effects of particles on the respiratory tract have indicated that there is an impact of particles at their place of deposition. In addition, numerous studies have revealed that particles also have effects on the cardiovascular system, including acute-phase reactions, increased hospital admissions, and also an increase in cardiovascular disease mortality in association with elevated particle concentrations. For PM10 consistent effects were found. Furthermore, the analyses showed that no threshold value could be established, but a linear dose-effect relation. Studies measuring PM2.5 point to fine particles being mainly responsible for these effects. Current studies show that in addition to fine particles, ultra-fine particles can cause further health effects. (orig.)

  12. Theoretical Model of Separation of Fine Particles in a Rotating Ferrofluid

    OpenAIRE

    Mockovčiaková, Annamária; Lovás, Michal; Jakabský, Štefan

    1995-01-01

    The application of centrifugal forces to a ferrofluid with finely grained particles located in a non—homogeneous magnetic field is the basis of the theoretical model of separation outlined in this paper. An analytical solution of the equation of the particle motion, its application under certain conditions, as well as the graphic representation of the results are presented.

  13. Fine particles measurement techniques. Application to some atmospheric phenomena

    International Nuclear Information System (INIS)

    A continous flow condensation nuclei counter (CNC) was first studied, this device being used for counting submicronic aerosol particles. A model describing heat and mass transfers inside a cooled pipe and the simultaneous condensational growth was developed; a comparison with experimental results showed excellent agreement. This model accounts for the defaults already observed with this type of apparatus. A new method for measuring the size distribution of aerosols with diameter ranging from 0.008 to 0.3 micron m is described. This technique is based upon particles bipolar charging, by contact with ions emitted from a beta source, and a subsequent differential electrical mobility analysis. The selected particles are detected by means of the CNC. A numerical inversion procedure is needed to recover the original aerosol size distribution. This method was compared with those currently in use: Electrical Mobility Analyser and Diffusion Battery

  14. Chemical composition and source of fine and nanoparticles from recent direct injection gasoline passenger cars: Effects of fuel and ambient temperature

    Science.gov (United States)

    Fushimi, Akihiro; Kondo, Yoshinori; Kobayashi, Shinji; Fujitani, Yuji; Saitoh, Katsumi; Takami, Akinori; Tanabe, Kiyoshi

    2016-01-01

    Particle number, mass, and chemical compositions (i.e., elemental carbon (EC), organic carbon (OC), elements, ions, and organic species) of fine particles emitted from four of the recent direct injection spark ignition (DISI) gasoline passenger cars and a port fuel injection (PFI) gasoline passenger car were measured under Japanese official transient mode (JC08 mode). Total carbon (TC = EC + OC) dominated the particulate mass (90% on average). EC dominated the TC for both hot and cold start conditions. The EC/TC ratios were 0.72 for PFI and 0.88-1.0 (average = 0.92) for DISI vehicles. A size-resolved chemical analysis of a DISI car revealed that the major organic components were the C20-C28 hydrocarbons for both the accumulation-mode particles and nanoparticles. Contribution of engine oil was estimated to be 10-30% for organics and the sum of the measured elements. The remaining major fraction likely originated from gasoline fuel. Therefore, it is suggested that soot (EC) also mainly originated from the gasoline. In experiments using four fuels at three ambient temperatures, the emission factors of particulate mass were consistently higher with regular gasoline than with premium gasoline. This result suggest that the high content of less-volatile compounds in fuel increase particulate emissions. These results suggest that focusing on reducing fuel-derived EC in the production process of new cars would effectively reduce particulate emission from DISI cars.

  15. Diesel emissions significantly influence composition and mutagenicity of ambient particles: a case study in Sao Paulo, Brazil

    International Nuclear Information System (INIS)

    In 2003, a bus strike paralyzed the fleet of buses in Sao Paulo, Brazil during 3 days, from 6 to 8 of April, the complete interruption of services being achieved on the 7th. We evaluated the effect of the absence of this source of pollution on the composition, mutagenicity, and toxicity of the fine particulate material collected during this period. Particles were sampled in glass fiber filters on days 7 and 15 of April of 2003 (strike and nonstrike days, respectively), using a high-volume sampler. Trace element determinations (As, Br, Co, Cl, Fe, La, Mn, Sb, Sc, and Th) of particulate material samples were carried out by neutron activation analysis. Sulfur determination was done by X-ray fluorescence analysis. The ratio between nonstrike/strike concentrations of hydrocarbons associated with automotive emissions (benzene, toluene, ethyl-benzene, and xylenes; BTEX) was determined by gas chromatography/mass spectrometry. Mutagenesis of testing solutions was determined by means of the Tradescantia micronucleus assay in early tetrads of Tradescantia pallida. The inhibition of mitosis of the cells of the primary meristema of the root tips of Allium cepa was used as an index of the toxicity. Fine particle trace element contents were lower during the strike. The concentrations of sulfur and BTEX were 50% and 39.3% lower, respectively, on the strike day. A significant (P=0.038) reduction of micronuclei induced by fine particles sampled during the strike was observed. No effect of the strike on toxicity was detected. These results indicate that a program aiming to reduce emissions of the bus fleet in our town may impact positively the air quality by reducing the mutagenic potential of ambient particles

  16. Measurement and characterization of the biological fraction of fine particles - BIOFINE

    Energy Technology Data Exchange (ETDEWEB)

    Rintala, H.; Toivola, M.; Hyvaerinen, A. [National Public Health Institute, Helsinki (Finland)

    2006-10-15

    Fine particles are mainly generated in burning processes and traffic. However, a part of the airborne particulate matter is of biological origin. Although many health aspects are associated with bioaerosols, their composition and behavior has not yet been well studied. Aerosol particle concentration in indoor air is affected by outdoor air. Simultaneous measuring of both indoor and outdoor air can be used to exclude the outdoor sources and to define the indoor sources of fine particles and bioaerosols. The aims of the study were to investigate whether microbial damage of a building generates fine particles measurable with particle counting methods and to characterize the microbial fraction of the airborne fine particulate matter qualitatively and quantitatively with modern molecular biological, chemical and immunological techniques. The investigations were done in pairs of buildings; one building of the pair having moisture and microbial damage and reported building-related symptoms of workers. The reference building was an age- and building frame- matched control with no signs of moisture or microbial damage or known health complaints. In these building pairs, fine particles and microbial matter in indoor and outdoor air were measured. The 3-800 nm particles were measured using DMPS (differential mobility particle sizer) and the >0,3 {mu}m fraction with Climet CI-500 particle counter. Samples were taken from indoor and outdoor air, and settled dust. The composition of the microbial flora in these samples was be determined by large scale sequencing, quantitative PCR, chemical markers such as ergosterol and lipid biomarkers, such as PLFAs. The immunotoxic potential of the samples was determined using cell cultures. (orig.)

  17. Characterization of silver nanoparticles synthesized on titanium dioxide fine particles

    Energy Technology Data Exchange (ETDEWEB)

    Nino-Martinez, N [Facultad de Ciencias, UASLP, Alvaro Obregon 64, CP 78000, San Luis PotosI, SLP (Mexico); Martinez-Castanon, G A [Maestria en Ciencias Odontologicas, Facultad de EstomatologIa, UASLP, Avenida Manuel Nava 2, Zona Universitaria, San Luis PotosI, SLP (Mexico); Aragon-Pina, A [Instituto de Metalurgia, Facultad de IngenierIa, UASLP, Alvaro Obregon 64, CP 78000, San Luis PotosI, SLP (Mexico); Martinez-Gutierrez, F [Facultad de Ciencias Quimicas, UASLP, Alvaro Obregon 64, CP 78000, San Luis PotosI, SLP (Mexico); Martinez-Mendoza, J R [Facultad de Ciencias, UASLP, Alvaro Obregon 64, CP 78000, San Luis PotosI, SLP (Mexico); Ruiz, Facundo [Facultad de Ciencias, UASLP, Alvaro Obregon 64, CP 78000, San Luis PotosI, SLP (Mexico)

    2008-02-13

    Silver nanoparticles with a narrow size distribution were synthesized over the surface of two different commercial TiO{sub 2} particles using a simple aqueous reduction method. The reducing agent used was NaBH{sub 4}; different molar ratios TiO{sub 2}:Ag were also used. The nanocomposites thus prepared were characterized using transmission electron microscopy (TEM), scanning transmission electron microscopy (STEM), scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), x-ray photoelectron spectroscopy (XPS), x-ray diffraction (XRD), dynamic light scattering (DLS) and UV-visible (UV-vis) absorption spectroscopy; the antibacterial activity was assessed using the standard microdilution method, determining the minimum inhibitory concentration (MIC) according to the National Committee for Clinical Laboratory Standards. From the microscopy studies (TEM and STEM) we observed that the silver nanoparticles are homogeneously distributed over the surface of TiO{sub 2} particles and that the TiO{sub 2}:Ag molar ratio plays an important role. We used three different TiO{sub 2}Ag molar ratios and the size of the silver nanoparticles is 10, 20 and 80 nm, respectively. It was found that the antibacterial activity of the nanocomposites increases considerably comparing with separated silver nanoparticles and TiO{sub 2} particles.

  18. Characterization of silver nanoparticles synthesized on titanium dioxide fine particles

    International Nuclear Information System (INIS)

    Silver nanoparticles with a narrow size distribution were synthesized over the surface of two different commercial TiO2 particles using a simple aqueous reduction method. The reducing agent used was NaBH4; different molar ratios TiO2:Ag were also used. The nanocomposites thus prepared were characterized using transmission electron microscopy (TEM), scanning transmission electron microscopy (STEM), scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), x-ray photoelectron spectroscopy (XPS), x-ray diffraction (XRD), dynamic light scattering (DLS) and UV-visible (UV-vis) absorption spectroscopy; the antibacterial activity was assessed using the standard microdilution method, determining the minimum inhibitory concentration (MIC) according to the National Committee for Clinical Laboratory Standards. From the microscopy studies (TEM and STEM) we observed that the silver nanoparticles are homogeneously distributed over the surface of TiO2 particles and that the TiO2:Ag molar ratio plays an important role. We used three different TiO2Ag molar ratios and the size of the silver nanoparticles is 10, 20 and 80 nm, respectively. It was found that the antibacterial activity of the nanocomposites increases considerably comparing with separated silver nanoparticles and TiO2 particles

  19. EDITORIAL Invited papers from the 7th International Conference on Fine Particle Magnetism 2010 Invited papers from the 7th International Conference on Fine Particle Magnetism 2010

    Science.gov (United States)

    Nordblad, Per

    2010-12-01

    This cluster issue of Journal of Physics D: Applied Physics contains a collection of papers based on invited and contributed talks given at the 7th International Conference on Fine Particle Magnetism (ICFPM) held from 21-24 June, 2010 at the Ångström Laboratory, Uppsala University in Sweden. The ICFPM conferences have previously been held in Rome, Italy (1991), Bangor, UK (1996), Barcelona, Spain (1999), Pittsburgh, USA (2002), London, UK (2004) and Rome, Italy (2007); the 8th ICFPM is to be organized in Perpignan, France (2013). The aim of this series of conferences is to bring together experts in the field of fine particle magnetism to discuss recent fundamental experimental and theoretical findings as well as new technological developments and applications. Thus, the conference programme included sessions ranging from basic studies of nanomagnetism to biomedical applications of fine magnetic particles. The local organizers of ICFPM-2010 want to thank the Swedish Research Council (VR), the Center for Nanointegration Duisburg-Essen (CeNIDE) and LOT-Oriel Group Europe for financial support. We also acknowledge Akademikonferens for effective administration of the conference and Uppsala University for support and for providing the venue. Last but not least, we thank all participants for making the conference scientifically interesting and socially enjoyable.

  20. Size-dependent hydroxyl radicals generation induced by SiO2 ultra-fine particles: The role of surface iron

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Oxidative stress and hydroxyl radicals (·OH) play important roles in adverse health effects caused by inhalable ambient air particles (PM10). The ultra-fine fraction of PM10 has been hypothesized as one of the critical contributors to ·OH generation. Both in vivo and in vitro studies have shown that ultra-fine particles (UFPs) or nano-particles generate more ·OH than larger particles with identical mass and composition. Both the surface area and surface-adsorbed redox-active metals have been suggested as factors to determine the oxidative capacity of UFPs. In this study, the ·OH-generating capability of dif-ferent sizes of SiO2 particles was investigated in order to determine which factor influences particle-induced ·OH generation. The amount of ·OH generated in both acellular and cellular systems was quantified using a capillary electrophoresis method following exposure to SiO2 particles with diameters of 14, 100, and 500 nm. The amount of ·OH was strongly dependent on particle size, and a significant enhancement was observed only with 14 nm particles. Further studies indicated a close association between ·OH and iron ion concentration (R2 = 0.812, p<0.01). Washed particles, with their surface iron being removed, did not generate ·OH. The iron-containing leachate from these washings was able to enhance ·OH production as untreated particles did. Therefore, the presence of adsorbed iron on the surface of the SiO2 particles is presented as a possible mechanism of UPFs-induced ·OH generation. The SiO2 acted as an inert substrate, and the surface of ultra-fine SiO2 particles acted as a carrier for iron.

  1. An Euler-Lagrange model for simulating fine particle suspension in liquid flows

    Science.gov (United States)

    Chou, Yi-Ju; Gu, Shih-Hung; Shao, Yun-Chuan

    2015-10-01

    This article presents a two-way coupled Euler-Lagrange model to simulate the suspension of fine particles in liquid flows. The goal is to develop a three-dimensional numerical model that is capable of replicating the detailed features of particle-laden turbulent flow. A two-phase fractional-step projection method is developed to ensure mixture incompressibility by solving a modified Poisson equation for pressure, which in turn affects the particle motion through the pressure gradient. An efficient particle-moving algorithm that exchanges particles between Eulerian meshes is developed that automatically retains the necessary particle information at each time step and does not require any Lagrangian particle tracking. A soft-sphere particle collision model is employed to avoid excessive particle overlap and to achieve the random closed packing limit for depositing particles. Since particles are all inherently localized in Eulerian meshes, efficient particle searches can be achieved when calculating particle-particle collision. This model is then used to simulate the gravitational settling of particles, and the results confirm the effect of mixture incompressibility and demonstrate that the model is capable of reaching the random closed packing limit. Numerical examples for the flow problems of particle-induced stratification are conducted, and the model is able to reveal the detailed features of particle-laden flows. Sensitivity on the grid resolution and deviations from the existing single-phase model results are also discussed.

  2. Atmospheric fate and transport of fine volcanic ash: Does particle shape matter?

    Science.gov (United States)

    White, C. M.; Allard, M. P.; Klewicki, J.; Proussevitch, A. A.; Mulukutla, G.; Genareau, K.; Sahagian, D. L.

    2013-12-01

    Volcanic ash presents hazards to infrastructure, agriculture, and human and animal health. In particular, given the economic importance of intercontinental aviation, understanding how long ash is suspended in the atmosphere, and how far it is transported has taken on greater importance. Airborne ash abrades the exteriors of aircraft, enters modern jet engines and melts while coating interior engine parts causing damage and potential failure. The time fine ash stays in the atmosphere depends on its terminal velocity. Existing models of ash terminal velocities are based on smooth, quasi-spherical particles characterized by Stokes velocity. Ash particles, however, violate the various assumptions upon which Stokes flow and associated models are based. Ash particles are non-spherical and can have complex surface and internal structure. This suggests that particle shape may be one reason that models fail to accurately predict removal rates of fine particles from volcanic ash clouds. The present research seeks to better parameterize predictive models for ash particle terminal velocities, diffusivity, and dispersion in the atmospheric boundary layer. The fundamental hypothesis being tested is that particle shape irreducibly impacts the fate and transport properties of fine volcanic ash. Pilot studies, incorporating modeling and experiments, are being conducted to test this hypothesis. Specifically, a statistical model has been developed that can account for actual volcanic ash size distributions, complex ash particle geometry, and geometry variability. Experimental results are used to systematically validate and improve the model. The experiments are being conducted at the Flow Physics Facility (FPF) at UNH. Terminal velocities and dispersion properties of fine ash are characterized using still air drop experiments in an unconstrained open space using a homogenized mix of source particles. Dispersion and sedimentation dynamics are quantified using particle image

  3. Micromagnetic simulation of thermally activated switching in fine particles

    Energy Technology Data Exchange (ETDEWEB)

    Scholz, Werner; Schrefl, Thomas; Fidler, J. E-mail: fidler@tuwien.ac.at

    2001-08-01

    Effects of thermal activation are included in micromagnetic simulations by adding a random thermal field to the effective magnetic field. As a result, the Landau-Lifshitz equation is converted into a stochastic differential equation of Langevin type with multiplicative noise. The Stratonovich interpretation of the stochastic Landau-Lifshitz equation leads to the correct thermal equilibrium properties. The proper generalization of Taylor expansions to stochastic calculus gives suitable time integration schemes. For a single rigid magnetic moment the thermal equilibrium properties are investigated. It is found, that the Heun scheme is a good compromise between numerical stability and computational complexity. Small cubic and spherical ferromagnetic particles are studied.

  4. Micromagnetic simulation of thermally activated switching in fine particles

    International Nuclear Information System (INIS)

    Effects of thermal activation are included in micromagnetic simulations by adding a random thermal field to the effective magnetic field. As a result, the Landau-Lifshitz equation is converted into a stochastic differential equation of Langevin type with multiplicative noise. The Stratonovich interpretation of the stochastic Landau-Lifshitz equation leads to the correct thermal equilibrium properties. The proper generalization of Taylor expansions to stochastic calculus gives suitable time integration schemes. For a single rigid magnetic moment the thermal equilibrium properties are investigated. It is found, that the Heun scheme is a good compromise between numerical stability and computational complexity. Small cubic and spherical ferromagnetic particles are studied

  5. Morphological study of Sr2CeO4 blue phosphor with fine particles

    International Nuclear Information System (INIS)

    Morphological and spectroscopic studies of Sr2CeO4 blue phosphor in the form of fine particles prepared from a powdered multi-component precursor, via a combustion method, are reported. Samples were also prepared through a solid-state reaction and from a polymeric precursor for comparison. Citric acid or glycine as fuels in the combustion method lead to a mixture which is heated at 950 deg C for 4 h, resulting in spheroidal particles with a diameter between 250-550 nm. Samples from the polymeric precursor result in spheroidal particles (350-550 nm) and from the solid-state reaction in irregular particles (∼ 5 μm). Therefore, the combustion method is adequate for preparation of Sr2CeO4 in the form of spherical fine particles. (author)

  6. Characterization of fine particle components in Mexico City

    Energy Technology Data Exchange (ETDEWEB)

    Saitoh, K. [Akita Prefectural Institute of Environmental Science, Yabase-Shimoyabase, Akita (Japan); Sera, K. [Iwate Medical Univ., Cyclotron Research Center, Takizawa, Iwate (Japan); Perales, J.G.; Garcia, F.A. [Centro Nacional de Investigacion y Capacitacion Ambiental (CENICA), Av. Michoacan y la Purisima Col. Vicentina C.P. 09340 Mexico (Mexico); Suzuki, H. [Environmental Data Analysis Laboratory, System Design, Inc., Shinagawa, Tokyo (Japan)

    1999-07-01

    Particulate matter (PM-3.9 and PM-15.8) samples were collected in the three zones at the Northeast, Southwest and Southeast suburbs of Mexico City, from July to August 1998, for one week for each sampling site. The concentrations of several elements in the PM-3.9 and PM-15.8 samples were determined by Particle Induced X-ray Emission (PIXE). In the PM-3.9 samples, 21 elements were determined for each zone, and Na, Mg, Al, Si, S, K, Ca, Ti, Fe, Cu, Zn and Pb are found to be the major elemental components. On the other hand, 22 elements including P were determined on the PM-15.8 samples, and the dominant elements were the same as in the PM-3.9. Factor analysis is applied to the 28 variables (14 elements for each PM-3.9 and PM-15.8 groups) and for 21 samples (seven days for three zones) in order to identify possible sources of the particles. The result of factor analysis allows to identify five major sources, being soil the major contributor. (author)

  7. Bronchiolitis caused by occupational and ambient atmospheric particles.

    Science.gov (United States)

    Churg, Andrew; Wright, Joanne L

    2003-10-01

    Occupationally encountered mineral dusts such as asbestos, silica, silicates (talc, mica), and metals can produce a distinctive pattern of fibrosis and distortion of the small airways, particularly the distal membranous bronchioles (MB) and the respiratory bronchioles (RB). Recent reports show that the same types of changes, accompanied by considerable muscle hyperplasia, are found in individuals living in regions with high levels of particulate air pollutants (PM). Models and actual measurements suggest that these changes occur because the small airways are sites of high particle deposition, and inhaled and deposited particulates, including PM, enter the airway walls. Studies from our laboratory using a tracheal explant model have shown that, for many types of particles, entry into the airway wall causes expression of mediators that lead to airway wall fibrosis and airway wall smooth muscle hyperplasia, probably through oxidant mechanisms. These reactions are intrinsic properties of the particles and do not require exogenous inflammatory cells. There is considerable evidence that individuals with occupational exposure to a wide variety of mineral dusts, as well as individuals with chronic exposure to high levels of PM, develop chronic airflow obstruction. The type of small airway remodeling seen in particle-induced bronchiolitis appears to be one cause of chronic airflow obstruction in this setting. PMID:16088574

  8. Fine particle mass from the Diskus inhaler and Turbuhaler inhaler in children with asthma

    DEFF Research Database (Denmark)

    Bisgaard, H; Klug, B; Sumby, B S;

    1998-01-01

    in an inhalation profile simulator to assess drug delivery from both a Diskus inhaler and a Turbuhaler inhaler, and in particular to assess the proportion of drug emitted in the coarse (>4.7 microm) and fine (... represents the changes in flow rate over time through the device than the constant flow rate usually applied with an impactor alone. The aerosol cloud was released before the peak inspiratory effort had been achieved and accordingly the early part and not the peak of the inspiratory performance...... is a determinant of the quality of the aerosol. The mean (SD) amount of drug in large particles (>4.7 microm), fine particles (

  9. ambiental

    Directory of Open Access Journals (Sweden)

    Roque Leal Salcedo

    2008-01-01

    Full Text Available El derecho internacional ambiental es un conocimiento de carácter transversal, que entre otras consideraciones refleja las preocupaciones de la sociedad por la implementación de un modelo de desarrollo sustentable para el respeto a las reglas del medio natural que garantizan la integridad y renovación de los sistemas naturales. El presente artículo enfoca esta visión a través del análisis de material documental revisado, entre ellos tratados internacionales que permiten distinguir el desarrollo del derecho internacional ambiental y el papel de Organización de las Naciones Unidas (ONU, en el propósito común del derecho individual y colectivo de disfrutar de una vida, un ambiente seguro, sano y ecológicamente equilibrado. En función a estas disertaciones las consideraciones finales exponen parte de la visión que ha estructurado la ONU y que representan un aporte considerable en el fomento de la conciencia mundial sobre la necesidad de establecer vínculos entre las naciones para el continuo desarrollo de esta rama del derecho.

  10. Microwave non-resonant absorption in fine cobalt ferrite particles

    Energy Technology Data Exchange (ETDEWEB)

    Mata-Zamora, M.E. [Depto. Investigacion Aplicada, Centro de Ciencias Aplicadas y Desarrollo Tecnologico, Universidad Nacional Autonoma de Mexico, 04510 (Mexico)]. E-mail: memzamora@yahoo.com.mx; Montiel, H. [Depto. Investigacion Aplicada, Centro de Ciencias Aplicadas y Desarrollo Tecnologico, Universidad Nacional Autonoma de Mexico, 04510 (Mexico); Alvarez, G. [Depto. Metalicos y Ceramicos, Instituto de Investigaciones en Materiales, Universidad Nacional Autonoma de Mexico, 04510 (Mexico); Saniger, J.M. [Depto. Investigacion Aplicada, Centro de Ciencias Aplicadas y Desarrollo Tecnologico, Universidad Nacional Autonoma de Mexico, 04510 (Mexico); Zamorano, R. [Escuela Superior de Fisica y Matematicas, IPN, 07738 (Mexico); Valenzuela, R. [Depto. Metalicos y Ceramicos, Instituto de Investigaciones en Materiales, Universidad Nacional Autonoma de Mexico, 04510 (Mexico)

    2007-09-15

    Cobalt ferrite particles of average crystallite size of 11 nm were obtained by a sol-gel process at 400 deg. C . The powders were annealed at temperatures of 500, 600, 700 and 800 deg. C in air. Derivative microwave power absorption (dP/dH) measurements were carried out as a function of magnetic field (H {sub DC}) at X band (9.4 GHz), in the field range -80-796 kA/m for all annealed temperatures. In order to compare the response of saturation magnetization measurements with high frequency measurements, we calculated the areas inside both the magnetization (A {sub M}) and the absorption hysteresis loops (A {sub LFS}). The dependence of these areas as a function of crystallite size is remarkably similar in both experiments.

  11. Microwave non-resonant absorption in fine cobalt ferrite particles

    International Nuclear Information System (INIS)

    Cobalt ferrite particles of average crystallite size of 11 nm were obtained by a sol-gel process at 400 deg. C . The powders were annealed at temperatures of 500, 600, 700 and 800 deg. C in air. Derivative microwave power absorption (dP/dH) measurements were carried out as a function of magnetic field (H DC) at X band (9.4 GHz), in the field range -80-796 kA/m for all annealed temperatures. In order to compare the response of saturation magnetization measurements with high frequency measurements, we calculated the areas inside both the magnetization (A M) and the absorption hysteresis loops (A LFS). The dependence of these areas as a function of crystallite size is remarkably similar in both experiments

  12. Sources and chemical composition of atmospheric fine and coarse particles in the Helsinki area

    Energy Technology Data Exchange (ETDEWEB)

    Pakkanen, T.A.; Loukkola, K.; Korhonen, C.H. [Finnish Meteorological Institute, Helsinki (FI)] (and others)

    2001-07-01

    During April 1996 - June 1997 size-segregated atmospheric aerosol particles were collected at an urban and a rural site in the Helsinki area by utilising virtual impactors (VI) and Berner low-pressure impactors (BLPI). In addition, VI samples were collected at a semi-urban site during October 1996 - May 1997. The average PM{sub 2.3} (fine particle) concentrations at the urban and rural sites were 11.8 and 8.4 {mu}g/m{sup 3}, and the PM{sub 2.3}-{sub 15} (coarse particle) concentrations were 12.8 and about 5{mu}g/m{sup 3}, respectively. The difference in fine particle mass concentrations suggests that on average, more than one third of the fine mass at the urban site is of local origin. Evaporation of fine particle nitrate from the VI Teflon filters during sampling varied similarly at the three sites, the average evaporation being about 50-60 per cent. The average fine particle concentrations of the chemical components (25 elements and 13 ions) appeared to be fairly similar at the three sites for most components, which suggests that despite the long-range transport, the local emissions of these components were relatively evenly distributed in the Helsinki area. Exceptions were the average fine particles Ba, Fe, Sb and V concentrations that were clearly highest at the urban site pointing to traffic (Ba, Fe, Sb) and to combustion of heavy fuel oil (V) as the likely sources. The average coarse particle concentrations for most components were highest at the urban site and lowest at the rural site. Average chemical composition of fine particles was fairly similar at the urban and rural sites: non-analysed fraction (mainly carbonaceous material and water) 43 per cent and 37 per cent, sulphate 21 per cent and 25 per cent, crustal matter 12 per cent and 13 per cent, nitrate 12 per cent and 11 per cent, ammonium 9 per cent and 10 per cent and sea-salt 2.5 per cent and 3.2 per cent, respectively. At the semi-urban site also, the average fine particle composition was similar

  13. NUMBER CONCENTRATION, SIZE DISTRIBUTION AND FINE PARTICLE FRACTION OF TROPOSPHERIC AND STRATOSPHERIC AEROSOLS

    Institute of Scientific and Technical Information of China (English)

    Li Xu; Guangyu Shi; Li Zhang; Jun Zhou; Yasunobu Iwasaka

    2003-01-01

    Aerosol observations were carried out at Xianghe Scientific Balloon Base (39.45°N, 117°E) using a stratospheric balloon. The particle number concentrations of the tropospheric and stratospheric aerosols were directly explored.The vertical distributions of the number concentration, number-size (that is, particle number versus particle size)distribution, and the fraction of fine particles (0.5 μm>r>0.15 μm/r>0.15 μm) are reported in this paper. The profiles of particle concentration present multi-peak phenomenon. The pattern of size distribution for atmospheric aerosol indicates a tri-modal (r=~0.2 μm, ~0.88 μm and ~7.0 μm) and a bi-modal (r=~0.13 μm and 2.0 μm). The number-size distribution almost fits the Junge distribution for particles with r<0.5 μm in the stratosphere of 1993 and the troposphere of 1994. But the distributions of coarse particles (r>0.5 μm) are not uniform. The number-size distribution exhibits also a wide size range in the troposphere of 1993. The results demonstrate that fine particles represent the major portion in the troposphere during the measurement period, reaching as high as 95% in 1994. Certain coarse particle peaks in the troposphere were attributed to clouds and other causes, and in the stratosphere to volcanic eruption. The stratospheric aerosol layer consists of unique fractions of fine or coarse particles depending on their sources. In summary, the process of gas-to-particles conversion was active and the coarse particles were rich over the Xianghe area. The measurements also demonstrate that the spatial and temporal atmospheric aerosol distributions are nonuniform and changeful.

  14. Translocation of particles and inflammatory responses after exposure to fine particles and nanoparticles in an epithelial airway model

    Directory of Open Access Journals (Sweden)

    Musso Claudia

    2007-09-01

    Full Text Available Abstract Background Experimental studies provide evidence that inhaled nanoparticles may translocate over the airspace epithelium and cause increased cellular inflammation. Little is known, however, about the dependence of particle size or material on translocation characteristics, inflammatory response and intracellular localization. Results Using a triple cell co-culture model of the human airway wall composed of epithelial cells, macrophages and dendritic cells we quantified the entering of fine (1 μm and nano-sized (0.078 μm polystyrene particles by laser scanning microscopy. The number distribution of particles within the cell types was significantly different between fine and nano-sized particles suggesting different translocation characteristics. Analysis of the intracellular localization of gold (0.025 μm and titanium dioxide (0.02–0.03 μm nanoparticles by energy filtering transmission electron microscopy showed differences in intracellular localization depending on particle composition. Titanium dioxide nanoparticles were detected as single particles without membranes as well as in membrane-bound agglomerations. Gold nanoparticles were found inside the cells as free particles only. The potential of the different particle types (different sizes and different materials to induce a cellular response was determined by measurements of the tumour necrosis factor-α in the supernatants. We measured a 2–3 fold increase of tumour necrosis factor-α in the supernatants after applying 1 μm polystyrene particles, gold nanoparticles, but not with polystyrene and titanium dioxide nanoparticles. Conclusion Quantitative laser scanning microscopy provided evidence that the translocation and entering characteristics of particles are size-dependent. Energy filtering transmission electron microscopy showed that the intracellular localization of nanoparticles depends on the particle material. Both particle size and material affect the cellular

  15. Productivity control of fine particle transport to equatorial Pacific sediment

    Science.gov (United States)

    Thomas, E.; Turekian, K. K.; Wei, K.-Y.

    2000-09-01

    Accumulation rates of 3He (from cosmic dust), 230Th (produced in the water column), barite (produced in the water column during decay of organic matter), and Fe and Ti (arriving with wind-borne dust) all are positively correlated in an equatorial Pacific core (TT013-PC72; 01.1°N, 139.4°W; water depth 4298 m). These accumulation rates are also positively correlated with the accumulation rates of noncarbonate material. They are not significantly correlated to the mass accumulation rate of carbonate, which makes up the bulk of the sediment. The fluctuations in accumulation rates of these various components from different sources thus must result from variations in some process within the oceans and not from variations in their original sources. Sediment focusing by oceanic bottom currents has been proposed as this process [Marcantonio et al., 1996]. We argue that the variations in the accumulation rates of all these components are dominantly linked to changes in productivity and particle scavenging (3He, 230Th, Fe, Ti) by fresh phytoplankton detritus (which delivers Ba upon its decay) in the equatorial Pacific upwelling region. We speculate that as equatorial Pacific productivity is a major component of global oceanic productivity, its variations over time might be reflected in variations in atmospheric levels of methanesulfonic acid (an atmospheric reaction product of dimethyl sulfide, which is produced by oceanic phytoplankton) and recorded in Antarctic ice cores.

  16. NUMERICAL SIMULATION OF FINE PARTICLE SEPARATION IN A ROTATIONAL TUBE SEPARATOR

    Institute of Scientific and Technical Information of China (English)

    Jinyu Jiao; Ying Zheng; Guogang Sun

    2005-01-01

    This paper presents a numerical analysis of gas-solid separation in a rotational tube separator. This separator which collects fine particles from gas in laminar flow is effective for fine particle separation. The separation efficiency and critical particle diameter of the separator were simulated using CFD package (FLUENT 6.0). The simulation showed that separation efficiency can be significantly decreased due to the presence of turbulence. The simulation also showed that the Saffman lift force has little effect on the efficiency of this separator. The critical particle diameter of this tube separator was also calculated theoretically. Some experimental data were provided to validate the simulation results. Comparison between experimental results and simulation predictions on separation efficiency showed satisfactory agreement.

  17. Particle size distribution and property of bacteria attached to carbon fines in drinking water treatment

    Institute of Scientific and Technical Information of China (English)

    Wang Leilei; Chen Wei; Lin Tao

    2008-01-01

    The quantitative change and size distribution of particles in the effluents from a sand filter and a granular activated carbon (GAC) filter in a drinking water treatment plant were investigated. The average total concentration of particles in the sand filter effluent during a filter cycle was 148 particles/mL, 27 of which were larger than 2 μm in size. The concentration in the GAC effluent (561 particles/mL) was significantly greater than that in the sand filter effluent. The concentration of particles larger than 2 μm in the GAC filter effluent reached 201 particles/mL, with the amount of particles with sizes between 2 μm and 15 μm increasing. The most probable number (MPN) of carbon fines reached 43 unit/L after six hours and fines between 0.45 μm and 8.0 μm accounted for more than 50%. The total concentration of outflowing bacteria in the GAC filter effluent, 350 CFU (colony-forming units) /mL, was greater than that in the sand filter effluent, 210 CFU/mL. The desorbed bacteria concentration reached an average of 310 CFU/mg fines. The disinfection efficiency of desorbed bacteria was lower than 40% with 1.5 mg/L of chlorine. The disinfection effect showed that the inactivation rate with 2.0 mg/L of chloramine (90%) was higher than that with chlorine (70%). Experimental results indicated that the high particle concentration in raw water and sedimentation effluent led to high levels of outflowing particles in the sand filter effluent. The activated carbon fines in the effluent accounted for a small proportion of the total particle amount, but the existing bacteria attached to carbon fines may influence the drinking water safety. The disinfection efficiency of desorbed bacteria was lower than that of free bacteria with chlorine, and the disinfection effect on bacteria attached to carbon fines with chloramine was better than that with only chlorine.

  18. Dust-cloud structures behind a shock wave moving over a deposited layer of fine particles

    Institute of Scientific and Technical Information of China (English)

    WANG Boyi; XIONG Yi; CHEN Qian; A.N. OSIPTSOV

    2005-01-01

    The present paper investigates dispersed-phase flow structures of a dust cloud induced by a normal shock wave moving at a constant speed over a flat surface deposited with fine particles. In the shock-fitted coordinates, the general equations of dusty-gas boundary layer flows are formulated within the framework of a multi-fluid model and parametric numerical studies of the carrier- and dispersedphase flow fields are performed. The problem associated with crossing particle trajectories and the formation of local particle accumulation regions are solved by using the full Lagrangian method for the dispersed phase. The basic features of the near-wall two-phase flow under consideration including the role of Saffman force in the particle entrainment and the development of discontinuities or singularities in the particle density profiles are discussed. The effects associated with account of the non-uniformity of particle size and the finiteness of the particle Knudsen numbers are studied in detail.

  19. Human pulmonary responses to experimental inhalation of high concentration fine and ultrafine magnesium oxide particles.

    OpenAIRE

    Kuschner, W G; Wong, H; D'Alessandro, A; Quinlan, P; Blanc, P.D.

    1997-01-01

    Exposure to air polluted with particles less than 2.5 micron in size is associated epidemiologically with adverse cardiopulmonary health consequences in humans. The goal of this study was to characterize human pulmonary responses to controlled experimental high-dose exposure to fine and ultrafine magnesium oxide particles. We quantified bronchoalveolar lavage (BAL) cell and cytokine concentrations, pulmonary function, and peripheral blood neutrophil concentrations in six healthy volunteers 18...

  20. Prediction of the Fountain Heights in Fine Particle Spouted Bed Systems

    OpenAIRE

    ERBİL, Ayşe Çeçen

    1998-01-01

    New empirical correlations are proposed to predict the fountain heights in spouted bed systems operating with fine particles. These correlations can be used for predicting the total spouted bed vessel height which is composed of the maximum spoutable bed height and the fountain height. It is important to be able to predict the total vessel height from the fluid and particle proporties and the spouted bed gemotery since further detailed information may not be available in the initial design...

  1. Improved blend and tablet properties of fine pharmaceutical powders via dry particle coating.

    Science.gov (United States)

    Huang, Zhonghui; Scicolone, James V; Han, Xi; Davé, Rajesh N

    2015-01-30

    The improvements in the flow and packing of fine pharmaceutical powder blends due to dry coating of micronized acetaminophen (mAPAP, ∼11μm), a model poorly flowing drug, are quantified. Poor flow and packing density of fine excipients (∼20μm) allowed testing the hypothesis that dry coating of cohesive API may counteract poor flow and packing of fine pharmaceutical powder blends. Further, fine excipients could improve compaction and reduce segregation tendency. It was found that flow function coefficient (FFC) and bulk density enhancements for 10%, 30%, and 60% (w/w), API loading blends with dry coated API are significantly higher than those without coated silica. At the highest API loading, for which coarser excipients were also used as reference, the flow and packing of dry coated mAPAP blends were significantly increased regardless of the excipient particle size, exceeding those of a well compacting excipient, Avicel 102. In addition, tensile strength of tablets with fine excipients was significantly higher, indicating improved compactibility. These results show for the first time that dry coating of fine, cohesive API powder leads to significantly improved flow and packing of high API loading blends consisting of fine excipients, while achieving improved tablet compactibility, suggesting suitability for direct compaction. PMID:25475016

  2. Combustion characteristics of water-insoluble elemental and organic carbon in size selected ambient aerosol particles

    OpenAIRE

    Wittmaack, K.

    2005-01-01

    Combustion of elemental carbon (EC) and organic carbon (OC) contained in ambient aerosol matter was explored using scanning electron microscopy (SEM) in combination with energy dispersive X-ray analysis (EDX). To ease identification of the particles of interest and to avoid or at least reduce interaction with simultaneously sampled inorganic oxides and salts, the approach used in this work differed in two ways from commonly applied procedures. First, rather than using a mixture of particles o...

  3. Case report: Atrial fibrillation following exposure to ambient air pollution particles

    Science.gov (United States)

    CONTEXT: Exposure to air pollution can result in the onset of atrial fibrillation. CASE PRESENTATION: We present a case of a 58 year old woman who volunteered to participate in a controlled exposure to concentrated ambient particles (CAPs). Twenty minutes into the exposure, there...

  4. A concept of an automated function control for ambient aerosol measurements using mobility particle size spectrometers

    Science.gov (United States)

    Bastian, S.; Löschau, G.; Wiedensohler, A.

    2014-04-01

    An automated function control unit was developed to regularly check the ambient particle number concentration derived from a mobility particle size spectrometer as well as its zero-point behaviour. The function control allows unattended quality assurance experiments at remote air quality monitoring or research stations under field conditions. The automated function control also has the advantage of being able to get a faster system stability response than the recommended on-site comparisons with reference instruments. The method is based on a comparison of the total particle number concentration measured by a mobility particle size spectrometer and a condensation particle counter while removing diffusive particles smaller than 20 nm in diameter. In practice, the small particles are removed by a set of diffusion screens, as traditionally used in a diffusion battery. Another feature of the automated function control is to check the zero-point behaviour of the ambient aerosol passing through a high-efficiency particulate air (HEPA) filter. The performance of the function control is illustrated with the aid of a 1-year data set recorded at Annaberg-Buchholz, a station in the Saxon air quality monitoring network. During the period of concern, the total particle number concentration derived from the mobility particle size spectrometer slightly overestimated the particle number concentration recorded by the condensation particle counter by 2 % (grand average). Based on our first year of experience with the function control, we developed tolerance criteria that allow a performance evaluation of a tested mobility particle size spectrometer with respect to the total particle number concentration. We conclude that the automated function control enhances the quality and reliability of unattended long-term particle number size distribution measurements. This will have beneficial effects for intercomparison studies involving different measurement sites, and help provide a higher

  5. Electron density modification in ionospheric E layer by inserting fine dust particles

    Energy Technology Data Exchange (ETDEWEB)

    Misra, Shikha, E-mail: shikhamish@gmail.com [Centre for Energy Studies (CES), Indian Institute of Technology Delhi (IITD), New Delhi 110016 (India); Mishra, S. K. [Institute for Plasma Research (IPR), Gandhinagar 382428 (India)

    2015-02-15

    In this paper, we have developed the kinetics of E-region ionospheric plasma comprising of fine dust grains and shown that the electron density in E-layer can purposely be reduced/enhanced up to desired level by inserting fine dust particles of appropriate physical/material properties; this may certainly be promising for preferred rf-signal processing through these layers. The analytical formulation is based on average charge theory and includes the number and energy balance of the plasma constituents along with charge balance over dust particles. The effect of varying number density, work function, and photo-efficiency of dust particles on ionospheric plasma density at different altitude in E-layer has been critically examined and presented graphically.

  6. Electron density modification in ionospheric E layer by inserting fine dust particles

    Science.gov (United States)

    Misra, Shikha; Mishra, S. K.

    2015-02-01

    In this paper, we have developed the kinetics of E-region ionospheric plasma comprising of fine dust grains and shown that the electron density in E-layer can purposely be reduced/enhanced up to desired level by inserting fine dust particles of appropriate physical/material properties; this may certainly be promising for preferred rf-signal processing through these layers. The analytical formulation is based on average charge theory and includes the number and energy balance of the plasma constituents along with charge balance over dust particles. The effect of varying number density, work function, and photo-efficiency of dust particles on ionospheric plasma density at different altitude in E-layer has been critically examined and presented graphically.

  7. Characteristics of Fine Particles in an Urban Atmosphere—Relationships with Meteorological Parameters and Trace Gases

    Science.gov (United States)

    Zhang, Tianhao; Zhu, Zhongmin; Gong, Wei; Xiang, Hao; Fang, Ruimin

    2016-01-01

    Atmospheric fine particles (diameter < 1 μm) attract a growing global health concern and have increased in urban areas that have a strong link to nucleation, traffic emissions, and industrial emissions. To reveal the characteristics of fine particles in an industrial city of a developing country, two-year measurements of particle number size distribution (15.1 nm–661 nm), meteorological parameters, and trace gases were made in the city of Wuhan located in central China from June 2012 to May 2014. The annual average particle number concentrations in the nucleation mode (15.1 nm–30 nm), Aitken mode (30 nm–100 nm), and accumulation mode (100 nm–661 nm) reached 4923 cm−3, 12193 cm−3 and 4801 cm−3, respectively. Based on Pearson coefficients between particle number concentrations and meteorological parameters, precipitation and temperature both had significantly negative relationships with particle number concentrations, whereas atmospheric pressure was positively correlated with the particle number concentrations. The diurnal variation of number concentration in nucleation mode particles correlated closely with photochemical processes in all four seasons. At the same time, distinct growth of particles from nucleation mode to Aitken mode was only found in spring, summer, and autumn. The two peaks of Aitken mode and accumulation mode particles in morning and evening corresponded obviously to traffic exhaust emissions peaks. A phenomenon of “repeated, short-lived” nucleation events have been created to explain the durability of high particle concentrations, which was instigated by exogenous pollutants, during winter in a case analysis of Wuhan. Measurements of hourly trace gases and segmental meteorological factors were applied as proxies for complex chemical reactions and dense industrial activities. The results of this study offer reasonable estimations of particle impacts and provide references for emissions control strategies in industrial cities of

  8. DYNAMIC RHEOLOGICAL BEHAVIOR OF POLYPROPYLENE FILLED WITH ULTRA-FINE POWDERED RUBBER PARTICLES

    Institute of Scientific and Technical Information of China (English)

    Qiang Zheng; Yan-xia Cao; Miao Du

    2004-01-01

    Dynamic rheological characteristics of polypropylene (PP) filled with ultra-fine full-vulcanized powdered rubber (UFPR) composed of styrene-butadiene copolymer were studied through dynamic rheological measurements on an Advanced Rheometric Expansion System (ARES). A specific viscoelastic phenomenon, i.e. "the second plateau", appeared at low frequencies, and exhibits a certain dependence on the amount of rubber particles and the dispersion state in the matrix. This phenomenon is attributed to the formation of aggregation structure of rubber particles. The analyses of Cole-Cole diagrams of the dynamic viscoelastic functions suggest that the heterogeneity of the composites is enhanced on increasing both particle content and temperature.

  9. Drinking water biotic safety of particles and bacteria attached to fines in activated carbon process

    Institute of Scientific and Technical Information of China (English)

    CHEN Wei; LIN Tao; WANG Leilei

    2007-01-01

    In this paper,the drinking water biotic safety of particles and bacteria attached to fines in activated carbon process was investigated by actual treatment process and advanced treatment pilot trial with granular activated carbon.In the experiment,the particles were detected by IBR particle calculating instrument,the activated carbon fines were counted on the basis of the most probable number (MPN) with a microscope,the total number of bacteria was analyzed between the conventional agar culture medium and the one with R2A,and the bacteria attached to activated carbon fines was resolved by the homogenization technique.The experimental results showed that the average total number of particles was 205 CNT/mL in the activated carbon effluent during a filter cycle,of which the number of particles with sizes>2μm was 77 CNT/mL more than the present particle control criterion of the American drinking water product standard (50 CNT/mL).The backwash of low density and long duration lowered particle number in the effluent.The MPN of activated carbon frees in the effluent was between 400 and 600 CNT/L,which accounted for less than 5‰ of the total particles from activated carbon filtration for a poor relative level (R2= 0.34).The microorganisms in activated carbon effluent consisted mostly of heterotrophic bacillus and the total bacteria number was five times as high as that of the inflow,i.e.the effluent from sand filter.The actual bacteria number may be truly indicated by the detection technique with R2A culture medium compared with the traditional agar cultivation.The inactivation efficiency of bacteria attached to activated carbon fines was less than 40% under 1.1 mg/L of chlorine contacting for 40 min.Results showed that the particles and bacteria attached to activated carbon fines may influence drinking water biotic safety,and that the effective control measures need to be further investigated.

  10. On dithiothreitol (DTT as a measure of oxidative potential for ambient particles: evidence for the importance of soluble transition metals

    Directory of Open Access Journals (Sweden)

    J. G. Charrier

    2012-05-01

    Full Text Available The rate of consumption of dithiothreitol (DTT is increasingly used to measure the oxidative potential of particulate matter (PM, which has been linked to the adverse health effects of PM. While several quinones are known to be very reactive in the DTT assay, it is unclear what other chemical species might contribute to the loss of DTT in PM extracts. To address this question, we quantify the rate of DTT loss from individual redox-active species that are common in ambient particulate matter. While most past research has indicated that the DTT assay is not sensitive to metals, our results show that seven out of the ten transition metals tested do oxidize DTT, as do three out of the five quinones tested. While metals are less efficient at oxidizing DTT compared to the most reactive quinones, concentrations of soluble transition metals in fine particulate matter are generally much higher than those of quinones. The net result is that metals appear to dominate the DTT response for typical ambient PM2.5 samples. Based on particulate concentrations of quinones and soluble metals from the literature, and our measured DTT responses for these species, we estimate that for typical fine particle samples approximately 80% of DTT loss is from transition metals (especially copper and manganese, while quinones account for approximately 20%. We find a similar result for DTT loss measured in a small set of PM2.5 samples from the San Joaquin Valley of California. Because of the important contribution from metals, we also tested how the DTT assay is affected by EDTA, a chelator that is sometimes used in the assay. EDTA significantly suppresses the response from both metals and quinones; we therefore recommend that EDTA should not be included in the DTT assay.

  11. Low-velocity pneumatic conveying in horizontal pipe for coarse particles and fine powders

    Institute of Scientific and Technical Information of China (English)

    Yuji Tomita; Vijay Kumar Agarwal; Hiroyuki Asou; Katsuya Funatsu

    2008-01-01

    First,the characteristics of low-velocity conveying of particles having different hardness are experimentally investigated in a horizontal pipeline in terms of flow pattern and pressure drop to show that the slug flow can be classified into two types depending on the settling of particles along the pipeline,and the period is small for slug flow without the settled layer,which is called solitary slug flow.The pressure drop for soft particles is shown to be larger than that for hard particles.Then,experimental results are presented on horizontal fluidized-bed conveying of fine powders to show that air release from the top surface of the conveying channel is an important factor for high mass flow rate of particles.

  12. The cumulative effects of using fine particles and cyanobacteria for rehabilitation of disturbed active sand dunes

    Science.gov (United States)

    Zaady, Eli; Katra, Itzhak; Barkai, Daniel; Knoll, Yaakov; Sarig, Shlomo

    2016-04-01

    One of the main problems in desertified lands worldwide is active wind-borne sand dunes, which lead to covering of fertile soils and agricultural fields. In regions with more than 100 mm of annual rainfall, sand dunes may be naturally stabilized by biocrusts (biological soil crusts). One of the main restraints of biocrust development is the typical lack of fine particles in sand dunes. Our study investigated the combined application of fine particles [coal fly-ash <100 micrometer] and bio-inoculant of filamentous cyanobacteria, isolated from nearby natural stabilized sand dunes, on the soil surface of active sands for increasing resistance to wind erosion. Boundary-layer wind tunnel experiments were conducted in experimental plots within a greenhouse for examining the effects of adding coal fly-ash and bio-inoculant to active sands. The biocrust development was evaluated via several physical and bio-physiological variables. In all the physical measurements and the bio-physiological variables, the treatment of "sand+inoculum+coal fly-ash" showed significant differences from the "sand-control". The combination led to the best results of surface stabilization in boundary-layer wind tunnel experiments, with the lowest sand fluxes. The filamentous cyanobacteria use the fine particles of the coal fly-ash as bridges for growing toward and adhering to the large sand particles. The cumulative effects of biocrusts and coal fly-ash enhance soil surface stabilization and may allow long-term sustainability.

  13. Electrophoretic deposition of adsorbed arsenic on fine iron oxide particles in tap water

    Science.gov (United States)

    Sharif, Syahira Mohd; Bakar, Noor Fitrah Abu; Naim, M. Nazli; Rahman, Norazah Abd; Talib, Suhaimi Abdul

    2016-02-01

    Electrophoretic deposition (EPD) technique has been demonstrated to remove arsenic with natural adsorbent (fine iron oxide particles) in tap water samples. Characterizations of metal element particularly arsenic and fine iron oxide particles in tap water from two different locations, i.e. commercial and residential areas, were conducted. Results showed that the concentration of arsenic in tap water from residential area was higher than commercial area samples i.e. 0.022 ± 0.004 and 0.016 ± 0.008 ppm, respectively. The same finding was observed in zeta potential value where it was higher in the residential area than commercial area, i.e. -42.27 ± 0.12 and -34.83 ± 0.23 mV, respectively. During the removal of arsenic using the EPD technique, direct current (DC) voltage was varied from 5 to 25V at a constant electrode distance of 30 mm. Effect of zeta potential, voltage and electrode type were intensively investigated. High percentage removal of arsenic was obtained from carbon plate than carbon fibre electrode. The percentage removal of arsenic from all samples slightly decreased with increasing of the applied voltage. EDX analysis confirmed that arsenic has adsorbed onto deposited iron oxide particles on the anode electrode. Overall, EPD technique was found to be successful in removing arsenic onto fine iron oxide particles in tap water with 26% ± 1.05 of removal.

  14. A novel permanently magnetised high gradient magnetic filter using assisted capture for fine particles

    Energy Technology Data Exchange (ETDEWEB)

    Watson, J.H.P. [Univ. of Southampton (United Kingdom)

    1995-02-01

    This paper describes the structure and properties of a novel permanently magnetised magnetic filter for fine friable radioactive material. Previously a filter was described and tested. This filter was designed so that the holes in the filter are left open as capture proceeds which means the pressure drop builds up only slowly. This filter is not suitable for friable composite particles which can be broken by mechanical forces. The structure of magnetic part of the second filter has been changed so as to strongly capture particles composed of fine particles weakly bound together which tend to break when captured. This uses a principle of assisted-capture in which coarse particles aid the capture of the fine fragments. The technique has the unfortunate consequence that the pressure drop across the filter rises faster as capture capture proceeds than the filter described previously. These filters have the following characteristics: (1) No external magnet is required. (2) No external power is required. (3) Small is size and portable. (4) Easily interchangeable. (5) Can be cleaned without demagnetising.

  15. The cumulative effects of using fine particles and cyanobacteria for rehabilitation of disturbed active sand dunes

    Science.gov (United States)

    Zaady, Eli; Katra, Itzhak; Barkai, Daniel; Knoll, Yaakov; Sarig, Shlomo

    2016-04-01

    One of the main problems in desertified lands worldwide is active wind-borne sand dunes, which lead to covering of fertile soils and agricultural fields. In regions with more than 100 mm of annual rainfall, sand dunes may be naturally stabilized by biocrusts (biological soil crusts). One of the main restraints of biocrust development is the typical lack of fine particles in sand dunes. Our study investigated the combined application of fine particles [coal fly-ash coal fly-ash and bio-inoculant to active sands. The biocrust development was evaluated via several physical and bio-physiological variables. In all the physical measurements and the bio-physiological variables, the treatment of "sand+inoculum+coal fly-ash" showed significant differences from the "sand-control". The combination led to the best results of surface stabilization in boundary-layer wind tunnel experiments, with the lowest sand fluxes. The filamentous cyanobacteria use the fine particles of the coal fly-ash as bridges for growing toward and adhering to the large sand particles. The cumulative effects of biocrusts and coal fly-ash enhance soil surface stabilization and may allow long-term sustainability.

  16. The measurement of mass and black carbon of fine particles over Klang valley, Kuala Lumpur

    International Nuclear Information System (INIS)

    Fine particles (PM 2.5) of airborne air pollutants samples were collected on weekly basis during the period from 2004-2008 at Klang Valley, Kuala Lumpur. They were analyzed for their mass and black carbon contents. Samples were collected using impactor type air pollutant sampler unit i.e Gent stack sampler capable of collecting of two (2) size groups of air particulate matter, fine (3 and the black carbon was 3.9 - 5.4 μg/m3. The component of BC was about 17% as relative to the gravimetric fine mass. The value for both PM 2.5 and BC were found to be slightly higher during the southwest monsoon May to September due to the haze occasion reported during this season. (Author)

  17. Mercury speciation and fine particle size distribution on combustion of Chinese coals

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Lei; Wang, Shuxiao; Hao, Jiming [Tsinghua Univ., Beijing (China). Dept. of Environmental Science and Engineering and State Key Joint Lab. of Environment Simulation and Pollution Control; Daukoru, Michael; Torkamani, Sarah; Biswas, Pratim [Washington Univ., St. Louis, MO (United States). Aerosol and Air Quality Research Lab.

    2013-07-01

    Coal combustion is the dominant anthropogenic mercury emission source of the world. Electrostatic precipitator (ESP) can remove almost all the particulate mercury (Hg{sub p}), and wet flue gas desulfurization (WFGD) can retain a large part of the gaseous oxidized mercury (Hg{sup 2+}). Only a small percentage of gaseous elemental mercury (Hg{sup 0}) can be abated by the air pollution control devices (APCDs). Therefore, the mercury behavior across APCDs largely depends on the mercury speciation in the flue gas exhausting from the coal combustor. To better understand the formation process of three mercury species, i.e. Hg{sup 0}, Hg{sup 2+} and Hg{sub p}, in gaseous phase and fine particles, bench-scale measurements for the flue gas exhausting from combustion of different types of coal in a drop-tube furnace set-up, were carried out. It was observed that with the limitation of reaction kinetics, higher mercury concentration in flue gas will lead to lower Hg{sup 2+} proportion. The concentration of chlorine has the opposite effect, not as significantly as that of mercury though. With the chlorine concentration increasing, the proportion of Hg{sup 2+} increases. Combusting the finer coal powder results in the formation of more Hg{sup 2+}. Mineral composition of coal and coal particle size has a great impact on fine particle formation. Al in coal is in favor of finer particle formation, while Fe in coal can benefit the formation of larger particles. The coexistence of Al and Si can strengthen the particle coagulation process. This process can also be improved by the feeding of more or finer coal powder. The oxy-coal condition can make for both the mercury oxidation process and the metal oxidation in the fine particle formation process.

  18. Empirical modeling of the fine particle fraction for carrier-based pulmonary delivery formulations

    Directory of Open Access Journals (Sweden)

    Pacławski A

    2015-01-01

    Full Text Available Adam Pacławski,1 Jakub Szlęk,1 Raymond Lau,2 Renata Jachowicz,1 Aleksander Mendyk1 1Department of Pharmaceutical Technology and Biopharmaceutics, Jagiellonian University Medical College, Kraków, Poland; 2School of Chemical and Biomedical Engineering, College of Engineering, Nanyang Technological University, Singapore Abstract: In vitro study of the deposition of drug particles is commonly used during development of formulations for pulmonary delivery. The assay is demanding, complex, and depends on: properties of the drug and carrier particles, including size, surface characteristics, and shape; interactions between the drug and carrier particles and assay conditions, including flow rate, type of inhaler, and impactor. The aerodynamic properties of an aerosol are measured in vitro using impactors and in most cases are presented as the fine particle fraction, which is a mass percentage of drug particles with an aerodynamic diameter below 5 µm. In the present study, a model in the form of a mathematical equation was developed for prediction of the fine particle fraction. The feature selection was performed using the R-environment package “fscaret”. The input vector was reduced from a total of 135 independent variables to 28. During the modeling stage, techniques like artificial neural networks, genetic programming, rule-based systems, and fuzzy logic systems were used. The 10-fold cross-validation technique was used to assess the generalization ability of the models created. The model obtained had good predictive ability, which was confirmed by a root-mean-square error and normalized root-mean-square error of 4.9 and 11%, respectively. Moreover, validation of the model using external experimental data was performed, and resulted in a root-mean-square error and normalized root-mean-square error of 3.8 and 8.6%, respectively. Keywords: fine particle fraction, pulmonary delivery, deposition modeling, genetic programming, feature selection

  19. Environmental Ultrafine, Fine and Coarse Particles in a Highway Tunnel and at a Roadside

    Czech Academy of Sciences Publication Activity Database

    Chen, S.C.; Tsai, C.J.; Chen, S.J.; Lin, C.C.; Chou, Ch.C.K.; Lung, S.C.; Roam, G.D.; Wu, W.Y.; Smolík, Jiří; Ondráčková, Lucie

    Prague : Orgit, 2009 - (Smolík, J.; O'Dowd, C.), S.200-203 ISBN 978-80-02-12161-2. [International Conference Nucleation and Atmospheric Aerosols /18./. Prague (CZ), 10.08.2009-14.08.2009] Grant ostatní: EPA (TW) 97/U1U1/02/106 Institutional research plan: CEZ:AV0Z40720504 Keywords : ultrafine particle * ambient aerosols * sampling and analysis Subject RIV: CF - Physical ; Theoretical Chemistry http://www.icnaa.cz/

  20. Restraint of fatigue crack growth by wedge effects of fine particles

    CERN Document Server

    Takahashi, I; Kotani, N

    2000-01-01

    Presents some experimental results which demonstrate restraint of fatigue crack growth in an Al-Mg alloy by wedge effects of fine particles. Fatigue test specimens were machined from a JIS A5083P-O Al-Mg alloy plate of 5 mm thickness and an EDM starter notch was introduced to each specimen. Three kinds of fine particles were prepared as the materials to be wedged into the fatigue cracks, i.e. magnetic particles and two kinds of alumina particles having different mean particle sizes of 47.3 mu m and 15.2 mu m. Particles of each kind were suspended in an oil to form a paste, which was applied on the specimen surface covering the notch zone prior to the fatigue tests. In order to make some fracture mechanics approaches, in situ observations of fatigue cracks were performed for the two cases using a CCD microscope, with a magnification of *1000. The crack length and the crack opening displacement (COD) at the notch root, delta , were measured. The crack retardation effect continues almost through the entire lifet...

  1. The 2005 Study of Organic Aerosols at Riverside (SOAR-1: instrumental intercomparisons and fine particle composition

    Directory of Open Access Journals (Sweden)

    K. S. Docherty

    2011-02-01

    Full Text Available Multiple state-of-the-art instruments sampled ambient aerosol in Riverside, California during the 2005 Study of Organic Aerosols at Riverside (SOAR to investigate sources and chemical composition of fine particles (PMf in the inland region of Southern California. This paper briefly summarizes the spatial, meteorological and gas-phase conditions during SOAR-1 (15 July–15 August and provides detailed intercomparisons of complementary measurements and average PMf composition during this period. Daily meteorology and gas-phase species concentrations were highly repetitive with meteorological and gas-phase species concentrations displaying clear diurnal cycles and weekday/weekend contrast, with organic aerosol (OA being the single largest component contributing approximately one-third of PMf mass. In contrast with historical characterizations of OA in the region, several independent source apportionment efforts attributed the vast majority (~80% of OA mass during SOAR-1 to secondary organic aerosol (SOA. Given the collocation of complementary aerosol measurements combined with a dominance of SOA during SOAR-1, this paper presents new results on intercomparisons among several complementary measurements and on PMf composition during this period. Total non-refractory submicron (NR-PM1 measurements from a high-resolution aerosol mass spectrometer (HR-AMS are compared with measurements by tapered element oscillating microbalances (TEOM including a filter dynamics measurement system (TEOMFDMS. NR-PM1 is highly correlated with PM2.5 TEOMFDMS measurements and accounts for the bulk of PM2.5 mass with the remainder contributed primarily by refractory material. In contrast, measurements from a heated TEOM show substantial losses of semi-volatile material, including ammonium nitrate and semi-volatile organic material. Speciated HR-AMS measurements are

  2. Rotational particle separator: a new method for separating fine particles and mists from gases

    OpenAIRE

    Brouwers, Bert

    1996-01-01

    An account is given of the patented technique of the rotational particle separator for separating solid and liquid particles of diameter 0.1 µm and larger from gases. Attention is focused on the working principle, fluid mechanical constraints, particle design, separation performance, power consumption, dimensions, filter cleaning and costs. Furthermore, an overview is given of current developments to introduce this technique in industrial dust removal, in electricity generation and in the con...

  3. High-resolving electrostatic charged particles energy analyzer with fine tuning for space investigations

    International Nuclear Information System (INIS)

    The paper presents results of numerical calculations of a high-resolving electrostatic energy analyzer, based on a bounded cylindrical field, for investigations of flows of charged particles in space. The analyzer possesses with ability of fine tuning of focusing characteristics, using an additional tuning potential, applied to one of electrodes. A combination of high energy resolution ability with high transmission, simple design and compactness makes this instrument very promising for space technologies

  4. Induction of oxidative stress and inhibition of plasminogen activator inhibitor-1 production in endothelial cells following exposure to organic extracts of diesel exhaust particles and urban fine particles

    Energy Technology Data Exchange (ETDEWEB)

    Furuyama, Akiko; Koike, Eiko [National Institute for Environmental Studies, Inhalation toxicology Team, Tsukuba (Japan); Hirano, Seishiro [National Institute for Environmental Studies, Environmental Health Sciences Division, Tsukuba (Japan); Kobayashi, Takahiro [National Institute for Environmental Studies, Inhalation toxicology Team, Tsukuba (Japan); National Institute for Environmental Studies, Environmental Health Sciences Division, Tsukuba (Japan)

    2006-03-15

    Endothelial cells play important roles in anticoagulant and fibrinolytic systems. Recent studies suggest that increases in ambient particulate matter (PM) levels have been associated with an increase in mortality rate from cardiovascular diseases. We examined the production of heme oxygenase-1 (HO-1) and factors related to the fibrinolytic function by rat heart microvessel endothelial cells exposed to organic extracts of diesel exhaust particles (OE-DEP) and urban fine particles (OE-UFP) to investigate the direct effects of these soluble organic fractions in these PM on the fibrinolytic function of endothelial cells. The cell monolayer exposed to 10 {mu}g/ml OE-DEP produced a larger amount of HO-1 than cells exposed to 10 {mu}g/ml OE-UFP. OE-DEP and OE-UFP exposure reduced plasminogen activator inhibitor-1 (PAI-1) production by the cells but did not affect the production of thrombomodulin, tissue-type plasminogen activator, or urokinase-type plasminogen activator. Increased PAI-1 synthesis in response to treatment with 1.0 ng/ml tumor necrosis factor-{alpha} or 0.5 ng/ml transforming growth factor-{beta}1 was reduced by OE-DEP exposure. Suppression of PAI-1 production by OE-DEP exposure was mediated through oxidative stress and was independent of HO-1 activity. These results suggest that exposure to the soluble organic fraction of PM and DEP induced oxidative stress and reduced the PAI-1 production of endothelial cells. (orig.)

  5. Spatial coherences of the sound pressure and the particle velocity in underwater ambient noise

    Institute of Scientific and Technical Information of China (English)

    YAN Jin; LUO Xianzhi; HOU Chaohuan

    2007-01-01

    The spatial coherences were investigated between the sound pressure and the three orthogonal components of the particle velocity in underwater ambient noise. Based on the ray theory, integral expression was derived for the spatial coherence matrix of the sound pressure and the particle velocity in a stratified ocean with dipole noise sources homogenously distributed on the surface. The integrand includes a multiplying factor of the vertical directivity of the noise intensity, and the layered ocean environment affects the spatial coherences via this directivity factor. For a shallow water environment and a semi-infinite homogenous medium, the coherence calculation results were given. It was showed that the sound speed profile and the sea bottom could not be neglected in determining the spatial coherences of the ambient noise vector field.

  6. High volume electrostatic field-sampler for collection of fine particle bulk samples

    Science.gov (United States)

    Kumar Sharma, Anoop; Wallin, Håkan; Alstrup Jensen, Keld

    A high volume electrostatic field-sampler was developed for collection of fine particles, which easily can be recovered for subsequent sample characterisation and bioassays. The sampler was based on a commercial office air cleaner and consisted of a prefilter followed by electrostatic collection plates operating at 2.7 kV. The sampler performance was characterised for 26 nm to 5.4 μm-size particles in urban street air. The collection efficiency reached a maximum (60-70%) between 0.2 and 0.8 μm and dropped to ˜25% at 30 nm and 2.5 μm, respectively. After extraction in water, the particle loss wasozone generating capacity of the corona discharge during operation was on the order of 10 ppb. A polycyclic aromatic hydrocarbons (PAH) degradation test using benzo[a]pyrene as a model showed that ˜85% was degraded after 24 h. However, similar results were observed when the corona discharge was switched off. Hence, the ozone and other corona discharge reactants do not appear to contribute considerably to PAH-degradation. The overall results show that the sampler type is a promising alternative to traditional sampling of fine particles for bulk analysis and bioassays. The main advantages are simple operation, high stability, high quantifiable particle recovery rates and low cost.

  7. Fe fine particles encapsulated by titanium oxides with high magnetization for biomedical application

    International Nuclear Information System (INIS)

    Iron (Fe) fine particles encapsulated by titanium oxide (TiO2) were synthesized through a solid-phase reaction. The structure of Fe cores and TiO2 shells consisted of α-Fe and rutile TiO2, respectively. The average particle size was 0.8 μm, in which a Fe particle with a diameter of ∼750 nm was encapsulated by a TiO2 shell with a thickness of ∼100 nm. The Fe particles had a high saturation magnetization of 127 Am2/kg and low coercivity of 1.6 kA/m. They also exhibited excellent corrosion resistance, similar to Fe3O4 in a soaking test

  8. Briquetting of coal fines and sawdust - effect of particle-size distribution

    Energy Technology Data Exchange (ETDEWEB)

    Patil, D.P.; Taulbee, D.; Parekh, B.K.; Honaker, R. [University of Kentucky, Lexington, KY (United States). Center for Applied Energy Research

    2009-07-01

    The coal industry usually discards fine-size (-150 microns) coal because of its high-moisture content and handling problems. One avenue for utilization is to either pelletize or briquette this material. However, industry has not adopted this route due in large part to significant drying and binder costs. In an effort to reduce these costs, compacting and briquetting studies were conducted to determine the effect of combining a coarse (1.18x0.15mm) spiral separator product with a fine coal flotation product (-150microns), with and without adding sawdust. Maximizing the packing density of the coal and wood waste mixture could potentially reduce the binder requirement by minimizing the void space as well as reducing shipping costs. Accordingly, work reported here focused on evaluating the impact of the particle-size distribution of different blends of fine and coarse coal, with and without sawdust and/or binder. The modified Proctor density of compacted blends along with the porosity and compressive strengths of briquettes made from each blend were determined. For the coal-only blends, the packing density was maximized by a relatively high (70% to 80%) coarse coal content. However, the packing density did not correlate with the compressive strength of the briquette that instead maximized with 100% fine flotation coal and continuously decreased as higher proportions of coarse coal were added. Similar compaction and compressive-strength results were obtained with mixtures of sawdust and varying proportions of coarse and fine coal. With the addition of a binder, the highest strengths were no longer obtained with 100% fine coal but instead maximized between 20% and 50% coarse coal addition depending on how long the briquettes were cured.

  9. Quantifying short-term and long-term health benefits of attaining ambient fine particulate pollution standards in Guangzhou, China

    Science.gov (United States)

    Lin, Hualiang; Liu, Tao; Xiao, Jianpeng; Zeng, Weilin; Li, Xing; Guo, Lingchuan; Xu, Yanjun; Zhang, Yonghui; Vaughn, Michael G.; Nelson, Erik J.; Qian, Zhengmin (Min); Ma, Wenjun

    2016-07-01

    In 2012, Chinese Environmental Bureau modified its National Ambient Air Quality Standards to include fine particulate matter (PM2.5). Recent air pollution monitoring data shows that numerous locations have exceeded this standard, which may have resulted in avoidable adverse health effects. For example, among the 74 Chinese cities with PM2.5 monitoring data in 2013, only three cities attained the annual air quality standard (35 μg/m3). This study aimed to quantify the potential short- and long-term health benefits from achieving the Chinese ambient air quality standard and WHO's air quality objectives. A generalized additive model was used to estimate the short-term association of mortality with changes in daily PM2.5 concentrations, based on which we estimated the potential premature mortality reduction that would have been achieved during the period of 2012-2015 if the daily air quality standard had been met in Guangzhou, China; we also estimated the avoidable deaths if attaining the annual air quality standard using the relative risk obtained from a previous cohort study. During the study period, there were 160 days exceeding the national daily PM2.5 standard (75 μg/m3) in Guangzhou, and the annual average concentration (47.7 μg/m3) was higher than the air quality standard of 35 μg/m3. Significant associations between PM2.5 and mortality were observed. An increase of 10 μg/m3 in PM2.5 was associated with increases in daily death counts of 0.95% (95% CI: 0.56%, 1.34%) in natural mortality, 1.31% (95% CI: 0.75%, 1.87%) in cardiovascular mortality, and 1.06% (95% CI: 0.19%, 1.94%) in respiratory mortality. The health benefits of attaining the national daily air quality standard of PM2.5 (75 μg/m3) would have prevented 143 [95% confidence interval (CI): 84, 203] fewer natural deaths, including 84 (95% CI: 48, 121) fewer cardiovascular deaths and 27 (95% CI: 5, 49) fewer respiratory deaths. Had the annual PM2.5 levels been reduced to 35 μg/m3, an estimated 3875

  10. Comparison of physicochemical properties between fine (PM2.5) and coarse airborne particles at cold season in Korea.

    Science.gov (United States)

    Choung, Sungwook; Oh, Jungsun; Han, Weon Shik; Chon, Chul-Min; Kwon, Youngsang; Kim, Do Yeon; Shin, Woosik

    2016-01-15

    Although it has been well-known that atmospheric aerosols affect negatively the local air quality, human health, and climate changes, the chemical and physical properties of atmospheric aerosols are not fully understood yet. This study experimentally measured the physiochemical characteristics of fine and coarse aerosol particles at the suburban area to evaluate relative contribution to environmental pollution in consecutive seasons of autumn and winter, 2014-2015, using XRD, SEM-EDX, XNI, ICP-MS, and TOF-SIMS. For these experimental works, the fine and coarse aerosols were collected by the high volume air sampler for 7 days each season. The fine particles contain approximately 10 μg m(-3) of carbonaceous aerosols consisting of 90% organic and 10% elemental carbon. The spherical-shape carbonaceous particles were observed for the coarse samples as well. Interestingly, the coarse particles in winter showed the increased frequency of carbon-rich particles with high contents of heavy metals. These results suggest that, for the cold season, the coarse particles could contribute relatively more to the conveyance of toxic contaminants compared to the fine particles in the study area. However, the fine particles showed acidic properties so that their deposition to surface may cause facilitate the increase of mobility for toxic heavy metals in soil and groundwater environments. The fine and coarse particulate matters, therefore, should be monitored separately with temporal variation to evaluate the impact of atmospheric aerosols to environmental pollution and human health. PMID:26476059

  11. Fine lattice stochastic modeling of particle fuels in HTGR fuel elements

    International Nuclear Information System (INIS)

    There is growing interest worldwide in high temperature gas-cooled reactors (HTGRs) as candidates for next generation reactor systems. Either in a pebble type or in a prismatic type HTGR, coated particle fuel (TRISO fuel) appears to be the most promising fuel candidate to be used. For design and analysis of such a reactor, transport models, in particular, stochastic models that permit the simulation of neutron transport through the stochastic mixture of fuel and moderator materials, are becoming essential and gaining importance. Naturally, the Monte Carlo methods have been used for this situation. However, the methods reported in the literature all have their own deficiencies. In this thesis, we propose a new Monte Carlo method named fine lattice stochastic (FLS) modeling that is distinct from others. This method is based on fine lattice system in which a lattice circumscribes a fuel particle. Once the problem is given, an interface Fortran code gives out the TRISO particle fuel configurations (a set of lattice center points only) for MCNP input. The number of available lattice center points is far larger than the number of fuel particles according to packing fraction of the fuel element. We apply discrete random sampling here to choose a certain number of lattices to fill with fuel particles. In this aspect, FLS modeling allows more realistic fuel particle distributions. In this thesis, only simple cube (SC) structure is used in cubic lattice. However, FLS model can be easily extended to BCC, FCC structures or hexagonal prism type lattice. The criticality calculations for our FLS modeling were first tested on a small cube problem and compared with other models. The results indicate that the new stochastic model is an accurate and efficient approach to analyze TRISO particle fuel configurations. Then the FLS modeling was performed to analyze HTGR fuel elements for both pebble type and prismatic type and the results were also good as expected

  12. Affinity of finely dispersed montmorillonite colloidal particles for americium and lanthanides

    International Nuclear Information System (INIS)

    We studied (i) the affinity of the finely dispersed montmorillonite colloidal particles (3+ and lanthanide ions (Ln3+: Nd3+, Eu3+, Gd3+), and (ii) the differences between the sorption behavior of Am3+ and Ln3+ onto the colloidal particles and that onto the massive montmorillonite solids. The ion-exchange stoichiometry of sorption reaction of Am3+ and Ln3+ onto the colloidal particles was 1:3 in the low Na+ concentration region. In the high Na+ concentration region, the sorption ratio was constant, and specific for Am3+ and each Ln3+. The influence of Na+ and Ca2+ on the sorption of Ln3+ onto the finely dispersed Na- and Ca-montmorillonite colloidal particles at different NaCl and CaCl2 concentrations was examined. It was found that the coverage of the sorption sites increased with the Ln3+ concentration. The affinity for Ln3+ was discussed by selectivity and a Langmuir-type isotherm. (orig.)

  13. Measurement of ambient aerosols in northern Mexico City by single particle mass spectrometry

    Directory of Open Access Journals (Sweden)

    R. C. Moffet

    2007-05-01

    Full Text Available Continuous ambient measurements with aerosol time-of-flight mass spectrometry (ATOFMS were carried out in an industrial/residential section in the northern part of Mexico City as part of the Mexico City Metropolitan Area – 2006 campaign (MCMA-2006 between 7–27 March, 2006. Biomass and organic carbon (OC particle types were found to dominate the accumulation mode both day and night. The concentrations of both organic carbon and biomass particles were roughly equal early in the morning, but biomass became the largest contributor to the accumulation mode mass from the late morning until early evening. The diurnal pattern can be attributed to aging and/or a change in meteorology. Fresh elemental carbon (EC particles were observed during rush hour. The majority of the EC particles were mixed with nitrate, sulfate, organic carbon and potassium. Submicron particles from industrial sources in the northeast were composed of an internal mixture of Pb, Zn, EC and Cl and peaked early in the morning. A unique nitrogen-containing organic (NOC particle type was observed, and is hypothesized to be from industrial emissions based on the temporal profile and back trajectory analysis. This study provides unique insights into the real-time changes in single particle mixing state as a function of size and time for aerosols in Mexico City. These new findings indicate that biomass burning and industrial operations make significant contributions to particles in Mexico City. These sources have received relatively little attention in previous intensive field campaigns.

  14. Individual Particle Analysis of Ambient PM 2.5 Using Advanced Electron Microscopy Techniques

    Energy Technology Data Exchange (ETDEWEB)

    Gerald J. Keeler; Masako Morishita

    2006-12-31

    The overall goal of this project was to demonstrate a combination of advanced electron microscopy techniques that can be effectively used to identify and characterize individual particles and their sources. Specific techniques to be used include high-angle annular dark field scanning transmission electron microscopy (HAADF-STEM), STEM energy dispersive X-ray spectrometry (EDX), and energy-filtered TEM (EFTEM). A series of ambient PM{sub 2.5} samples were collected in communities in southwestern Detroit, MI (close to multiple combustion sources) and Steubenville, OH (close to several coal fired utility boilers). High-resolution TEM (HRTEM) -imaging showed a series of nano-metal particles including transition metals and elemental composition of individual particles in detail. Submicron and nano-particles with Al, Fe, Ti, Ca, U, V, Cr, Si, Ba, Mn, Ni, K and S were observed and characterized from the samples. Among the identified nano-particles, combinations of Al, Fe, Si, Ca and Ti nano-particles embedded in carbonaceous particles were observed most frequently. These particles showed very similar characteristics of ultrafine coal fly ash particles that were previously reported. By utilizing HAADF-STEM, STEM-EDX, and EF-TEM, this investigation was able to gain information on the size, morphology, structure, and elemental composition of individual nano-particles collected in Detroit and Steubenville. The results showed that the contributions of local combustion sources - including coal fired utilities - to ultrafine particle levels were significant. Although this combination of advanced electron microscopy techniques by itself can not identify source categories, these techniques can be utilized as complementary analytical tools that are capable of providing detailed information on individual particles.

  15. Physicochemical characteristics and occupational exposure to coarse, fine and ultrafine particles during building refurbishment activities

    International Nuclear Information System (INIS)

    Understanding of the emissions of coarse (PM10 ≤10 μm), fine (PM2.5 ≤2.5 μm) and ultrafine particles (UFP <100 nm) from refurbishment activities and their dispersion into the nearby environment is of primary importance for developing efficient risk assessment and management strategies in the construction and demolition industry. This study investigates the release, occupational exposure and physicochemical properties of particulate matter, including UFPs, from over 20 different refurbishment activities occurring at an operational building site. Particles were measured in the 5–10,000-nm-size range using a fast response differential mobility spectrometer and a GRIMM particle spectrometer for 55 h over 8 days. The UFPs were found to account for >90 % of the total particle number concentrations and <10 % of the total mass concentrations released during the recorded activities. The highest UFP concentrations were 4860, 740, 650 and 500 times above the background value during wall-chasing, drilling, cementing and general demolition activities, respectively. Scanning electron microscopy, X-ray photoelectron spectroscopy and ion beam analysis were used to identify physicochemical characteristics of particles and attribute them to probable sources considering the size and the nature of the particles. The results confirm that refurbishment activities produce significant levels (both number and mass) of airborne particles, indicating a need to develop appropriate regulations for the control of occupational exposure of operatives undertaking building refurbishment.

  16. Physicochemical characteristics and occupational exposure to coarse, fine and ultrafine particles during building refurbishment activities

    Energy Technology Data Exchange (ETDEWEB)

    Azarmi, Farhad; Kumar, Prashant, E-mail: p.kumar@surrey.ac.uk, E-mail: prashant.kumar@cantab.net; Mulheron, Mike [University of Surrey, Department of Civil and Environmental Engineering, Faculty of Engineering and Physical Sciences (United Kingdom); Colaux, Julien L.; Jeynes, Chris [University of Surrey, Faculty of Engineering and Physical Sciences, Ion Beam Centre (United Kingdom); Adhami, Siavash; Watts, John F. [University of Surrey, The Surface Analysis Laboratory, Faculty of Engineering and Physical Sciences (United Kingdom)

    2015-08-15

    Understanding of the emissions of coarse (PM{sub 10} ≤10 μm), fine (PM{sub 2.5} ≤2.5 μm) and ultrafine particles (UFP <100 nm) from refurbishment activities and their dispersion into the nearby environment is of primary importance for developing efficient risk assessment and management strategies in the construction and demolition industry. This study investigates the release, occupational exposure and physicochemical properties of particulate matter, including UFPs, from over 20 different refurbishment activities occurring at an operational building site. Particles were measured in the 5–10,000-nm-size range using a fast response differential mobility spectrometer and a GRIMM particle spectrometer for 55 h over 8 days. The UFPs were found to account for >90 % of the total particle number concentrations and <10 % of the total mass concentrations released during the recorded activities. The highest UFP concentrations were 4860, 740, 650 and 500 times above the background value during wall-chasing, drilling, cementing and general demolition activities, respectively. Scanning electron microscopy, X-ray photoelectron spectroscopy and ion beam analysis were used to identify physicochemical characteristics of particles and attribute them to probable sources considering the size and the nature of the particles. The results confirm that refurbishment activities produce significant levels (both number and mass) of airborne particles, indicating a need to develop appropriate regulations for the control of occupational exposure of operatives undertaking building refurbishment.

  17. Acoustic agglomeration of fine particles based on a high intensity acoustical resonator

    Science.gov (United States)

    Zhao, Yun; Zeng, Xinwu; Tian, Zhangfu

    2015-10-01

    Acoustic agglomeration (AA) is considered to be a promising method for reducing the air pollution caused by fine aerosol particles. Removal efficiency and energy consuming are primary parameters and generally have a conflict with each other for the industry applications. It was proved that removal efficiency is increased with sound intensity and optimal frequency is presented for certain polydisperse aerosol. As a result, a high efficiency and low energy cost removal system was constructed using acoustical resonance. High intensity standing wave is generated by a tube system with abrupt section driven by four loudspeakers. Numerical model of the tube system was built base on the finite element method, and the resonance condition and SPL increase were confirmd. Extensive tests were carried out to investigate the acoustic field in the agglomeration chamber. Removal efficiency of fine particles was tested by the comparison of filter paper mass and particle size distribution at different operating conditions including sound pressure level (SPL), and frequency. The experimental study has demonstrated that agglomeration increases with sound pressure level. Sound pressure level in the agglomeration chamber is between 145 dB and 165 dB from 500 Hz to 2 kHz. The resonance frequency can be predicted with the quarter tube theory. Sound pressure level gain of more than 10 dB is gained at resonance frequency. With the help of high intensity sound waves, fine particles are reduced greatly, and the AA effect is enhanced at high SPL condition. The optimal frequency is 1.1kHz for aerosol generated by coal ash. In the resonace tube, higher resonance frequencies are not the integral multiplies of the first one. As a result, Strong nonlinearity is avoided by the dissonant characteristic and shock wave is not found in the testing results. The mechanism and testing system can be used effectively in industrial processes in the future.

  18. Tribological Properties of Aluminum Alloy treated by Fine Particle Peening/DLC Hybrid Surface Modification

    Directory of Open Access Journals (Sweden)

    Nanbu H.

    2010-06-01

    Full Text Available In order to improve the adhesiveness of the DLC coating, Fine Particle Peening (FPP treatment was employed as pre-treatment of the DLC coating process. FPP treatment was performed using SiC shot particles, and then AA6061-T6 aluminum alloy was DLC-coated. A SiC-rich layer was formed around the surface of the aluminum alloy by the FPP treatment because small chips of shot particles were embedded into the substrate surface. Reciprocating sliding tests were conducted to measure the friction coefficients. While the DLC coated specimen without FPP treatment showed a sudden increase in friction coefficient at the early stage of the wear cycles, the FPP/DLC hybrid treated specimen maintained a low friction coefficient value during the test period. Further investigation revealed that the tribological properties of the substrate after the DLC coating were improved with an increase in the amount of Si at the surface.

  19. XRF-analysis of fine and ultrafine particles emitted from laser printing devices.

    Science.gov (United States)

    Barthel, Mathias; Pedan, Vasilisa; Hahn, Oliver; Rothhardt, Monika; Bresch, Harald; Jann, Oliver; Seeger, Stefan

    2011-09-15

    In this work, the elemental composition of fine and ultrafine particles emitted by ten different laser printing devices (LPD) is examined. The particle number concentration time series was measured as well as the particle size distributions. In parallel, emitted particles were size-selectively sampled with a cascade impactor and subsequently analyzed by the means of XRF. In order to identify potential sources for the aerosol's elemental composition, materials involved in the printing process such as toner, paper, and structural components of the printer were also analyzed. While the majority of particle emissions from laser printers are known to consist of recondensated semi volatile organic compounds, elemental analysis identifies Si, S, Cl, Ca, Ti, Cr, and Fe as well as traces of Ni and Zn in different size fractions of the aerosols. These elements can mainly be assigned to contributions from toner and paper. The detection of elements that are likely to be present in inorganic compounds is in good agreement with the measurement of nonvolatile particles. Quantitative measurements of solid particles at 400 °C resulted in residues of 1.6 × 10(9) and 1.5 × 10(10) particles per print job, representing fractions of 0.2% and 1.9% of the total number of emitted particles at room temperature. In combination with the XRF results it is concluded that solid inorganic particles contribute to LPD emissions in measurable quantities. Furthermore, for the first time Br was detected in significant concentrations in the aerosol emitted from two LPD. The analysis of several possible sources identified the plastic housings of the fuser units as main sources due to substantial Br concentrations related to brominated flame retardants. PMID:21809840

  20. Combustion characteristics of water-insoluble elemental and organic carbon in size selected ambient aerosol particles

    Directory of Open Access Journals (Sweden)

    K. Wittmaack

    2005-04-01

    Full Text Available Combustion of elemental carbon (EC and organic carbon (OC contained in ambient aerosol matter was explored using scanning electron microscopy (SEM in combination with energy dispersive X-ray analysis (EDX. To ease identification of the particles of interest and to avoid or at least reduce interaction with simultaneously sampled inorganic oxides and salts, the approach used in this work differed in two ways from commonly applied procedures. First, rather than using a mixture of particles of vastly different sizes, as in PM10 or PM2.5, aerosol matter was collected in a 5-stage impactor. Second, the water soluble fraction of the collected matter was removed prior to analysis. Diesel soot particles, which appeared in the well-known form of chain-type aggregates, constituted the major fraction of EC. In contrast, OC containing particles were observed in a variety of shapes, including a sizable amount of bioaerosol matter appearing mostly in the size range above about 1 µm. During heating in ambient air for 1 h, diesel soot particles were found to be stable up to 480°C, but complete combustion occurred in a narrow temperature interval between about 490 and 510°C. After diesel soot combustion, minute quantities of ''ash'' were observed in the form of aggregated tiny particles with sizes less than 10 nm. These particles could be due to elemental or oxidic contaminants of diesel soot. Combustion of OC was observed over a wide range of temperatures, from well below 200°C to at least 500°C. Incompletely burnt bioaerosol matter was still found after heating to 600°C. The results imply that the EC fraction in aerosol matter can be overestimated significantly if the contribution of OC to a thermogram is not well separated.

  1. Combustion characteristics of water-insoluble elemental and organic carbon in size selected ambient aerosol particles

    Directory of Open Access Journals (Sweden)

    K. Wittmaack

    2005-01-01

    Full Text Available Combustion of elemental carbon (EC and organic carbon (OC contained in ambient aerosol matter was explored using scanning electron microscopy (SEM in combination with energy dispersive X-ray analysis (EDX. To ease identification of the particles of interest and to avoid or at least reduce interaction with simultaneously sampled inorganic oxides and salts, the approach used in this work differed in two ways from commonly applied procedures. First, rather than using a mixture of particles of vastly different sizes, as in PM10 or PM2.5, aerosol matter was collected in a 5-stage impactor. Second, the water soluble fraction of the collected matter was removed prior to analysis. Diesel soot particles, which appeared in the well-known form of chain-type aggregates, constituted the major fraction of EC. In contrast, OC containing particles were observed in a variety of shapes, including a sizable amount of bioaerosol matter appearing mostly in the size range above about 1 µm. During heating in ambient air for 1h, diesel soot particles were found to be stable up to 470°C, but complete combustion occurred in a narrow temperature interval between about 480 and 510°C. After diesel soot combustion, minute quantities of 'ash' were observed in the form of aggregated tiny particles with sizes less than 10 nm. These particles could be due to elemental or oxidic contaminants of diesel soot. Combustion of OC was observed over a wide range of temperatures, from well below 200°C to at least 500°C. Incompletely burnt bioaerosol matter was still found after heating to 600°C. The results imply that the EC fraction in aerosol matter can be overestimated significantly if the contribution of OC to a thermogram is not well separated.

  2. Contrasting macrophage activation by fine and ultrafine titanium dioxide particles is associated with different uptake mechanisms

    Directory of Open Access Journals (Sweden)

    Schmidt Annette M

    2011-10-01

    Full Text Available Abstract Inhalation of (nanoparticles may lead to pulmonary inflammation. However, the precise mechanisms of particle uptake and generation of inflammatory mediators by alveolar macrophages (AM are still poorly understood. The aim of this study was to investigate the interactions between particles and AM and their associated pro-inflammatory effects in relation to particle size and physico-chemical properties. NR8383 rat lung AM were treated with ultrafine (uf, fine (f TiO2 or fine crystalline silica (DQ12 quartz. Physico-chemical particle properties were investigated by transmission electron microscopy, elemental analysis and thermogravimetry. Aggregation and agglomeration tendency of the particles were determined in assay-specific suspensions by means of dynamic light scattering. All three particle types were rapidly taken up by AM. DQ12 and ufTiO2 , but not fTiO2 , caused increased extracellular reactive oxygen species (ROS, heme oxygenase 1 (HO-1 mRNA expression and tumor necrosis factor (TNF-α release. Inducible nitric oxide synthase (iNOS mRNA expression was increased most strongly by ufTiO2 , while DQ12 exclusively triggered interleukin (IL 1β release. However, oscillations of intracellular calcium concentration and increased intracellular ROS were observed with all three samples. Uptake inhibition experiments with cytochalasin D, chlorpromazine and a Fcγ receptor II (FcγRII antibody revealed that the endocytosis of fTiO2 by the macrophages involves actin-dependent phagocytosis and macropinocytosis as well as clathrin-coated pit formation, whereas the uptake of ufTiO2 was dominated by FcγIIR. The uptake of DQ12 was found to be significantly reduced by all three inhibitors. Our findings suggest that the contrasting AM responses to fTiO2 , ufTiO2 and DQ12 relate to differences in the involvement of specific uptake mechanisms.

  3. 78 FR 55225 - Determination of Attainment for the Chico Nonattainment Area for the 2006 Fine Particle Standard...

    Science.gov (United States)

    2013-09-10

    ... Fine Particle Implementation Rule'' (72 FR 20586, April 25, 2007) and the ``Implementation of the New... AGENCY 40 CFR Part 52 Determination of Attainment for the Chico Nonattainment Area for the 2006 Fine... Executive Order Reviews I. Summary of EPA's Proposed Action On October 30, 2012 (77 FR 65651), EPA...

  4. Preparation of semi-solid slurry containing fine and globular particles for wrought aluminum alloy 2024

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The semi-solid slurry of wrought aluminum alloy 2024 was prepared by a well developed rheocasting process, low superheat pouring with shearing field(LSPSF). The appreciate combination of pouring temperature and rotation speed of barrel, can give rise to a transition of the growth morphology of primary α(Al) from coarse-dendritic to coarse-particle-like and further to fine-globular. The combined effects of both localized rapid cooling and vigorous mixing during the initial stage of solidification can enhance wall nucleation and nuclei survival, which leads to the formation of fine-globular primary α(Al). By using semi-solid slurry prepared by LSPSF, direct squeeze cast cup-shaped component with improved mechanical properties such as yield strength of 198MPa, ultimate tensile strength of 306 MPa and elongation of 10.4%, can be obtained.

  5. Response of spontaneously hypertensive rats to inhalation of fine and ultrafine particles from traffic: experimental controlled study

    Directory of Open Access Journals (Sweden)

    Dormans Jan AMA

    2006-05-01

    Full Text Available Abstract Background Many epidemiological studies have shown that mass concentrations of ambient particulate matter (PM are associated with adverse health effects in the human population. Since PM is still a very crude measure, this experimental study has explored the role of two distinct size fractions: ultrafine (3 to 3613 μg/m3 for fCAP and from 269μg/m3 to 556 μg/m3 for u+fCAP. Results Ammonium, nitrate, and sulphate ions accounted for 56 ± 16% of the total fCAP mass concentrations, but only 17 ± 6% of the u+fCAP mass concentrations. Unambiguous particle uptake in alveolar macrophages was only seen after u+fCAP exposures. Neither fCAP nor u+fCAP induced significant changes of cytotoxicity or inflammation in the lung. However, markers of oxidative stress (heme oxygenase-1 and malondialdehyde were affected by both fCAP and u+fCAP exposure, although not always significantly. Additional analysis revealed heme oxygenase-1 (HO-1 levels that followed a nonmonotonic function with an optimum at around 600 μg/m3 for fCAP. As a systemic response, exposure to u+fCAP and fCAP resulted in significant decreases of the white blood cell concentrations. Conclusion Minor pulmonary and systemic effects are observed after both fine and ultrafine + fine PM exposure. These effects do not linearly correlate with the CAP mass. A greater component of traffic CAP and/or a larger proportion ultrafine PM does not strengthen the absolute effects.

  6. Highly time-resolved chemical characterization of atmospheric fine particles during 2010 Shanghai World Expo

    Directory of Open Access Journals (Sweden)

    X.-F. Huang

    2012-01-01

    Full Text Available Shanghai, with a population of over 20 million, is the largest mega-city in China. Rapidly increasing industrial and metropolitan emissions have deteriorated its air quality in the past decades, with fine particle pollution as one of the major issues. However, systematic characterization of atmospheric fine particles with advanced measurement techniques has been very scarce in Shanghai. During 2010 Shanghai World Expo, we deployed a high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS and a single particle soot photometer (SP2 in urban Shanghai between 15 May and 10 June 2010 to measure fine particles with a high time resolution. The 4-min resolution PM1 mass concentration ranged from 5.5 to 155 μg m−3, with an average of 29.2 μg m−3. On average, sulfate and organic matter (OM were the most abundant PM1 components, accounting for 33.3 and 28.7% of the total mass, respectively, while the fraction of nitrate showed an increasing trend with the increasing PM1 loading, indicating the photochemical nature of high fine particle pollution in Shanghai. Taking advantage of HR-ToF-AMS and SP2, OM was found to have an average OM/OC ratio (organic matter mass/organic carbon mass of 1.55 and black carbon (BC had an average number fraction of internally mixed BC of 41.2%. Positive matrix factorization (PMF analysis on the high resolution organic mass spectral dataset identified a hydrocarbon-like (HOA, a semi-volatile oxygenated (SV-OOA, and a low-volatility oxygenated (LV-OOA organic aerosol component, which on average accounted for 24.0, 46.8, and 29.2% of the total organic mass, respectively. The diurnal patterns of them with interesting time delay possibly implied a photochemical oxidizing process from HOA (and/or its concurrently emitted gaseous organic pollutants to SV-OOA to LV-OOA. Back trajectory analysis indicated that the northwesterly continental air mass represented the

  7. Chemo-Mechanical Characteristics of Mud Formed from Environmental Dust Particles in Humid Ambient Air

    Science.gov (United States)

    Hassan, Ghassan; Yilbas, B. S.; Said, Syed A. M.; Al-Aqeeli, N.; Matin, Asif

    2016-01-01

    Mud formed from environmental dust particles in humid ambient air significantly influences the performance of solar harvesting devices. This study examines the characterization of environmental dust particles and the chemo-mechanics of dry mud formed from dust particles. Analytical tools, including scanning electron microscopy, atomic force microscopy, energy dispersive spectroscopy, particle sizing, and X-ray diffraction, are used to characterize dry mud and dust particles. A micro/nano tribometer is used to measure the tangential force and friction coefficient while tensile tests are carried out to assess the binding forces of dry mud pellets. After dry mud is removed, mud residuals on the glass surface are examined and the optical transmittance of the glass is measured. Dust particles include alkaline compounds, which dissolve in water condensate and form a mud solution with high pH (pH = 7.5). The mud solution forms a thin liquid film at the interface of dust particles and surface. Crystals form as the mud solution dries, thus, increasing the adhesion work required to remove dry mud from the surface. Optical transmittance of the glass is reduced after dry mud is removed due to the dry mud residue on the surface. PMID:27445272

  8. Chemo-Mechanical Characteristics of Mud Formed from Environmental Dust Particles in Humid Ambient Air

    Science.gov (United States)

    Hassan, Ghassan; Yilbas, B. S.; Said, Syed A. M.; Al-Aqeeli, N.; Matin, Asif

    2016-07-01

    Mud formed from environmental dust particles in humid ambient air significantly influences the performance of solar harvesting devices. This study examines the characterization of environmental dust particles and the chemo-mechanics of dry mud formed from dust particles. Analytical tools, including scanning electron microscopy, atomic force microscopy, energy dispersive spectroscopy, particle sizing, and X-ray diffraction, are used to characterize dry mud and dust particles. A micro/nano tribometer is used to measure the tangential force and friction coefficient while tensile tests are carried out to assess the binding forces of dry mud pellets. After dry mud is removed, mud residuals on the glass surface are examined and the optical transmittance of the glass is measured. Dust particles include alkaline compounds, which dissolve in water condensate and form a mud solution with high pH (pH = 7.5). The mud solution forms a thin liquid film at the interface of dust particles and surface. Crystals form as the mud solution dries, thus, increasing the adhesion work required to remove dry mud from the surface. Optical transmittance of the glass is reduced after dry mud is removed due to the dry mud residue on the surface.

  9. Coarse and fine particles but not ultrafine particles in urban air trigger hospital admission for asthma in children

    DEFF Research Database (Denmark)

    Iskandar, Amne; Andersen, Zorana Jovanovic; Bønnelykke, Klaus;

    2012-01-01

    BackgroundShort-term exposure to air pollution can trigger hospital admissions for asthma in children, but it is not known which components of air pollution are most important. There are no available studies on the particular effect of ultrafine particles (UFPs) on paediatric admissions for asthma.......AimTo study whether short-term exposure to air pollution is associated with hospital admissions for asthma in children. It is hypothesised that (1) the association between asthma admissions and air pollution is stronger with UFPs than with coarse (PM(10)) and fine (PM(2.5)) particles, nitrogen oxides (NO......(x)) or nitrogen dioxide (NO(2)); and (2) infants are more susceptible to the effects of exposure to air pollution than older children.MethodDaily counts of admissions for asthma in children aged 0-18 years to hospitals located within a 15 km radius of the central fixed background urban air pollution...

  10. The 2005 Study of Organic Aerosols at Riverside (SOAR-1): instrumental intercomparisons and fine particle composition

    Science.gov (United States)

    Docherty, K. S.; Aiken, A. C.; Huffman, J. A.; Ulbrich, I. M.; Decarlo, P. F.; Sueper, D.; Worsnop, D. R.; Snyder, D. C.; Peltier, R. E.; Weber, R. J.; Grover, B. D.; Eatough, D. J.; Williams, B. J.; Goldstein, A. H.; Ziemann, P. J.; Jimenez, J. L.

    2011-12-01

    Multiple state-of-the-art instruments sampled ambient aerosol in Riverside, California during the 2005 Study of Organic Aerosols at Riverside (SOAR) to investigate the chemical composition and potential sources of fine particles (PMf) in the inland region of Southern California. In this paper, we briefly summarize the spatial, meteorological and gas-phase conditions during SOAR-1 (15 July-15 August), provide detailed intercomparisons of high-resolution aerosol mass spectrometer (HR-AMS) measurements against complementary measurements, and report the average composition of PMf including the composition of the organic fraction measured by the HR-AMS. Daily meteorology and gas-phase species concentrations were highly consistent, displaying clear diurnal cycles and weekday/weekend contrast. HR-AMS measurements of non-refractory submicron (NR-PM1) mass are consistent and highly correlated with those from a filter dynamics measurement system tapered-element oscillating microbalance (TEOM), while the correlation between HR-AMS and heated TEOM measurements is lower due to loss of high volatility species including ammonium nitrate from the heated TEOM. Speciated HR-AMS measurements are also consistent with complementary measurements as well as with measurements from a collocated compact AMS while HR-AMS OC is similar to standard semi-continuous Sunset measurements within the combined uncertainties of both instruments. A correction intended to account for the loss of semi-volatile OC from the Sunset, however, yields measurements ~30% higher than either HR-AMS or standard Sunset measurements. On average, organic aerosol (OA) was the single largest component of PMf. OA composition was investigated using both elemental analysis and positive matrix factorization (PMF) of HR-AMS OA spectra. Oxygen is the main heteroatom during SOAR-1, with O/C exhibiting a diurnal minimum of 0.28 during the morning rush hour and maximum of 0.42 during the afternoon. O/C is broadly anti

  11. Reproducing the optical properties of fine desert dust aerosols using ensembles of simple model particles

    International Nuclear Information System (INIS)

    Single scattering optical properties are calculated for a proxy of fine dust aerosols at a wavelength of 0.55 μm. Spherical and spheroidal model particles are employed to fit the aerosol optical properties and to retrieve information about the physical parameters characterising the aerosols. It is found that spherical particles are capable of reproducing the scalar optical properties and the forward peak of the phase function of the dust aerosols. The effective size parameter of the aerosol ensemble is retrieved with high accuracy by using spherical model particles. Significant improvements are achieved by using spheroidal model particles. The aerosol phase function and the other diagonal elements of the Stokes scattering matrix can be fitted with high accuracy, whereas the off-diagonal elements are poorly reproduced. More elongated prolate and more flattened oblate spheroids contribute disproportionately strongly to the optimised shape distribution of the model particles and appear to be particularly useful for achieving a good fit of the scattering matrix. However, the clear discrepancies between the shape distribution of the aerosols and the shape distribution of the spheroidal model particles suggest that the possibilities of extracting shape information from optical observations are rather limited

  12. Benthic biofilm structure controls the deposition-resuspension dynamics of fine clay particles

    Science.gov (United States)

    Hunter, W. R.; Roche, K. R.; Drummond, J. D.; Boano, F.; Packman, A. I.; Battin, T. J.

    2015-12-01

    In fluvial ecosystems the alternation of deposition and resuspension of particles represents an important pathway for the downstream translocation of microbes and organic matter. Such particles can originate from algae and microbes, the spontaneous auto-aggregation of organic macromolecules (e.g., "river sown"), terrestrial detritus (traditionally classified as "particulate organic matter"), and erosive mineral and organo-mineral particles. The transport and retention of particles in headwater streams is associated with biofilms, which are surface-attached microbial communities. Whilst biofilm-particle interactions have been studied in bulk, a mechanistic understanding of these processes is lacking. Parallel macroscale/microscale observations are required to unravel the complex feedbacks between biofilm structure, coverage and the dynamics of deposition and resuspension. We used recirculating flume mesocosms to test how changes in biofilm structure affected the deposition and resuspension of clay-sized (Biofilms were grown in replicate 3-m-long recirculating flumes over variable lengths of time (0, 14, 21, 28, and 35) days. Fixed doses of fluorescent clay-sized particles were introduced to each flume and their deposition was traced over 30 minutes. A flood event was then simulated via a step increase in flowrate to quantify particle resuspension. 3D Optical Coherence Tomography was used to determine roughness, areal coverage and height of biofilms in each flume. From these measurements we characterised particle deposition and resuspension rates, using continuous time random walk modelling techniques, which we then tested as responses to changes in biofilm coverage and structure under both base-flow and flood-flow scenarios. Our results suggest that biofilm structural complexity is a primary control upon the retention and downstream transport of fine particles in stream mesocosms.

  13. Profiling of fine- and coarse-mode particles with LIRIC (LIdar/Radiometer Inversion Code

    Directory of Open Access Journals (Sweden)

    M. R. Perrone

    2014-08-01

    Full Text Available The paper investigates numerical procedures that allow determining the dependence on altitude of aerosol properties from multi wavelength elastic lidar signals. In particular, the potential of the LIdar/Radiometer Inversion Code (LIRIC to retrieve the vertical profiles of fine and coarse-mode particles by combining 3-wavelength lidar measurements and collocated AERONET (AErosol RObotic NETwork sun/sky photometer measurements is investigated. The used lidar signals are at 355, 532 and 1064 nm. Aerosol extinction coefficient (αL, lidar ratio (LRL, and Ångstrom exponent (ÅL profiles from LIRIC are compared with the corresponding profiles (α, LR, and Å retrieved from a Constrained Iterative Inversion (CII procedure to investigate the LIRIC retrieval ability. Then, an aerosol classification framework which relies on the use of a graphical framework and on the combined analysis of the Ångstrom exponent (at the 355 and 1064 nm wavelength pair, Å(355, 1064 and its spectral curvature (ΔÅ = Å(355, 532–Å(532, 1064 is used to investigate the ability of LIRIC to retrieve vertical profiles of fine and coarse-mode particles. The Å-ΔÅ aerosol classification framework allows estimating the dependence on altitude of the aerosol fine modal radius and of the fine mode contribution to the whole aerosol optical thickness, as discussed in Perrone et al. (2014. The application of LIRIC to three different aerosol scenarios dealing with aerosol properties dependent on altitude has revealed that the differences between αL and α vary with the altitude and on average increase with the decrease of the lidar signal wavelength. It has also been found that the differences between ÅL and corresponding Å values vary with the altitude and the wavelength pair. The sensitivity of Ångstrom exponents to the aerosol size distribution which vary with the wavelength pair was responsible for these last results. The aerosol classification framework has revealed that

  14. Sources and characteristics of fine and ultrafine particles in ambient air

    OpenAIRE

    Lorenzo, Ronny; Grobéty, Bernard

    2007-01-01

    Le sujet de cette thèse de doctorat couvre de nombreux aspects de la science des aérosols. Ainsi les différentes études de ce travail abordent des domaines variés dont le point commun est le thème global des aérosols de l’environnement. Une de ces études a été consacrée à l’identification et la quantification des particules émises par le trafic ferroviaire (chapitre 2). Pour cela, des échantillons de PM10 ont été récoltés à proximité d’une ligne de chemin de fer à fort trafic au moyen d’un éq...

  15. A comparison of hydroxyl radical and hydrogen peroxide generation in ambient particle extracts and laboratory metal solutions

    Science.gov (United States)

    Shen, Huiyun; Anastasio, Cort

    2012-01-01

    Generation of reactive oxygen species (ROS) - including superoxide ( rad O 2-), hydrogen peroxide (HOOH), and hydroxyl radical ( rad OH) - has been suggested as one mechanism underlying the adverse health effects caused by ambient particulate matter (PM). In this study we compare HOOH and rad OH production from fine and coarse PM collected at an urban (Fresno) and rural (Westside) site in the San Joaquin Valley (SJV) of California, as well as from laboratory solutions containing dissolved copper or iron. Samples were extracted in a cell-free, phosphate-buffered saline (PBS) solution containing 50 μM ascorbate (Asc). In our laboratory solutions we find that Cu is a potent source of both HOOH and rad OH, with approximately 90% of the electrons that can be donated from Asc ending up in HOOH and rad OH after 4 h. In contrast, in Fe solutions there is no measurable HOOH and only a modest production of rad OH. Soluble Cu in the SJV PM samples is also a dominant source of HOOH and rad OH. In both laboratory copper solutions and extracts of ambient particles we find much more production of HOOH compared to rad OH: e.g., HOOH generation is approximately 30-60 times faster than rad OH generation. The formation of HOOH and rad OH are positively correlated, with roughly 3% and 8% of HOOH converted to rad OH after 4 and 24 h of extraction, respectively. Although the SJV PM produce much more HOOH than rad OH, since rad OH is a much stronger oxidant it is unclear which species might be more important for oxidant-mediated toxicity from PM inhalation.

  16. Fine particle control of radiocesium accumulation in contaminated flood plain soils

    International Nuclear Information System (INIS)

    Fine particles are known to play an important role in trace element concentration and their redistribution in the environment. Their specific behavior in flooding processes can lead to considerable accumulation of the incorporated technical pollution in particular elementary landscapes at the corresponding geo-morphological levels and soil depths in case of a strong pollutant fixation that is typical for 137Cs. The main goal of the study was to reveal the natural texture-dependent patterns of radiocesium redistribution in flood plain soils contaminated due to air or water radiocesium releases. (authors)

  17. Detection of biological particles in ambient air using Bio-Aerosol Mass Spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    McJimpsey, E L; Steele, P T; Coffee, K R; Fergenson, D P; Riot, V J; Woods, B W; Gard, E E; Frank, M; Tobias, H J; Lebrilla, C

    2006-03-16

    The Bio-Aerosol Mass Spectrometry (BAMS) system is an instrument used for the real time detection and identification of biological aerosols. Particles are drawn from the atmosphere directly into vacuum and tracked as they scatter light from several continuous wave lasers. After tracking, the fluorescence of individual particles is excited by a pulsed 266nm or 355nm laser. Molecules from those particles with appropriate fluorescence properties are subsequently desorbed and ionized using a pulsed 266nm laser. Resulting ions are analyzed in a dual polarity mass spectrometer. During two field deployments at the San Francisco International Airport, millions of ambient particles were analyzed and a small but significant fraction were found to have fluorescent properties similar to Bacillus spores and vegetative cells. Further separation of non-biological background particles from potential biological particles was accomplished using laser desorption/ionization mass spectrometry. This has been shown to enable some level of species differentiation in specific cases, but the creation and observation of higher mass ions is needed to enable a higher level of specificity across more species. A soft ionization technique, matrix-assisted laser desorption/ionization (MALDI) is being investigated for this purpose. MALDI is particularly well suited for mass analysis of biomolecules since it allows for the generation of molecular ions from large mass compounds that would fragment under normal irradiation. Some of the initial results from a modified BAMS system utilizing this technique are described.

  18. Detection of biological particles in ambient air using Bio-Aerosol Mass Spectrometry

    International Nuclear Information System (INIS)

    The Bio-Aerosol Mass Spectrometry (BAMS) system is an instrument used for the real time detection and identification of biological aerosols. Particles are drawn from the atmosphere directly into vacuum and tracked as they scatter light from several continuous wave lasers. After tracking, the fluorescence of individual particles is excited by a pulsed 266nm or 355nm laser. Molecules from those particles with appropriate fluorescence properties are subsequently desorbed and ionized using a pulsed 266nm laser. Resulting ions are analyzed in a dual polarity mass spectrometer. During two field deployments at the San Francisco International Airport, millions of ambient particles were analyzed and a small but significant fraction were found to have fluorescent properties similar to Bacillus spores and vegetative cells. Further separation of non-biological background particles from potential biological particles was accomplished using laser desorption/ionization mass spectrometry. This has been shown to enable some level of species differentiation in specific cases, but the creation and observation of higher mass ions is needed to enable a higher level of specificity across more species. A soft ionization technique, matrix-assisted laser desorption/ionization (MALDI) is being investigated for this purpose. MALDI is particularly well suited for mass analysis of biomolecules since it allows for the generation of molecular ions from large mass compounds that would fragment under normal irradiation. Some of the initial results from a modified BAMS system utilizing this technique are described

  19. Measurement of ambient aerosols in northern Mexico City by single particle mass spectrometry

    Directory of Open Access Journals (Sweden)

    R. C. Moffet

    2008-08-01

    Full Text Available Continuous ambient measurements with aerosol time-of-flight mass spectrometry (ATOFMS were made in an industrial/residential section in the northern part of Mexico City as part of the Mexico City Metropolitan Area-2006 campaign (MCMA-2006. Results are presented for the period of 15–27 March 2006. The submicron size mode contained both fresh and aged biomass burning, aged organic carbon (OC mixed with nitrate and sulfate, elemental carbon (EC, nitrogen-organic carbon, industrial metal, and inorganic NaK inorganic particles. Overall, biomass burning and aged OC particle types comprised 40% and 31%, respectively, of the submicron mode. In contrast, the supermicron mode was dominated by inorganic NaK particle types (42% which represented a mixture of dry lake bed dust and industrial NaK emissions mixed with soot. Additionally, aluminosilicate dust, transition metals, OC, and biomass burning contributed to the supermicron particles. Early morning periods (2–6 a.m. showed high fractions of inorganic particles from industrial sources in the northeast, composed of internal mixtures of Pb, Zn, EC and Cl, representing up to 73% of the particles in the 0.2–3μm size range. A unique nitrogen-containing organic carbon (NOC particle type, peaking in the early morning hours, was hypothesized to be amines from local industrial emissions based on the time series profile and back trajectory analysis. A strong dependence on wind speed and direction was observed in the single particle types that were present during different times of the day. The early morning (3:30–10 a.m. showed the greatest contributions from industrial emissions. During mid to late mornings (7–11 a.m., weak northerly winds were observed along with the most highly aged particles. Stronger winds from the south picked up in the late morning (after 11 a.m., resulting in a decrease in the concentrations of the major aged particle types and an increase in the number fraction of fresh

  20. Physicochemical characteristics of ambient particles settling upon leaf surfaces of urban plants in Beijing.

    Science.gov (United States)

    Wang, Lei; Liu, Lian-you; Gao, Shang-yu; Hasi, Eerdun; Wang, Zhi

    2006-01-01

    Particulate pollution is a serious health problem throughout the world, exacerbating a wide range of respiratory and vascular illnesses in urban areas. Urban plants play an important role in reducing particulate pollution. Physicochemical characteristics of ambient particles settling upon leaf surfaces of eleven roadside plants at four sites of Beijing were studies. Results showed that density of particles on the leaf surfaces greatly varied with plant species and traffic condition. Fraxinus chinensis, Sophora japonica, A ilanthus altissima, Syringa oblata and Prunus persica had larger densities of particles among the tall species. Due to resuspension of road dust, the densities of particles of Euonymus japonicus and Parthenocissus quinquefolia with low sampling height were 2-35 times to other taller tree species. For test plant species, micro-roughness of leaf surfaces and density of particles showed a close correlation. In general, the larger micro-roughness of leaf surfaces is, the larger density of particles is. Particles settling upon leaf surfaces were dominantly PM, (particulate matter less than 10 microm in aerodynamic diameter; 98.4%) and PM25 (particulate matter less than 2.5 microm in aerodynamic diameter; 64.2%) which were closely relative to human health. Constant elements of particles were C, O, K, Ca, Si, Al, Mg, Na, Fe, S, Cl and minerals with higher content were SiO2, CaCO3, CaMg(CO3)2, NaCI and 2CaSO4 x H20, SiO2. CaCO3 and CaMg(CO3)2 mainly came from resuspension of road dust. 2CaSO4 x H20 was produced by the reaction between CaCO3 derived from earth dust or industrial emission and SO2, H2SO4 or sulfate. NaCl was derived from sea salt. PMID:17278748

  1. NANODERM. Quality of skin as a barrier to ultra-fine particles

    International Nuclear Information System (INIS)

    Complete text of publication follows. The EU5 project carried out by a consortium of 12 European universities and research institutes under the leadership of the Faculty of Physics and Geosciences, University of Leipzig started in 2003 and ended with the publication of its final report in 2007. The main goal of the project was to get quantitative information on the penetration of ultra-fine particles in all strata of skin, on their penetration pathways as well as on their impact on human health. Details of the project can be found on the following website: http://www.uni-leipzig.de/"~nanoderm. The Hungarian team was lead by the Department of Dermatology, University of Debrecen, who provided human skin grafted on SCID (Severe Combined Immune Deficiency) mice as a suitable model for studying particle penetration. In the Institute of Physiology, University of Debrecen, the cellular effects of the nanoparticles were assessed. The ATOMKI group performed ion beam analytical investigations using proton induced x-ray emission and scanning transmission ion microscopy techniques to determine the particle distribution on porcine, SCID graft and human skin samples on which various nanoparticle (TiO2) formulations including commercially available sunscreens were applied. Several pre-treatments of the skin were tested, too. The skin samples were cryofixed native specimens, reducing considerably the possibility of creating artefacts. Results Titanium was only detected in the stratum corneum for healthy skin. Penetration to layers consisting of living cells was not observed. No diffusion profile was present therefore we conclude that the penetration takes place through mechanical action. Deep penetration into hair follicles was also observed, but not into vital tissue. Clearance is expected via desquamation and sebum excretion respectively for corneocyte layers and hair follicles. In conclusion, the NANODERM group does not expect any harmful effects of sunscreens containing ultra-fine

  2. Structures and properties of Fe-C fine particles prepared by AC arc discharge

    Science.gov (United States)

    Li, Jian; Liu, Cunye; Zhao, Baogang; Lin, Yaoqiang; Deng, Zhaojing

    1999-05-01

    Fe-C fine particles are produced by an alternating arc discharge between iron and carbon electrodes in an Ar gas atmosphere at pressures of 8, 14 and 18 kPa. The crystal structure, morphology and surface composition have been studied, respectively, by X-ray diffraction, transmission electron microscopy, selected area electron diffraction and X-ray photoelectron spectroscopy. Magnetic properties and Curie temperatures have also been determined by a vibrating sample magnetometer. Results show that the particles are of two different crystal structures, one is hexagonal FeC and the other is cubic iron. The iron particles have a multi-layered structure composed of an α-Fe core wrapped by Fe 3O 4, FeO and FeO(OH) shells. It is found that the compositions and the specific saturation magnetization of the Fe-C particles prepared in different pressures of Ar gas are not the same, but their Curie temperatures are all 580±5°C.

  3. Laser trapped single fine particle as a probe of plasma parameters

    Science.gov (United States)

    Yamashita, Daisuke; Soejima, Masahiro; Ito, Teppei; Seo, Hyunwoong; Itagaki, Naho; Koga, Kazunori; Shiratani, Masaharu

    2015-09-01

    Here we report evaluation of electron density and temperature using optically trapped single fine particle. Experiments were carried out with a radio frequency low pressure plasma reactor, where we set two quartz windows as top and bottom flanges to irradiate an infrared laser light of 1064 nm wavelength from the bottom side. Ar plasmas were generated between a powered ring-electrode set at the bottom of the reactor and a grounded mesh placed at the center of the reactor at 100 Pa by applying 13.56 MHz voltage. The particles injected into the plasmas were monodisperse methyl methacrylate-polymer spheres of 10 μm in diameter. A negatively charged particle, which is suspended plasma sheath boundary, was trapped at the focal point of the irradiated laser light due to the transfer of momentum from the scattering of incident photons. At the beginning of the trapping, particle of 10 μm in size was trapped above 505 μm from the bottom window. After 230 min, the size and position were 9.56 μm and 520 μm, respectively. From the results, the electron density and temperature are deduced to be 1.7×109 cm-3 and 1.9 eV.

  4. Insights into metals in individual fine particles from municipal solid waste using synchrotron radiation-based micro-analytical techniques

    Institute of Scientific and Technical Information of China (English)

    Yumin Zhu; Hua Zhang; Liming Shao; Pinjing He

    2015-01-01

    Excessive inter-contamination with heavy metals hampers the application of biological treatment products derived from mixed or mechanically-sorted municipal solid waste (MSW).In this study,we investigated fine particles of <2 mm,which are small fractions in MSW but constitute a significant component of the total heavy metal content,using bulk detection techniques.A total of 17 individual fine particles were evaluated using synchrotron radiation-based micro-X-ray fluorescence and micro-X-ray diffraction.We also discussed the association,speciation and source apportionment of heavy metals.Metals were found to exist in a diffuse distribution with heterogeneous intensities and intense hot-spots of <10 μm within the fine particles.Zn-Cu,Pb-Fe and Fe-Mn-Cr had significant correlations in terms of spatial distribution.The overlapped enrichment,spatial association,and the mineral phases of metals revealed the potential sources of fine particles from size-reduced waste fractions (such as scraps of organic wastes or ceramics) or from the importation of other particles.The diverse sources of heavy metal pollutants within the fine particles suggested that separate collection and treatment of the biodegradable waste fraction (such as food waste) is a preferable means of facilitating the beneficial utilization of the stabilized products.

  5. STROBE-Long-Term Exposure to Ambient Fine Particulate Air Pollution and Hospitalization Due to Peptic Ulcers.

    Science.gov (United States)

    Wong, Chit-Ming; Tsang, Hilda; Lai, Hak-Kan; Thach, Thuan-Quoc; Thomas, G Neil; Chan, King-Pan; Lee, Siu-Yin; Ayres, Jon G; Lam, Tai-Hing; Leung, Wai K

    2016-05-01

    Little is known about the effect of air pollution on the gastrointestinal (GI) system. We investigated the association between long-term exposures to outdoor fine particles (PM2.5) and hospitalization for peptic ulcer diseases (PUDs) in a large cohort of Hong Kong Chinese elderly.A total of 66,820 subjects aged ≥65 years who were enrolled in all 18 Government Elderly Health Service centers of Hong Kong participated in the study voluntarily between 1998 and 2001. They were prospectively followed up for more than 10 years. Annual mean exposures to PM2.5 at residence of individuals were estimated by satellite data through linkage with address details including floor level. All hospital admission records of the subjects up to December 31, 2010 were retrieved from the central database of Hospital Authority. We used Cox regression to estimate the hazard ratio (HR) for PUD hospitalization associated with PM2.5 exposure after adjustment for individual and ecological covariates.A total of 60,273 subjects had completed baseline information including medical, socio-demographic, lifestyle, and anthropometric data at recruitment. During the follow-up period, 1991 (3.3%) subjects had been hospitalized for PUD. The adjusted HR for PUD hospitalization per 10 μg/m of PM2.5 was 1.18 (95% confidence interval: 1.02-1.36, P = 0.02). Further analysis showed that the associations with PM2.5 were significant for gastric ulcers (HR 1.29; 1.09-1.53, P = 0.003) but not for duodenal ulcers (HR 0.98; 0.78 to 1.22, P = 0.81).Long-term exposures to PM2.5 were associated with PUD hospitalization in elder population. The mechanism underlying the PM2.5 in the development of gastric ulcers warrants further research. PMID:27149464

  6. Particle-bound Dechlorane Plus and polybrominated diphenyl ethers in ambient air around Shanghai, China

    International Nuclear Information System (INIS)

    In present study, atmospheric particles from Shanghai, the biggest city and the most important industrial base in China, were analyzed for polybrominated diphenyl ethers (PBDEs) and Dechlorane Plus (DP). Concentrations of Σ20PBDEs and DP both exhibited the changing trend of industrial area > urban areas. Jiading District had the highest levels of particulate PBDEs and DP with values of 744 ± 152 pg/m3 and 5.48 ± 1.28 pg/m3, respectively. Compared with similar data in other areas of the world, PBDEs in Shanghai were at medium pollution level, while DP was at lower level, which reflected their different production and use in Shanghai. The results from multiple linear regression analysis suggested that deca-BDE mixture was the most important contributor of particulate PBDEs in Shanghai. The fractions of anti-DP showed no significant differences to those of the technical mixtures (p > 0.05), which suggested that no obviously stereoselective process occurred in ambient air around Shanghai. - Highlights: → Atmospheric PBDEs of Shanghai were at moderate levels and dominated by BDE-209. → Particulate DP was low even Shanghai is not far from the DP manufacturing factory. → DP showed no obviously stereoselective process in air particles from Shanghai. → Significant positive correlation was found between particulate PBDEs and PBDD/Fs. - The moderate PBDEs levels with deca-BDE being the most important contributor and low DP levels in ambient air around Shanghai reflected their different usage in this area.

  7. Incipient flow properties of two-component fine powder mixtures: Changing the flowability of smaller particles

    Science.gov (United States)

    Kojima, Takehiro; Elliott, James A.

    2013-06-01

    Understanding the flow properties of two-component fine powder systems with micrometre-sized constituents is important for the quality control of electrophotographic printing applications such as photocopiers. In previous work, we studied the incipient flow properties of model powder mixtures of large (d50 ˜ 70 μm) and small (d50 ˜ 6-8 μm) particles under a consolidation stress of 2 kPa, and reported that they were strongly related to the properties of the small particles where the volume ratio of small powder (xs) exceeds ˜0.1 [1]. In this follow-up study, we examine the effect of changing the flowability of the smaller components on the structure and flow properties of the binary mixtures. For the smaller particles, we used poly(styrene-co-divinylbenzene) (PS-DVB) microspheres (d50 = 7.84 μm). The particle surfaces were modified by adding silica nanoparticles in order to prepare PS-DVB powders with a range of flowabilities. These were then mixed with glass ballotini (d50 = 71.9 μm), and the flow properties of these mixtures were evaluated using the shear testing technique. The cohesion of the mixtures showed essentially the same trend as reported in [1] in terms of their dependence on xs and was related to the number of contacts between the PS-DVB particles. Also, it was strongly dependent on the cohesion of the PS-DVB powders despite a very small xs (xs DVB powder was similar, it also showed a correlation with the number of contacts between PS-DVB particles.

  8. FT-IR TRANSMISSION SPECTROSCOPY FOR QUANTITATION OF AMMONIUM BISULFATE IN FINE PARTICULATE MATTER COLLECTED ON TEFLON FILTERS

    Science.gov (United States)

    A quantitative measurement method for fine particle bisulfatein ammonium bisulfate collected from the ambient air onto Teflon filters is described. nfrared absorbance measurements of the Teflon filters are made before and after particle collection. ubtraction of the two spectra r...

  9. Environmental and health impacts of fine and ultrafine metallic particles: Assessment of threat scores

    International Nuclear Information System (INIS)

    This study proposes global threat scores to prioritize the harmfulness of anthropogenic fine and ultrafine metallic particles (FMP) emitted into the atmosphere at the global scale. (Eco)toxicity of physicochemically characterized FMP oxides for metals currently observed in the atmosphere (CdO, CuO, PbO, PbSO4, Sb2O3, and ZnO) was assessed by performing complementary in vitro tests: ecotoxicity, human bioaccessibility, cytotoxicity, and oxidative potential. Using an innovative methodology based on the combination of (eco)toxicity and physicochemical results, the following hazard classification of the particles is proposed: CdCl2∼CdO>CuO>PbO>ZnO>PbSO4>Sb2O3. Both cadmium compounds exhibited the highest threat score due to their high cytotoxicity and bioaccessible dose, whatever their solubility and speciation, suggesting that cadmium toxicity is due to its chemical form rather than its physical form. In contrast, the Sb2O3 threat score was the lowest due to particles with low specific area and solubility, with no effects except a slight oxidative stress. As FMP physicochemical properties reveal differences in specific area, crystallization systems, dissolution process, and speciation, various mechanisms may influence their biological impact. Finally, this newly developed and global approach could be widely used in various contexts of pollution by complex metal particles and may improve risk management. - Highlights: • Seven micro- and nano- monometallic characterized particles were studied as references. • Bioaccessibility, eco and cytotoxicity, and oxidative potential assays were performed. • According to calculated threat scores: CdCl2∼CdO>CuO>PbO>ZnO>PbSO4>Sb2O3

  10. Fine Adjustment of Interfacial Potential between pH-Responsive Hydrogels and Cell-Sized Particles.

    Science.gov (United States)

    Monzel, Cornelia; Veschgini, Mariam; Madsen, Jeppe; Lewis, Andrew L; Armes, Steven P; Tanaka, Motomu

    2015-08-11

    We quantitatively determined interfacial potentials between cell-sized particles and stimulus-responsive hydrogels using a microinterferometer. The hydrogel is based on physically interconnected ABA triblock copolymer micelles comprising an inner biocompatible PMPC block and two outer pH-responsive PDPA blocks. The out-of-plane temporal fluctuation in the position of the cell-sized particles was calculated from changes in the interference pattern measured by Reflection Interference Contrast Microscopy (RICM), thus yielding the particle-substrate interaction potential V (Δh). Measurements in pH buffers ranging from 7.0 to 7.8 resulted in a systematic reduction in height of the potential minima ⟨Δh⟩ and a concomitant increase in the potential curvature V″ (Δh). The experimental data were analyzed by applying the modified Ross and Pincus model for polyelectrolytes, while accounting for gravitation, lubrication and van der Waals interactions. Elastic moduli calculated from V″ (Δh) were in good agreement with those measured by Atomic Force Microscopy. The ability to fine-tune both the gel elasticity and the interfacial potential at around physiological pH makes such triblock copolymer hydrogels a promising biocompatible substrate for dynamic switching of cell-material interactions. PMID:26190346

  11. Production of De-asphalted Oil and Fine Asphalt Particles by Supercritical Extraction

    Institute of Scientific and Technical Information of China (English)

    赵锁奇; 许志明; 王仁安

    2003-01-01

    A continuous three-stage supercritical fluid extraction (SFE) process with a capacity of 1.0kg.h-1 was setup to extract petroleum residue by pentane to obtain more oil for further upgrading. A discharging system integrated to the bottom of the extractor was used to recover solvent as gas while asphalt was obtained as fine particles. The influence of operating conditions on the yield and quality of extracts, i.e., deasphalted oil (DAO) and resin, was studied in the range of temperature 150-220℃, pressure of 4.0-6.0 MPa and the mass ratio of solvent to oil feed (S/O) 2.5-5.0. The particle size distribution, apparent forms and the packing density, which vary with operating pressure, were measured. The particle structures were observed by SEM as well. With the modification to conventional processes, furnace can be eliminated for solvent recovery from asphalt phase, so as to reduce energy consumption.

  12. Formation of fine solid particles from aqueous solutions of sodium chloropalladate by gamma-ray irradiation

    International Nuclear Information System (INIS)

    Studies have been carried out on the radiation chemical formation of palladium fine particles in argon saturated aqueous solutions of sodium chloropalladate without organic stabilizer. The solutions were irradiated with gamma-rays from a cobalt gamma-ray source and the irradiated solutions were subjected to the dynamic light scattering analysis for the particle diameter measurements, and to the UV-visible optical absorption spectroscopy for the measurements of turbidity (absorption at 700 nm) and remaining chloropalladate ion concentrations in the solution. In the solution of pH = 1.95 by HCl, the turbidity increased after the irradiation and then decreased with time. The concentration of remaining palladate ion in the solution decreased by the irradiation, but it gradually increased with time after the irradiation. These phenomena were qualitatively explained by the reaction scheme in that a precursor to the solid particles still exists in the solution after the irradiation was terminated, and that intermediates including the precursor reacted with chloride ion to re-form chloropalladate ions. The average diameter of the particles after the irradiation was ca. 20 nm and it increased with time to 40 nm at 2.75 kGy, and to 80 nm at 8.25 kGy absorption of radiation. The solution of pH = 0.65 by HCl was found to give lower yields of particles than those observed for the solution of pH = 1.95, and to give the particles of diameters about 150-200 nm. In the solution containing HClO4 instead of HCl, palladium particles were also formed by the irradiation, whereas no backward reaction after the irradiation was observed due to the low concentration of chloride ion in the solution. The average diameter of the particles after the irradiation was about 300 nm and increased with time after the irradiation to a final values which was found to depend on pH of the solution and dose. (author)

  13. Ion beam analysis techniques for the elemental fingerprinting of fine particle smoke from vegetation burning in NSW

    Energy Technology Data Exchange (ETDEWEB)

    Cohen, D. [Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW (Australia)

    1996-12-31

    Accelerator based ion beam analysis (IBA) techniques, including PIXE, PIGME, RBS and PESA, have been used to analyse elemental compositions of airborne particles covering a 60,000 square kilometres area of Wollongong, Sydney and Newcastle. These IBA techniques provide elemental concentrations for over 20 different elements from hydrogen to lead, they include H, C, N, O, F, Na, Al, Si, P, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Cu, Ni, Zn, Br and Pb. The four ion beam techniques are performed simultaneously on the 3MV Van de Graaff accelerator at ANSTO and have been described in detail elsewhere. They are sufficiently sensitive to analyse for many of these elements to levels around 10 ng/m{sup 3} or less in about five minutes of accelerator running time per filter. This is more than adequate for aerosol analyses as most filters contain around 150 {mu}g/cm{sup 2} of material which corresponds to about 10{mu}g/m{sup 3} of fine particles in the atmosphere. For this work fine particles are those with diameters less than 2.5{mu}m. Fine particle data has been collected twice a week and analysed for each of the above elements by ANSTO since 1991 at more than 25 different sites throughout NSW. This large dataset set allows us to not only determine the composition of fine particles and to look for signature elements for particular sources but also to use multivariate statistics to define elemental source fingerprints and then to determine the percentage contributions of these fingerprints to the total fine particle mass in the atmosphere. This paper describes the application of these techniques to the study of domestic wood fires and vegetation burning in NSW over a two year period from 1992-93. It also presents, for the first time, fine particle data related to the January 1994 bushfires in NSW. 6 refs., 1 tab., 5 figs.

  14. Ion beam analysis techniques for the elemental fingerprinting of fine particle smoke from vegetation burning in NSW

    International Nuclear Information System (INIS)

    Accelerator based ion beam analysis (IBA) techniques, including PIXE, PIGME, RBS and PESA, have been used to analyse elemental compositions of airborne particles covering a 60,000 square kilometres area of Wollongong, Sydney and Newcastle. These IBA techniques provide elemental concentrations for over 20 different elements from hydrogen to lead, they include H, C, N, O, F, Na, Al, Si, P, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Cu, Ni, Zn, Br and Pb. The four ion beam techniques are performed simultaneously on the 3MV Van de Graaff accelerator at ANSTO and have been described in detail elsewhere. They are sufficiently sensitive to analyse for many of these elements to levels around 10 ng/m3 or less in about five minutes of accelerator running time per filter. This is more than adequate for aerosol analyses as most filters contain around 150 μg/cm2 of material which corresponds to about 10μg/m3 of fine particles in the atmosphere. For this work fine particles are those with diameters less than 2.5μm. Fine particle data has been collected twice a week and analysed for each of the above elements by ANSTO since 1991 at more than 25 different sites throughout NSW. This large dataset set allows us to not only determine the composition of fine particles and to look for signature elements for particular sources but also to use multivariate statistics to define elemental source fingerprints and then to determine the percentage contributions of these fingerprints to the total fine particle mass in the atmosphere. This paper describes the application of these techniques to the study of domestic wood fires and vegetation burning in NSW over a two year period from 1992-93. It also presents, for the first time, fine particle data related to the January 1994 bushfires in NSW. 6 refs., 1 tab., 5 figs

  15. Changes in the Community of Ectomycorrhizal Fungi and Increased Fine Root Number Under Adult Beech Trees Chronically Fumigated with Double Ambient Ozone Concentration

    OpenAIRE

    Grebenc, Tine; Kraigher, Hojka

    2007-01-01

    Forest soils are an important but under-studied part of forest ecosystems. The effects of O3 on below-ground processes in a mature forest have only received limited attention so far. In our study, we have analysed the community of ectomycorrhizal fungi and beech fine root dynamics over two growing seasons (2003–2004) in a 70-year old mixed spruce-beech forest stand, in which two groups of five adult beech trees were either fumigated by 2 × ambient ozone concentration or used as control. The m...

  16. Enlargement of fine particles in oil sands industry : flocculation and thickening

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Y.; Hamza, H. [Natural Resources Canada, CANMET Advanced Separation Technologies Laboratory, Devon, AB (Canada); Matthews, J. [Syncrude Canada Ltd., Edmonton, AB (Canada). Edmonton Research Centre

    2004-07-01

    Research efforts at Syncrude Canada Ltd. have focused on developing alternative tailings management and reclamation techniques and optimizing production efficiency and environmental sustainability by improving water and energy conservation. Bitumen from open-pit oil sands mines north of Fort McMurray are recovered by flotation circuits. This paper reviewed bench-scale and pilot scale tests conducted by Canada's Centre for Mineral and Energy Technology (CANMET) on thickened tailings technology. Tailings, flocculants and experimental procedures were outlined. The study provided insight into flocculation and thickening of caustic and noncaustic affected oil sand tailings. Caustic and noncaustic processes generate tailings with different water chemistries, which in turn affect the flocculation behaviour of the tailings. Caustic addition results in tailings with high pH because of the high bicarbonate content. The fine particles in noncaustic tailings are less dispersed. It was shown that oil sand fine tailings can be effectively flocculated using high-molecular-weight, medium charged anionic polymers. High settling rates were achieved with properly flocculated solids in caustic and noncaustic tailings. This enabled the recycling of warm water from the overflow. 11 refs., 11 figs.

  17. Deposition velocities to Sorbus aria, Acer campestre, Populus deltoides x trichocarpa 'Beaupre', Pinus nigra and x Cupressocyparis leylandii for coarse, fine and ultra-fine particles in the urban environment

    Energy Technology Data Exchange (ETDEWEB)

    Freer-Smith, P.H.; Beckett, K.P.; Taylor, Gail

    2005-01-01

    Trees are effective in the capture of particles from urban air to the extent that they can significantly improve urban air quality. As a result of their aerodynamic properties conifers, with their smaller leaves and more complex shoot structures, have been shown to capture larger amounts of particle matter than broadleaved trees. This study focuses on the effects of particle size on the deposition velocity of particles (Vg) to five urban tree species (coniferous and broadleaved) measured at two field sites, one urban and polluted and a second more rural. The larger uptake to conifers is confirmed, and for broadleaves and conifers Vg values are shown to be greater for ultra-fine particles (Dp<1.0 {mu}m) than for fine and coarse particles. This is important since finer particles are more likely to be deposited deep in the alveoli of the human lung causing adverse health effects. The finer particle fraction is also shown to be transported further from the emission source; in this study a busy urban road. In further sets of data the aqueous soluble and insoluble fractions of the ultra-fines were separated, indicating that aqueous insoluble particles made up only a small proportion of the ultra-fines. Much of the ultra-fine fraction is present as aerosol. Chemical analysis of the aqueous soluble fractions of coarse, fine and ultra-fine particles showed the importance of nitrates, chloride and phosphates in all three size categories at the polluted and more rural location.

  18. Measurement of Ambient Air Particle (TSP, PM10, PM2,5) Around Candidate Location of PLTN Semenanjung Lemahabang

    International Nuclear Information System (INIS)

    Measurement analysis of ambient air particle (TSP, PM10, PM2,5) around location candidate of PLTN (Power Station of Nuclear Energy) Semenanjung Lemahabang has been carried out. The measurement was conducted in May 2007 with a purpose to providing information about concentration of ambient air particle (TSP, PM10, PM2,5) and diameter distribution of its air particle. The measurement was conducted in three locations i.e. 1). Balong village 2). Bayuran 3). Bondo. Concentration of TSP, PM10, and PM2,5 per 24 hours in all measured locations in area candidate of PLTN exceed quality standard of national ambient air is specified by government. All measurement locations for the TSP, PM10, and PM2,5 was include category of ISPU (Standard Index of Air Pollution) moderate. (author)

  19. Charged particle beam structure having electrostatic coarse and fine double deflection system with dynamic focus and diverging beam

    International Nuclear Information System (INIS)

    An electron beam or other charged particle beam tube of the compound fly's eye type having a coarse deflection system is described. The beam tube comprises an evacuated housing together with an electron gun or other charged particle beam producing means disposed at one end of the evacuated housing for producing a beam of electrons or other charged particles. A coarse deflector, a compound micro lens assembly, and a fine deflector are disposed in the housing in the path of the electron or other charged particle beam for first selecting a lenslet and thereafter finely deflecting an electron or other charged particle beam to a desired spot on a target plane. The electron or other charged particle beam tube is designed in a manner such that the electron or other charged particle beam is caused to diverge at a small angle of divergence in advance of passing through the coarse deflector by appropriately locating the virtual origin or point source of the charged particle a small distance in advance of the coarse deflector. In addition, a dynamic focusing correction potential is supplied to the micro lens assembly along with a high voltage energizing potential with the dynamic focusing correction potential being derived from components of both the coarse deflection potentials and the fine deflection potentials

  20. Multimodal particle size distributions of fine-grained sediments: mathematical modeling and field investigation

    Science.gov (United States)

    Lee, Byung Joon; Toorman, Erik; Fettweis, Michael

    2014-03-01

    Multimodal particle size distributions (PSDs) of fine-grained cohesive sediments are common in marine and coastal environments. The curve-fitting software in this study decomposed such multimodal PSDs into subordinate log-normal PSDs. Four modal peaks, consisting of four-level ordered structures of primary particles, flocculi, microflocs, and macroflocs, were identified and found to alternately rise and sink in a flow-varying tidal cycle due to shear-dependent flocculation. The four modal PSD could be simplified further into two discrete size groups of flocculi and flocs. This allowed the development of a two-class population balance equation (TCPBE) model with flocculi and flocs to simulate flocculation involving multimodal PSDs. The one-dimensional vertical (1-DV) TCPBE model further incorporated the Navier-Stokes equation with the k- ɛ turbulence closure and the sediment mass balance equations. Multimodal flocculation as well as turbulent flow and sediment transport in a flow-varying tidal cycle could be simulated well using the proposed model. The 1-DV TCPBE was concluded to be the simplest model that is capable of simulating multimodal flocculation in the turbulent flow field of marine and coastal zones.

  1. Cooling of an internal-heated debris bed with fine particles

    International Nuclear Information System (INIS)

    In this paper, an analytical model on dryout heat flux of ex-vessel debris beds with fines particles under top flooding conditions has been developed. The parametric study is performed on the effect of the stratification of the debris beds on the dryout heat flux. The calculated results show that the stratification configuration of the debris beds with smaller particles and lower porosity layer resting on the top of another layer of the beds has profound effect on the dryout heat flux for the debris beds both with and without a downcomer. The enhancement of the dryout heat flux by the downcomer is significant. The efficiency of the single downcomer on the enhancement of the dryout heat flux is also analyzed. This, in general, agrees well with experimental data. The model is also employed to perform the assessment on the coolability of the ex-vessel debris bed under representative accidental conditions. One conservative case is chosen, and it is found that the downcomer could be efficient measure to cool the debris bed and hence terminate the severe accident. (authors)

  2. Ventilation dependence of concentration metrics of Ultra-fine Particles in a coagulating household smoke.

    Science.gov (United States)

    Anand, S; Sreekanth, B; Mayya, Y S

    2016-01-01

    Role of Ultra-fine Particles (UFPs) in causing adverse health effects among large population across the world, attributable to household smoke, is being increasingly recognized. However, there is very little theoretical perspective available on the complex behavior of the UFP metrics with respect to controlling factors, such as ventilation rate and particle emission rate from the combustion sources. This numerical study examines through coagulation dynamics, the dependence of UFP metrics, viz., number (PN), mass (PM(0.1)) and surface area (PA(0.1)) concentrations below 0.1 μm diameter, on ventilation and the number emission rate from household smoke. For strong sources, the steady-state concentrations of these metrics are found to increase initially with increasing Air Exchange Rate (AER), reach a peak value and then decrease. Counter correlations are seen between UFP metric and PM(2.5) concentrations. The concepts of Critical Air Exchange Rate (CAER) and Half-Value Air Exchange Rate (HaVAER) have been introduced which indicate a feasibility of mitigation of PM(0.1) and PA(0.1), unlike PN, by ventilation techniques. The study clearly brings forth complex differential behavior of the three UFP metrics. The results are further discussed. PMID:26795205

  3. Measurement and capture of fine and ultrafine particles from a pilot-scale pulverized coal combustor with an electrostatic precipitator.

    Science.gov (United States)

    Li, Ying; Suriyawong, Achariya; Daukoru, Michael; Zhuang, Ye; Biswas, Pratim

    2009-05-01

    Experiments were carried out in a pilot-scale pulverized coal combustor at the Energy and Environmental Research Center (EERC) burning a Powder River Basin (PRB) subbituminous coal. A scanning mobility particle sizer (SMPS) and an electrical low-pressure impactor (ELPI) were used to measure the particle size distributions (PSDs) in the range of 17 nm to 10 microm at the inlet and outlet of the electrostatic precipitator (ESP). At the ESP inlet, a high number concentration of ultrafine particles was found, with the peak at approximately 75 nm. A trimodal PSD for mass concentration was observed with the modes at approximately 80-100 nm, 1-2 microm, and 10 microm. The penetration of ultrafine particles through the ESP increased dramatically as particle size decreased below 70 nm, attributable to insufficient or partial charging of the ultrafine particles. Injection of nanostructured fine-particle sorbents for capture of toxic metals in the flue gas caused high penetration of the ultrafine particles through the ESP. The conventional ESP was modified to enhance charging using soft X-ray irradiation. A slipstream of flue gas was introduced from the pilot-scale facility and passed through this modified ESP. Enhancement of particle capture was observed with the soft X-ray irradiation when moderate voltages were used in the ESP, indicating more efficient charging of fine particles. PMID:19583155

  4. Separation and Recovery of Fine Particles from Waste Circuit Boards Using an Inflatable Tapered Diameter Separation Bed

    OpenAIRE

    2014-01-01

    Recovering particle materials from discarded printed circuit boards can enhance resource recycling and reduce environmental pollution. Efficiently physically separating and recovering fine metal particles (−0.5 mm) from the circuit boards are a key recycling challenge. To do this, a new type of separator, an inflatable tapered diameter separation bed, was developed to study particle motion and separation mechanisms in the bed’s fluid flow field. For 0.5–0.25 mm circuit board particles, metal ...

  5. Exposure to ultrafine and fine particles and noise during cycling and driving in 11 Dutch cities

    Science.gov (United States)

    Boogaard, Hanna; Borgman, Frank; Kamminga, Jaap; Hoek, Gerard

    Recent studies have suggested that exposures during traffic participation may be associated with adverse health effects. Traffic participation involves relatively short but high exposures. Potentially relevant exposures include ultrafine particles, fine particles (PM 2.5) and noise. Simultaneously, detailed real time exposure of particle number concentration (PNC), PM 2.5 and noise has been measured while driving and cycling 12 predefined routes of approximately 10-20 min duration. Sampling took place in eleven medium-sized Dutch cities on eleven weekdays in August till October 2006. To investigate variability in cyclists exposure, we systematically collected information on meteorology, GPS coordinates, type of road, traffic intensity, passing vehicles and mopeds while cycling. The overall mean PNC of car drivers was 5% higher than the mean PNC of cyclists. The overall mean concentration of PM 2.5 in the car was 11% higher than during cycling. Slightly higher 1-min peak concentrations were measured in the car (PNC 14%; PM 2.5 29% for 95-percentiles). Shorter duration peaks of PNC were higher during cycling (43% for 99-percentile of 1-s averages). Peaks in PNC typically last for less than 10 s. A large variability of exposure was found within and between routes. Factors that significantly predicted PNC variability during cycling were: passing vehicles (mopeds, cars), waiting for traffic lights, passing different types of (large) intersections and bicycle lanes and bike paths close to motorized traffic. No relation was found between PM 2.5 and those predictor variables. The correlation between PNC and noise was moderate (median 0.34). PM 2.5 had very low correlations with PNC and noise. PNC and PM 2.5 exposure of car drivers was slightly higher than that of cyclists. PNC was largely uncorrelated with PM 2.5 and reflected local traffic variables more than PM 2.5. Different factors were associated with high PNC and high noise exposures.

  6. Handbook on simultaneous x-ray and γ-ray ion beam methods for fine particle analysis

    International Nuclear Information System (INIS)

    Sampling, measurement, characterisation and source appointment of fine atmospheric particles has become increasingly important in recent times. This is due in part to the realisation that the fine particle pollution caused by anthropogenic activities plays a key role in certain aspects of human health, pollution transport and global climate change. This publication discusses accelerator based ion beam analysis (IBA) methods of particle induced X-ray emission (PIXE) and particle induced γ-ray emission (PIGE) as applied to aerosol analysis. These techniques are sensitive, multielemental, mainly non-destructive, require no sample preparation, have short analysis times and can be used to analyse hundreds of filter samples a day in batch processing with minimum operator interaction. The aspects discussed in the publication include: the basics of the techniques; spectrum analysis; system calibration and blank subtraction; quantification; sensitivity; measurement errors

  7. Applications of particle induced X-ray emission analysis to ambient aerosol studies

    International Nuclear Information System (INIS)

    The characteristics of Particle Induced X-ray Emission (PIXE) analysis in conjunction with different ambient aerosol samplers have been studied. Correction factors have been calculated for homogeneous and inhomogeneous rural and urban aerosol samples. The Nuclepore two stage filter sampler provided the most useful combination of the resolution and particle size fractionation in urban, rural and remote environments. The PIXE-analysis technique in combination with different samplers was employed in aerosol composition studies in rural and remote environments. Particular emphasis was laid on studies of aerosol long range transport. Based on air mass trajectory analysis and aerosol composition measurements the foreign contribution in southern Sweden was estimated to be 70 - 80% for S and Pb but only 30 - 50% for V and Ni. The spatial and temporal extension of a long range transport episode was studied using high time resolution continuous filter samplers in a network in southern Sweden. The variation in the concentration levels of sulphur agreed well with changes in the air mass history. Arctic summer elemental concentration levels as measured during the Swedish YMER-80 icebreaker expedition were typically one order of magnitude lower than Arctic winter levels. The combination of chemical information, optical properties and size distribution data supports the hypothesis of long range transport of air pollution into the Arctic especially during the winter. This takes place during the winter season because the Polar front is further south making conditions for long range transport up to the Arctic more favourable. (Auth.)

  8. Fine-tuning of process conditions to improve product uniformity of polystyrene particles used for wind tunnel velocimetry

    Science.gov (United States)

    Ray, Asit K.

    1990-01-01

    Monodisperse polymer particles (having uniform diameter) were used for the last two decades in physical, biological, and chemical sciences. In NASA Langley Research Center monodisperse polystyrene particles are used in wind tunnel laser velocimeters. These polystyrene (PS) particles in latex form were formulated at the Engineering Laboratory of FENGD using emulsion-free emulsion polymerization. Monodisperse PS latices particles having different particle diameters were formulated and useful experimental data involving effects of process conditions on particle size were accumulated. However, similar process conditions and chemical recipes for polymerization of styrene monomer have often yielded monodisperse particles having varying diameters. The purpose was to improve the PS latex product uniformity by fine-tuning the process parameters based on the knowledge of suspension and emulsion polymerization.

  9. Size distribution, chemical composition, and hygroscopicity of fine particles emitted from an oil-fired heating plant.

    Science.gov (United States)

    Happonen, Matti; Mylläri, Fanni; Karjalainen, Panu; Frey, Anna; Saarikoski, Sanna; Carbone, Samara; Hillamo, Risto; Pirjola, Liisa; Häyrinen, Anna; Kytömäki, Jorma; Niemi, Jarkko V; Keskinen, Jorma; Rönkkö, Topi

    2013-12-17

    Heavy fuel oil (HFO) is a commonly used fuel in industrial heating and power generation and for large marine vessels. In this study, the fine particle emissions of a 47 MW oil-fired boiler were studied at 30 MW power and with three different fuels. The studied fuels were HFO, water emulsion of HFO, and water emulsion of HFO mixed with light fuel oil (LFO). With all the fuels, the boiler emitted considerable amounts of particles smaller than 200 nm in diameter. Further, these small particles were quite hygroscopic even as fresh and, in the case of HFO+LFO emulsion, the hygroscopic growth of the particles was dependent on particle size. The use of emulsions and the addition of LFO to the fuel had a reducing effect on the hygroscopic growth of particles. The use of emulsions lowered the sulfate content of the smallest particles but did not affect significantly the sulfate content of particles larger than 42 nm and, further, the addition of LFO considerably increased the black carbon content of particulate matter. The results indicate that even the fine particles emitted from HFO based combustion can have a significant effect on cloud formation, visibility, and air quality. PMID:24245691

  10. The influence of fine char particles burnout on bed agglomeration during the fluidized bed combustion of a biomass fuel

    Energy Technology Data Exchange (ETDEWEB)

    Scala, Fabrizio; Chirone, Riccardo [Istituto di Ricerche sulla Combustione, CNR, P.le V. Tecchio, 80-80125 Naples (Italy); Salatino, Piero [Dipartimento di Ingegneria Chimica, Universita degli Studi di Napoli Federico II, P.le V. Tecchio, 80-80125 Naples (Italy)

    2003-11-15

    The combustion of biomass char in a bubbling fluidized bed is hereby addressed, with specific reference to the influence that the combustion of fine char particles may exert on ash deposition and bed agglomeration phenomena. Experiments of steady fluidized bed combustion (FBC) of powdered biomass were carried out with the aim of mimicking the postcombustion of attrited char fines generated in the fluidized bed combustion of coarse char. Experimental results showed that the char elutriation rate is much smaller than expected on the basis of the average size of the biomass powder and of the carbon loading in the combustor. Samples of bed material collected after prolonged operation of the combustor were characterized by scanning electron microscopy (SEM)-EDX analysis and revealed the formation of relatively coarse sand-ash-carbon aggregates. The phenomenology is consistent with the establishment of a char phase attached to the bed material as a consequence of adhesion of char fines onto the sand particles. Combustion under sound-assisted fluidization conditions was also tested. As expected, enhancement of fines adhesion on bed material and further reduction of the elutriation rate were observed. Experimental results are interpreted in the light of a simple model which accounts for elutriation of free fines, adhesion of free fines onto bed material and detachment of attached fines by attrition of char-sand aggregates. Combustion of both free and attached char fines is considered. The parameters of the model are assessed on the basis of the measured carbon loadings and elutriation rates. Model computations are directed to estimate the effective size and the peak temperature of char-sand aggregates. The theoretical estimates of the effective aggregate size match fairly well those observed in the experiments.

  11. 77 FR 65651 - Determination of Attainment for the Chico Nonattainment Area for the 2006 Fine Particle Standard...

    Science.gov (United States)

    2012-10-30

    ... individual areas, based on a determination of attainment. See 60 FR 36723 (July 18, 1995) (Salt Lake and.... See Clean Air Fine Particle Implementation Rule, 72 FR 20586 (April 25, 2007); Final Rule To Implement... AGENCY 40 CFR Part 52 Determination of Attainment for the Chico Nonattainment Area for the 2006...

  12. Estimating source-attributable health impacts of ambient fine particulate matter exposure: global premature mortality from surface transportation emissions in 2005

    International Nuclear Information System (INIS)

    Exposure to ambient fine particular matter (PM2.5) was responsible for 3.2 million premature deaths in 2010 and is among the top ten leading risk factors for early death. Surface transportation is a significant global source of PM2.5 emissions and a target for new actions. The objective of this study is to estimate the global and national health burden of ambient PM2.5 exposure attributable to surface transportation emissions. This share of health burden is called the transportation attributable fraction (TAF), and is assumed equal to the proportional decrease in modeled ambient particulate matter concentrations when surface transportation emissions are removed. National population-weighted TAFs for 190 countries are modeled for 2005 using the MOZART-4 global chemical transport model. Changes in annual average concentration of PM2.5 at 0.5 × 0.67 degree horizontal resolution are based on a global emissions inventory and removal of all surface transportation emissions. Global population-weighted average TAF was 8.5 percent or 1.75 μg m−3 in 2005. Approximately 242 000 annual premature deaths were attributable to surface transportation emissions, dominated by China, the United States, the European Union and India. This application of TAF allows future Global Burden of Disease studies to estimate the sector-specific burden of ambient PM2.5 exposure. Additional research is needed to capture intraurban variations in emissions and exposure, and to broaden the range of health effects considered, including the effects of other pollutants. (letter)

  13. Respiratory disease and particulate air pollution in Santiago Chile: Contribution of erosion particles from fine sediments

    International Nuclear Information System (INIS)

    Air pollution in Santiago is a serious problem every winter, causing thousands of cases of breathing problems within the population. With more than 6 million people and almost two million vehicles, this large city receives rainfall only during winters. Depending on the frequency of storms, statistics show that every time it rains, air quality improves for a couple of days, followed by extreme levels of air pollution. Current regulations focus mostly on PM10 and PM2.5, due to its strong influence on respiratory diseases. Though more than 50% of the ambient PM10s in Santiago is represented by soil particles, most of the efforts have been focused on the remaining 50%, i.e. particulate material originating from fossil and wood fuel combustion, among others. This document emphasizes the need for the creation of erosion/sediment control regulations in Chile, to decrease respiratory diseases on Chilean polluted cities. - We emphasize the urgent need to implement erosion and sediment control politics in Santiago, to decrease PM10 concentrations in the city's air, based on the US experience

  14. Micro translocation study of fine Fe2O3 particles in rat brain by synchrotron radiation X-ray fluorescence

    International Nuclear Information System (INIS)

    Fine and ultrafine iron oxide particle has been widely used for coloring rubber, plastic products, cement goods, building structures, and various kinds of paints including anti-rusting paint, spray paint, and magnetic paint etc. Therefore, the possibility for people exposure to these particles is increasing. Depending on the particle size, inhaled particles are easily deposited in nasal, tracheobronchial, and alveolar regions. Moreover, the elevated iron levels in brain are related to many types of neurodegenerative diseases, such as Alzheimer's, Parkinson's and Huntington's diseases. The objective of this study is to investigate whether the fine iron oxide particle (Fe2O3, ∼150 nm) could enter brain via olfactory bulb route. The micro distributions of iron and other trace elements in olfactory bulb and cerebellum were investigated by Synchrotron Radiation X-ray fluorescence (SRXRF). The experimental mice were intranasally instilled with Fe2O3 suspension at a dose of 40 mg/kg b.wt., while the control mice were instilled with sodium carboxy methyl cellulose solution instead. Two weeks later, the olfactory bulb and cerebellum of the mice were collected and the tissues were cut into 80 μm by freeze section technique. The slice was fixed onto a polycarbonate film. The micro distributions of iron, copper, and zinc were scanned by SRXRF. The results showed that the fine Fe203 particles could transfer into the olfactory bulb and mainly accumulate in the olfactory nerve layer (ON), glomerular layer (Gl), external plexiform layer (EPl), anterior olfactory nucleus layer (AOE) and lateral olfactory tract (lo). More significantly, Fe2O3 was found to translocate into the cerebellum. The iron in the cerebellum mainly existed in the spontaneous postsynaptic currents (sPSC) and medullary reticular nucleus ventral (Mdv) regions. Meanwhile, the effects of fine Fe203 particles on the distributions of Cu and Zn in the brain were also studied.

  15. Source apportionment of size segregated fine/ultrafine particle by PMF in Beijing

    Science.gov (United States)

    Tan, Ji-hua; Duan, Jing-chun; Chai, Fa-he; He, Ke-bin; Hao, Ji-Ming

    2014-03-01

    Considering the adverse health effects to human body, the number concentration of atmospheric PM (particulate material) is more important than the mass concentration. CO, NO, NO2, SO2 and number concentrations of PM were obtained from a remote site (Miyun), a roadside site (North Fourth Ring Road) and an urban residential site (Tsinghua University) in Beijing in winter. The size distribution and the possible sources of number concentrations were examined using EPA PMF (positive matrix factorization) model. A data set of totally 9610 of number concentration with the size range of 0.028 μm to 0.948 μm was included in the PMF analysis. The highest total particle number, mass and area of fine particles concentrations were observed at the North Fourth Ring Road site and the lowest were observed at Miyun site. Four factors were identified at Miyun site, as Factor 1 and Factor 4 may be related to long distance transportation, and Factor 2 and Factor 3 may be assigned as coal combustion and locomotive emission nearby, respectively; three factors were identified at North Fourth Ring Road, of which Factor 1 and Factor 3 are traffic related and Factor 2 may be coal combustion related. Compared with Factor 1, the contributions of Factor 3 to NOx and SO2 were 4-5 times higher. Additionally, Factor 3 was also a major contributor to CO. It suggested that Factor 1 and Factor 3 had the same source emission of motor vehicle, but different engine types, fuel types or exhaust treatments. Three factors were identified at Tsinghua site, as Factor 1 may come from aging vehicle emission, and Factor 2 and Factor 3 may be coal combustion related.

  16. Trace element concentrations on fine particles in the Ohio River Valley

    International Nuclear Information System (INIS)

    Atmospheric particles were collected from May, 1980 to Dec., 1981 at 3 sampling sites in the Ohio River Valley (ORV). The collected samples were analyzed by x-ray fluorescence (XRF) for elemental concentrations and their masses determined by β gauging. The XRF data and associated wind trajectories were used to select a subset (200) of ORV samples in the fine fraction for further analysis by instrumental neutron activation analysis (INAA). Combined XRF and INAA data provided concentration values for up to 40 elements. Chemical mass balances with 11 sources were used to fit trace element concentrations. About 90% of the predicted mass arises from the regional sulfate component, which accounts for most of the observed sulfur. Sulfate concentrations are nearly as high at the west station (in KY) as at the center (IN) and east (OH) stations in disagreement with the usual picture of build-up of sulfate in air masses as they move up the valley, picking up SO2, which is slowly converted to sulfate. Even when back trajectories are used to limit consideration to samples of air masses coming from the southwest, the picture remains despite the lack of strong sources upwind in MO, AK and OK. The authors find no reasonable way in which to fit observed sulfate concentrations and SSe ratios with a simple hybrid receptor model

  17. Probing the nature of the contact between fine particles by using ultrasound propagation

    Institute of Scientific and Technical Information of China (English)

    Antonio Castellanos; Xiaoping Jia; Carlos Soria-Hoyo; Jose Manuel Valverde

    2011-01-01

    The propagation velocity (vs) of an ultrasonic signal through a granular material depends on the type of interparticle contact.For noncohesive glass beads,a power law behavior vs ασc1/6 for consolidation stresses applied (ρc) above 1 MPa has been measured in previous work.This equation is compatible with Hertz's interaction law between elastic solids.In the present work,we have tested the propagation velocity of ultrasound signals through a sample of fine powder.The tensile strength and compactivity of the powder were previously measured by means of the Seville powder tester (SPT),indicating plastic deformation of the surface asperities in contact for small to moderate consolidation stresses.However,the measurements of ultrasound propagation at high consolidations presented here are compatible with Hertz's law.This finding suggests that for high consolidation stresses,surface asperities are flattened,and it is therefore the elastic deformation of the bulk of the particles that determines the transmission of ultrasonic pulses.

  18. Dynamics of fine particles and photo-oxidants in the Eastern Mediterranean (SUB-AERO)

    Science.gov (United States)

    Lazaridis, M.; Eleftheriadis, K.; Smolik, J.; Colbeck, I.; Kallos, G.; Drossinos, Y.; Zdimal, V.; Vecera, Z.; Mihalopoulos, N.; Mikuska, P.; Bryant, C.; Housiadas, C.; Spyridaki, A.; Astitha, Marina; Havranek, V.

    As part of the European project SUB-AERO, comprehensive aerosol and gaseous pollutant measurement campaigns were performed at the Finokalia station (July 2000 and January 2001) on the island of Crete (Greece) in combination with boat measurements in the eastern part of the Mediterranean area. The measurements were performed with the participation of nine European research institutions. The objective of the measurement campaigns was to evaluate and assess the spatial and temporal variability of photochemical pollutants and fine particles. The current overview paper presents the framework and main results of the measurements and modelling studies performed during the project. Extensive measurements of gaseous and atmospheric-aerosol physical, chemical and optical characteristics were performed during the measurement campaigns in conjunction with detailed chemical analyses of the aerosol species. Along with the experimental work mesoscale modelling, using a combination of the UAM-AERO air quality model together with the RAMS prognostic meteorological model, was used to reveal the dynamics of particulate matter and photo-oxidants. Furthermore, regional chemistry transport models were applied to determine the background and initial conditions for the mesoscale modelling.

  19. Tracing the source of difficult to settle fine particles which cause turbidity in the Hitotsuse Reservoir, Japan.

    Science.gov (United States)

    Murakami, Toshiki; Suzuki, Yoshihiro; Oishi, Hiroyuki; Ito, Kenichi; Nakao, Toshio

    2013-05-15

    A unique method to trace the source of "difficult-to-settle fine particles," which are a causative factor of long-term turbidity in reservoirs was developed. This method is characterized by cluster analysis of XRD (X-ray diffraction) data and homology comparison of major component compositions between "difficult-to-settle fine particles" contained in landslide soil samples taken from the upstream of a dam, and suspended "long-term turbid water particles" in the reservoir, which is subject to long-term turbidity. The experiment carried out to validate the proposed method, demonstrated a high possibility of being able to make an almost identical match between "difficult-to-settle fine particles" taken from landslide soils at specific locations and "long-term turbid water particles" taken from a reservoir. This method has the potential to determine substances causing long-term turbidity and the locations of soils from which those substances came. Appropriate countermeasures can then be taken at those specific locations. PMID:23500107

  20. Impact of superplasticizer concentration and of ultra-fine particles on the rheological behaviour of dense mortar suspensions

    International Nuclear Information System (INIS)

    This work aims at investigating the impact of the addition of superplasticizer and of ultra-fine particles, namely of silica fume and of precipitated titania, on the rheological behaviour of water-lean mortar pastes. The pastes are characterised in terms of their spread, their flowing behaviour and by means of performing a shear test, giving access to viscosity/shear gradient correlations. Adding superplasticizer is shown to shift the onset of shear thickening of the referring pastes to higher shear rates and to attenuate its otherwise rapid evolution, possibly by means of favouring steric particle-particle interactions. The workability of these mortars, which is characterised in terms of spread values and draining, is also improved. For the case of fly ash based mortars, adding ultra-fine particles is another way of (slightly) 'retarding' shear thickening and of attenuating its evolution, possibly because of resulting in - on the average - lower hydrodynamic forces and reduced attractive Van der Waals interactions between particles. However, at the same time these mortars are characterised by a worsening in workability which is attributed to the huge amount of surface area provided by the ultra-fines

  1. Ultra-fine particles release from hardcopy devices: sources, real-room measurements and efficiency of filter accessories.

    Science.gov (United States)

    Wensing, Michael; Schripp, Tobias; Uhde, Erik; Salthammer, Tunga

    2008-12-15

    The release of ultra-fine particles (UFP, d job was about ten times slower than in the test chamber. A toxicological assessment of the emitted particles requires that their chemical composition be known. Due to the low mass of the released UFPs chemical analysis needs a prior enrichment on a feasible media. Experiments using electrostatic precipitation showed a flame retardant (tri-xylyl phosphate) whose concentration on the media was dependent on the number of pages printed. Whether this compound was particle-bound could not be determined. PMID:18809204

  2. PREFACE: 8th International Conference on Fine Particle Magnetism (ICFPM2013)

    Science.gov (United States)

    2014-06-01

    The 8th International Conference on Fine Particle Magnetism (ICFPM) was held in Perpignan from 24 to 27 June 2013, and was the continuation of the previous meetings held in Bangor (1996), Rome (1991), Barcelona (1999), Pittsburg (2002), London (2004), Rome (2007) and Uppsala (2010). The next meeting will be organized by Profs. Robert D. Shull, George Hadjipanayis and Cindi Dennis, in 2016 at NIST, Gaithersburg (USA). ICFPM is a small-sized conference focused on the magnetism of nanoparticles. It provides an international forum for discussing the state-of-the-art understanding of physics of these systems, of their properties and the underlying phenomena, as approached from a variety of directions: theory and modelling, experiments on well characterized or model systems (both fabricated and synthetised), as well as experiments on technologically-relevant non-ideal systems. This meeting brought together about 120 participants working on experimental, theoretical and applied topics of the multidisciplinary research areas covered by magnetic nanoparticles, with focused interest on either single-particle or collective phenomena. The technical program of the conference was based on keynote conferences, invited talks, oral contributions and poster sessions, covering the following aspects: . Fabrication, synthesis, characterization . Single particle, surface and finite-size effects on magnetic properties . Magnetization dynamics, micro-wave assisted switching, dynamical coupling . Assemblies, collective effects, self-assembling and nanostructuring . Applications : hyperthermia, drug delivery, magneto-caloric, magneto-resistance, magneto-plasmonics, magnetic particle imaging This ICFPM edition was organized by the group Nanoscale Spin Systems of the laboratory PROMES of the CNRS (UPR8521), and Université de Perpignan Via Domitia. The meeting took place at the Congress Center of the city of Perpignan providing high-quality facilities for the technical program as well for the

  3. NOx, FINE PARTICLE AND TOXIC METAL EMISSIONS FROM THE COMBUSTION OF SEWAGE SLUDGE/COAL MIXTURES: A SYSTEMATIC ASSESSMENT

    Energy Technology Data Exchange (ETDEWEB)

    Jost O.L. Wendt

    2001-05-04

    This research project focuses on pollutants from the combustion of mixtures of dried municipal sewage sludge (MSS) and coal. The objective is to determine the relationship between (1) fraction sludge in the sludge/coal mixture, and (2) combustion conditions on (a) NO{sub x} concentrations in the exhaust, (b) the size segregated fine and ultra-fine particle composition in the exhaust, and (c) the partitioning of toxic metals between vapor and condenses phases, within the process. To this end we shall use an existing 17kW downflow laboratory combustor, available with coal and sludge feed capabilities. The proposed study will be conducted in concert with an existing ongoing research on toxic metal partitioning mechanisms for very well characterized pulverized coals alone. Both high NO{sub x} and low NO{sub x} combustion conditions will be investigated (unstaged and staged combustion). The proposed work uses existing analytical and experimental facilities and draws on 20 years of research on NO{sub x} and fine particles that has been funded by DOE in this laboratory. Four barrels of dried sewage sludge are currently in the laboratory. Insofar as possible pertinent mechanisms will be elucidated. Tradeoffs between CO{sub 2} control, NO{sub x} control, and inorganic fine particle and toxic metal emissions will be determined.

  4. Separation and recovery of fine particles from waste circuit boards using an inflatable tapered diameter separation bed.

    Science.gov (United States)

    Duan, Chenlong; Sheng, Cheng; Wu, Lingling; Zhao, Yuemin; He, Jinfeng; Zhou, Enhui

    2014-01-01

    Recovering particle materials from discarded printed circuit boards can enhance resource recycling and reduce environmental pollution. Efficiently physically separating and recovering fine metal particles (-0.5 mm) from the circuit boards are a key recycling challenge. To do this, a new type of separator, an inflatable tapered diameter separation bed, was developed to study particle motion and separation mechanisms in the bed's fluid flow field. For 0.5-0.25 mm circuit board particles, metal recovery rates ranged from 87.56 to 94.17%, and separation efficiencies ranged from 87.71 to 94.20%. For 0.25-0.125 mm particles, metal recovery rates ranged from 84.76 to 91.97%, and separation efficiencies ranged from 84.74 to 91.86%. For superfine products (-0.125 mm), metal recovery rates ranged from 73.11 to 83.04%, and separation efficiencies ranged from 73.00 to 83.14%. This research showed that the inflatable tapered diameter separation bed achieved efficient particle separation and can be used to recover fine particles under a wide range of operational conditions. The bed offers a new mechanical technology to recycle valuable materials from discarded printed circuit boards, reducing environmental pollution. PMID:25379546

  5. Separation and Recovery of Fine Particles from Waste Circuit Boards Using an Inflatable Tapered Diameter Separation Bed

    Directory of Open Access Journals (Sweden)

    Chenlong Duan

    2014-01-01

    Full Text Available Recovering particle materials from discarded printed circuit boards can enhance resource recycling and reduce environmental pollution. Efficiently physically separating and recovering fine metal particles (−0.5 mm from the circuit boards are a key recycling challenge. To do this, a new type of separator, an inflatable tapered diameter separation bed, was developed to study particle motion and separation mechanisms in the bed’s fluid flow field. For 0.5–0.25 mm circuit board particles, metal recovery rates ranged from 87.56 to 94.17%, and separation efficiencies ranged from 87.71 to 94.20%. For 0.25–0.125 mm particles, metal recovery rates ranged from 84.76 to 91.97%, and separation efficiencies ranged from 84.74 to 91.86%. For superfine products (−0.125 mm, metal recovery rates ranged from 73.11 to 83.04%, and separation efficiencies ranged from 73.00 to 83.14%. This research showed that the inflatable tapered diameter separation bed achieved efficient particle separation and can be used to recover fine particles under a wide range of operational conditions. The bed offers a new mechanical technology to recycle valuable materials from discarded printed circuit boards, reducing environmental pollution.

  6. Ambient pressure effects on the sputter particle distribution of insulating materials

    International Nuclear Information System (INIS)

    The effect of ion bombardment on several grades of alumina was investigated. Changes in the electrical resistance of the substrate as a function of incoming ion energy were of particular interest. Attention was also paid to the sputter particle distribution as a function of ambient pressure. This distribution was found to be dependent on the ion to substrate mass ratio. In general, the distribution follows a curve of growth; approximating a cosine distribution at the lower pressures and mass ratio, becoming isotropic at higher pressures. Pressures in the range of 10-2 to 10-4 Pascals have been used along with mass ratios in the range of 0.40 to 1.3. Samples of up to 80 cm2 were subjected to a 10 cm diameter ion beam at energies of up to 6.25 keV. Average ion current densities of 1ma/cm2 were used. Substrate temperatures while subjected to the ion beam were also monitored

  7. Characteristics of water-soluble ions and carbon in fine and coarse particles collected near an open burning site

    Science.gov (United States)

    Lin, Chih-Chung; Huang, Kuo-Lin; Tsai, Jen-Hsiung; Lee, Wen-Jhy; Chen, Shui-Jen; Lin, Shao-Kai

    2012-05-01

    This study investigates the chemical characteristics of particles that were collected from the open burning of wax apple agricultural waste, and evaluates the impact of such burning on regional air quality. The water-soluble ions, elemental carbon (EC), and organic carbon (OC) in fine (Dp ≤ 2.5 μm) and coarse (2.5 burning (0.90) was higher than those both before and after burning (0.57 and 0.55, respectively). The particle distributions before and during burning were bi-modal and uni-modal, respectively. During the open burning, the OC or K+ content markedly increased; however, that of secondary aerosol (NH4+, NO3- and SO42-) decreased. The Na+/Cl- molar ratios of fine particles before, after, and during the open burning 0.40, 0.18, and 0.24, respectively; however, the corresponding (Na+ + K+)/Cl- molar ratios were 0.74, 0.99, and 0.39, respectively. OC, K+ and Cl- were quite abundant in the open burning of agricultural waste (wax apple), and the OC/Na+, K+/Na+, and Cl-/Na+ (mass) ratios in fine particles (318, 10.2, and 10.5, respectively) may be used as reference indexes associated with the open burning of wax apple waste.

  8. Correlations between urban atmospheric light extinction coefficients and fine particle mass concentrations

    Energy Technology Data Exchange (ETDEWEB)

    Trier, A.; Cabrini, N.; Ferrer, J. [Facultad de Ciencia, Universidad de Santiago de Chile, Santiago 2 (Chile); Olaeta, I. [SESMA, Santiago 1 (Chile)

    1997-07-01

    Total horizontal atmospheric light extinction coefficients as well as particle mass concentrations have been measured in downtown areas of Santiago de Chile, a heavily polluted city. Measurement campaigns were carried out in 1994 in 1995. Extinction measurements were made by a telephotometric technique in four wavelength bands; oscillating mass balance type instruments were used to measure PM2.5 and PM10 mass concentrations. The latter type instrument had not been available heretofore. The extensive continuous PM2.5 measurements are the first for this city. Strong and highly significant statistical correlations were found between extinction coefficients and mass concentrations, especially with the fine respirable or PM2.5 mass concentrations. Angstrom exponents and, in one case, mass extinction coefficients have been estimated. [Spanish] Se ha medido coeficientes atmosfericos totales horizontales de extincion de luz asi como concentraciones de masa de particulas atmosfericas en zonas centricas de Santiago de Chile, una ciudad altamente contaminada. Las campanas de medicion se han hecho en 1994 y en 1995. Las mediciones de extincion se han hecho por un metodo telefotometrico en cuatro bandas espectrales; las concentraciones de masa PM2.5 y PM10 se han medido con instrumentos del tipo de balanzas de masa oscilantes. Tales instrumentos no han estado disponibles durante trabajos anteriores. Las extensas mediciones continuas de concentraciones de masa PM2.5 son las primeras para Santiago de Chile. Se han encontrado fuertes correlaciones estadisticas, altamente significativas, entre coeficientes de extincion y concentraciones de masa, especialmente las concentraciones de particulas finas respirables PM2.5. Se han estimado tambien exponentes de Angstrom y, en un caso, coeficientes masicos de extincion.

  9. The fine structure constant alpha: relevant for a model of a self-propelling photon and for particle masses

    Science.gov (United States)

    Greulich, Karl O.

    2015-09-01

    A model for a self propelling (i.e. massless) photon1 is based on oscillations of a pair of charges amounting to elementary charge divided by SQRT alpha, where alpha is the fine structure (Sommerfeld) constant. When one assumes a similar model for particles that do have rest mas (i.e. which are non- self propelling), alpha plays also a role in the rest masses of elementary particles. Indeed all fundamental elementary particle masses can be described by the alpha / beta rule2 --> m(particle) = alpha-n * betam* 27.2 eV /c2 where beta is the proton to electron mass ratio 183612 and n= 0….14, m= -1,0 or Thus, photons and particle masses are intimately related to the fine structure constant. If the latter would not have been strictly constant throughout all times, this would have had consequences for the nature of light and for all masses including those of elementary particles.

  10. In vitro effects on macrophages induced by noncytotoxic doses of silica particles possibly relevant to ambient exposure

    International Nuclear Information System (INIS)

    The RAW 246.7 macrophage cell line was exposed in vitro to aged crystalline silica particles of respirable size for 24 h at a range of doses starting from 15 μg/2x106 cells, which is a realistic exposure level of macrophages in the airways of ambiently exposed individuals. The particle sample used for the experiments was prepared to mimic some aspects of ambient crystalline silica particles: size distribution, morphology, and surface reactivity. Our purpose was to determine whether a nontoxic quartz load comparable to that of ambient exposure would be able to induce macrophage activation and impairment of the phagocytic ability, factors altering the lung's capacity to deal with increased particle loads (as occurs during high-pollution episodes) or infections and affecting the local and systemic responses through the release of biologically active compounds (cytokines, reactive oxygen species, NO, isoprostanes). Exposure of RAW 264.7 cells to aged silica particles induced macrophage activation (evidenced by the morphological features observed with scanning electron microscopy and by the release of TNF-α and IL-6) and impairment of phagocytosis of test particles, even at noncytotoxic doses. The reduction of the phagocytic function of the cells after silica treatment was dose-dependent, as evidenced by an increase of the population of unphagocytic cells, paralleled by a decrease of the actively phagocytizing cell population. We evaluated the oxidative stress induced by aged silica particles, quantifying the peroxidation products (8-isoprostanes) in the culture media of treated cells, and found a strong release at low doses. Isoprostanes are a complex family of compounds which have been used as in vivo markers of lipid peroxidation in human disorders, but that, as far as we know, have never been evaluated in relation to airborne particulate matter exposure. Lipid peroxides are involved in various cellular events in the inflammatory response, and isoprostanes are also

  11. Emissions and measure analysis of fine particles 2000-2020; Emissionen und Massnahmenanalyse Feinstaub 2000-2020

    Energy Technology Data Exchange (ETDEWEB)

    Joerss, Wolfram; Handke, Volker [Institut fuer Zukunftsstudien und Technologiebewertung gGmbH (IZT), Berlin (Germany)

    2007-08-15

    With this study, the Federal Environmental Agency's emission inventory on total suspended particles and the fine fractions PM{sub 1}0 and PM{sub 2}.5 was updated. On that basis, a reference scenario was developed for anthropogenic emissions of particulate matter up to the years 2010, 2015 and 2020. In addition, potential additional emission reduction measures were systematically collected and quantified. At the source groups which contribute most strongly to the emissions there are clear differences between the fine fractions and in the course of time. In particular, with the total fine the emission freight is very broadly distributed over many source groups. With PM{sub 2}.5, the emissions are more strongly concentrated on a limited number of source groups. The decrease of the emissions in the years between 2000 and 2020 in the reference scenario takes place in source groups with high portions of PM{sub 2}.5 of the emissions of total fine particles.

  12. Measurements of the evaporation and hygroscopic response of single fine-mode aerosol particles using a Bessel beam optical trap.

    Science.gov (United States)

    Cotterell, Michael I; Mason, Bernard J; Carruthers, Antonia E; Walker, Jim S; Orr-Ewing, Andrew J; Reid, Jonathan P

    2014-02-01

    A single horizontally-propagating zeroth order Bessel laser beam with a counter-propagating gas flow was used to confine single fine-mode aerosol particles over extended periods of time, during which process measurements were performed. Particle sizes were measured by the analysis of the angular variation of light scattered at 532 nm by a particle in the Bessel beam, using either a probe beam at 405 nm or 633 nm. The vapour pressures of glycerol and 1,2,6-hexanetriol particles were determined to be 7.5 ± 2.6 mPa and 0.20 ± 0.02 mPa respectively. The lower volatility of hexanetriol allowed better definition of the trapping environment relative humidity profile over the measurement time period, thus higher precision measurements were obtained compared to those for glycerol. The size evolution of a hexanetriol particle, as well as its refractive index at wavelengths 532 nm and 405 nm, were determined by modelling its position along the Bessel beam propagation length while collecting phase functions with the 405 nm probe beam. Measurements of the hygroscopic growth of sodium chloride and ammonium sulfate have been performed on particles as small as 350 nm in radius, with growth curves well described by widely used equilibrium state models. These are the smallest particles for which single-particle hygroscopicity has been measured and represent the first measurements of hygroscopicity on fine mode and near-accumulation mode aerosols, the size regimes bearing the most atmospheric relevance in terms of loading, light extinction and scattering. Finally, the technique is contrasted with other single particle and ensemble methods, and limitations are assessed. PMID:24346588

  13. Using multiple continuous fine particle monitors to characterize tobacco, incense, candle, cooking, wood burning, and vehicular sources in indoor, outdoor, and in-transit settings

    Science.gov (United States)

    Ott, Wayne R.; Siegmann, Hans C.

    This study employed two continuous particle monitors operating on different measurement principles to measure concentrations simultaneously from common combustion sources in indoor, outdoor, and in-transit settings. The pair of instruments use (a) photo-charging (PC) operating on the principle ionization of fine particles that responds to surface particulate polycyclic aromatic hydrocarbons (PPAHs), and (b) diffusion charging (DC) calibrated to measure the active surface area of fine particles. The sources studied included: (1) secondhand smoke (cigarettes, cigars, and pipes), (2) incense (stick and cone), (3) candles used as food warmers, (4) cooking (toasting bread and frying meat), (5) fireplaces and ambient wood smoke, and (6) in-vehicle exposures traveling on California arterials and interstate highways. The ratio of the PC to the DC readings, or the PC/DC ratio, was found to be different for major categories of sources. Cooking, burning toast, and using a "canned heat" food warmer gave PC/DC ratios close to zero. Controlled experiments with 10 cigarettes averaged 0.15 ng mm -2 (ranging from 0.11 to 0.19 ng mm -2), which was similar to the PC/DC ratio for a cigar, although a pipe was slightly lower (0.09 ng mm -2). Large incense sticks had PC/DC ratios similar to those of cigarettes and cigars. The PC/DC ratios for ambient wood smoke averaged 0.29 ng mm -2 on 6 dates, or about twice those of cigarettes and cigars, reflecting a higher ratio of PAH to active surface area. The smoke from two artificial logs in a residential fireplace had a PC/DC ratio of 0.33-0.35 ng mm -2. The emissions from candles were found to vary, depending on how the candles were burned. If the candle flickered and generated soot, a higher PC/DC ratio resulted than if the candle burned uniformly in still air. Inserting piece of metal into the candle's flame caused high PPAH emissions with a record PC/DC reading of 1.8 ng mm -2. In-vehicle exposures measured on 43- and 50-min drives on a

  14. Effects of fine carbonaceous particles containing high and low unpaired electron spin densities on lungs of female mice.

    Science.gov (United States)

    Repine, John E; Reiss, Oscar K; Elkins, Nancy; Chughtai, Abdul R; Smith, Dwight M

    2008-10-01

    The negative impacts on human health that accompany inhalation of atmospheric particles are documented in numerous epidemiologic studies, but the effect of specific chemical properties of the particles is generally unknown. We developed and employed technology for generating inhalable aerosols of carbonaceous air pollution particles that have specific physical and chemical properties. We find that inhaling particles with greater unpaired electron spin (free radical) densities stimulates greater lung inflammatory and oxidative stress responses. Cultured alveolar macrophages take up more particles of greater free radical content, develop mitochondrial abnormalities, and release more leukotriene B(4) (LTB(4)) than alveolar macrophages exposed to lesser free-radical-containing particles in vitro. Mice exposed to high free radical particles in vivo also develop mitochondrial abnormalities in alveolar macrophages and increased oxidative stress, which is reflected by increases in lung nitrotyrosine staining and lung lavage nitrogen oxide levels compared with those of lesser free radical density. These results provide insight for the unexplained geographic differences and have implications for fossil fuel combustion conditions and the impact of fine particles on health and disease. PMID:18940721

  15. Characterizing chemical transport of ozone and fine particles in the Great Lakes region

    Science.gov (United States)

    Spak, Scott N.

    This dissertation presents a science framework relevant to evaluating impacts of land use policy scenarios, energy technologies, and climate on urban and regional air quality. Emerging from collaboration with urban planners, this work provides a means for employing atmospheric chemical transport modeling to understand environmental ramifications of long-term, spatially disaggregated changes in population and automobile emissions at the census tract level, and to assess the sensitivity of these changes to densification strategies. Toward these goals, the framework is used to evaluate model skill in resolving contemporary characteristics of ozone (O3) and speciated fine particles (PM2.5) in the Great Lakes region of North America, and to quantitatively explore meteorological processes that bring about observed features of these pollutants in the region. The Great Lakes were chosen due to a population concentrated in sprawling metropolitan areas, consistently high and widespread pollutant burdens, and seasonal effects of the lakes on the atmosphere. In annual simulation at 36 km resolution, the Community Multiscale Air Quality model is evaluated using speciated PM2.5 measurements taken at regulatory monitoring networks orientated to sample urban, rural, and remote areas. Performance relative to ad-hoc regional modeling goals and prior studies is average to excellent for most species throughout the year. Both pollution episodes and seasonality are captured. The Great Lakes affect pollution seasonality: strong winds advect aerosols around the deep marine boundary layer to lower surface PM2.5 in fall and winter, while O3 over the lakes is enhanced throughout the year, driven by temperature in the cool seasons and lake breeze circulation in spring and summer. Simulations confirm observational evidence that rural and small-city sources are responsible for most regional PM2.5. Sensitivities to urban and rural reductions are of comparable magnitude on a percentage basis

  16. The contribution of air-fluidization to the mobility of rapid flowslides involving fine particles

    Science.gov (United States)

    Stilmant, Frédéric; Dewals, Benjamin; Archambeau, Pierre; Erpicum, Sébastien; Pirotton, Michel

    2016-04-01

    Air-fluidization can be the origin of the long runout of gravitational flows involving fine particles such as ash. An excessive air pore pressure dramatically reduces the friction angle of the material as long as this pressure has not been dissipated, which occurs during the flow. This phenomenon can be modelled thanks to the 2D depth-averaged equations of mass and momentum conservation and an additional transport equation for basal pore pressure evolution (Iverson and Denlinger, 2001). In this contribution, we discuss the application of this model in relation to recent experimental results on air-fluidized flows by Roche et al. (2008) and Roche (2012). The experimental results were used to set a priori the value of the diffusion coefficient in the model, taking into account the difference of scale between the experiments and real-world applications. We also compare the model predictions against detailed observations of a well-documented historical event, the collapse of a fly-ash heap in Belgium (Stilmant et al., 2015). In particular, we analyse the influence of the different components of the model on the results (pore pressure dissipation vs. pore pressure generation). The diffusion coefficient which characterizes the dissipation of air pore pressure is found sufficiently low for maintaining a fluidized flow over hundreds of meters. The study concludes that an air-fluidization theory is consistent with the field observations. These findings are particularly interesting as they seem not in line with the mainstream acceptation in landslide modelling that air generally plays a secondary role (e.g., Legros, 2002). References Iverson, R.M., Denlinger, R.P., 2001. Flow of variably fluidized granular masses across three-dimensional terrain - 1. Coulomb mixture theory. J. Geophys. Res. 106, 537 552. Legros, F., 2002. The mobility of long-runout landslides. Eng. Geol. 63, 301-331. Roche, O., 2012. Depositional processes and gas pore pressure in pyroclastic flows: an

  17. Health impacts due to personal exposure to fine particles caused by insulation of residential buildings in Europe

    Science.gov (United States)

    Gens, Alexandra; Hurley, J. Fintan; Tuomisto, Jouni T.; Friedrich, Rainer

    2014-02-01

    The insulation of residential buildings affects human exposure to fine particles. According to current EU guidelines, insulation is regulated for energy saving reasons. As buildings become tighter, the air exchange rate is reduced and, thus, the indoor concentration of pollutants is increased if there are significant indoor sources. While usually the effects of heat insulation and increase of the air-tightness of buildings on greenhouse gas emissions are highlighted, the negative impacts on human health due to higher indoor concentrations are not addressed. Thus, we investigated these impacts using scenarios in three European countries, i. e. Czech Republic, Switzerland and Greece. The assessment was based on modelling the human exposure to fine particles originating from sources of particles within outdoor and indoor air, including environmental tobacco smoke. Exposure response relationships were derived to link (adverse) health effects to the exposure. Furthermore, probable values for the parameters influencing the infiltration of fine particles into residential buildings were modelled. Results show that the insulation and increase of the air-tightness of residential buildings leads to an overall increase of the mean population exposure - and consequently adverse health effects - in all considered countries (ranging for health effects from 0.4% in Czech Republic to 11.8% in Greece for 100% insulated buildings) due to an accumulation of particles indoors, especially from environmental tobacco smoke. Considering only the emission reductions in outdoor air (omitting changes in infiltration parameters) leads to a decrease of adverse health effects. This study highlights the importance of ensuring a sufficient air exchange rate when insulating buildings, e. g. by prescribing heat ventilation and air conditioning systems in new buildings and information campaigns on good airing practice in renovated buildings. It also shows that assessing policy measures based on the

  18. NOx, FINE PARTICLE AND TOXIC METAL EMISSIONS FROM THE COMBUSTION OF SEWAGE SLUDGE/COAL MIXTURES: A SYSTEMATIC ASSESSMENT

    Energy Technology Data Exchange (ETDEWEB)

    Jost O.L. Wendt

    2002-02-05

    This research project focuses on pollutants from the combustion of mixtures of dried municipal sewage sludge (MSS) and coal. The objective is to determine the relationship between (1) fraction sludge in the sludge/coal mixture, and (2) combustion conditions on (a) NO{sub x} concentrations in the exhaust, (b) the size segregated fine and ultra-fine particle composition in the exhaust, and (c) the partitioning of toxic metals between vapor and condenses phases, within the process. To this end work is progress using an existing 17kW downflow laboratory combustor, available with coal and sludge feed capabilities. The proposed study will be conducted in concert with an existing ongoing research on toxic metal partitioning mechanisms for very well characterized pulverized coals alone. Both high NO{sub x} and low NO{sub x} combustion conditions will be investigated (unstaged and staged combustion). The proposed work uses existing analytical and experimental facilities and draws on 20 years of research on NO{sub x} and fine particles that has been funded by DOE in this laboratory. Four barrels of dried sewage sludge are currently in the laboratory. Insofar as possible pertinent mechanisms will be elucidated. Tradeoffs between CO{sub 2} control, NO{sub x} control, and inorganic fine particle and toxic metal emissions will be determined. Progress in the Sixth Quarter (January 1, 2002 through March 31, 2002) was slow because of slagging problems in the combustor. These required the combustor to be rebuilt, a job that is not yet complete. A paper describing our results heretofore has been accepted by the Journal Environmental Science and Technology.

  19. 78 FR 54394 - Determination of Attainment for the West Central Pinal Nonattainment Area for the 2006 Fine...

    Science.gov (United States)

    2013-09-04

    ... 2006 Fine Particle Standard; Arizona; Determination Regarding Applicability of Clean Air Act...-hour fine particle (PM 2.5 ) National Ambient Air Quality Standard (NAAQS). This determination is based... Action On July 12, 2013 (78 FR 41901), EPA proposed to determine that the West Central...

  20. 78 FR 1760 - Determination of Attainment for the San Francisco Bay Area Nonattainment Area for the 2006 Fine...

    Science.gov (United States)

    2013-01-09

    ... the 2006 Fine Particle Standard; California; Determination Regarding Applicability of Clean Air Act... 2006 24-hour fine particle (PM 2.5 ) National Ambient Air Quality Standard (NAAQS). This determination... Action On October 29, 2012 (77 FR 65521), EPA proposed to determine that the San Francisco Bay...

  1. 78 FR 2211 - Determination of Attainment for the Yuba City-Marysville Nonattainment Area for the 2006 Fine...

    Science.gov (United States)

    2013-01-10

    ... 2006 Fine Particle Standard; California; Determination Regarding Applicability of Clean Air Act... 24- hour fine particle (PM 2.5 ) National Ambient Air Quality Standard (NAAQS). This determination is... Action On October 30, 2012 (77 FR 65646), EPA proposed to determine that the Yuba...

  2. Identification of metals into fine particles (PM2.5) during the dry cold season in the Toluca City

    International Nuclear Information System (INIS)

    To know the elemental content of fine particles PM2.5 that can affect people in the Toluca City, such as metals and another, it was made a campaign collection of fine particles during dry-cold ( November 2006-March 2007). The aerosol samples were collected on Teflon filters with an equipment BGI model PQ200 mark authorized by the Environment Protection Agency (EPA), every other day with a time resolution of 24 h. The determination of the elemental composition of the samples was performed by means of the technique Particle Induced X-Ray Emission (PIXE). The results of the analysis showed consistently 13 elements S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, as, throughout the collection period. We calculated the enrich factor that separates the elements of the natural component of the anthropogenic component. The correlation matrix shows the pairs of elements that are contained in the same air mass as Vanadium and Nickel. From the results it is concluded that the sources that gave rise to these particles are the burning of fossil fuels in motor vehicles, lubricants, additives and burning tires wear of automotive vehicles, besides the products used in agricultural activities. (Author)

  3. The Secretome of Human Bronchial Epithelial Cells Exposed to Fine Atmospheric Particles Induces Fibroblast Proliferation

    Directory of Open Access Journals (Sweden)

    Laurent Martinon

    2013-08-01

    Full Text Available Chronic exposure to particulate pollution is suspected to exacerbate inflammatory respiratory diseases such as asthma characterized by an airway remodelling involving fibrosis. Our study aims to investigate whether the secretome from human bronchial epithelial (HBE cells exposed to fine particulate matter (PM induces fibroblast proliferation. Primary HBE cells grown on air liquid interface were repeatedly exposed to fine PM at 5 and 10 µg/cm² (four treatments, 48 hours apart and maintained in culture for five weeks. Collected basolateral culture medium was used as a conditioned medium for the subsequent treatment of fibroblasts. We observed that the conditioned medium collected from HBE cells treated with fine PM increased the growth rate of fibroblasts compared to the conditioned medium collected from control HBE cells. Fibroblast phenotype assessed by the observation of the vimentin network was well preserved. The mitogenic effect of conditioned medium was reduced in the presence of anti-epidermal growth factor receptor (EGFR, anti-amphiregulin or anti-TGFa, underlining the role of EGFR ligands in fibroblast proliferation. When fibroblasts were co-cultured with HBE cells treated once with fine PM, they exhibited a higher growth rate than fibroblasts co-cultured with non-treated HBE cells. Altogether these data show that the exposure of HBE cells to fine PM induced the production of EGFR ligands in sufficient amount to stimulate fibroblast proliferation providing insight into the role of PM in airway remodelling.

  4. Formation and emission of fine particles from two coal-fired power plants

    DEFF Research Database (Denmark)

    Nielsen, M.T.; Livbjerg, H.; Fogh, C.L.; Jensen, J.N.; Simonsen, P.; Lund, C.; Poulsen, K.; Sander, B.

    2002-01-01

    into the many particle-affecting processes in a power plant. In the boiler the size of particles extends over four decades, from approximately 20 nm to 200 nm, with the largest mass contained in particles in the size range 10-100 mum. Approximately 99.9% of the particles are removed in the......The generation and emission of combustion particles from two full-scale coal-fired power plants was studied by field measurements during which particles are sampled for size classification and chemical analysis simultaneously at three positions in the plants: before the electrostatic precipitator......, before the desulfurisation plant, and in the stack. The following sampling techniques are used: scanning mobility particle sizer, low pressure cascade impactor, dichotomous PM2.5 sampler, and total particle filter. The so-called multi-platform method used in this work Proves useful for gaining insight...

  5. Formation and emission of fine particles from two coal-fired power plants

    DEFF Research Database (Denmark)

    Nielsen, M.T.; Livbjerg, H.; Fogh, C.L.;

    2002-01-01

    The generation and emission of combustion particles from two full-scale coal-fired power plants was studied by field measurements during which particles are sampled for size classification and chemical analysis simultaneously at three positions in the plants: before the electrostatic precipitator...... into the many particle-affecting processes in a power plant. In the boiler the size of particles extends over four decades, from approximately 20 nm to 200 nm, with the largest mass contained in particles in the size range 10-100 mum. Approximately 99.9% of the particles are removed in the electrostatic......, before the desulfurisation plant, and in the stack. The following sampling techniques are used: scanning mobility particle sizer, low pressure cascade impactor, dichotomous PM2.5 sampler, and total particle filter. The so-called multi-platform method used in this work Proves useful for gaining insight...

  6. Continuous and discontinuous grain coarsening in a fine-grained particle-containing Al-Sc alloy

    International Nuclear Information System (INIS)

    An Al-0.2 wt% Sc alloy was solution treated, deformed by equal channel angular pressing (ECAP) to an effective true strain of 9.2 then aged for 3 h at 350 deg C to produce a fine-grained (0.8 μm diameter) microstructure containing a large fraction (∼0.7) of high angle grain boundaries (HAGBs). This ageing treatment also generated a relatively uniform dispersion of 5 nm diameter Al3Sc particles. Grain stability was investigated at temperatures up to 550 deg C using SEM, EBSD and TEM. It was found that the fine-grain structure was remarkably stable at temperatures up to 500 deg C with grain coarsening occurring gradually with no marked change in the grain size distribution, texture and grain boundary character. This homogeneous coarsening behaviour is usually termed continuous recrystallization. In this regime, both the fine-grained microstructure and Al3Sc particles exhibit third order coarsening kinetics with dR/dt ∝ dr/dt which indicates that grain coarsening is controlled by the rate of particle growth with the latter controlled by bulk diffusion of scandium in the Al matrix. During extended annealing at 500 deg C and for short times at higher temperatures, there is a notable transition from continuous to discontinuous grain coarsening whereby a small number of grains grow rapidly to produce a coarse (>10 μm) grain size. An analytical mean field model of grain coarsening in particle-containing alloys was shown to adequately predict this transition in coarsening behaviour

  7. Pollution characteristics of atmospheric fine particles and their secondary components in the atmosphere of Shenzhen in summer and in winter

    Institute of Scientific and Technical Information of China (English)

    NIU Yuwen; HE Lingyan; HU Min; ZHANG Jing; ZHAO Yunliang

    2006-01-01

    Two field measurements for atmospheric fine particles were conducted in Baoan district of Shenzhen during the summer and winter in 2004. Totally 30 sets of 24 h samples were collected, and then the mass concentrations and chemical compositions were determined. The seasonal variations and secondary pollution characteristics of fine particles during the sampling periods were discussed with meteorological factors. The results show that seasonal variations of atmospheric particles are significant in Shenzhen. The average mass concentrations of PM2.5 and PM10 in summer were 35 μg·m-3 and 57 μg·m-3, respectively, and those in winter were 99 μg·m-3 and 135 μg·m-3, respectively. The concentrations of both PM2.5 and PM10 in winter increased 184% and 137%, respectively, compared to those in summer. PM2.5 accounted for 61% and 75% of PM10 in summer and in winter, respectively, indicating severe fine particle pollution in Shenzhen. During the summer and winter sampling periods, the mean OC/EC ratios were 3.4 and 1.6, respectively. The estimated secondary organic carbon (SOC) averagely accounted for 56% and 6% of the total OC in summer and in winter, respectively, which implies a major contribution of SOC to OC in summer. During the continuous high temperature period in summer, both the concentrations and fractions of secondary aerosol components in PM2.5 were highly elevated, suggesting severe secondary pollution again. The prevailing wind was from South China Sea in summer, and the air quality was good. The prevailing wind in winter was from Mainland China to the north, and the polluted air mass led to poor air quality.

  8. A simple methodological validation of the gas/particle fractionation of polycyclic aromatic hydrocarbons in ambient air

    Science.gov (United States)

    Kim, Yong-Hyun; Kim, Ki-Hyun

    2015-07-01

    The analysis of polycyclic aromatic hydrocarbons (PAH) in ambient air requires the tedious experimental steps of both sampling and pretreatment (e.g., extraction or clean-up). To replace pre-existing conventional methods, a simple, rapid, and novel technique was developed to measure gas-particle fractionation of PAH in ambient air based on ‘sorbent tube-thermal desorption-gas chromatograph-mass spectrometer (ST-TD-GC-MS)’. The separate collection and analysis of ambient PAHs were achieved independently by two serially connected STs. The basic quality assurance confirmed good linearity, precision, and high sensitivity to eliminate the need for complicated pretreatment procedures with the detection limit (16 PAHs: 13.1 ± 7.04 pg). The analysis of real ambient PAH samples showed a clear fractionation between gas (two-three ringed PAHs) and particulate phases (five-six ringed PAHs). In contrast, for intermediate (four ringed) PAHs (fluoranthene, pyrene, benz[a]anthracene, and chrysene), a highly systematic/gradual fractionation was established. It thus suggests a promising role of ST-TD-GC-MS as measurement system in acquiring a reliable database of airborne PAH.

  9. Mixing state of ambient aerosols in Nanjing city by single particle mass spectrometry

    Science.gov (United States)

    Wang, Honglei; An, Junlin; Shen, Lijuan; Zhu, Bin; Xia, Li; Duan, Qing; Zou, Jianan

    2016-05-01

    To investigate the mixing state and size-resolved aerosol in Nanjing, measurements were carried out for the period 14th January-1st February 2013 by using a Single Particle Aerosol Mass Spectrometer (SPAMS). A total of 10,864,766 particles were sized with vacuum aerodynamic diameter (dva) in the range of 0.2-2.0 μm. Of which, 1,989,725 particles were successfully ionized. Aerosol particles employed for analyzing SPAMS data utilized 96% of the hit particles to identify 5 main particle groups. The particle classes include: K-rich particles (K-CN, K-Nitrate, K-Sulfate and K-Secondary), sodium particles, ammonium particles, carbon-rich particles (OC, EC and OCEC) and heavy-metal particles (Fe-Secondary, Pb-Nitrate, Cu-Mn-Secondary and V-Secondary). EC was the largest contributor with a fraction of 21.78%, followed by K-Secondary (17.87%), K-Nitrate (12.68%) and K-CN (11.25%). High particle level and high RH (relative humidity) are two important factors decreasing visibility in Nanjing. Different particle classes have distinct extinction effects. It anti-correlated well with visibility for the K-secondary, sodium, ammonium, EC, Fe-Secondary and K-Nitrate particles. The proportion of EC particles at 0.65-1.4 μm was up to 25% on haze days and was below 10% on clean days.

  10. Mixing state of ambient aerosols in Nanjing city by single particle mass spectrometry

    Science.gov (United States)

    Wang, Honglei; An, Junlin; Shen, Lijuan; Zhu, Bin; Xia, Li; Duan, Qing; Zou, Jianan

    2016-05-01

    To investigate the mixing state and size-resolved aerosol in Nanjing, measurements were carried out for the period 14th January-1st February 2013 by using a Single Particle Aerosol Mass Spectrometer (SPAMS). A total of 10,864,766 particles were sized with vacuum aerodynamic diameter (dva) in the range of 0.2-2.0 μm. Of which, 1,989,725 particles were successfully ionized. Aerosol particles employed for analyzing SPAMS data utilized 96% of the hit particles to identify 5 main particle groups. The particle classes include: K-rich particles (K-CN, K-Nitrate, K-Sulfate and K-Secondary), sodium particles, ammonium particles, carbon-rich particles (OC, EC and OCEC) and heavy-metal particles (Fe-Secondary, Pb-Nitrate, Cu-Mn-Secondary and V-Secondary). EC was the largest contributor with a fraction of 21.78%, followed by K-Secondary (17.87%), K-Nitrate (12.68%) and K-CN (11.25%). High particle level and high RH (relative humidity) are two important factors decreasing visibility in Nanjing. Different particle classes have distinct extinction effects. It anti-correlated well with visibility for the K-secondary, sodium, ammonium, EC, Fe-Secondary and K-Nitrate particles. The proportion of EC particles at 0.65-1.4 μm was up to 25% on haze days and was below 10% on clean days.

  11. Measurement of Fine Particles From Mobile and Stationary Sources, and Reducing the Air Conditioner Power Consumption in Hybrid Electric Vehicles

    Science.gov (United States)

    Brewer, Eli Henry

    We study the PM2.5and ultrafine exhaust emissions from a new natural gas-fired turbine power facility to better understand air pollution in California. To characterize the emissions from new natural gas turbines, a series of tests were performed on a GE LMS100 gas turbine. These tests included PM2.5 and wet chemical tests for SO2/SO 3 and NH3, as well as ultrafine (less than 100 nm in diameter) particulate matter measurements. The turbine exhaust had an average particle number concentration that was 2.3x103 times higher than ambient air. The majority of these particles were nanoparticles; at the 100 nm size, stack particle concentrations were about 20 times higher than ambient, and increased to 3.9x104 times higher on average in the 2.5 - 3 nm particle size range. This study also found that ammonia emissions were higher than expected, but in compliance with permit conditions. This was possibly due to an ammonia imbalance entering the catalyst, some flue gas bypassing the catalyst, or not enough catalyst volume. SO3 accounted for an average of 23% of the total sulfur oxides emissions measured. Some of the SO3 is formed in the combustion process, it is likely that the majority formed as the SO2 in the combustion products passed across the oxidizing CO catalyst and SCR catalyst. The 100 MW turbine sampled in this study emitted particle loadings similar to those previously measured from turbines in the SCAQMD area, however, the turbine exhaust contained far more particles than ambient air. The power consumed by an air conditioner accounts for a significant fraction of the total power used by hybrid and electric vehicles especially during summer. This study examined the effect of recirculation of cabin air on power consumption of mobile air conditioners both in-lab and on-road. Real time power consumption and vehicle mileage were recorded by an On Board Diagnostic monitor and carbon balance method. Vehicle mileage improved with increased cabin air recirculation. The

  12. Determination of air exchange rates of rooms and deposition factors for fine particles by means of photoelectric aerosol sensors

    International Nuclear Information System (INIS)

    Indoor and outdoor concentrations or airborne fine particles from internal combustion engines have been measured over periods of 24 h with a time resolution of 10 s. With this time series, the ventilation air exchange rate of different rooms has been computed using a novel approach to the solution of the mass balance equation. A 'mixing time' parameter has been introduced in order to account for the initial non-homogeneous distribution of the pollutants in the rooms. It is demonstrated that this method can be used to determine the impact of health relevant outdoor particles on the indoor particle concentration. This yields information on the protection a building offers against pollutants entering from outdoors. (author)

  13. Liquefaction of coals using ultra-fine particle, unsupported catalysts: In situ particle generation by rapid expansion of supercritical fluid solutions. Final technical report

    Energy Technology Data Exchange (ETDEWEB)

    1994-05-01

    The research conducted by Textron Defense Systems (TDS) represents a potential new and innovative concept for dispersed coal liquefaction. The technical approach is generation of ultra-fine catalyst particles from supercritical solutions by rapid expansion of either catalyst only, or mixtures of catalyst and coal material in supersaturated solvents. The process of rapid expansion of supercritical fluid solutions was developed at Battelle`s Pacific Northwest Laboratories for the intended purpose of providing a new analytical technique for characterizing supercritical fluids. The concept forming the basis of this research is that ultra-fine particles can be generated from supercritical solutions by rapid expansion of either catalyst or catalyst/coal-material mixtures in supersaturated solvents, such as carbon dioxide or water. The focal point of this technique is the rapid transfer of low vapor pressure solute (i.e., catalyst), dissolved in the supercritical fluid solvent, to the gas phase as the solution is expanded through an orifice. The expansion process is characterized by highly nonequilibrium conditions which cause the solute to undergo extremely rapid supersaturation with respect to the solvent, leading to nucleation and particle growth resulting in nanometer size catalyst particles. A supercritical expansion system was designed and built by TDS at their Haverhill facility.

  14. Microwave-assisted Extraction of Rare Earth Elements from Petroleum Refining Catalysts and Ambient Fine Aerosols Prior to Inductively Coupled Plasma - Mass Spectrometry

    Science.gov (United States)

    Mittlefehldt, David W.; Kulkarni, Pranav; Chellam, Shankar

    2006-01-01

    In the absence of a certified reference material, a robust microwave-assisted acid digestion procedure followed by inductively coupled plasma - mass spectrometry (ICP-MS) was developed to quantify rare earth elements (REEs) in fluidized-bed catalytic cracking (FCC) catalysts and atmospheric fine particulate matter (PM2.5). High temperature (200 C), high pressure (200 psig), acid digestion (HNO3, HF, and H3BO3) with 20 minute dwell time effectively solubilized REEs from six fresh catalysts, a spent catalyst, and PM2.5. This method was also employed to measure 27 non-REEs including Na, Mg, Al, Si, K, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, As, Se, Rb, Sr, Zr, Mo, Cd, Cs, Ba, Pb, and U. Complete extraction of several REEs (Y, La, Ce, Pr, Nd, Tb, Dy, and Er) required HF indicating that they were closely associated with the aluminosilicate structure of the zeolite FCC catalysts. Internal standardization using 115In quantitatively corrected non-spectral interferences in the catalyst digestate matrix. Inter-laboratory comparison using ICP-optical emission spectroscopy (ICP-OES) and instrumental neutron activation analysis (INAA) demonstrated the applicability of the newly developed analytical method for accurate analysis of REEs in FCC catalysts. The method developed for FCC catalysts was also successfully implemented to measure trace to ultra-trace concentrations of La, Ce, Pr, Nd, Sm, Gd, Eu, and Dy in ambient PM2.5 in an industrial area of Houston, TX.

  15. 78 FR 887 - Determination of Attainment for the Nogales Nonattainment Area for the 2006 Fine Particle...

    Science.gov (United States)

    2013-01-07

    ... AGENCY 40 CFR Part 52 Determination of Attainment for the Nogales Nonattainment Area for the 2006 Fine.... Statutory and Executive Order Reviews I. Summary of Proposed Action On October 30, 2012 (77 FR 65656), EPA... FR 51735, October 4, 1993); Does not impose an information collection burden under the provisions...

  16. The effect of the presence of fine YSZ particles on the performance of porous nickel electrodes

    NARCIS (Netherlands)

    Boer, de B.; Gonzalez, M.; Bouwmeester, H.J.M.; Verweij, H.

    2000-01-01

    The electrochemical performance of a porous nickel electrode with its surface modified by deposition with fine yttria-stabilised zirconia (YSZ) powder is compared with that of the ‘bare’ electrode. Image analysis of the electrode microstructure yields values for the triple phase boundary (TPB) lengt

  17. Heavy metal pollution in sediment from Sisimiut, Greenland. Adsorption to organic matter and fine particles

    DEFF Research Database (Denmark)

    Ottosen, Lisbeth M.; Villumsen, Arne

    2006-01-01

    . The pollution could be linked to human activities in Sisimiut, a link that have not been investigated previously in Greenland. Except from the most polluted samples there was good correlation between heavy metal concentration and organic matter. Also some relation between fine fraction and heavy metal...

  18. Particle Formation from Pulsed Laser Irradiation of SootAggregates studied with scanning mobility particle sizer, transmissionelectron microscope and near-edge x-ray absorption fine structure.

    Energy Technology Data Exchange (ETDEWEB)

    Michelsen, Hope A.; Tivanski, Alexei V.; Gilles, Mary K.; vanPoppel, Laura H.; Dansson, Mark A.; Buseck, Peter R.; Buseck, Peter R.

    2007-02-20

    We investigated the physical and chemical changes induced in soot aggregates exposed to laser radiation using a scanning mobility particle sizer, a transmission electron microscope, and a scanning transmission x-ray microscope to perform near-edge x-ray absorption fine structure spectroscopy. Laser-induced nanoparticle production was observed at fluences above 0.12 J/cm(2) at 532 nm and 0.22 J/cm(2) at 1064 nm. Our results indicate that new particle formation proceeds via (1) vaporization of small carbon clusters by thermal or photolytic mechanisms, followed by homogeneous nucleation, (2) heterogeneous nucleation of vaporized carbon clusters onto material ablated from primary particles, or (3) both processes.

  19. Fine particle collection of an electrostatic precipitator in CO2-rich gas conditions for oxy-fuel combustion.

    Science.gov (United States)

    Han, Bangwoo; Kim, Hak Joon; Kim, Yong Jin

    2010-10-01

    The collection of particles in CO(2)-enriched environments has long been important for the capture of CO(2) in order to clean gases via oxy-fuel combustion. We here report on the collection characteristics of fine and ultrafine particles using an electrostatic precipitator (ESP) in a CO(2)-enriched atmosphere. In order to understand the characteristics of particle collection in CO(2)-rich gas mixtures, the ionic properties of a CO(2)-enriched atmosphere was also investigated. The electrical mobility of the ions in a CO(2)-enriched atmosphere was found to be about 0.56 times that found in a conventional air atmosphere, due to the higher mass of CO(2) gas compared to that of air. The low electrical mobility of ions resulted in a low corona current under CO(2)-enriched conditions. The collection efficiency of particles in a CO(2)-rich atmosphere for a given power consumption was thus somewhat lower than that found in air, due to the low quantity of particle charging in CO(2)-enriched air. At the same time, higher temperatures led to the higher electrical mobility of ions, which resulted in a greater collection efficiency for a given power. The presence of a negative corona also led to a greater collection efficiency of particles in an ESP than that achieved for a positive corona. PMID:20692021

  20. Effects of concentration of dispersions on particle sizing during production of fine particles in wet grinding process

    OpenAIRE

    Inam, Muhammad Asif; Ouattara, Soualo; Frances, Christine

    2011-01-01

    Stirred media milling is a prospective technology for producing colloidal dispersions by means of wet grinding process. In the past, many researchers have studied the effects of different operating parameters such as size, shape, nature and quantity of grinding medium, the speed of agitator in grinding chamber, the feed rate of dispersions, etc. in stirred media mills. However, it is still less known how particle sizing which generates valuable information of particle size of the product to i...

  1. Biosynthesis of silver fine particles and particles decorated with nanoparticles using the extract of Illicium verum (star anise) seeds

    Science.gov (United States)

    Luna, Carlos; Chávez, V. H. G.; Barriga-Castro, Enrique Díaz; Núñez, Nuria O.; Mendoza-Reséndez, Raquel

    2015-04-01

    Given the upsurge of new technologies based on nanomaterials, the development of sustainable methods to obtain functional nanostructures has become an imperative task. In this matter, several recent researches have shown that the biodegradable natural antioxidants of several plant extracts can be used simultaneously as reducing and stabilizing agents in the wet chemical synthesis of metallic nanoparticles, opening new opportunities to design greener synthesis. However, the challenge of these new techniques is to produce stable colloidal nanoparticles with controlled particle uniformity, size, shape and aggregation state, in similar manner than the well-established synthetic methods. In the present work, colloidal metallic silver nanoparticles have been synthesized using silver nitrate and extracts of Illicium verum (star anise) seeds at room temperature in a facile one-step procedure. The resulting products were colloidal suspensions of two populations of silver nanoparticles, one of them with particle sizes of few nanometers and the other with particles of tens of nm. Strikingly, the variation of the AgNO3/extract weight ratio in the reaction medium yielded to the variation of the spatial distribution of the nanoparticles: high AgNO3/extract concentration ratios yielded to randomly dispersed particles, whereas for lower AgNO3/extract ratios, the biggest particles appeared coated with the finest nanoparticles. This biosynthesized colloidal system, with controlled particle aggregation states, presents plasmonic and SERS properties with potential applications in molecular sensors and nanophotonic devices.

  2. Isotope ratio measurement of individual fine particles containing nuclear materials in safeguards environmental samples

    International Nuclear Information System (INIS)

    Isotope ratio measurement for individual particles containing uranium in swipe samples taken at nuclear facilities is a powerful tool to verify the absence of undeclared nuclear activities. In order to develop the analysis technique, we have investigated a series of methods: particle recovery from the swipe sample, particle screening and isotope ratio analysis for individual particles. An aspiration method as a new approach for particle recovery was introduced and found to be more suitable for subsequent SIMS analysis than conventional methods (adhesion, ultrasoneration and plasma ashing). For the particle screening, we applied total-reflection X-ray fluorescence spectrometry (TXRF) to the estimation of the amount of nuclear materials in the sample. Here, a molybdenum X-ray beam was used for the excitation. The result showed that the detection limit of uranium was about 20 pg when silicon was used as the sample carrier material. The value was improved by five orders of magnitude compared with that by conventional X-ray fluorescence spectrometry. The isotope ratio measurement for individual particles was performed by secondary ion mass spectrometry (SIMS) with microprobe mode. The particle was irradiated with a primary ion beam of O2+ of 15 keV and 30 nA. As the result, the 235U/238U ratio was determined with the relative standard deviation within 2.0% for the particle with a diameter of 1 μm. (author)

  3. Statistics of fine dispersion structures events in energetic particle spectra: their origin and role in the outer magnetosphere

    OpenAIRE

    V. N. Lutsenko; E. A. Gavrilova; T. V. Grechko

    2008-01-01

    Fine Dispersion Structures (FDS) in energetic particle spectra in outer magnetosphere were discovered in DOK-2 experiments onboard of Interball-1 and -2 spacecrafts (1995–2000). First results of these studies were published in 2000–2005. It was shown that FDS can be a result of a gradient-curvature drift of ions and electrons around the Earth after their pulse injection from the geotail plasma sheet to some point in the night side of the outer magnetosphere. Since that time hundreds of such e...

  4. Principles, techniques and recent advances in fine particle aggregation for solid-liquid separation

    International Nuclear Information System (INIS)

    Waste water discharged from various chemical and nuclear processing operations contains dissolved metal species that are highly toxic and, in some cases, radioactive. When the waste is acidic in nature, neutralization using reagents such as lime is commonly practiced to reduce both the acidity and the amount of waste (Kuyucak et al.). The sludge that results from the neutralization process contains metal oxide or hydroxide precipitates that are colloidal in nature and is highly stable. Destabilization of colloidal suspensions can be achieved by aggregation of fines into larger sized agglomerates. Aggregation of fines is a complex phenomenon involving a multitude of forces that control the interparticle interaction. In order to understand the colloidal behavior of suspensions a fundamental knowledge of physicochemical properties that determine the various forces is essential. In this review, a discussion of basic principles governing the aggregation of colloidal fines, various ways in which interparticle forces can be manipulated to achieve the desired aggregation response and recent advances in experimental techniques to probe the interfacial characteristics that control the flocculation behavior are discussed

  5. Magnetization anomalies of fine particles interpreted as surface effects by inelastic neutron scattering

    International Nuclear Information System (INIS)

    Inelastic neutron scattering experiments on small Fe particles (R=12 Angstrom) reveal that some part of the magnetic intensity is paramagnetic at 300 K. As T decreases it freezes and develops short range ferromagnetic correlations. It is attributed to spins at the particle surface. (authors). 3 figs., 5 refs

  6. Fine-particle magnetism in nanocrystalline Fe-Cu-Nb-Si-B at elevated temperatures

    International Nuclear Information System (INIS)

    Magnetic interactions between the nanocrystalline particles in FeCuNbSiB are studied above the Curie temperature of the intergranular amorphous phase. It is shown that with increasing volume fraction of nanocrystalline particles, the interparticle interaction increasingly suppresses superparamagnetic fluctuations and the transition to superferromagnetic behavior is observed. ((orig.))

  7. ON THE PROPORTIONALITY OF FINE MASS CONCENTRATION AND EXTINCTION COEFFICIENT FOR BIMODAL SIZE DISTRIBUTIONS

    Science.gov (United States)

    For a bimodal size distribution of ambient aerosol, an upper limit in particle size can be chosen for the fine aerosol fraction so that the extinction coefficient for light scattering and absorption is directly proportional to the fine mass concentration, with no dependence on th...

  8. Characterization of concentration, particle size distribution, and contributing factors to ambient hexavalent chromium in an area with multiple emission sources

    Science.gov (United States)

    Yu, Chang Ho; Huang, Lihui; Shin, Jin Young; Artigas, Francisco; Fan, Zhi-hua (Tina)

    2014-09-01

    Airborne hexavalent chromium (Cr(VI)) is a known pulmonary carcinogen and can be emitted from both natural and anthropogenic sources, including diesel emissions. However, there is limited knowledge about ambient Cr(VI) concentration levels and its particle size distribution. This pilot study characterized ambient Cr(VI) concentrations in the New Jersey Meadowlands (NJ ML) district, which is close to the heavily trafficked New Jersey Turnpike (NJTPK) as well as Chromium Ore Processing Residue (COPR) waste sites. Monitoring was simultaneously conducted at two sites, William site (∼50 m from NJTPK) and MERI site (∼700 m from NJTPK). The distance between the two sites is approximately 6.2 km. Ambient Cr(VI) concentrations and PM2.5 mass concentrations were concurrently measured at both sites during summer and winter. The summer concentrations (mean ± S.D. [median]), 0.13 ± 0.06 [0.12] ng/m3 at the MERI site and 0.08 ± 0.05 [0.07] ng/m3 at the William site, were all significantly higher than the winter concentrations, 0.02 ± 0.01 [0.02] ng/m3 and 0.03 ± 0.01 [0.03] ng/m3 at the MERI and William sites, respectively. The site difference (i.e., MERI > William) was observed for summer Cr(VI) concentrations; however, no differences for winter and pooled datasets. These results suggest higher Cr(VI) concentrations may be attributed from stronger atmospheric reactions such as photo-oxidation of Cr(III) to Cr(VI) in the summer. The Cr(VI) distribution as a function of particle size, ranging from 0.18 to 18 μm, was determined at the William site. It was found that Cr(VI) was enriched in the particles less than 2.5 μm in diameter (PM2.5). This finding suggested potential health concerns, because PM2.5 are easily inhaled and deposited in the alveoli. A multiple linear regression analysis confirmed ambient Cr(VI) concentrations were significantly affected by meteorological factors (i.e., temperature and humidity) and reactive gases/particles (i.e., O3, Fe and Mn).

  9. Toxicity of Ambient Particulate Matter. III. Acute toxicity study in asthmatic mice following 3-day exposure to ultrafine and fine ammonium nitrate, a model compound for secondary aerosol fraction of PM10

    NARCIS (Netherlands)

    Cassee FR; Dormans JAMA; Loveren H van; Bree L van; Rombout PJA; LEO; LPI

    1998-01-01

    Ammonium nitrate is the most prominent component of secondary PM10 in the Netherlands. In our study, healthy and asthmatic mice were exposed to fine (CMD = 0.3 mum; 4 x 10 exp. 3 particles per cm3) and ultrafine (CMD = 0.03 mum; 2 x 10. exp. 5 particles per cm3) ammonium nitrate. The mean mass conc

  10. Measurement of overall uptake coefficients for HO2 radicals by aerosol particles sampled from ambient air at Mts. Tai and Mang, China

    OpenAIRE

    H. Akimoto; Z. Wang; K. Okuzawa; K. Kawamura; Li, J.; Liu, Y; P. Pochanart; Taketani, F.; Y. Kanaya

    2012-01-01

    HO2 uptake coefficients for ambient aerosol particles, collected on quartz filter using a high-volume air sampler in China, were measured using an aerosol flow tube coupled with a chemical conversion/laser-induced fluorescence technique at 760 Torr and 298 K, with a relative humidity of 75%. Aerosol particles were regenerated with an atomizer using the water extracts from the aerosol particles. Over 10 samples, the measured HO2 uptake coefficients for the aerosol particles at the Mt. ...

  11. Ambient measurements of biological aerosol particles near Killarney, Ireland: a comparison between real-time fluorescence and microscopy techniques

    Directory of Open Access Journals (Sweden)

    D. A. Healy

    2014-02-01

    Full Text Available Primary biological aerosol particles (PBAP can contribute significantly to the coarse particle burden in many environments, may thus influence climate and precipitation systems as cloud nuclei, and can spread disease to humans, animals, and plants. Measurements of PBAP in natural environments taken at high time- and size- resolution are, however, sparse and so large uncertainties remain in the role that biological particles play in the Earth system. In this study two commercial real-time fluorescence particle sensors and a Sporewatch single-stage particle impactor were operated continuously from 2 August to 2 September 2010 at a rural sampling location in Killarney National Park in south western Ireland. A cascade impactor was operated periodically to collect size-resolved particles during exemplary periods. Here we report the first ambient comparison of the waveband integrated bioaerosol sensor (WIBS-4 with the ultraviolet aerodynamic particle sizer (UV-APS and also compare these real-time fluorescence techniques with results of fluorescence and optical microscopy of impacted samples. Both real-time instruments showed qualitatively similar behaviour, with increased fluorescent bioparticle concentrations at night when relative humidity was highest and temperature was lowest. The fluorescent particle number from the FL3 channel of the WIBS-4 and from the UV-APS were strongly correlated and dominated by a 3 μm mode in the particle size distribution. The WIBS FL2 channel exhibited particle modes at approx. 1 and 3 μm, and each were correlated with the concentration of fungal spores commonly observed in air samples collected at the site (ascospores, basidiospores, Ganoderma spp.. The WIBS FL1 channel exhibited variable multi-modal distributions turning into a broad featureless single mode after averaging and exhibited poor correlation with fungal spore concentrations, which may be due to the detection of bacterial and non-biological fluorescent

  12. Ambient measurements of biological aerosol particles near Killarney, Ireland: a comparison between real-time fluorescence and microscopy techniques

    Science.gov (United States)

    Healy, D. A.; Huffman, J. A.; O'Connor, D. J.; Pöhlker, C.; Pöschl, U.; Sodeau, J. R.

    2014-08-01

    Primary biological aerosol particles (PBAPs) can contribute significantly to the coarse particle burden in many environments. PBAPs can thus influence climate and precipitation systems as cloud nuclei and can spread disease to humans, animals, and plants. Measurement data and techniques for PBAPs in natural environments at high time- and size resolution are, however, sparse, and so large uncertainties remain in the role that biological particles play in the Earth system. In this study two commercial real-time fluorescence particle sensors and a Sporewatch single-stage particle impactor were operated continuously from 2 August to 2 September 2010 at a rural sampling location in Killarney National Park in southwestern Ireland. A cascade impactor was operated periodically to collect size-resolved particles during exemplary periods. Here we report the first ambient comparison of a waveband integrated bioaerosol sensor (WIBS-4) with a ultraviolet aerodynamic particle sizer (UV-APS) and also compare these real-time fluorescence techniques with results of fluorescence and optical microscopy of impacted samples. Both real-time instruments showed qualitatively similar behavior, with increased fluorescent bioparticle concentrations at night, when relative humidity was highest and temperature was lowest. The fluorescent particle number from the FL3 channel of the WIBS-4 and from the UV-APS were strongly correlated and dominated by a 3 μm mode in the particle size distribution. The WIBS FL2 channel exhibited particle modes at approx. 1 and 3 μm, and each was correlated with the concentration of fungal spores commonly observed in air samples collected at the site (ascospores, basidiospores, Ganoderma spp.). The WIBS FL1 channel exhibited variable multimodal distributions turning into a broad featureless single mode after averaging, and exhibited poor correlation with fungal spore concentrations, which may be due to the detection of bacterial and non-biological fluorescent

  13. Chemical characterization of individual particles (PM10) from ambient air in Guiyang City, China

    International Nuclear Information System (INIS)

    PM10 samples were collected during 5 days in Guiyang, China in July 2003. A total of about 2300 particles was analyzed by an automated Scanning Electron Microscope with Energy-Dispersive Spectrometer (SEM-EDS). Hierarchical cluster analysis (HCA) was used to identify different particle types that occurred in the aerosol. Seventeen particle types were identified and presented in the order of decreasing number abundance as: silicomanganese slag, soil and fly ash, coal burning, silicomanganese, quartz, syngenite, S-bearing iron, calcium rich, gypsum, sphalerite, dolomite, iron, alloy, lead sulfate, zinc rich, sulfur-rich particles and aluminum manufacturing dust. The majority of the particles in the studied size range are of anthropogenic origin, especially from metallurgical industry. The study illustrates the complexity of particle pollution in air of an industrial Chinese city and the results should be useful in planning mitigation measures

  14. NOx, FINE PARTICLE AND TOXIC METAL EMISSIONS FROM THE COMBUSTION OF SEWAGE SLUDGE/COAL MIXTURES: A SYSTEMATIC ASSESSMENT

    Energy Technology Data Exchange (ETDEWEB)

    Jost O.L. Wendt

    2002-08-15

    This research project focuses on pollutants from the combustion of mixtures of dried municipal sewage sludge (MSS) and coal. The objective is to determine the relationship between (1) fraction sludge in the sludge/coal mixture, and (2) combustion conditions on (a) NOx concentrations in the exhaust, (b) the size segregated fine and ultra-fine particle composition in the exhaust, and (c) the partitioning of toxic metals between vapor and condenses phases, within the process. The proposed study will be conducted in concert with an existing ongoing research on toxic metal partitioning mechanisms for very well characterized pulverized coals alone. Both high NOx and low NOx combustion conditions will be investigated (unstaged and staged combustion). Tradeoffs between CO2 control, NOx control, and inorganic fine particle and toxic metal emissions will be determined. Previous research has yielded data on trace metal partitioning for MSS by itself, with natural gas assist, for coal plus MSS combustion together, and for coal alone. We have re-evaluated the inhalation health effects of ash aerosol from combustion of MSS both by itself and also together with coal. We have concluded that ash from the co-combustion of MSS and coal is very much worse from an inhalation health point of view, than ash from either MSS by itself or coal by itself. The reason is that ZnO is not the ''bad actor'' as had been suspected before, but the culprit is, rather, sulfated Zn. The MSS supplies the Zn and the coal supplies the sulfur, and so it is the combination of coal and MSS that makes that process environmentally bad. If MSS is to be burned, it should be burned without coal, in the absence of sulfur.

  15. Experimental and Theoretical Characterization on the Sublimation (Evaporation) Kinetics of Fine Aerosol Particles (Droplets)

    OpenAIRE

    Ding, Haomin

    2008-01-01

    Sublimation (Evaporation) is widely used in different industrial applications. The important applications are the sublimation (evaporation) of small particles (solid and liquid), e.g., spray drying and fuel droplet evaporation. Since a few decades, sublimation technology has been used widely together with aerosol technology. This combination is aiming to get various products with desired compositions and morphologies. It can be used in the fields of nanoparticles generation, particle coating ...

  16. Evaluation of correlating factors between 238U concentration measured in fine and course atmospheric particles

    International Nuclear Information System (INIS)

    Air quality is ever more important in function of the enormous proportion of human actions that have affected the environment over the last two centuries. Particulate material is one among many pollutants that can cause great risk to human health and the environment. It can be classified as: Total Suspended Particles (TSP), defined simply as particles with less than 50 μm aerodynamic diameter (one group of these particles can be inhaled and may cause health problems, while others may unfavorably affect the population's quality of life, interfering in environmental conditions and impairing normal community activities); and Inhalable Particles (PM10), defined as those particles with less than 10 μm aerodynamic diameter. These particles penetrate the respiratory system and can reach pulmonary alveoli due to their small size, causing serious health damage. The Nuclear Technology Development Center (CDTN) has monitored air quality around its installations since 2000. CDTN's Environmental Monitoring Program (EMP) includes monitoring radioactivity levels contained in atmospheric TSP. In order to optimize its program, CDTN is carrying out a study to estimate the correlation between concentrations of particulate material measured in TSP and those measured in PM10, PI2.5 and PI1, as well as determination of activity concentration for each controlled radionuclide in all parts. The objective of this study is to present preliminary results and report 238U activity concentration results. (author)

  17. Evaluation of correlating factors between {sup 238}U concentration measured in fine and course atmospheric particles

    Energy Technology Data Exchange (ETDEWEB)

    Peixoto, Claudia Marques; Jacomino, Vanusa Maria Feliciano; Barreto, Alberto Avelar; Dias, Vagner Silva, E-mail: cmp@cdtn.b, E-mail: vmfj@cdtn.b, E-mail: aab@cdtn.b [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil); Dias, Fabiana Ferrari, E-mail: fdias@cnen.gov.b [Brazilian Nuclear Energy Commission (CNEN-/MG), Pocos de Caldas, MG (Brazil). Lab. de Pocos de Caldas (LAPOC)

    2009-07-01

    Air quality is ever more important in function of the enormous proportion of human actions that have affected the environment over the last two centuries. Particulate material is one among many pollutants that can cause great risk to human health and the environment. It can be classified as: Total Suspended Particles (TSP), defined simply as particles with less than 50 mum aerodynamic diameter (one group of these particles can be inhaled and may cause health problems, while others may unfavorably affect the population's quality of life, interfering in environmental conditions and impairing normal community activities); and Inhalable Particles (PM{sub 10}), defined as those particles with less than 10 mum aerodynamic diameter. These particles penetrate the respiratory system and can reach pulmonary alveoli due to their small size, causing serious health damage. The Nuclear Technology Development Center (CDTN) has monitored air quality around its installations since 2000. CDTN's Environmental Monitoring Program (EMP) includes monitoring radioactivity levels contained in atmospheric TSP. In order to optimize its program, CDTN is carrying out a study to estimate the correlation between concentrations of particulate material measured in TSP and those measured in PM{sub 10}, PI{sub 2.5} and PI{sub 1}, as well as determination of activity concentration for each controlled radionuclide in all parts. The objective of this study is to present preliminary results and report {sup 238}U activity concentration results. (author)

  18. Measurement of Soluble and Total Hexavalent Chromium in the Ambient Airborne Particles in New Jersey

    Science.gov (United States)

    Huang, Lihui; Yu, Chang Ho; Hopke, Philip K.; Lioy, Paul J.; Buckley, Brian T.; Shin, Jin Young; Fan, Zhihua (Tina)

    2015-01-01

    Hexavalent chromium (Cr(VI)) in ambient airborne particulate matter (PM) is a known pulmonary carcinogen and may have both soluble and insoluble forms. The sum of the two forms is defined as total Cr(VI). Currently, there were no methods suitable for large-scale monitoring of total Cr(VI) in ambient PM. This study developed a method to measure total Cr(VI) in ambient PM. This method includes PM collection using a Teflon filter, microwave extraction with 3% Na2CO3-2% NaOH at 95°C for 60 minutes, and Cr(VI) analysis by 1,5-diphenylcarbazide colorimetry at 540 nm. The recoveries of total Cr(VI) were 119.5 ± 10.4% and 106.3 ± 16.7% for the Cr(VI)-certified reference materials, SQC 012 and SRM 2700, respectively. Total Cr(VI) in the reference urban PM (NIST 1648a) was 26.0 ± 3.1 mg/kg (%CV = 11.9%) determined by this method. The method detection limit was 0.33 ng/m3. This method and the one previously developed to measure ambient Cr(VI), which is soluble in pH ~9.0 aqueous solution, were applied to measure Cr(VI) in ambient PM10 collected from three urban areas and one suburban area in New Jersey. The total Cr(VI) concentrations were 1.05–1.41 ng/m3 in the winter and 0.99–1.56 ng/m3 in the summer. The soluble Cr(VI) concentrations were 0.03–0.19 ng/m3 in the winter and 0.12–0.37 ng/m3 in the summer. The summer mean ratios of soluble to total Cr(VI) were 14.3–43.7%, significantly higher than 4.2–14.4% in the winter. The winter concentrations of soluble and total Cr(VI) in the suburban area were significantly lower than in the three urban areas. The results suggested that formation of Cr(VI) via atmospheric chemistry may contribute to the higher soluble Cr(VI) concentrations in the summer. PMID:26120324

  19. Advection, dispersion, and filtration of fine particles within emergent vegetation of the Florida Everglades

    Science.gov (United States)

    Huang, Y.H.; Saiers, J.E.; Harvey, J.W.; Noe, G.B.; Mylon, S.

    2008-01-01

    The movement of particulate matter within wetland surface waters affects nutrient cycling, contaminant mobility, and the evolution of the wetland landscape. Despite the importance of particle transport in influencing wetland form and function, there are few data sets that illuminate, in a quantitative way, the transport behavior of particulate matter within surface waters containing emergent vegetation. We report observations from experiments on the transport of 1 ??m latex microspheres at a wetland field site located in Water Conservation Area 3A of the Florida Everglades. The experiments involved line source injections of particles inside two 4.8-m-long surface water flumes constructed within a transition zone between an Eleocharis slough and Cladium jamaicense ridge and within a Cladium jamaicense ridge. We compared the measurements of particle transport to calculations of two-dimensional advection-dispersion model that accounted for a linear increase in water velocities with elevation above the ground surface. The results of this analysis revealed that particle spreading by longitudinal and vertical dispersion was substantially greater in the ridge than within the transition zone and that particle capture by aquatic vegetation lowered surface water particle concentrations and, at least for the timescale of our experiments, could be represented as an irreversible, first-order kinetics process. We found generally good agreement between our field-based estimates of particle dispersion and water velocity and estimates determined from published theory, suggesting that the advective-dispersive transport of particulate matter within complex wetland environments can be approximated on the basis of measurable properties of the flow and aquatic vegetation. Copyright 2008 by the American Geophysical Union.

  20. [Pollution characteristics and source of the atmospheric fine particles and secondary inorganic compounds at Mount Dinghu in autumn season].

    Science.gov (United States)

    Liu, Zi-Rui; Wang, Yue-Si; Liu, Quan; Liu, Lu-Ning; Zhang, De-Qiang

    2011-11-01

    Real-time measurements of PM2.5, secondary inorganic compounds in PM2.5 (SO4(2-), NH4(+), and NO3(-)) and related gaseous pollutants were conducted at Mount Dinghu, a regional background station of the Pearl River Delta (PRD), in October and November 2008 by using a conventional R&P TEOM and a system of rapid collection of fine particles and ion chromatography (RCFP-IC). Sources and transportation of atmospheric particles during the experiment were discussed with principal component analysis and backward trajectories calculated using HYSPLIT model. The average daily mass concentrations of PM2.5 were 76.9 microg x m(-3) during sampling period, and average daily mass concentrations of SO4(2-), NH4(+), and NO3(-) were 20.0 microg x m(-3), 6.8 microg x m(-3) and 2.6 microg x m(-3), respectively. The sum of these three secondary inorganic compounds accounted for more than one third of the PM2.5 mass concentration, which had become the major source of atmospheric fine particles at Mount Dinghu. The diurnal variation of PM2.5, SO4(2-), and NH4(+) all showed a "bimodal" distribution with two peaks appeared at 10:00 am and at 16:00 pm, respectively, whereas NO3(-s) howed "single peak" distribution peaked at 10:00 am. The mass concentrations of SO4(2-) in PM2.5 had the similar diurnal variation with that of SO2, SO4(2-) in PM2.5 was mainly transformed from SO2, whereas NO3(-) showed difference diurnal variation with that of NO2, and the second conversion rate of NO2 was far lower than that of SO2. NH4(+) in PM2.5 existed mainly in the form of sulfate, nitrate and chloride. Both of principal component analysis and back trajectory analysis showed that the variations of PM2.5 and secondary inorganic compounds at Mount Dinghu were mainly affected by the long-range transport air mass passed over Guangzhou, Huizhou and other highly industrialized areas which carried air pollutants to the observation site, at the same time local sulfate originated from secondary formation also

  1. 超细颗粒卤化银的制备与稳定性%PREPARATION OF ULTRA-FINE SILVER HALIDE PARTICLES AND THEIR STABILITY

    Institute of Scientific and Technical Information of China (English)

    崔兴品; 岳军

    1999-01-01

    With gelatin or gelatin+PVA as colloid protective medium and under proper reactive condition, ultra-fine silver iodobromide particles with average diameter of about 20 nm and better monodispersity were prepared by direct reaction of silver nitrate with mixture of potassium bromide and potassium iodide. According to TEM data, it was discovered that gelatin+PVA showed stronger colloid protective power for these ultra-fine particles, which restrained particles' coalescence and growth effectively during physical and chemical ripening, so that there was not observable change of particle size and monodispersity to be found. In the case of only gelatin as colloid protective medium to prepare ultra-fine silver iodobromide particles, particles'stability in the process of physical ripening depended on the ratio of gelatin amount to silver content as the preparing reaction. It appears that there exists a critical ratio of gelatin amount to silver content for particles′ stability. When experimental ratio of gelatin amount to silver content in the reaction was over this critical ratio, gelatin can protect ultra-fine particles against coalescence and growth to a considerable degree. On the contrary, the particle size beacme significantly large in the process of physical ripening due to decrease of gelatin protective power if the experimental ratio was lower than this critical ratio.

  2. Capture Efficiency of Cooking-Related Fine and Ultrafine Particles by Residential Exhaust Hoods

    Energy Technology Data Exchange (ETDEWEB)

    Lunden, Melissa M.; Delp, William W.

    2014-06-05

    Effective exhaust hoods can mitigate the indoor air quality impacts of pollutant emissions from residential cooking. This study reports capture efficiencies (CE) measured for cooking generated particles for scripted cooking procedures in a 121-m3 chamber with kitchenette. CEs also were measured for burner produced CO2 during cooking and separately for pots and pans containing water. The study used four exhaust hoods previously tested by Delp and Singer (Environ. Sci. Technol., 2012, 46, 6167-6173). For pan-frying a hamburger over medium heat on the back burner, CEs for particles were similar to those for burner produced CO2 and mostly above 80percent. For stir-frying green beans in a wok (high heat, front burner), CEs for burner CO2 during cooking varied by hood and airflow: CEs were 34-38percent for low (51?68 L s-1) and 54?72percent for high (109?138 L s-1) settings. CEs for 0.3?2.0 ?m particles during front burner stir-frying were 3?11percent on low and 16?70percent on high settings. Results indicate that CEs measured for burner CO2 are not predictive of CEs of cooking-generated particles under all conditions, but they may be suitable to identify devices with CEs above 80percent both for burner combustion products and for cooking-related particles.

  3. Effect of structural defects in fine particle on heat energy flow toward the boundary layer

    International Nuclear Information System (INIS)

    As the number of swipe samples around nuclear facilities is apt to increase, establishing simple and speedy analysis technique has become an urgent subject for the Fission Track (FT) method. In this method, a lot of trajectories induced by nuclear fission fragments will lead to drop an interested particle containing fissile materials from a film during etching process. Nuclear fission fragments are highly charged, so they can ionize, scatter and excite the other constituent molecules along their trajectory. This physical process could cause local temperature increase within or without the particle through the molecular collision. We try to investigate the relationship between the structural defects of the particle and heat energy flow toward the boundary layer by Molecular Dynamics Method. In this report, the computer code we have been developing is presented and what problems we should overcome to carry on this study are also stated. (author)

  4. Photophoresis on particles hotter or colder than the ambient gas in the free molecular flow

    CERN Document Server

    Loesche, C; Jankowski, T; Kuepper, M

    2016-01-01

    Aerosol particles experience significant photophoretic forces at low pressure. Previous work assumed the average particle temperature to be very close to the gas temperature. This might not always be the case. If the particle temperature or the thermal radiation field differs significantly from the gas temperature (optically thin gases), given approximations overestimate the photophoretic force by an order of magnitude on average with maximum errors up to more than three magnitudes. We therefore developed a new general approximation which on average only differs by 1 % from the true value.

  5. NEXAFS microscopy studies of the association of hydrocarbon thin films with fine clay particles

    International Nuclear Information System (INIS)

    The nature of organic species associated with clay minerals plays a significant role in several processes, from hydrocarbon recovery in oil sands to contaminated soil remediation and water treatment. In this work, we address the use of scanning transmission X-ray microscopy (STXM) in conjunction with near edge X-ray absorption fine structure (NEXAFS) spectroscopy to study the microstructure and chemistry of organic-clay associations in situ. A model system based on methylene blue and illite is used to explore the sensitivity of NEXAFS microscopy to these interactions, and to identify and resolve experimental challenges in these measurements. We find that sample contamination from X-ray induced photodeposition is a significant problem in STXM microscopy, but also that this problem can be substantially reduced with a liquid nitrogen cooled anticontaminator. With appropriate sample preparation and experimental procedures, we find that STXM microscopy is sensitive to thin carbon adsorbates on clay surfaces.

  6. Characterization of ambient particles size in workplace of manufacturing physical fitness equipments

    OpenAIRE

    Lin, Chih-Chung; Chen, Mei-Ru; CHANG, Sheng-Lang; LIAO, Wei-Heng; Chen, Hsiu-Ling

    2014-01-01

    The manufacturing of fitness equipment involves several processes, including the cutting and punching of iron tubes followed by welding. Welding operations produce hazardous gases and particulate matter, which can enter the alveolar, resulting in adverse health effects. This study sought to verify the particle size distribution and exposure concentrations of atmospheric air samples in various work areas of a fitness equipment manufacturing industry. Observed particle concentrations are presen...

  7. Developing an in vitro technology to study the inflammation potential of ambient particle types

    Science.gov (United States)

    Haddrell, Allen E.

    Elevated levels of suspended particles in the troposphere, termed particulate matter, elicit a myriad of adverse health effects in humans, ranging from shortness of breath and wheezing to myocardial infarction and death. It is currently believed that the adverse health effects associated with particulate matter are mediated by the inflammatory response initiated by the lung following particulate matter inhalation. What remains an area of much interest is elucidating the specific properties of particulate matter, physical or chemical, that cause the upregulation of proinflammatory mediators. The basic premise of this thesis was to identify the specific chemical components of particulate matter responsible for its adverse health effects. To address this issue, instrumentation and methodology were developed wherein one could design, create, levitate and deposit particles of both known chemical composition and size onto lung cells, in vitro, followed by the monitoring of the downstream biological response. An initial study focused on the role of the endotoxin component in particulate matter toxicity. Through a series of blocking studies we found that endotoxin acted synergistically with the particle core to elicit upregulation of proinflammatory mediators, including IL-1beta, TNF-alpha and ICAM-1; all of which are associated with the NF-kappaB pathway. Through characterizing this relatively simple system, one observation became apparent: the presence of the insoluble particle core had a profound effect on the cellular response; that is to say, the particle core was not simply a delivery vector, but a determinant factor in the final intracellular location of the toxic chemical. The latter observation held true as other particle types were studied and in addition, it was found that the nature of the actual chemical species itself plays a dual role in particle toxicity; first by retaining its toxic properties and second by altering the physical properties of the particle

  8. Measurement of overall uptake coefficients for HO2 radicals by aerosol particles sampled from ambient air at Mts. Tai and Mang (China)

    OpenAIRE

    Taketani, F.; Y. Kanaya; P. Pochanart; Liu, Y; Li, J.; K. Okuzawa; K. Kawamura; Z. Wang; H. Akimoto

    2012-01-01

    HO2 uptake coefficients for ambient aerosol particles, collected on quartz fiber filter using a high-volume air sampler in China, were measured using an aerosol flow tube coupled with a chemical conversion/laser-induced fluorescence technique at 760 Torr and 298 K, with a relative humidity of 75%. Aerosol particles were regenerated with an atomizer using the water extracts from the aerosol particles. Over 10 samples, the measured HO2 uptake coefficients for the aerosol parti...

  9. Effect of selective catalytic reduction (SCR) on fine particle emission from two coal-fired power plants in China

    Science.gov (United States)

    Li, Zhen; Jiang, Jingkun; Ma, Zizhen; Wang, Shuxiao; Duan, Lei

    2015-11-01

    Nitrogen oxides (NOx) emission abatement of coal-fired power plants (CFPPs) requires large-scaled installation of selective catalytic reduction (SCR), which would reduce secondary fine particulate matter (PM2.5) (by reducing nitrate aerosol) in the atmosphere. However, our field measurement of two CFPPs equipped with SCR indicates a significant increase of SO42- and NH4+ emission in primary PM2.5, due to catalytic enhancement of SO2 oxidation to SO3 and introducing of NH3 as reducing agent. The subsequent formation of (NH4)2SO4 or NH4HSO4 aerosol is commonly concentrated in sub-micrometer particulate matter (PM1) with a bimodal pattern. The measurement at the inlet of stack also showed doubled primary PM2.5 emission by SCR operation. This effect should therefore be considered when updating emission inventory of CFPPs. By rough estimation, the enhanced primary PM2.5 emission from CFPPs by SCR operation would offset 12% of the ambient PM2.5 concentration reduction in cities as the benefit of national NOx emission abatement, which should draw attention of policy-makers for air pollution control.

  10. Ambient black carbon particle hygroscopic properties controlled by mixing state and composition

    Directory of Open Access Journals (Sweden)

    D. Liu

    2013-02-01

    Full Text Available The wet removal of black carbon aerosol (BC in the atmosphere is a crucial factor in determining its atmospheric lifetime and thereby the vertical and horizontal distributions, dispersion on local and regional scales, and the direct, semi-direct and indirect radiative forcing effects. The in-cloud scavenging and wet deposition rate of freshly emitted hydrophobic BC will be increased on acquisition of more-hydrophilic components by coagulation or coating processes. The lifetime of BC is still subject to considerable uncertainty for most of the model inputs, which is largely due to the insufficient constraints on the BC hydrophobic-to-hydrophilic conversion process from observational field data. This study was conducted at a site along UK North Norfolk coastline, where the BC particles were transported from different regions within Western Europe. A hygroscopicity tandem differential mobility analyser (HTDMA was coupled with a single particle soot photometer (SP2 to measure the hygroscopic properties of BC particles and associated mixing state in real time. In addition, a Soot Particle AMS (SP-AMS measured the chemical compositions of additional material associated with BC particles. The ensemble of BC particles persistently contained a less-hygroscopic mode at a growth factor (gf of around 1.05 at 90% RH (dry diameter 163 nm. Importantly, a more-hygroscopic mode of BC particles was observed throughout the experiment, the gf of these BC particles extended up to ~1.4–1.6 with the minimum between this and the less hygroscopic mode at a gf ~1.25, or equivalent effective hygroscopicity parameter κ ~0.1. The gf of BC particles (gfBC was highly influenced by the composition of associated soluble material: increases of gfBC were associated with secondary inorganic components, and these increases were more pronounced when ammonium nitrate was in the BC particles; however the presence of secondary organic matter suppressed

  11. Optical properties of atmospheric fine particles near Beijing during the HOPE-J3A campaign

    OpenAIRE

    Xu, Xuezhe; Zhao, Weixiong; Zhang, Qilei; Wang, Shuo; Fang, Bo; Chen, Weidong; Venables, Dean S.; Wang, Xinfeng; Pu, Wei; wang, xin; Gao, Xiaoming; Zhang, Weijun

    2016-01-01

    The optical properties and chemical composition of PM1.0 particles in a suburban environment (Huairou) near the megacity of Beijing were measured during the HOPE-J3A (Haze Observation Project Especially for Jing–Jin–Ji Area) field campaign. The campaign covered the period November 2014 to January 2015 during the winter coal heating season. The average values and standard deviations of the extinction, scattering, absorption coefficients, and the aerosol single scattering albe...

  12. Flocculation of fine fluorite particles with Corynebacterium xerosis and commercial long chain polymers

    Directory of Open Access Journals (Sweden)

    Rigo Lisandra N.

    2002-01-01

    Full Text Available This work aimed to study, comparatively, the flocculation of fluorite particles with Corynebacterium xerosis cells and three commercial long chain polymers. Best flocculation results were obtained with cells of C. xerosis and with an anionic polyacrylamide. Both were effective in solids removal and water clarification, although flocculation with C. xerosis cells requires a higher dosage of reagent per mass unit of processed ore.

  13. On dithiothreitol (DTT) as a measure of oxidative potential for ambient particles: evidence for the importance of soluble transition metals

    Science.gov (United States)

    Charrier, J. G.; Anastasio, C.

    2012-10-01

    The rate of consumption of dithiothreitol (DTT) is increasingly used to measure the oxidative potential of particulate matter (PM), which has been linked to the adverse health effects of PM. While several quinones are known to be very reactive in the DTT assay, it is unclear what other chemical species might contribute to the loss of DTT in PM extracts. To address this question, we quantify the rate of DTT loss from individual redox-active species that are common in ambient particulate matter. While most past research has indicated that the DTT assay is not sensitive to metals, our results show that seven out of the ten transition metals tested do oxidize DTT, as do three out of the five quinones tested. While metals are less efficient at oxidizing DTT compared to the most reactive quinones, concentrations of soluble transition metals in fine particulate matter are generally much higher than those of quinones. The net result is that metals appear to dominate the DTT response for typical ambient PM2.5 samples. Based on particulate concentrations of quinones and soluble metals from the literature, and our measured DTT responses for these species, we estimate that for typical PM2.5 samples approximately 80% of DTT loss is from transition metals (especially copper and manganese), while quinones account for approximately 20%. We find a similar result for DTT loss measured in a small set of PM2.5 samples from the San Joaquin Valley of California. Because of the important contribution from metals, we also tested how the DTT assay is affected by EDTA, a chelator that is sometimes used in the assay. EDTA significantly suppresses the response from both metals and quinones; we therefore recommend that EDTA should not be included in the DTT assay.

  14. The heavy metal partition in size-fractions of the fine particles in agricultural soils contaminated by waste water and smelter dust

    International Nuclear Information System (INIS)

    Highlights: ► A continuous flow ultra-centrifugation method has been developed to obtain fine particles from polluted agricultural soil. ► Pollution source affected the heavy metal fractionation in size-fractions by changing soil particle properties. ► The iron oxides affected the distribution of lead species more than other metals in the smelter dust polluted particles. -- Abstract: The partitioning of pollutant in the size-fractions of fine particles is particularly important to its migration and bioavailability in soil environment. However, the impact of pollution sources on the partitioning was seldom addressed in the previous studies. In this study, the method of continuous flow ultra-centrifugation was developed to separate three size fractions (<1 μm, <0.6 μm and <0.2 μm) of the submicron particles from the soil polluted by wastewater and smelter dust respectively. The mineralogy and physicochemical properties of each size-fraction were characterized by X-ray diffraction, transmission electron microscope etc. Total content of the polluted metals and their chemical speciation were measured. A higher enrichment factor of the metals in the fractions of <1 μm or less were observed in the soil contaminated by wastewater than by smelter dust. The organic substance in the wastewater and calcite from lime application were assumed to play an important role in the metal accumulation in the fine particles of the wastewater polluted soil. While the metal accumulation in the fine particles of the smelter dust polluted soil is mainly associated with Mn oxides. Cadmium speciation in both soils is dominated by dilute acid soluble form and lead speciation in the smelter dust polluted soil is dominated by reducible form in all particles. This implied that the polluted soils might be a high risk to human health and ecosystem due to the high bioaccessblity of the metals as well as the mobility of the fine particles in soil

  15. Separation and chemical characterization of finely-sized fly-ash particles

    International Nuclear Information System (INIS)

    The concentrations of 43 major, minor, and trace elements were measured by x-ray fluorescence, atomic absorption, and instrumental neutron activation for nine well-defined size fractions, with mass median diameters of 0.5 μ to 50 μm, of fly ash from a western coal-fired steam plant. There was generally good agreement in concentrations of elements analyzed by more than one technique. Concentration profiles as a function of mean particle size were established for various elements. Based on the concentration profiles, the elements can be divided into three distinct groups. One group consists primarily of the volatile elements or elements partially volatilized during coal combustion (examples include As, Se, Zn, Ga, etc.), and their concentrations decrease with increasing particle size. A second group, which shows a minor or direct dependence on particle size, as in the case of Si, is apparently associated primarily with the fly-ash matrix. The last group of elements, which includes Ca, Sr, Y, and the rare earths, shows small changes in their concentration profiles with a maximum in concentration at approximately 5 μm. 6 tables, 6 figures

  16. Study of fine particles (PM2.5) during the dry-hot time in the Toluca city

    International Nuclear Information System (INIS)

    The first obtained results of the analysis of the fine fraction particulate material (PM2.5) samples collected in the Toluca City are presented. The samples analyzed are part of a more extensive campaign that contemplates the low project the one which one carries out this work and that it integrates three climatic times (dry-hot, of rains and dry-cold time) with the purpose of investigating the events of contamination in one complete year. The obtained results correspond to the dry-hot time and its include mainly the database starting from which the temporal variation graphs were obtained, the correlations among elements and the enrichment factor, as well as a multiple correlation analysis. Additionally the gravimetry was measured. Its are not observed significant episodes, however, it was found an element of the traces order, little common in other atmospheric studies as it is arsenic. From the gravimetry it was deduced that the air quality standard of fine particle, it does not violate. (Author)

  17. Formation of fine particles in co-combustion of coal and solid recovered fuel in a pulverized coal-fired power station

    DEFF Research Database (Denmark)

    Wu, Hao; Pedersen, Anne Juul; Glarborg, Peter;

    2011-01-01

    Fine particles formed from combustion of a bituminous coal and co-combustion of coal with 7 th% (thermal percentage) solid recovered fuel (SRF) in a pulverized coal-fired power plant were sampled and characterized in this study. The particles from dedicated coal combustion and co-combustion both...... showed an ultrafine mode centered at approximately 0.1 μm. Compared with coal combustion, co-combustion of coal and SRF increased the formation of submicron particles, especially ultrafine particles below 0.2 μm. The morphology of the particles indicated that supermicron particles were primarily formed...... appear to be an important formation mechanism. The elemental composition of the particles from coal combustion showed that S and Ca were significantly enriched in ultrafine particles and P was also enriched considerably. However, compared with supermicron particles, the contents of Al, Si and K were...

  18. Analysis on thermophoretic deposit of fine particle on water wall of 10 MW high temperature gas-cooled reactor

    Institute of Scientific and Technical Information of China (English)

    ZHOU Tao; YANG Rui-Chang; JIA Dou-Nan

    2005-01-01

    The water wall is an important part of the passive natural circulation residual heat removal system in a high temperature gas-cooled reactor. The maximum temperatures of the pressure shell and the water wall are calculated using annular vertical closed cavity model. Fine particles can deposit on the water wall due to the thermophore sis effect. This deposit can affect heat transfer. The thermophoretic deposit efficiency is calculated by using Batch and Shen's formula fitted for both laminar flow and turbulent flow. The calculated results indicate that natural convection is turbulent in the closed cavity. The transient thermophoretic deposit efficiency rises with the increase of the pressure shell's temperature. Its maximum value is 14%.

  19. Size-resolved source apportionment of ambient particles by positive matrix factorization

    Science.gov (United States)

    Han, J. S.; Moon, K. J.; Lee, S. J.; Kim, Y. J.; Ryu, S. Y.; Cliff, S. S.; Yi, S. M.

    2005-07-01

    Size- and time-resolved aerosol samples were collected using an eight-stage DRUM sampler from 29 March to 29 May in 2002 at Gosan, Jeju Island, Korea, which is one of the representative background sites in East Asia. These samples were analyzed using synchrotron X-ray fluorescence for 3-h average concentrations of 19 elements consisting of S, Si, Al, Fe, Ca, Cl, Cu, Zn, Ti, K, Mn, Pb, Ni, V, Se, As, Rb, Cr, Br. The size-resolved data sets were then analyzed using the positive matrix factorization (PMF) technique in order to identify possible sources and estimate their contribution to particulate matter mass. PMF analysis uses the uncertainty of the measured data to provide an optimal weighting. Fifteen sources were resolved in eight size ranges (0.07-12 µm) and included Chinese aerosol, soil dust, sea salt, biomass burning, coal combustion, oil heating furnace, residual oil-fired boiler, municipal incineration, nonferrous metal source, ferrous metal source, gasoline vehicle, diesel vehicle, copper smelter, and volcano emission. PMF analysis of size-resolved source contributions showed that natural sources represented by soil dust, sea salt and Chinese aerosol contributed about 79% to the predicted primary PM mass in the coarse size range (1.15-12 µm). On the other hand, anthropogenic sources such as coal combustion and biomass burning contributed about 60% in the fine size range (0.56-2.5 µm). The diesel vehicle source contributed the most in the ultra-fine size range (0.07-0.56 µm) and was responsible for about 52% of the primary PM mass.

  20. Fine particles (PM2.5) at a CAWNET background site in Central China: Chemical compositions, seasonal variations and regional pollution events

    Science.gov (United States)

    Zhang, Fan; Cheng, Hai-rong; Wang, Zu-wu; Lv, Xiao-pu; Zhu, Zhong-min; Zhang, Gan; Wang, Xin-ming

    2014-04-01

    Fine particle (PM2.5) samples were collected at Jinsha (JSH), a regional background China Atmosphere Watch Network (CAWNET) site in Central China from March 2012 to March 2013. The mass concentrations of water-soluble inorganic ions (WSIIs), organic carbon (OC) and elemental carbon (EC) in PM2.5 were measured. The average PM2.5 mass concentration was 48.7 ± 26.9 μg m-3, exceeding the Chinese National Ambient Air Quality Standards (NAAQS) (35 μg m-3), implying that PM2.5 is a pollutant of regional concern in Central China. The average concentrations of total WSIIs, OC and EC were 26.1 ± 18.8, 7.5 ± 3.5 and 0.7 ± 0.5 μg m-3, accounting for 53.5%, 15.1% and 1.5% of the PM2.5 concentrations at JSH, respectively. Clear seasonal variations in PM2.5 and the levels of its main chemical species were observed in the following order: winter > autumn > spring > summer. Backward air trajectory analysis and potential source contribution function (PSCF) analysis implied that the areas north and northeast of JSH contributed significantly to the levels of SO42-, NO3-, NH4+ and OC, while sandstorms originating from Mongolia and traveling across Northwest China may have contributed significantly to the levels of Na+, Ca2+, and Mg2+ in PM2.5 at JSH. Two pollution events, related to regional biomass burning and haze, respectively, were recorded at JSH during the sampling campaign.

  1. Measurement and analysis of the relationship between ammonia, acid gases, and fine particles in eastern North Carolina.

    Science.gov (United States)

    Baek, Bok Haeng; Aneja, Viney P

    2004-05-01

    An annular denuder system, which consisted of a cyclone separator; two diffusion denuders coated with sodium carbonate and citric acid, respectively; and a filter pack consisting of Teflon and nylon filters in series, was used to measure acid gases, ammonia (NH3), and fine particles in the atmosphere from April 1998 to March 1999 in eastern North Carolina (i.e., an NH3-rich environment). The sodium carbonate denuders yielded average acid gas concentrations of 0.23 microg/m3 hydrochloric acid (standard deviation [SD] +/- 0.2 microg/m3); 1.14 microg/m3 nitric acid (SD +/- 0.81 microg/m3), and 1.61 microg/m3 sulfuric acid (SD +/- 1.58 microg/m3). The citric acid denuders yielded an average concentration of 17.89 microg/m3 NH3 (SD +/- 15.03 microg/m3). The filters yielded average fine aerosol concentrations of 1.64 microg/m3 ammonium (NH4+; SD +/- 1.26 microg/m3); 0.26 microg/m3 chloride (SD +/- 0.69 microg/m3), 1.92 microg/m3 nitrate (SD +/- 1.09 microg/m3), and 3.18 microg/m3 sulfate (SO4(2-); SD +/- 3.12 microg/m3). From seasonal variation, the measured particulates (NH4+, SO4(2-), and nitrate) showed larger peak concentrations during summer, suggesting that the gas-to-particle conversion was efficient during summer. The aerosol fraction in this study area indicated the domination of ammonium sulfate particles because of the local abundance of NH3, and the long-range transport of SO4(2-) based on back trajectory analysis. Relative humidity effects on gas-to-particle conversion processes were analyzed by particulate NH4+ concentration originally formed from the neutralization processes with the secondary pollutants in the atmosphere. PMID:15149049

  2. Spatial variability of fine and coarse particle composition and sources in Cyprus

    Science.gov (United States)

    Achilleos, Souzana; Wolfson, Jack M.; Ferguson, Stephen T.; Kang, Choong-Min; Hadjimitsis, Diofantos G.; Hadjicharalambous, Marios; Achilleos, Constantia; Christodoulou, Andri; Nisanzti, Argyro; Papoutsa, Christiana; Themistocleous, Kyriacos; Athanasatos, Spyros; Perdikou, Skevi; Koutrakis, Petros

    2016-03-01

    Southern and Eastern European countries exceed WHO and EU air quality standards very often, and are influenced by both local and external sources from Europe, Asia and Africa. However, there are limited data on particle composition and source profiles. We collected PM2.5 and PM10 samples (particulate matter with aerodynamic diameter less than 2.5 and 10 μm, respectively) in four cities in Cyprus using Harvard Impactors. Measurements were conducted between January 2012 and January 2013. We analyzed these samples for mass concentration and chemical composition, and conducted a source apportionment analysis using Positive Matrix Factorization (PMF). All sites complied with PM2.5 and PM10 WHO daily standards for most of the days. As in other Eastern European countries, we found higher sulfate contribution and less organic carbon than in the Western and central Europe. For PM2.5, seven source types were identified including regional sulfur, traffic emissions, biomass, re-suspended soil, oil combustion, road dust, and sea salt. In all four sites, regional sulfur was the predominant source (> 30%). High inter-site correlations were observed for both PM2.5 component concentrations and source contributions, may be because a large fraction of PM2.5 is transported. Finally, for PM10 -2.5 (coarse particles with aerodynamic diameter between 2.5 and 10 μm) three sources were identified, which include road dust, soil, and sea salt. Significant inter-site correlations were also observed for coarse particles. All dust storm samples, except one, had PM levels below the daily standard. However, mineral dust, defined as the total mass of crustal metal oxides, increased up to ten times during the dust events.

  3. Enhanced oxidative stress and endothelial dysfunction in streptozotocin-diabetic rats exposed to fine particles.

    Science.gov (United States)

    Lei, Yu-Chen; Hwang, Jing-Shiang; Chan, Chang-Chuan; Lee, Chung-Te; Cheng, Tsun-Jen

    2005-11-01

    The association between ambient particulate matter (PM) and cardiovascular diseases has been demonstrated in epidemiological studies. Recent studies suggest that diabetic patients are at greater risk for PM-associated cardiovascular events. Although diabetes and PM exposure individually have been reported to be associated with increased oxidative stress, inflammation, and endothelial dysfunction, it is not clear whether PM may induce synergistic interaction effects on these parameters in diabetics. Strepotozotocin-induced diabetic (n=4) and healthy (n=4) rats were intratracheally administered with PM2.5 collected from a busy traffic area in a dose of 200 microg suspended in 0.5 mL phosphate-buffered saline (PBS). The same number of rats was exposed to PBS as controls. Cell and differential counts and protein and lactate dehydrogenase activity were determined in bronchoalveolar lavage. Markers of 8-hydroxydeoxy-guanosine (8-OHdG), endothelin-1 (ET-1), and [nitrate+nitrite], an indicator of nitric oxide (NO) production, in addition to C-reactive protein (CRP), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-alpha) in peripheral blood were also determined. Our results showed that diabetic rats were associated with increased 8-OHdG, IL-6, and ET-1 decreased [nitrate+nitrite]. In nondiabetic rats PM exposure was also associated with increased 8-OHdG, IL-6, TNF-alpha, and CRP but decreased [nitrate+nitrite]. Interestingly, increases of 8-OHdG and ET-1 after PM exposure were more prominent in diabetic rats than in nondiabetic rats. The general linear model further indicated that there were interactions between diabetes and PM on 8-OHdG (P<0.01) and ET-1 (P=0.08). We suggest that PM exposure may enhance the risk of cardiovascular diseases through interaction between PM and diabetes on excess reactive oxygen species generation and endothelial dysfunction. These findings provide further support for previous epidemiological studies. PMID:16307975

  4. Measurements and source apportionment of particle-associated polycyclic aromatic hydrocarbons in ambient air in Riyadh, Saudi Arabia

    Science.gov (United States)

    Bian, Qijing; Alharbi, Badr; Collett, Jeffrey; Kreidenweis, Sonia; Pasha, Mohammad J.

    2016-07-01

    Ambient air samples were obtained in Riyadh, the capital and largest city of Saudi Arabia, during two measurement campaigns spanning September 2011 to September 2012. Sixteen particle-phase polycyclic aromatic hydrocarbons (PAH) were quantified in 167 samples. Pyrene and fluoranthene were the most abundant PAH, with average of 3.37 ± 14.01 ng m-3 and 8.00 ± 44.09 ng m-3, respectively. A dominant contribution from low molecular weight (LMW) PAH (MW industrial emissions on PAH concentrations. Monte Carlo source apportionment using diagnostic ratios showed that 80 ± 10% of the average LMW PAH concentrations were contributed by petroleum vapor emissions, while 53 ± 19% of high molecular weight (HMW) PAH were from solid fuel combustion emissions. The positive matrix factorization model estimated that oil combustion emissions dominated total PAH concentrations, accounting for on average 96%, likely due to widespread use of oil fuels in energy production (power plants and industries). Our results demonstrate the significant influence of petroleum product production and consumption on particulate-phase PAH concentrations in Riyadh, but also point to the importance of traffic and solid fuel burning, including coke burning and seasonal biomass burning, especially as they contribute to the ambient levels of HMW PAH.

  5. Ambient bioaerosol particle dynamics observed during haze and sunny days in Beijing.

    Science.gov (United States)

    Wei, Kai; Zou, Zhuanglei; Zheng, Yunhao; Li, Jing; Shen, Fangxia; Wu, Chang-Yu; Wu, Yusheng; Hu, Min; Yao, Maosheng

    2016-04-15

    The chemical characteristics of airborne particulate matter (PM) have been extensively studied; however, little information exists for its biological components (bioaerosol) especially during a haze event in mega cities. Herein, we studied the bioaerosol (fluorescent particle) dynamics on both haze and sunny days in Beijing from Dec. 2013 to March 2014 by employing a widely used real-time bioaerosol sensor-ultraviolet aerodynamic particle spectrometer (UV-APS). Firstly, we studied the fluorescent particle (BioPM) concentration and size distributions during three independent haze and three independent sunny days. Secondly, we investigated BioPM dynamics over a two-week long monitoring period which included consecutive haze days and alternated sunny days. In addition, we analyzed bacterial community structures and endotoxin levels in the air samples using pyrosequencing and Limulus amebocyte lysate (LAL) method, respectively. More than 6-fold higher fluorescent particle concentrations up to 5×10(5)/m(3) with peaks at night or early dawn were detected at the time of haze occurrences than those observed on sunny days. When the haze episode progressed for 3-5days, the BioPM concentrations were observed to decrease to the levels that were typically observed on sunny days. In general, ozone levels were found to be elevated at noon, while BioPM, NOx and relative humidity were reduced. Gene sequence analysis revealed no significant difference in abundances and community structures for top 13 bacterial genera between haze and sunny days, yet about twice higher endotoxin levels (12.4EU/m(3)) were detected on haze days than on sunny days. The results here facilitate a better understanding of atmospheric fluorescent particle dynamics including those under haze events. PMID:26849339

  6. Inter-comparison of Seasonal Variation, Chemical Characteristics, and Source Identification of Atmospheric Fine Particles on Both Sides of the Taiwan Strait

    OpenAIRE

    Tsung-Chang Li; Chung-Shin Yuan; Hu-Ching Huang; Chon-Lin Lee; Shui-Ping Wu; Chuan Tong

    2016-01-01

    The spatiotemporal distribution and chemical composition of atmospheric fine particles in areas around the Taiwan Strait were firstly investigated. Fine particles (PM2.5) were simultaneously collected at two sites on the west-side, one site at an offshore island, and three sites on the east-side of the Taiwan Strait in 2013–2014. Field sampling results indicated that the average PM2.5 concentrations at the west-side sampling sites were generally higher than those at the east-side sampling sit...

  7. Changes in the surface electronic states of semiconductor fine particles induced by high energy ion irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Yamaki, Tetsuya; Asai, Keisuke; Ishigure, Kenkichi [Tokyo Univ. (Japan); Shibata, Hiromi

    1997-03-01

    The changes in the surface electronic states of Q-sized semiconductor particles in Langmuir-Blodgett (LB) films, induced by high energy ion irradiation, were examined by observation of ion induced emission and photoluminescence (PL). Various emission bands attributed to different defect sites in the band gap were observed at the initial irradiation stage. As the dose increased, the emissions via the trapping sites decreased in intensity while the band-edge emission developed. This suggests that the ion irradiation would remove almost all the trapping sites in the band gap. The low energy emissions, which show a multiexponential decay, were due to a donor-acceptor recombination between the deeply trapped carriers. It was found that the processes of formation, reaction, and stabilization of the trapping sites would predominantly occur under the photooxidizing conditions. (author)

  8. [Effects of biodiesel on fine particles (PM2.5) and polycyclic aromatic hydrocarbons from diesel engine].

    Science.gov (United States)

    Tan, Ji-hua; Shi, Xiao-yan; Zhang, Jie; He, Ke-bin; Ma, Yong-liang; Ge, Yun-shan; Tan, Jian-wei

    2009-10-15

    PM2.5 emissions and polycyclic aromatic hydrocarbons (PAHs) in PM2.5 of pure biodiesel derived from different feedstocks were investigated and compared with diesel fuel. B100-1 (soyabean oil derived), B100-2 (waste oil derived) and diesel fuel were tested on a diesel engine bench at four operating conditions, including two steady speeds of different loads. The fine particles were collected by fiber quartz filter and particle phase PAHs were analyzed by GC-MS. Compared with diesel fuel, biodiesel decreased PM2.5 emission rates with a maximal reduction rate of 37.3% at operating modes of high loads, while increased PM2.5 emission rates at low loads. PAHs emission rates from biodiesel decreased at all tested modes, with a maximal reduction rate of 77.6%. The emission rates of PM2.5 and PAHs of B100-2 were 14.7% and 17.8% times of B100-1. Low molecular weight PAHs dominated in the emission of three fuels with phenanthrene as maxima and 2-ring and 3-ring PAHs accounted for more than 50% of the total PAHs. Toxic equivalence of PAHs emissions of biodiesel was decreased greatly compared with that of diesel. PMID:19968095

  9. Photo-induced valence-number changes and defects in Eu2O3 fine particle films

    Science.gov (United States)

    Mochizuki, Shosuke; Fujishiro, Fumito; Ishiwata, Ken'ichiro

    2005-01-01

    Different Eu2O3 fine particle films were prepared by the laser ablation method. Under a continuous wave (CW) 325 nm laser light irradiation, their photoluminescence spectra are measured both in vacuum and in O2 gas atmosphere. All the specimens display reversible spectral change and clear luminescence colour changes (red luminescence leftrightarrow white luminescence) for changing specimen atmosphere. Moreover, the white-luminescent state is stored for more than several years at room temperature in air under room light. The obtained results suggest that the spectral changes arise from both the photo-induced valence (Eu3+ → Eu2+) change of europium ions and the photo-generated oxygen defect structure at Eu2O3 particle surfaces in vacuum, which is expressed by the following reaction, Eu2O3 in lattice + CW 325 nm photon → (Eu2+-oyygen vacancy-Eu2+) complex +½O2. The obtained results are discussed in the light of the exciton theory.

  10. Impact of aerosol–meteorology interactions on fine particle pollution during China’s severe haze episode in January 2013

    International Nuclear Information System (INIS)

    In January 2013, a severe regional haze occurred over the North China Plain. An online-coupled meteorology-chemistry model was employed to simulate the impacts of aerosol–meteorology interactions on fine particles (PM2.5) pollution during this haze episode. The response of PM2.5 to meteorology change constituted a feedback loop whereby planetary boundary layer (PBL) dynamics amplified the initial perturbation of PM2.5. High PM2.5 concentrations caused a decrease of surface solar radiation. The maximal decrease in daily average solar radiation reached 53% in Beijing, thereby leading to a more stable PBL. The peak PBL height in Beijing decreased from 690 m to 590 m when the aerosol extinction was considered. Enhanced PBL stability suppressed the dispersion of air pollutants, and resulted in higher PM2.5 concentrations. The maximal increase of PM2.5 concentrations reached 140 μg m−3 in Beijing. During most PM2.5 episodes, primary and secondary particles increased simultaneously. These results imply that the aerosol–radiation interactions played an important role in the haze episode in January 2013. (letter)

  11. Heterogeneous reaction of peroxyacetic acid and hydrogen peroxide on ambient aerosol particles under dry and humid conditions: kinetics, mechanism and implications

    Directory of Open Access Journals (Sweden)

    Q. Q. Wu

    2015-02-01

    Full Text Available Hydrogen peroxide (H2O2 and organic peroxides play important roles in the cycle of oxidants and the formation of secondary aerosols in the atmosphere. Recent field observations suggest that peroxyacetic acid (PAA, CH3C(OOOH is one of the most important organic peroxides in the atmosphere, whose budget is potentially related to the aerosols. Here we present the first laboratory measurements of the uptake coefficient of gaseous PAA and H2O2 onto the ambient fine particulate matter (PM2.5 as a function of relative humidity (RH at 298 K. The results show that the PM2.5, which was collected in an urban area, can take up PAA and H2O2 at the uptake coefficient (γ of 10−4, and both γPAA and γH2O2 increase with increasing RH. However, γPAA is more sensitive to the RH variation than is γH2O2, which indicates that the enhanced uptake of peroxide compounds on PM2.5 under humid conditions is dominated by chemical processes rather than dissolution. Considering that mineral dust is one of the main components of PM2.5, we also determined the uptake coefficients of gaseous PAA and H2O2 on authentic Asian Dust Storm (ADS and Arizona Test Dust (ATD particles. Compared to ambient PM2.5, ADS shows a similar γ value and RH dependence in its uptake coefficient for PAA and H2O2, while ATD gives a negative dependence on RH. The present study indicates that in addition to the mineral dust in PM2.5, other components (e.g., inorganic soluble salts are also important to the uptake of peroxide compounds. When the heterogeneous reaction of PAA on PM2.5 is considered, its atmospheric lifetime is estimated to be 3.3 h on haze days and 7.6 h on non-haze days, values which agree well with the field observed result.

  12. Surface area of particle administered versus mass in determining the pulmonary toxicity of ultrafine and fine carbon black: comparison to ultrafine titanium dioxide

    Directory of Open Access Journals (Sweden)

    Sager Tina M

    2009-05-01

    Full Text Available Abstract Background Nanoparticles are characterized by having a high surface area per mass. Particulate surface area has been reported to play an important role in determining the biological activity of nanoparticles. However, recent reports have questioned this relationship. This study was conducted to determine whether mass of particles or surface area of particles is the more appropriate dose metric for pulmonary toxicity studies. In this study, rats were exposed by intratracheal instillation to various doses of ultrafine and fine carbon black. At 1, 7, or 42 days post-exposure, inflammatory and cytotoxic potential of each particle type was compared on both a mass dosage (mg/rat as well as an equal surface area dosage (cm2 of particles per cm2 of alveolar epithelium. In an additional study, the pulmonary responses to instillation of ultrafine carbon black were compared to equivalent particle surface area doses of ultrafine titanium dioxide. Results Ultrafine carbon black particles caused a dose dependent but transient inflammatory and cytotoxic response. On a mass basis, these responses were significantly (65 fold greater than those for fine sized carbon black. However, when doses were equalized based on surface area of particles given, the ultrafine carbon black particles were only slightly (non-significantly more inflammogenic and cytotoxic compared to the fine sized carbon black. At one day post-exposure, inflammatory potencies of the ultrafine carbon black and ultrafine titanium dioxide particles were similar. However, while the pulmonary reaction to ultrafine carbon black resolved with time, the inflammatory effects of ultrafine titanium dioxide were more persistent over a 42 day post-exposure period. Conclusion These results indicate that for low toxicity low solubility materials, surface area of particles administered rather than mass burden of particles may be a more appropriate dose metric for pulmonary toxicity studies. In addition

  13. Optical properties of atmospheric fine particles near Beijing during the HOPE-J3A campaign

    Science.gov (United States)

    Xu, Xuezhe; Zhao, Weixiong; Zhang, Qilei; Wang, Shuo; Fang, Bo; Chen, Weidong; Venables, Dean S.; Wang, Xinfeng; Pu, Wei; Wang, Xin; Gao, Xiaoming; Zhang, Weijun

    2016-05-01

    The optical properties and chemical composition of PM1.0 particles in a suburban environment (Huairou) near the megacity of Beijing were measured during the HOPE-J3A (Haze Observation Project Especially for Jing-Jin-Ji Area) field campaign. The campaign covered the period November 2014 to January 2015 during the winter coal heating season. The average values and standard deviations of the extinction, scattering, absorption coefficients, and the aerosol single scattering albedo (SSA) at λ = 470 nm during the measurement period were 201 ± 240, 164 ± 202, 37 ± 43 Mm-1, and 0.80 ± 0.08, respectively. The average values for the real and imaginary components of the effective complex refractive index (CRI) over the campaign were 1.40 ± 0.06 and 0.03 ± 0.02, while the average mass scattering and absorption efficiencies (MSEs and MAEs) of PM1.0 were 3.6 and 0.7 m2 g-1, respectively. Highly time-resolved air pollution episodes clearly show the dramatic evolution of the PM1.0 size distribution, extensive optical properties (extinction, scattering, and absorption coefficients), and intensive optical properties (SSA and CRI) during haze formation, development, and decline. Time periods were classified into three different pollution levels (clear, slightly polluted, and polluted) for further analysis. It was found that (1) the relative contributions of organic and inorganic species to observed aerosol composition changed significantly from clear to polluted days: the organic mass fraction decreased from 50 to 43 % while the proportion of sulfates, nitrates, and ammonium increased strongly from 34 to 44 %. (2) Chemical apportionment of extinction, calculated using the IMPROVE algorithm, tended to underestimate the extinction compared to measurements. Agreement with measurements was improved by modifying the parameters to account for enhanced absorption by elemental carbon (EC). Organic mass was the largest contributor (52 %) to the total extinction of PM1.0, while EC

  14. Ignition and growth modeling of short pulse shock initiation experiments on fine particle Hexanitrostilbene (HNS)

    International Nuclear Information System (INIS)

    Hexanitrostilbene (HNS) is a booster explosive that is usually initiated using short pulse duration shock waves produced by high velocity impacts with thin flyer plates. HNS is generally used at a density of 1.60 g/cm3 which implies a porosity of 8%. It has been produced in several forms (I – IV, ultrafine, etc.) with various particle surface areas. The threshold flyer velocities for shock induced detonation versus failure to detonate for these different surface area materials vary slightly, but, in this paper, an average Ignition and Growth reactive flow model parameter set was determined using all of the experimental data from several aluminium and KaptonTM flyer plate studies. This data ranged from shock pressures of 4 GPa to above the Chapman-Jouguet (C-J) detonation pressure (∼20 GPa) and from 1 to 120 nanoseconds in time duration. Good agreement was obtained for the available short pulse duration detonation verses failure to threshold flyer velocity data using the Ignition and Growth model.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-12-15

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

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

    International Nuclear Information System (INIS)

    This study is the first national attempt to assess the levels of PMs in Beirut city and consequently understand air pollution distribution. Aerosol sampling was carried out using three PM10 and three PM2.5 samplers which were installed at three locations lying along the SE-NW direction over Beirut. The sampling of PM10 and PM2.5 was done during a period extending from May till December 2009. The random collection of the particles (1 in 6 days) was carried out on Teflon filters, for a period of 24-h. The elemental analysis of particulate matter was performed using proton induced X-ray emission technique PIXE at the Lebanese 1.7 MV Tandem-Pelletron accelerator of Beirut. Na, Mg, Al, Si, P, S and Cl were quantified using 1 MeV proton beam, while K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn and Pb were determined using 3 MeV-energy of proton beam.

  17. Chemical composition of fine particles in fresh smoke plumes from boreal wild-land fires in Europe.

    Science.gov (United States)

    Saarnio, Karri; Aurela, Minna; Timonen, Hilkka; Saarikoski, Sanna; Teinilä, Kimmo; Mäkelä, Timo; Sofiev, Mikhail; Koskinen, Jarkko; Aalto, Pasi P; Kulmala, Markku; Kukkonen, Jaakko; Hillamo, Risto

    2010-05-15

    A series of smoke plumes was detected in Helsinki, Finland, during a one-month-lasting period in August 2006. The smoke plumes originated from wildfires close to Finland, and they were short-term and had a high particulate matter (PM) concentration. Physical and chemical properties of fine particles in those smokes were characterised by a wide range of real-time measurements that enabled the examination of individual plume events. Concurrently PM(1) filter samples were collected and analysed off-line. Satellite observations employing MODIS sensor on board of NASA EOS Terra satellite with the dispersion model SILAM and the Fire Assimilation System were used for evaluation of the emission fluxes from wildfires. The model predicted well the timing of the plumes but the predicted PM concentrations differed from the observed. The measurements showed that the major growth in PM concentration was caused by submicrometer particles consisting mainly of particulate organic matter (POM). POM had not totally oxidised during the transport based on the low WSOC-to-OC ratio. The fresh plumes were compared to another major smoke episode that was observed in Helsinki during April-May 2006. The duration and the source areas of the two episode periods differed. The episode in April-May was a period of nearly constantly upraised level of long-range transported PM and it was composed of aged particles when arriving in Helsinki. The two episodes had differences also in the chemical composition of PM. The mass concentrations of biomass burning tracers (levoglucosan, potassium, and oxalate) increased during both the episodes but different concentration levels of elemental carbon and potassium indicated that the episodes differed in the form of burning as well as in the burning material. In spring dry crop residue and hay from the previous season were burnt whereas in August smokes from smouldering and incomplete burning of fresh vegetation were detected. PMID:20359735

  18. Instrument for measuring total alpha particle energies of alpha emitters in ambient air

    Energy Technology Data Exchange (ETDEWEB)

    Kronenberg, S.; Brucker, G.J.; Cummings, B.; Bechtel, E.; Gentner, F.; Horne, S

    2000-11-11

    This paper describes the design, fabrication, testing and evaluation of a self-reading, carbon fiber, electrometer-type instrument. It is used for measuring the total energy of alpha particles emitted in air by progenies of {sup 222}Rn ({sup 218}Po, {sup 214}Pb, and {sup 214}Bi), and sometimes by other types of alpha emitters (e.g. {sup 212}Pb, {sup 238}U, and {sup 239}Pu). The purpose of these measurements is to assess the energy delivered by alpha emission from these sources to the lung tissue. A sample (charged progenies attached to aerosols) is collected on filter paper from a known volume of air and placed on the instrument. The discharge rate indicates the alpha energy in MeV l{sup -1} of air per min that is produced by the alpha emitters. The calibration procedure shows that the instrument has an energy sensitivity for alpha particles of 800.5 MeV/scale unit. The range of the readout scale is 30 units. Measurements of alpha contamination in air were made using this instrument in buildings, private homes and in a standard chamber. The value of the radon concentration in this chamber is traceable back to the US Environmental Protection Agency (EPA) and to the National Institute of Standards and Technology (NIST)

  19. A new parametrization for ambient particle formation over coniferous forests and its potential implications for the future

    Science.gov (United States)

    Bonn, B.; Boy, M.; Kulmala, M.; Groth, A.; Trawny, K.; Borchert, S.; Jacobi, S.

    2009-10-01

    Atmospheric new particle formation is a general phenomenon observed over coniferous forests. So far nucleation is either parameterised as a function of gaseous sulphuric acid concentration only, which is unable to explain the observed seasonality of nucleation events at different measurement sites, or as a function of sulphuric acid and organic molecules. Here we introduce different nucleation parameters based on the interaction of sulphuric acid and terpene oxidation products and elucidate the individual importance. They include basic trace gas and meteorological measurements such as ozone and water vapour concentrations, temperature (for terpene emission) and UV B radiation as a proxy for OH radical formation. We apply these new parameters to field studies conducted at conducted at Finnish and German measurement sites and compare these to nucleation observations on a daily and annual scale. General agreement was found, although the specific compounds responsible for the nucleation process remain speculative. This can be interpreted as follows: During cooler seasons the emission of biogenic terpenes and the OH availability limits the new particle formation while towards warmer seasons the ratio of ozone and water vapour concentration seems to dominate the general behaviour. Therefore, organics seem to support ambient nucleation besides sulphuric acid or an OH-related compound. Using these nucleation parameters to extrapolate the current conditions to prognosed future concentrations of ozone, water vapour and organic concentrations leads to a significant potential increase in the nucleation event number.

  20. Examining intra-urban variation in fine particle mass constituents using GIS and constrained factor analysis

    Science.gov (United States)

    Clougherty, Jane E.; Houseman, E. Andres; Levy, Jonathan I.

    Recent studies have used land use regression (LUR) techniques to explain spatial variability in exposures to PM 2.5 and traffic-related pollutants. Factor analysis has been used to determine source contributions to measured concentrations. Few studies have combined these methods, however, to construct and explain latent source effects. In this study, we derive latent source factors using confirmatory factor analysis constrained to non-negative loadings, and develop LUR models to predict the influence of outdoor sources on latent source factors using GIS-based measures of traffic and other local sources, central site monitoring data, and meteorology. We collected 3-4 day samples of nitrogen dioxide (NO 2) and PM 2.5 outside of 44 homes in summer and winter, from 2003 to 2005 in and around Boston, Massachusetts. Reflectance analysis, X-ray fluorescence spectroscopy (XRF), and high-resolution inductively-coupled plasma mass spectrometry (ICP-MS) were performed on particle filters to estimate elemental carbon (EC), trace element, and water-soluble metals concentrations. Within our constrained factor analysis, a five-factor model was optimal, balancing statistical robustness and physical interpretability. This model produced loadings indicating long-range transport, brake wear/traffic exhaust, diesel exhaust, fuel oil combustion, and resuspended road dust. LUR models largely corroborated factor interpretations through covariate significance. For example, 'long-range transport' was predicted by central site PM 2.5 and season; 'brake wear/traffic exhaust' and 'resuspended road dust' by traffic and residential density; 'diesel exhaust' by percent diesel traffic on nearest major road; and 'fuel oil combustion' by population density. Results suggest that outdoor residential PM 2.5 source contributions can be partially predicted using GIS-based terms, and that LUR techniques can support factor interpretation for source apportionment. Together, LUR and factor analysis

  1. Ambient new particle formation parameter indicates potential rise in future events

    Directory of Open Access Journals (Sweden)

    B. Bonn

    2009-01-01

    Full Text Available Atmospheric new particle formation is a general phenomenon observed over coniferous forests. So far nucleation is described as a function of gaseous sulfuric acid concentration only, which is unable to explain the observed seasonality of nucleation events at different measurement sites. Here we introduce a new nucleation parameter including ozone and water vapor concentrations as well as UV-B radiation as a proxy for OH radical formation. Applying this new parameter to field studies conducted at Finnish and German measurement sites it is found capable to predict the occurrence of nucleation events and their seasonal and annual variation indicating a significant role of organics. Extrapolation to possible future conditions of ozone, water vapor and organic concentrations leads to a significant potential increase in nucleation event number.

  2. Characterization of virus-like particles by atomic force microscopy in ambient conditions

    Science.gov (United States)

    Oropesa, Reinier; Ramos, Jorge R.; Falcón, Viviana; Felipe, Ariel

    2013-06-01

    Recombinant virus-like particles (VLPs) are attractive candidates for vaccine design since they resemble native viroids in size and morphology, but they are non-infectious due to the absence of a viral genome. The visualization of surface morphologies and structures can be used to deepen the understanding of physical, chemical, and biological phenomena. Atomic force microscopy (AFM) is a useful tool for the visualization of soft biological samples in a nanoscale resolution. In this work we have investigated the morphology of recombinant surface antigens of hepatitis B (rHBsAg) VLPs from Cuban vaccine against hepatitis B. The rHBsAg VLPs sizes estimated by AFM between 15 and 30 nm are similar to those reported on previous transmission electron microscopy (TEM) studies.

  3. Characterization of virus-like particles by atomic force microscopy in ambient conditions

    International Nuclear Information System (INIS)

    Recombinant virus-like particles (VLPs) are attractive candidates for vaccine design since they resemble native viroids in size and morphology, but they are non-infectious due to the absence of a viral genome. The visualization of surface morphologies and structures can be used to deepen the understanding of physical, chemical, and biological phenomena. Atomic force microscopy (AFM) is a useful tool for the visualization of soft biological samples in a nanoscale resolution. In this work we have investigated the morphology of recombinant surface antigens of hepatitis B (rHBsAg) VLPs from Cuban vaccine against hepatitis B. The rHBsAg VLPs sizes estimated by AFM between 15 and 30 nm are similar to those reported on previous transmission electron microscopy (TEM) studies. (paper)

  4. Optical properties of atmospheric fine particles near Beijing during the HOPE-J3A Campaign

    Science.gov (United States)

    Xu, X.; Zhao, W.; Zhang, Q.; Wang, S.; Fang, B.; Chen, W.; Venables, D. S.; Wang, X.; Pu, W.; Wang, X.; Gao, X.; Zhang, W.

    2015-11-01

    The optical properties and chemical composition of PM1.0 (particulate with an aerodynamic diameter of less than 1.0 μm) particles in a suburban environment (Huairou) near the mega-city Beijing were measured during the HOPE-J3A (Haze Observation Project Especially for Jing-Jin-Ji Area) field campaign. The campaign covered the period November 2014 to January 2015 during the winter coal heating season. The average and standard deviations for the extinction, scattering, absorption coefficients, and the aerosol single scattering albedo (SSA) at λ = 470 nm during the measurement period were 201 ± 240, 164 ± 202, 37 ± 43 Mm-1, and 0.80 ± 0.08, respectively. The mean mass scattering (MSE) and absorption (MAE) efficiencies were 4.77 ± 0.01 and 0.87 ± 0.03 m2g-1, respectively. Highly time-resolved air pollution episodes clearly show the dramatic evolution of the PM1.0 size distribution, extensive optical properties (extinction, scattering, and absorption coefficients) and intensive optical properties (single scattering albedo and complex refractive index) during haze formation, development and decline. Time periods were classified into three different pollution levels (clear, slightly polluted, and polluted) for further analysis. It was found that: (1) The diurnal patterns of the aerosol extinction, scattering, absorption coefficients, and SSA differed for the three pollution classes. (2) The real and imaginary part of complex refractive index (CRI) increased, while the SSA decreased from clear to polluted days. (3) The relative contributions of organic and inorganic species to observed aerosol composition changed significantly from clear to polluted days: the organic mass fraction decreased (50 to 43 %) while the proportion of sulfates, nitrates, and ammonium increased strongly (34 to 44 %). (4) The fractional contribution of chemical components to extinction coefficients was calculated by using the modified IMPROVE algorithm. Organic mass was the largest

  5. Public health risks of prolonged fine particle events associated with stagnation and air quality index based on fine particle matter with a diameter <2.5 μm in the Kaoping region of Taiwan

    Science.gov (United States)

    Lai, Li-Wei

    2016-04-01

    The increasing frequency of droughts in tropical and sub-tropical areas since 1970 due to climate change requires a better understanding of the relationship between public health and long-duration fine particle events (FPE; defined as a day with an average PM2.5 ≥ 35.5 μg/m3) associated with rainfall and wind speed. In the Kaoping region of Taiwan, 94.46 % of the daily average PM2.5 in winter exceeds the limit established by 2005 World Health Organization (WHO) guidelines. This study investigated the differences in winter weather characteristics and health effects between non-FPE and FPE days, and the performance of air quality indexes on FPE days. Z-statistics for one-tailed tests, multiplicative decomposition models, logarithmic regression, and product-moment correlations were used for the analysis. The results indicate that mean wind speeds, rainfall hours, and air temperature were significantly decreased on FPE days. Daily mean PM2.5 concentrations were positively correlated to the duration of FPE days. The duration of FPE days was positively related to the length of drought (r = 0.97, P 15 years experienced the largest average reduction in asthma admissions on lag-days. Compared to the pollutant standard index (PSI) and revised air quality index (RAQI), the PM2.5 index is more representative and sensitive to changes in PM2.5 concentrations.

  6. Ambient gas/particle partitioning. 3. Estimating partition coefficients of apolar, polar, and ionizable organic compounds by their molecular structure.

    Science.gov (United States)

    Arp, Hans Peter H; Gosses, Kai-Uwe

    2009-03-15

    Equilibrium gas/particle partitioning coefficients of terrestrial aerosols, Kip, are dependent on various intermolecular interactions that can be quantified by experimentally determined compound-specific descriptors. For many compounds of environmental interest, such as emerging contaminants and atmospheric phototransformation products, these compound-specific descriptors are unknown or immeasurable. Often, only the molecular structure is known. Here we present the ability of two computer programs to predict equilibrium partitioning to terrestrial aerosols solely on the basis of molecular structure: COSMOtherm and SPARC. The greatest hurdle with designing such an approach is to identify suitable molecular surrogates to represent the dominating sorbing phases, which for ambient terrestrial aerosols are the water insoluble organic matter (WIOM) phase and the mixed-aqueous phase. For the WI0M phase, hypothetical urban secondary organic aerosol structural units from Kalberer et al. Science 2004, 303, 1659-1662 were investigated as input surrogates, and for the mixed-aqueous phase mildly acidic water was used as a surrogate. Using a validation data set of more than 1400 experimentally determined Kip values for polar, apolar, and ionic compounds ranging over 9 orders of magnitude (including semivolatile compounds such as PCDD/Fs, pesticides, and PBDEs), SPARC and COSMOtherm were generally able to predict Kip values well within an order of magnitude over an ambient range of temperature and relative humidity. This is remarkable as these two models were not fitted or calibrated to any experimental data. As these models can be used for potentially any organic molecule, they are particularly recommended for environmental screening purposes and for use when experimental compound descriptor data are not available. PMID:19368193

  7. Fine particle exposure of prescribed fire workers in the Southeastern United States and a comparison of several particulate matter sampling methods.

    Energy Technology Data Exchange (ETDEWEB)

    Yanosky, Jeffrey, David

    2001-07-01

    Personal exposure concentrations of particles with aerodynamic diameter <2.5 μm (PM2.5) of prescribed fire workers were measured at two locations in the southeastern United States. Non-impacted ambient concentrations were measured as an estimate of background concentrations during burn activities. Four sampling method comparison studies were designed and performed to compare the FRM with 1) other gravimetric PM2.5 sampling methods in ambient air, 2) optical PM2.5 sampling methods in indoor air, 3) an optical sampling method (Grimm) for particles with aerodynamic diameter <10 μm (PM10) in ambient air, and 4) a gravimetric PM2.5 sampling method downwind of prescribed fires. The gravimetric PM2.5 sampling methods agreed well in ambient air (R2>0.96 for all) except for the MiniVol, the optical PM2.5 sampling methods agree less well in indoor air,(R2>0.592), the Grimm optical PM10 method agrees well in ambient air(R2>0.944 for all), and the personal method agrees well (n=9, R2=0.994) downwind of prescribed fires.

  8. EFFECTS OF EXPOSURE TO CONCENTRATED AMBIENT PARTICLES FROM DETROIT AIR ON HEALTHY RATS AND RATS WITH FEATURES OF ASTHMA OR MILD BRONCHITIS

    Science.gov (United States)

    Investigators will conduct  a 2-year study with rats to evaluate the short-term effects of inhaling concentrated ambient particles derived from the air in an area of Detroit, Michigan that has a high incidence of childhood asthma. The investigators will use two animal ...

  9. In vitro and in vivo evaluation of the toxicities induced by metallic nickel nano and fine particles.

    Science.gov (United States)

    Magaye, Ruth; Gu, Yuanliang; Wang, Yafei; Su, Hong; Zhou, Qi; Mao, Guochuan; Shi, Hongbo; Yue, Xia; Zou, Baobo; Xu, Jin; Zhao, Jinshun

    2016-06-01

    Nickel nanoparticles (Ni NPs) have been applied in various fields along with the rapid development of nanotechnology. However, the potential adverse health effects of the Ni NPs are unclear. To investigate the cyto- and genotoxicity and compare the differences between the Ni NPs and the nickel fine particles (Ni FPs), Sprague-Dawley (SD) rats and A549 cells were treated with different doses of Ni NPs or FPs. Intra-tracheal instillation of Ni NPs and FPs caused acute toxicity in the lungs, liver and kidneys of the SD rats. Even though the histology of the lungs showed hyperplastic changes and the protein expression of HO-1 and Nrf2 detected by western blot showed lung burden overload, no significant increase was observed to the expression level of oncoprotein C-myc. The results from cell titer-Glo assay and comet assay indicated that Ni NPs were more potent in causing cell toxicity and genotoxicity in vitro than Ni FPs. In addition, Ni NPs increased the expression of C-myc in vitro, but these increases may not have been due to oxidative stress since no significant dose-dependent changes were seen in HO-1 and Nrf2 expressions. Although Ni NPs have the potential to cause DNA damage in A549 cells in vitro, the molecular mechanisms that led to these changes and their tumorigenic potential is still debatable. In short, Ni NPs were more potent in causing cell toxicity and genotoxicity in vitro than Ni FPs, and intra-tracheal instillation of Ni NPs and FPs caused toxicity in organs of the SD rats, while it showed similar to the effects for both particle types. These results suggested that both Ni NPs and FPs have the potential to be harmful to human health, and Ni NPs may have higher cyto- and genotoxic effects than Ni FPs under the same treatment dose. PMID:27010930

  10. Element determination of fine particles in environmental aerosols using PIXE; Determinacion elemental de paticulas finas en aerosoles ambientales usando PIXE

    Energy Technology Data Exchange (ETDEWEB)

    Garcia O, B. [ITT, 50000 Toluca (Mexico); Aldape U, F. [ININ, 52750 La Marquesa, Estado de Mexico (Mexico)]. e-mail: gaolivab@gmail.com

    2007-07-01

    The Mexico city is classified as one of the more populated cities of the world which presents a decrease in the air quality and that gives place to a severe problematic in atmospheric pollution. To cooperate in the solution of this problem it is necessary to carry out studies that allow a better knowledge of the atmosphere of the city. This study presents the results of a monitoring campaign of fine particle carried out from September 21 to December 12, 2001 in three sites of the Mexico City center area. The samples were collected every third day with a collector type unit of heaped filters (Gent). The analysis of these samples was carried out in the 2 MV accelerator of the National Institute of Nuclear Research (ININ) applying the PIXE technique and with this analysis its were identified in the samples approximately 15 elements in each one of the 3 sites and was calculated the concentration in that its were present. With these results a database was created and by means of it mathematical treatment the Enrichment factor (FE), the time series of each element and the multiple correlation matrix were evaluated. The obtained results showed that the Civil Registration site (Salto del Agua) it was the more polluted coinciding that to a bigger concentration of activities a bigger increase in the pollution is generated. (Author)

  11. The Physical and Chemical Properties of Fine Carbon Particles-Pinewood Resin Blends and Their Possible Utilization

    Directory of Open Access Journals (Sweden)

    Aviwe Melapi

    2015-01-01

    Full Text Available The application of biomass gasification technology is very important in the sense that it helps to relieve the dwindling supply of natural gas from fossil fuels, and the desired product of its gasification process is syngas. This syngas is a mixture of CO and H2; however, by-products such as char, tar, soot, ash, and condensates are also produced. This study, therefore, investigated selected by-products recovered from the gasification process of pinewood chips with specific reference to their potential application in other areas when used as blends. Three samples of the gasification by-products were obtained from a downdraft biomass gasifier system and were characterized in terms of chemical and physical properties. FTIR analysis confirmed similar spectra in all char-resin blends. For fine carbon particles- (soot- resin blends, almost the same functional groups as observed in char-resin blends appeared. In bomb calorimeter measurements, 70% resin/30% char blends gave highest calorific value, followed by 50% resin/50% soot blends with values of 35.23 MJ/kg and 34.75 MJ/kg consecutively. Provided these by-products meet certain criteria, they could be used in other areas such as varnishes, water purification, and wind turbine blades.

  12. Subway construction activity influence on polycyclic aromatic hydrocarbons in fine particles: Comparison with a background mountainous site

    Science.gov (United States)

    Kong, Shaofei; Li, Xuxu; Li, Qi; Yin, Yan; Li, Li; Chen, Kui; Liu, Dantong; Yuan, Liang; Pang, Xiaobing

    2015-07-01

    Intensive construction activities worsened the surrounding atmospheric environment in China. Eighteen polycyclic aromatic hydrocarbons (PAHs) in fine particles (PM2.5) were collected at a subway construction site (SC) of Nanjing and compared with a regional background mountainous site (BM) to examine the influence of anthropogenic activities on concentrations, sources and health risks of PAHs. Average PAH concentrations at SC were higher than BM at a factor of about 5.9. All PAH species at SC were higher than BM, with the SC/BM ratios ranging from 1.3 (NaP) to 10.3 (BaP). PAH profiles differed for the two sites. The SC site had higher mass fractions of PAHs from coal combustion and vehicle emission, while the BM site held higher mass percentages of PAHs from long-range transported wood combustion and industrial activities. Lower temperature at BM may lead to the higher mass percentages of low ring PAHs. Coal combustion, traffic emissions and biomass burning were the common sources for PAHs at both SC and BM. Construction workers were exposed to higher BaPeq concentrations, nearly ten times of the background site and their lifetime cancer risk reached to 0.6 per 1,000,000 exposed worker, owing to the influence of coal combustion, vehicle emission and industrial activities at the surroundings of SC.

  13. Activation of endothelial cells after exposure to ambient ultrafine particles: The role of NADPH oxidase

    International Nuclear Information System (INIS)

    Several studies have shown that ultrafine particles (UFPs) may pass from the lungs to the circulation because of their very small diameter, and induce lung oxidative stress with a resultant increase in lung epithelial permeability. The direct effects of UFPs on vascular endothelium remain unknown. We hypothesized that exposure to UFPs leads to endothelial cell O2·- generation via NADPH oxidase and results in activation of endothelial cells. Our results showed that UFPs, at a non-toxic dose, induced reactive oxygen species (ROS) generation in mouse pulmonary microvascular endothelial cells (MPMVEC) that was inhibited by pre-treatment with the ROS scavengers or inhibitors, but not with the mitochondrial inhibitor, rotenone. UFP-induced ROS generation in MPMVEC was abolished by p67phox siRNA transfection and UFPs did not cause ROS generation in MPMVEC isolated from gp91phox knock-out mice. UFP-induced ROS generation in endothelial cells was also determined in vivo by using a perfused lung model with imaging. Moreover, Western blot and immunofluorescence staining results showed that MPMVEC treated with UFPs resulted in the translocation of cytosolic proteins of NADPH oxidase, p47phox, p67phox and rac 1, to the plasma membrane. These results demonstrate that NADPH oxidase in the pulmonary endothelium is involved in ROS generation following exposure to UFPs. To investigate the activation of endothelial cells by UFP-induced oxidative stress, we determined the activation of the mitogen-activated protein kinases (MAPKs) in MPMVEC. Our results showed that exposure of MPMVEC to UFPs caused increased phosphorylation of p38 and ERK1/2 MAPKs that was blocked by pre-treatment with DPI or p67phox siRNA. Exposure of MPMVEC obtained from gp91phox knock-out mice to UFPs did not cause increased phosphorylation of p38 and ERK1/2 MAPKs. These findings confirm that UFPs can cause endothelial cells to generate ROS directly via activation of NADPH oxidase. UFP-induced ROS lead to

  14. Source apportionment of ambient particle number concentrations in central Los Angeles using positive matrix factorization (PMF)

    Science.gov (United States)

    Sowlat, Mohammad Hossein; Hasheminassab, Sina; Sioutas, Constantinos

    2016-04-01

    In this study, the positive matrix factorization (PMF) receptor model (version 5.0) was used to identify and quantify major sources contributing to particulate matter (PM) number concentrations, using PM number size distributions in the range of 13 nm to 10 µm combined with several auxiliary variables, including black carbon (BC), elemental and organic carbon (EC/OC), PM mass concentrations, gaseous pollutants, meteorological, and traffic counts data, collected for about 9 months between August 2014 and 2015 in central Los Angeles, CA. Several parameters, including particle number and volume size distribution profiles, profiles of auxiliary variables, contributions of different factors in different seasons to the total number concentrations, diurnal variations of each of the resolved factors in the cold and warm phases, weekday/weekend analysis for each of the resolved factors, and correlation between auxiliary variables and the relative contribution of each of the resolved factors, were used to identify PM sources. A six-factor solution was identified as the optimum for the aforementioned input data. The resolved factors comprised nucleation, traffic 1, traffic 2 (with a larger mode diameter than traffic 1 factor), urban background aerosol, secondary aerosol, and soil/road dust. Traffic sources (1 and 2) were the major contributor to PM number concentrations, collectively making up to above 60 % (60.8-68.4 %) of the total number concentrations during the study period. Their contribution was also significantly higher in the cold phase compared to the warm phase. Nucleation was another major factor significantly contributing to the total number concentrations (an overall contribution of 17 %, ranging from 11.7 to 24 %), with a larger contribution during the warm phase than in the cold phase. The other identified factors were urban background aerosol, secondary aerosol, and soil/road dust, with relative contributions of approximately 12 % (7.4-17.1), 2.1 % (1

  15. A twelve month study of PM2.5 and PM10 fine particle aerosol composition in the Sydney region using ion beam analysis techniques. Appendix 2

    International Nuclear Information System (INIS)

    The accelerator based ion beam (IBA) analysis techniques of PIXE, PIGME, PESA, and RBS have been used to characterise fine particles at selected sites in the Sydney region. The four techniques operating simultaneously provide elemental concentrations on 24 chemical species, including H, Q N, 0, F, Na, Al, Si, P, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Co, Cu, Ni, Zn, Br and Pb. The total mass and the elemental carbon by laser integrated plate techniques were also measured. A stacked filter system, built by the University of Gent, Belgium and supplied by the IAEA was used to provide fine particle data on PM2.5 and PM10 particles. While a cyclone sampler, built at ANSTO, Lucas Heights, was used to provide data on PM2.5 particles only. The two different types of units were operated along side each other for the whole of 1994 and the results compared. The use of the multi-elemental IBA techniques also allowed for some fine particle source fingerprinting to be performed. (author)

  16. Mixing state, composition, and sources of fine aerosol particles in the Qinghai-Tibetan Plateau and the influence of agricultural biomass burning

    Science.gov (United States)

    Li, W. J.; Chen, S. R.; Xu, Y. S.; Guo, X. C.; Sun, Y. L.; Yang, X. Y.; Wang, Z. F.; Zhao, X. D.; Chen, J. M.; Wang, W. X.

    2015-09-01

    Transmission electron microscopy (TEM) was employed to obtain morphology, size, composition, and mixing state of background fine particles with diameter less than 1 μm in the Qinghai-Tibetan Plateau (QTP) during 15 September to 15 October 2013. Individual aerosol particles mainly contained secondary inorganic aerosols (SIA-sulfate and nitrate) and organics during clean periods (PM2.5: particles less than 2.5 μg m-3). The presence of KCl-NaCl associated with organics and an increase of soot particles suggest that an intense biomass burning event caused the highest PM2.5 concentrations (> 30 μg m-3) during the study. A large number fraction of the fly ash-containing particles (21.73 %) suggests that coal combustion emissions in the QTP significantly contributed to air pollutants at the median pollution level (PM2.5: 10-30 μg m-3). We concluded that emissions from biomass burning and from coal combustion both constantly contribute to anthropogenic particles in the QTP atmosphere. Based on size distributions of individual particles in different pollution levels, we found that gas condensation on existing particles is an important chemical process for the formation of SIA with organic coating. TEM observations show that refractory aerosols (e.g., soot, fly ash, and visible organic particles) likely adhere to the surface of SIA particles larger than 200 nm due to coagulation. Organic coating and soot on surface of the aged particles likely influence their hygroscopic and optical properties in the QTP, respectively. To our knowledge, this study reports the first microscopic analysis of fine particles in the background QTP air.

  17. Real-time characterization of particle-bound polycyclic aromatic hydrocarbons in ambient aerosols and from motor-vehicle exhaust

    Directory of Open Access Journals (Sweden)

    A. Polidori

    2007-12-01

    Full Text Available A photo-electric aerosol sensor, a diffusion charger, an Aethalometer, and a continuous particle counter were used along with other real-time instruments to characterize the particle-bound polycyclic aromatic hydrocarbon (p-PAH content, and the physical/chemical characteristics of aerosols collected a in Wilmington (CA near the Los Angeles port and close to 2 major freeways, and b at a dynamometer testing facility in downtown Los Angeles (CA, where 3 diesel trucks were tested. In Wilmington, the p-PAH, surface area, particle number, and "black" carbon concentrations were 4–8 times higher at 09:00–11:00 a.m. than between 17:00 and 18:00 p.m., suggesting that during rush hour traffic people living in that area are exposed to a higher number of diesel combustion particles enriched in p-PAH coatings. Dynamometer tests revealed that the p-PAH emissions from the "baseline" truck (no catalytic converted were up to 200 times higher than those from the 2 vehicles equipped with advanced emission control technologies, and increased when the truck was accelerating. In Wilmington, integrated filter samples were collected and analyzed to determine the concentrations of the most abundant p-PAHs. A correlation between the total p-PAH concentration (μg/m3 and the measured photo-electric aerosol sensor signal (fA was also established. Estimated ambient p-PAH concentrations (Average = 0.64 ng/m3; Standard deviation = 0.46 ng/m3 were in good agreement with those reported in previous studies conducted in Los Angeles during a similar time period. Finally, we calculated the approximate theoretical lifetime (70 years per 24-h/day lung-cancer risk in the Wilmington area due to inhalation of multi-component p-PAHs and "black" carbon. Our results indicate that the lung-cancer risk is highest during rush hour traffic and lowest in the afternoon, and that the genotoxic risk of the considered p-PAHs does not seem to contribute to a

  18. Ambient air particle transport into the effluent of a cold atmospheric-pressure argon plasma jet investigated by molecular beam mass spectrometry

    International Nuclear Information System (INIS)

    Ambient air species, which are transported into the active effluent of an atmospheric-pressure plasma jet result in highly reactive oxygen and nitrogen species (RONS). Especially for the envisaged application field of plasma medicine, these RONS are responsible for strong biological responses. In this work, the effect of ambient air transport into the effluent of an atmospheric-pressure plasma argon jet on the on-axis densities of nitrogen, oxygen and argon was investigated by means of absolutely calibrated molecular beam mass spectrometry (MBMS). According to biomedical experiments a (bottomless) Petri dish was installed in front of the MBMS. In the following, the near flow field is referring to the region close to the nozzle exit and the far flow field is referring to the region beyond that. The absolute on-axis densities were obtained by three different methods, for the near flow field with VUV-absorption technique, for the far flow field with the MBMS and the total flow field was calculated with a computational fluid dynamics (CFD) simulation. The results of the ambient air particle densities of all independent methods were compared and showed an excellent agreement. Therefore the transport processes of ambient air species can be measured for the whole effluent of an atmospheric-pressure plasma jet. Additionally, with the validation of the simulation it is possible in future to calculate the ambient species transport for various gas fluxes in the same turbulent flow regime. Comparing the on-axis densities obtained with an ignited and with a non-ignited plasma jet shows that for the investigated parameters, the main influence on the ambient air species transport is due to the increased temperature in the case when the jet is switched on. Moreover, the presence of positive ions (e.g. ArN2+) formed due to the interaction of plasma-produced particles and ambient air species, which are transported into the effluent, is shown. (paper)

  19. Characteristics of particle number and mass emissions during heavy-duty diesel truck parked active DPF regeneration in an ambient air dilution tunnel

    Science.gov (United States)

    Yoon, Seungju; Quiros, David C.; Dwyer, Harry A.; Collins, John F.; Burnitzki, Mark; Chernich, Donald; Herner, Jorn D.

    2015-12-01

    Diesel particle number and mass emissions were measured during parked active regeneration of diesel particulate filters (DPF) in two heavy-duty diesel trucks: one equipped with a DPF and one equipped with a DPF + SCR (selective catalytic reduction), and compliant with the 2007 and 2010 emission standards, respectively. The emission measurements were conducted using an ambient air dilution tunnel. During parked active regeneration, particulate matter (PM) mass emissions measured from a 2007 technology truck were significantly higher than the emissions from a 2010 technology truck. Particle number emissions from both trucks were dominated by nucleation mode particles having a diameter less than 50 nm; nucleation mode particles were orders of magnitude higher than accumulation mode particles having a diameter greater than 50 nm. Accumulation mode particles contributed 77.8 %-95.8 % of the 2007 truck PM mass, but only 7.3 %-28.2 % of the 2010 truck PM mass.

  20. Ozone and fine particle in the western Yangtze River Delta: an overview of 1-yr data at the SORPES station

    Directory of Open Access Journals (Sweden)

    A. J. Ding

    2013-01-01

    Full Text Available This work presents an overview of 1-yr measurements of ozone (O3 and fine particular matter (PM2.5 and related trace gases at a recently developed regional background site, the Station for Observing Regional Processes of the Earth System (SORPES, in the western part of the Yangtze River Delta (YRD in East China. O3 and PM2.5 showed distinguished seasonal cycles but with contrast patterns: O3 reached a maximum in warm seasons but PM2.5 in cold seasons. Correlation analysis suggests a VOC-sensitive regime for O3 chemistry and also indicates a substantial formation of secondary aerosols under conditions of high O3 in summer. Compared with the National Ambient Air Quality Standards in China, our measurements report 15 days of O3 exceedance and 148 days of PM2.5 exceedance during the 1-yr period, suggesting a severe air pollution situation in this region. Case studies for typical O3 and PM2.5 episodes demonstrated that these episodes were generally associated with an air mass transport pathway over the mid-YRD, i.e. along the Nanjing-Shanghai axis with its city clusters, and showed that synoptic weather played an important role in air pollution, especially for O3. Agricultural burning activities caused high PM2.5 and O3 pollution during harvest seasons, especially in June. A calculation of potential source contributions based on Lagrangian dispersion simulations suggests that emissions from the YRD contributed to over 70% of the O3 precursor CO, with a majority from the middle-YRD. North-YRD and the North China Plain are the main contributors to PM2.5 pollution in this region, especially for the burning episode days. This work shows an important environmental impact from industrialization and urbanization in the YRD region, and suggests an urgent need for improving

  1. Acute pulmonary and systemic effects of inhaled coal fly ash in rats: Comparison to ambient environmental particles

    Energy Technology Data Exchange (ETDEWEB)

    Smith, K.R.; Veranth, J.M.; Kodavanti, U.P.; Aust, A.E.; Pinkerton, K.E. [University of California-Davis, Davis, CA (United States). Center of Health & Environmental

    2006-10-15

    The effect of coal fly ash (CFA) on pulmonary and systemic inflammation and injury was measured in male Sprague-Dawley rats exposed to filtered air or CFA for 4 h/day for 3 days. The average concentration of CFA particulate matter less than 2.5 {mu}m (PM2.5) was 1400 {mu} g/m{sup 3}, of which 600 {mu} g/m{sup 3} was PM1. Animals were examined 18 and 36 h postexposure. Chemical analysis of CFA detected silicon, calcium, aluminum, and iron as major components. Total number of neutrophils in bronchoalveolar lavage fluid (BALF) following exposure to CFA was significantly increased along with significantly elevated blood neutrophils. Exposure to CFA caused slight increases in macrophage inflammatory protein-2, and marked increases in transferrin in BALF. Interleukin-1 beta and total antioxidant potential in lung tissues were also increased in rats exposed to CFA. Histological examination of lung tissue demonstrated focal alveolar septal thickening and increased cellularity in select alveoli immediately beyond terminal bronchioles. These responses are consistent with the ability of CFA to induce mild neutrophilic inflammation in the lung and blood following short-term exposure at levels that could be occupationally relevant. However, when comparing the effects of CFA with those of concentrated ambient particles, CFA does not appear to have greater potency to cause pulmonary alterations.

  2. Volume reduction on all particle size of the contaminated soil. Continuous processing technology of attrition, chemical wash under an ambient temperature and pressure condition and magnetic separation

    International Nuclear Information System (INIS)

    An examination was conducted in order to establish a practical purification system that could largely reduce the storage volume of radioactive waste in the Intermediate Storage Facility. The examination consists of a 3-step washing treatment of contaminated soil, which includes “Milling Washing” of removed contaminated soil, chemical extraction of fine soil fraction resulted from the “Milling Washing” under an ambient temperature and pressure condition, and magnetic separation of cesium from the extracted solution. As a result of the examination, we succeeded in development of a safe system with low initial cost and running cost. (author)

  3. Monitoring of Pollution of Air Fine Particles (PM2.5) and Study on Their Genetic Toxicity

    Institute of Scientific and Technical Information of China (English)

    DONG-QUN XU; WEN-LI ZHANG

    2004-01-01

    To compare PM2.5 pollation level between the city of coal-fuel pollution (Taiyuan) and the city of pollution mixed with coal fuels and vehicle exhausts (Beijing), to analyze the concentration of B[a]p and Pb in the pollutants, and to study the DNA damage by PM2.5. Methods Air fine particles (PM2.5) were collected in Beijing and Taiyuan by means of the filter membrane method, the concentration of B[a]p and Pb were analyzed by high performance liquid chromatography and atomic absorption spectroscopy respectveily, and the damage of DNA by PM2.5 was detected by single cell gel-electrophoresis (SCGE) using the human lung epithelial cells (A549) as target cells. Results The concentration of PM2.5 in the winter of Beijing was 0.028-0.436 mg/m3, and that in Taiyuan was 0.132-0.681 mg/m3. The concentration of B[a]p was 0.104 and 0.156 μg/mg on PM2.5 of Beijing and Taiyuan, respectively, whereas the concentration of Pb was 1.094 and 1.137 μg/mg on PM2.5 of Beijing and Taiyuan, respectively. Exposure to PM2.5 at the concentrations of 5, 50, and 200 μg/mL for 12 h and 24 h caused DNA damage of the human alveolar epithelium, and the ratios of the tailing and length of the tail were all significantly different from those of the negative control group (P<0.05), and indicated a dose-response relationship. Conclusion PM2.5 has certain genetic toxicity.

  4. Ultrafine particle and fine trace metal (As, Cd, Cu, Pb and Zn) pollution episodes induced by industrial emissions in Huelva, SW Spain

    Science.gov (United States)

    Fernández-Camacho, R.; Rodríguez, S.; de la Rosa, J.; Sánchez de la Campa, A. M.; Alastuey, A.; Querol, X.; González-Castanedo, Y.; Garcia-Orellana, I.; Nava, S.

    2012-12-01

    Urban air quality impairment by ultrafine particles has become a matter of concern due to the adverse effects on human health. Most of the studies of ultrafine particles in urban air quality have focused on vehicle exhaust emissions. We studied how industrial emissions contribute to ultrafine particle concentrations in downwind urban ambient air. This research is based on experimental data collected in the ambient air of the industrial city of Huelva (SW Spain) over April 2008-December 2009 period (particle number, gaseous pollutants and black carbon concentrations and levels and chemical composition of PM10 and PM2.5 with daily and hourly resolution). This city is affected by emissions from the second largest Cu-smelter in Europe, phosphoric acid and fertilizer production plants and an oil refinery and petrochemical plant. Industrial emissions are the main cause of ultrafine particle episodes. When vehicle exhaust emissions are the main source, ultrafine particles typically show (24-h mean) concentrations within the range 14,700-5000 cm-3 (50th-1st), with 60% of these linked to this source and 30% to industrial emissions. In contrast, when daily mean levels of N are within the range 50,000-25,500 cm-3 (100th-70th), industrial and vehicle exhaust emissions accounted for 49 and 30%, respectively. High concentrations of toxic trace metals (As, Cu, Cd, Zn and Pb) were recorded when the study city suffered fumigations of the Cu-smelter plumes (e.g. 10-25 ng m-3 As, 1-2 ng m-3 Cd and >105 cm-3 of ultrafine particles). Because of these industrial emissions, ultrafine particle concentrations during daylight are about two times higher than those observed in other European cities. Recently, ultrafine particle emissions in vehicle exhausts have been subject to limit values in a recent stage of the EURO standards. Industrial emissions should also be considered.

  5. A land use regression model for ambient ultrafine particles in Montreal, Canada: A comparison of linear regression and a machine learning approach.

    Science.gov (United States)

    Weichenthal, Scott; Ryswyk, Keith Van; Goldstein, Alon; Bagg, Scott; Shekkarizfard, Maryam; Hatzopoulou, Marianne

    2016-04-01

    Existing evidence suggests that ambient ultrafine particles (UFPs) (mobile monitoring data collected from 414 road segments during the summer and winter months between 2011 and 2012. Two different approaches were examined for model development including standard multivariable linear regression and a machine learning approach (kernel-based regularized least squares (KRLS)) that learns the functional form of covariate impacts on ambient UFP concentrations from the data. The final models included parameters for population density, ambient temperature and wind speed, land use parameters (park space and open space), length of local roads and rail, and estimated annual average NOx emissions from traffic. The final multivariable linear regression model explained 62% of the spatial variation in ambient UFP concentrations whereas the KRLS model explained 79% of the variance. The KRLS model performed slightly better than the linear regression model when evaluated using an external dataset (R(2)=0.58 vs. 0.55) or a cross-validation procedure (R(2)=0.67 vs. 0.60). In general, our findings suggest that the KRLS approach may offer modest improvements in predictive performance compared to standard multivariable linear regression models used to estimate spatial variations in ambient UFPs. However, differences in predictive performance were not statistically significant when evaluated using the cross-validation procedure. PMID:26720396

  6. Formation of nitro-PAHs from the heterogeneous reaction of ambient particle-bound PAHs with NO3/N2O5

    Science.gov (United States)

    Zimmermann, K.; Jariyasopit, N.; Simonich, S. L.; Atkinson, R.; Arey, J.

    2012-12-01

    Polycyclic aromatic hydrocarbons (PAHs) and their nitrated derivatives (nitro-PAHs) have been shown to be mutagenic in bacterial and mammalian assays and are classified as probable human carcinogens. Semi-volatile PAHs partition between the gas and particulate phases, depending on their liquid-phase vapor pressures and ambient temperatures. These PAHs have been extensively measured in ambient particulate matter and can ultimately undergo long-range transport from source regions (e.g., China to the western USA) (1). During transport these particle-bound PAHs may undergo reaction with NO3/N2O5 to form nitro-PAH derivatives. Previous studies of heterogeneous nitration of PAHs have used particles composed of graphite, diesel soot, and wood smoke (2-4). This study investigates the heterogeneous formation of nitro-PAHs from ambient particle-bound PAHs from Beijing, China and sites located within the Los Angeles air basin. These ambient particle samples, along with filters coated with isotopically labeled PAHs, were exposed to a mix of NO2/NO3/N2O5 in a 7000 L Teflon chamber, with analysis focused on the heterogeneous formation of molecular weight 247 and 273 nitro-PAHs. The heterogeneous formation of certain nitro-PAHs (including1-nitropyrene and 1- and 2-nitrotriphenylene) was observed for some, but not all, ambient samples. Formation of nitro-PAHs typically formed through gas-phase reactions (2-nitrofluoranthene and 2-nitropyrene) was not observed. The effect of particle age and local photochemical conditions during sampling on the degree of nitration in environmental chamber reactions, as well as ambient implications, will be presented. 1. Primbs, T.; Simonich, S.; Schmedding, D.; Wilson, G.; Jaffe, D.; Takami, A.; Kato, S.; Hatakeyama, S.; Kajii, Y. Environ. Sci. Technol. 2007, 41, 3551-3558. 2. Esteve, W.; Budzinski, H.; Villenave, E. Atmospheric Environment 2004, 38, 6063-6072. 3. Nguyen, M.; Bedjanian, Y.; Guilloteau, A. Journal of Atmospheric Chemistry 2009, 62

  7. Effects of coarse grain size distribution and fine particle content on pore fluid pressure and shear behavior in experimental debris flows

    Science.gov (United States)

    Kaitna, Roland; Palucis, Marisa C.; Yohannes, Bereket; Hill, Kimberly M.; Dietrich, William E.

    2016-02-01

    Debris flows are typically a saturated mixture of poorly sorted particles and interstitial fluid, whose density and flow properties depend strongly on the presence of suspended fine sediment. Recent research suggests that grain size distribution (GSD) influences excess pore pressures (i.e., pressure in excess of predicted hydrostatic pressure), which in turn plays a governing role in debris flow behaviors. We report a series of controlled laboratory experiments in a 4 m diameter vertically rotating drum where the coarse particle size distribution and the content of fine particles were varied independently. We measured basal pore fluid pressures, pore fluid pressure profiles (using novel sensor probes), velocity profiles, and longitudinal profiles of the flow height. Excess pore fluid pressure was significant for mixtures with high fines fraction. Such flows exhibited lower values for their bulk flow resistance (as measured by surface slope of the flow), had damped fluctuations of normalized fluid pressure and normal stress, and had velocity profiles where the shear was concentrated at the base of the flow. These effects were most pronounced in flows with a wide coarse GSD distribution. Sustained excess fluid pressure occurred during flow and after cessation of motion. Various mechanisms may cause dilation and contraction of the flows, and we propose that the sustained excess fluid pressures during flow and once the flow has stopped may arise from hindered particle settling and yield strength of the fluid, resulting in transfer of particle weight to the fluid. Thus, debris flow behavior may be strongly influenced by sustained excess fluid pressures controlled by particle settling rates.

  8. Effect of the constituents (asphalt, clay materials, floating particles and fines) of construction and demolition waste on the properties of recycled concretes

    OpenAIRE

    Medina Martínez, César; Zhu, W; Howind, T.; Frías Rojas, Moisés; Sánchez de Rojas, María Isabel

    2015-01-01

    The present study explores the viability of reusing mixed recycled aggregate from construction and demolition waste as a partial (25 and 50 wt%) replacement for natural coarse aggregate in the manufacture of concretes with a compressive strength of 30 MPa. It further analyses the effect of some of the constituents (asphalt, clay-based materials, floating particles and fines) of these recycled aggregates on the properties of recycled concretes. Despite the high asphalt and floating...

  9. Laboratory and modeling studies on the effects of water and soot emissions and ambient conditions on the formation of contrail ice particles in the jet regime

    Directory of Open Access Journals (Sweden)

    H.-W. Wong

    2011-09-01

    Full Text Available Contrails and contrail-induced cirrus clouds are identified as the most uncertain components in determining aviation impacts on global climate change. Parameters affecting contrail ice particle formation immediately after engine exit plane (<5 s in plume age may be critical to ice particle properties used in large scale models predicting contrail radiative forcing. Despite this, detailed understanding of these parametric effects is still limited. In this paper, we present results from recent laboratory and modeling studies conducted to investigate the effects of water and soot emissions and ambient conditions on the near-field formation of contrail ice particles. The Particle Aerosol Laboratory (PAL at the NASA Glenn Research Center and the Aerodyne microphysical parcel model for contrail ice particle formation were employed. Our studies show that exhaust water concentrations have a significant impact on contrail ice particle formation. When soot was introduced, ice particle formation was observed only when exhaust water concentration was above a critical level. When no soot or sulfuric acid was introduced, homogeneous ice particle formation was unfavorable. Soot particles were found to compete for water vapor condensation, and higher soot concentrations emitted into the chamber resulted in smaller ice particles being formed. Chamber conditions corresponding to higher altitude standard day conditions were found to favor ice particle formation as expected. The microphysical model captures experimental trends well, but discrepancies between the model and the experiments exist as the model predicts narrower ice particle size distributions and ice particle sizes nearly a factor of two larger than measured. These discrepancies are likely due to the lack of treatment of turbulent mixing in the model and particle loss and scatter during the experimental sampling process. Future measurement activities are planned to investigate other important

  10. Quality factors, ambient and personal dose equivalent for neutrons, based on the new ICRU stopping power data for protons and alpha particles

    International Nuclear Information System (INIS)

    Quality factors and fluence-to-ambient and fluence-to personal-dose equivalent conversion factors for neutrons have been recalculated for neutrons with energies ranging from thermal to 20 MeV. The new calculations are based on the recommendations given in ICRU Publication 60 for the quality factor and on stopping power data for protons and alpha particles as recommended in the ICRU report 49. (author)

  11. The Effect of the Second Phase Particle Size on Fracture Behavior of Cu - 0.1% Sn Ultra-Fine-Grained Alloy

    Science.gov (United States)

    Faizova, S. N.; Raab, G. I.; Faizov, I. A.; Aksenov, D. A.; Zaripov, N. G.; Faizov, R. A.; Semenov, V. I.; Zemlyakova, N. V.

    2016-05-01

    The fracture behavior of Cu - 0.1% Sn alloy in samples of two types, namely with similar characteristics of ultra-fine-grained structure, but different in the second phase particle size has been investigated. These two types of samples were obtained by means of equal channel angular pressing with different number of passes. It has been found that with increase in the total strain the morphology and orientation of the fracture surface demonstrate changes corresponding to the development of shear mode. The arguments for the hypothesis that the fracture behavior change is connected with the decrease of the particle size and increase of their distribution density are given.

  12. Two- and three-particle states in a nonrelativistic four-fermion model in the fine-tuning renormalization scheme: Goldstone mode versus extension theory

    International Nuclear Information System (INIS)

    In a nonrelativistic contact four-fermion model we show that simple regularization prescriptions together with a definite fine-tuning of the cut-off parameter dependence of 'bare' quantities give the exact solutions for the two-particle sector and Goldstone modes. Their correspondence with the self-adjoint extension into Pontryagin space is established leading to self-adjoint semi-bounded Hamiltonians in three-particle sectors as well. Renormalized Faddeev equations for the bound states with Fredholm properties are obtained and analyzed. (author)

  13. Laboratory and modeling studies on the effects of water and soot emissions and ambient conditions on the properties of contrail ice particles in the jet regime

    Directory of Open Access Journals (Sweden)

    H.-W. Wong

    2013-10-01

    Full Text Available Contrails and contrail-induced cirrus clouds are identified as the most uncertain components in determining aviation impacts on global climate change. Parameters affecting contrail ice particle formation immediately after the engine exit plane (< 5 s in plume age may be critical to ice particle properties used in large-scale models predicting contrail radiative forcing. Despite this, detailed understanding of these parametric effects is still limited. In this paper, we present results from recent laboratory and modeling studies conducted to investigate the effects of water and soot emissions and ambient conditions on near-field formation of contrail ice particles and ice particle properties. The Particle Aerosol Laboratory (PAL at the NASA Glenn Research Center and the Aerodyne microphysical parcel model for contrail ice particle formation were employed. Our studies show that exhaust water concentration has a significant impact on contrail ice particle formation and properties. When soot particles were introduced, ice particle formation was observed only when exhaust water concentration was above a critical level. When no soot or sulfuric acid was introduced, no ice particle formation was observed, suggesting that ice particle formation from homogeneous nucleation followed by homogeneous freezing of liquid water was unfavorable. Soot particles were found to compete for water vapor condensation, and higher soot concentrations emitted into the chamber resulted in smaller ice particles being formed. Chamber conditions corresponding to higher cruising altitudes were found to favor ice particle formation. The microphysical model captures trends of particle extinction measurements well, but discrepancies between the model and the optical particle counter measurements exist as the model predicts narrower ice particle size distributions and ice particle sizes nearly a factor of two larger than measured. These discrepancies are likely due to particle

  14. Laboratory and modeling studies on the effects of water and soot emissions and ambient conditions on the properties of contrail ice particles in the jet regime

    Science.gov (United States)

    Wong, H.-W.; Beyersdorf, A. J.; Heath, C. M.; Ziemba, L. D.; Winstead, E. L.; Thornhill, K. L.; Tacina, K. M.; Ross, R. C.; Albo, S. E.; Bulzan, D. L.; Anderson, B. E.; Miake-Lye, R. C.

    2013-10-01

    Contrails and contrail-induced cirrus clouds are identified as the most uncertain components in determining aviation impacts on global climate change. Parameters affecting contrail ice particle formation immediately after the engine exit plane (< 5 s in plume age) may be critical to ice particle properties used in large-scale models predicting contrail radiative forcing. Despite this, detailed understanding of these parametric effects is still limited. In this paper, we present results from recent laboratory and modeling studies conducted to investigate the effects of water and soot emissions and ambient conditions on near-field formation of contrail ice particles and ice particle properties. The Particle Aerosol Laboratory (PAL) at the NASA Glenn Research Center and the Aerodyne microphysical parcel model for contrail ice particle formation were employed. Our studies show that exhaust water concentration has a significant impact on contrail ice particle formation and properties. When soot particles were introduced, ice particle formation was observed only when exhaust water concentration was above a critical level. When no soot or sulfuric acid was introduced, no ice particle formation was observed, suggesting that ice particle formation from homogeneous nucleation followed by homogeneous freezing of liquid water was unfavorable. Soot particles were found to compete for water vapor condensation, and higher soot concentrations emitted into the chamber resulted in smaller ice particles being formed. Chamber conditions corresponding to higher cruising altitudes were found to favor ice particle formation. The microphysical model captures trends of particle extinction measurements well, but discrepancies between the model and the optical particle counter measurements exist as the model predicts narrower ice particle size distributions and ice particle sizes nearly a factor of two larger than measured. These discrepancies are likely due to particle loss and scatter

  15. Detection of the density of fine particulate matter employing laser beam divergence and inertia-dependent particle motion

    Science.gov (United States)

    Schrobenhauser, R.; Strzoda, R.; Hartmann, A.; Fleischer, M.; Amann, M.-C.

    2014-10-01

    We present a miniaturized sensor setup capable of determining the density of airborne particles employing size information provided by an enhanced light-scattering intensity ratio technique and inertia-dependent particle motion. The method is based on the particle density-dependent spatial particle spreading, measured as the time of flight using a divergent laser beam. Measurement results using polystyrene latex and silica particles in a size range of 500-1,600 nm show good agreement with theoretical estimations.

  16. SPLAT II: An Ultra-Sensitive, High Precision Instrument for the In-Situ Characterization of the Size, Composition, Density, Shape, Hygroscopicity, and Fractal Dimension of Fine and Ultrafine Particle

    Science.gov (United States)

    Zelenyuk, A.; Yang, J.; Imre, D.

    2007-12-01

    Single particle mass spectrometers (SPMS) have been developed and deployed to characterize, in real-time the size and chemical compositions of individual ambient particles. SPMS have undeniably proven to be extremely valuable, improving our understanding of the properties and evolution of atmospheric aerosols. At the same time these instruments have also persistently been subject to criticism on a number of fronts. Recently we have completed the construction of our second generation single particle mass spectrometer - SPLAT II, in which we have made significant improvements that directly address the shortcomings that are often associated with SPMS. We will present the results of instrument characterization experiments demonstrating that considerable improvements in instrument performance have been accomplished. SPLAT II offers significantly improved detection sensitivity of small particles, such that 30% of all 100 nm particles that enter the instrument are detected and characterized. This represents an improvement of nearly 2 orders of magnitude over the previous instrument. The efficiency of detection of particles larger than 150 nm is 100%. SPLAT II can measure and record the vacuum aerodynamic diameters of up to 300 particles per second and record 100 individual particle mass spectra per second - an increase of a factor of 10 in temporal resolution over the previous instrument. SPLAT II uses an IR laser to evaporate the semivolatile fraction of the particle and a time delayed UV laser to generate ions. The IR and UV lasers are configured to assure that the individual particle mass spectra represent the complete composition of each particle. The semivolatile fraction is ionized in the gas phase, while the nonvolatile fraction is concurrently ablated. This approach yields extremely reproducible, high quality mass spectral signatures while providing complete particle characterization. The two step - IR/UV - approach is particularly suitable for the

  17. Water-soluble ions in nano/ultrafine/fine/coarse particles collected near a busy road and at a rural site

    International Nuclear Information System (INIS)

    This study investigated water-soluble ions in the sized particles (particularly nano (PM0.01-0.056)/ultrafine (PM0.01-0.1)) collected using MOUDI and Nano-MOUDI samplers near a busy road site and at a rural site. The analytical results demonstrate that nano and coarse particles exhibited the highest (16.3%) and lowest (8.37%) nitrate mass ratios, respectively. The mass ratio of NO3- was higher than that of SO42- in all the sized particles at the traffic site. The secondary aerosols all displayed trimodal distributions. The aerosols in ultrafine particles collected at the roadside site exhibited Aitken mode distributions indicating they were of local origin. This finding was not observed for those ultrafine particles collected at the rural site. The mass median diameters (MMDs) of the nano, ultrafine, and fine particles were smaller at the traffic site than at the rural site, possibly related to the contribution of mobile engine emissions. - NO3- > SO42- in mass ratio, different from common observations in rural areas, was found in (particularly the nano) traffic-associated particles

  18. Impact of vehicular emissions on the formation of fine particles in the Sao Paulo Metropolitan Area: a numerical study with the WRF-Chem model

    Science.gov (United States)

    Vara-Vela, A.; Andrade, M. F.; Kumar, P.; Ynoue, R. Y.; Muñoz, A. G.

    2016-01-01

    The objective of this work is to evaluate the impact of vehicular emissions on the formation of fine particles (PM2.5; ≤ 2.5 µm in diameter) in the Sao Paulo Metropolitan Area (SPMA) in Brazil, where ethanol is used intensively as a fuel in road vehicles. The Weather Research and Forecasting with Chemistry (WRF-Chem) model, which simulates feedbacks between meteorological variables and chemical species, is used as a photochemical modelling tool to describe the physico-chemical processes leading to the evolution of number and mass size distribution of particles through gas-to-particle conversion. A vehicular emission model based on statistical information of vehicular activity is applied to simulate vehicular emissions over the studied area. The simulation has been performed for a 1-month period (7 August-6 September 2012) to cover the availability of experimental data from the NUANCE-SPS (Narrowing the Uncertainties on Aerosol and Climate Changes in Sao Paulo State) project that aims to characterize emissions of atmospheric aerosols in the SPMA. The availability of experimental measurements of atmospheric aerosols and the application of the WRF-Chem model made it possible to represent some of the most important properties of fine particles in the SPMA such as the mass size distribution and chemical composition, besides allowing us to evaluate its formation potential through the gas-to-particle conversion processes. Results show that the emission of primary gases, mostly from vehicles, led to a production of secondary particles between 20 and 30 % in relation to the total mass concentration of PM2.5 in the downtown SPMA. Each of PM2.5 and primary natural aerosol (dust and sea salt) contributed with 40-50 % of the total PM10 (i.e. those ≤ 10 µm in diameter) concentration. Over 40 % of the formation of fine particles, by mass, was due to the emission of hydrocarbons, mainly aromatics. Furthermore, an increase in the number of small particles impaired the

  19. Diurnal concentrations variations, size distributions for ambient air particles and metallic pollutants (Cr, Mn, Ni, Cd, Pb) during summer season at a traffic area.

    Science.gov (United States)

    Fang, Guor-Cheng; Kuo, Yu-Chen; Zhuang, Yuan-Jie; Chen, Yu-Cheng

    2014-07-01

    This study characterized and discussed particulate ambient air particulate concentrations and seasonal variations for PM18, PM10, PM2.5, and PM1 during June 2013-July 2013 at this traffic sampling site. In addition, this study also characterized the ambient air particulates size distributions by using MOUDI-100S4 sampler to collect 1-day the ambient suspended particles (PM18, PM10, PM2.5, and PM1) at this sampling site. In addition, the study also showed that the main pollutants contributions were from traffic and residual areas. As for the pollutants seasonal concentrations variations, the results indicated that the average particle concentrations orders were all displayed as daytime > nighttime for PM18, PM10, PM2.5 and PM1 at this characteristic sampling site. The results further indicated that the mean highest of metal concentrations in this study indicated that the average metal concentration were all displayed as Mn > Cr > Ni > Pb > Cd for PM18, PM10, PM2.5 and PM1 on daytime and nighttime at this characteristic sampling site. PMID:24619364

  20. Co-formation of hydroperoxides and ultra-fine particles during the reactions of ozone with a complex VOC mixture under simulated indoor conditions

    DEFF Research Database (Denmark)

    Fan, Z.H.; Weschler, Charles J.; Han, IK;

    2005-01-01

    ) under simulated indoor conditions. The VOC mixture contained 23 compounds, including two terpenes (d-limonene and alpha-pinene), two unsaturated alkenes (1-decene and 1-octene), and 19 other saturated organic compounds. These compounds are commonly found in indoor air but their concentrations were......In this study we examined the co-formation of hydrogen peroxide and other hydroperoxides (collectively presented as H2O2*) as well as submicron particles, including ultra-fine particles (UFP), resulting from the reactions of ozone (O-3) with a complex mixture of volatile organic compounds (VOCs...... to achieve saturated concentrations of the condensable organics. When the 2 terpenes were removed from the O-3/23 VOCs mixture, no H2O2* or particles were formed, indicating that the reactions of O-3 With the two terpenes were the key processes contributing to the formation of H2O2* and submicron...

  1. Chemical composition modulates the adverse effects of particles on the mucociliary epithelium

    OpenAIRE

    Carvalho-Oliveira, Regiani; Pires-Neto, Ruy Camargo; Bustillos, José Oscar Viega; Macchione, Mariangela; Dolhnikoff, Marisa; Saldiva, Paulo H. Nascimento; Garcia, Maria Lúcia Bueno

    2015-01-01

    OBJECTIVE: We compared the adverse effects of two types of real ambient particles; i.e., total suspended particles from an electrostatic precipitator of a steel mill and fine air particles from an urban ambient particulate matter of 2.5 µm, on mucociliary clearance. METHOD: Mucociliary function was quantified by mucociliary transport, ciliary beating frequency and the amount of acid and neutral mucous in epithelial cells through morphometry of frog palate preparations. The palates were immers...

  2. Chemical composition modulates the adverse effects of particles on the mucociliary epithelium

    OpenAIRE

    Regiani Carvalho-Oliveira; Ruy Camargo Pires-Neto; José Oscar Viega Bustillos; Mariangela Macchione; Marisa Dolhnikoff; Paulo H. Nascimento Saldiva; Maria Lúcia Bueno Garcia

    2015-01-01

    OBJECTIVE:We compared the adverse effects of two types of real ambient particles; i.e., total suspended particles from an electrostatic precipitator of a steel mill and fine air particles from an urban ambient particulate matter of 2.5 µm, on mucociliary clearance.METHOD:Mucociliary function was quantified by mucociliary transport, ciliary beating frequency and the amount of acid and neutral mucous in epithelial cells through morphometry of frog palate preparations. The palates were immersed ...

  3. Fine-particle emissions from solid biofuel combustion studied with single-particle mass spectrometry: Identification of markers for organics, soot, and ash components

    OpenAIRE

    Pagels, Joakim; Dabrina D. Dutcher; Stolzenburg, Mark R.; McMurry, Peter H.; Gaelli, Markus E.; Gross, Deborah S.

    2013-01-01

    The effects of combustion phase and fuel on smoke particle emissions from a wood stove operated with three different wood fuels and from a corn stove were investigated. A single-particle mass spectrometer (aerosol time of flight mass spectrometer (ATOFMS)) was used for time-and size-resolved chemical signatures and a scanning mobility particle sizer (SMPS) was used for online mobility size distributions. Markers of particle phase organics and elemental carbon, PM1.5, and CO emissions were str...

  4. CHARACTERIZATION OF FINE PARTICULATE MATTER

    Science.gov (United States)

    Size distribution data processing and fitting Ultrafine, very fine and fine PM were collected nearly continuously from December 2000 through March 2003 at a Washington State Department of Ecology site on Beacon Hill in Seattle. Particle size distributio...

  5. Acute cardiopulmonary effects induced by the inhalation of concentrated ambient particles during seasonal variation in the city of São Paulo.

    Science.gov (United States)

    Brito, Jôse Mára de; Macchione, Mariângela; Yoshizaki, Kelly; Toledo-Arruda, Alessandra Choqueta; Saraiva-Romanholo, Beatriz Mangueira; Andrade, Maria de Fátima; Mauad, Thaís; Rivero, Dolores Helena Rodriguez Ferreira; Saldiva, Paulo Hilário Nascimento

    2014-09-01

    Ambient particles may undergo modifications to their chemical composition as a consequence of climatic variability. The determination of whether these changes modify the toxicity of the particles is important for the understanding of the health effects associated with particle exposure. The objectives were to determine whether low levels of particles promote cardiopulmonary effects, and to assess if the observed alterations are influenced by season. Mice were exposed to 200 μg/m(3) concentrated ambient particles (CAPs) and filtered air (FA) in cold/dry and warm/humid periods. Lung hyperresponsiveness, heart rate, heart rate variability, and blood pressure were evaluated 30 min after each exposure. After 24 h, blood and tissue samples were collected. During both periods (warm/humid and cold/dry), CAPs induced alterations in red blood cells and lung inflammation. During the cold/dry period, CAPs reduced the mean corpuscular volume levels and increased erythrocytes, hemoglobin, mean corpuscular hemoglobin concentration, and red cell distribution width coefficient variation levels compared with the FA group. Similarly, CAPs during the warm/humid period decreased mean corpuscular volume levels and increased erythrocytes, hemoglobin, hematocrit, and red cell distribution width coefficient variation levels compared with the FA group. CAPs during the cold/dry period increased the influx of neutrophils in the alveolar parenchyma. Short-term exposure to low concentrations of CAPs elicited modest but significant pulmonary inflammation and, to a lesser extent, changes in blood parameters. In addition, our data support the concept that changes in climate conditions slightly modify particle toxicity because equivalent doses of CAPs in the cold/dry period produced a more exacerbated response. PMID:25012028

  6. Continuous fine ash depressurization system

    Science.gov (United States)

    Liu, Guohai; Peng, Wan Wang; Vimalchand, Pannalal

    2011-11-29

    A system for depressurizing and cooling a high pressure, high temperature fine solid particles stream having entrained gas therein. In one aspect, the system has an apparatus for cooling the high pressure, high temperature fine solid particles stream having entrained gas therein and a pressure letdown device for depressurization by separating the cooled fine solid particles from a portion of the fine solid particles stream having entrained gas therein, resulting in a lower temperature, lower pressure outlet of solid particles for disposal or handling by downstream equipment.

  7. Real-Time ambient carbon monoxide and ultrafine particle concentration mapping in a near-road environment

    Science.gov (United States)

    Ambient air quality has traditionally been monitored using a network of fixed point sampling sites that are strategically placed to represent regional (e.g., county or town) rather than local (e.g., neighborhood) air quality trends. This type of monitoring data has been used to m...

  8. The ALSC upstate New York ambient trace metals monitoring program

    International Nuclear Information System (INIS)

    The primary goal of the monitoring program is to obtain a long-term and general rural background of ambient trace-metal concentrations in upstate New York. The resulting data will provide a baseline that may be used to track any future trends in atmospheric metallic loadings in that region. In this study, the ambient trace-metal concentrations at five rural sites will be monitored for 2 yr. Automatic dichotomous samplers with a PM10 inlet are being used to collect fine particles and coarse particles. During the 2-yr study, 7,300 samples will be collected. Of these, 1,498 fine-particle samples and 150 coarse-particle samples will be analyzed by instrumental neutron activation analysis (INAA). The remainder of the samples will be archived. Equipment has been installed at the sites, and sampling has continued since October 1, 1991. In addition to ambient particle collection, wet deposition samples are being collected weekly for a 2-yr period at the Moss Lake site. Similarly, samples will be collected at Lake Champlain starting in the spring of 1992. Portions of these samples will be freeze-dried and analyzed by INAA. Inductively coupled plasma mass spectrometry will be used to analyze some of the samples to verify these results for certain elements. In addition, the samples will be analyzed for SO4-2 and NO3-

  9. Ambient Fine Particulate Matter Exposure and Myocardial Ischemia in the Environmental Epidemiology of Arrhythmogenesis in the Women’s Health Initiative (EEAWHI) Study

    Science.gov (United States)

    Zhang, Zhu-ming; Whitsel, Eric A.; Quibrera, P. Miguel; Smith, Richard L.; Liao, Duanping; Anderson, Garnet L.; Prineas, Ronald J.

    2009-01-01

    Background Ambient particulate matter (PM) air pollution is associated with coronary heart disease, but the pathways underlying the association remain to be elucidated. Methods We studied the association between PM and ischemia among 57,908 Women’s Health Initiative clinical trial participants from 1999–2003. We used the Minnesota Code criteria to identify ST-segment and T-wave abnormalities, and estimated T amplitude (microvolt) from resting, standard 12-lead electrocardiogram (ECG). We used U.S. Environmental Protection Agency’s monitor data to estimate concentrations of PM < 2.5 μm (PM2.5) at geocoded participant addresses over 6 days before the ECGs (lag0 through lag5). We excluded 2,379 women with ECG QRS duration ≥ 120 msec. Results Overall, 6% of the remaining 55,529 women (52–90 years of age; 83% non-Hispanic white) had ST abnormalities and 16% had T abnormalities. Lead-specific T amplitude was normally distributed (range of means from −14 to 349 μV). PM2.5 (mean ± SD) averaged over lag0–2 was 14 ± 7 μg/m3. In logistic and linear regression models adjusted for demographic, clinical, temporal, and climatic factors, a 10-μg/m3 increase in lag0–2 PM2.5 was associated with a 4% [95% confidence interval (CI), −3%, to 10%] increase in the odds of ST abnormality and a 5% (95% CI, 0% to 9%) increase in the odds of T abnormality. We observed corresponding decreases in T amplitude in all exam sites and leads except lead V1, reaching a minimum of −2 μV (95% CI, −5 to 0 μV) in lead V3. Conclusions Short-term PM2.5 exposure is associated with ECG evidence of myocardial ischemia among postmenopausal women. The principal manifestations include subclinical but potentially arrhythmogenic ST–T abnormalities and decreases in T amplitude. PMID:19479017

  10. Fine-particle emissions from solid biofuel combustion studied with single-particle mass spectrometry: Identification of markers for organics, soot, and ash components

    Science.gov (United States)

    Pagels, Joakim; Dutcher, Dabrina D.; Stolzenburg, Mark R.; McMurry, Peter H.; GäLli, Markus E.; Gross, Deborah S.

    2013-01-01

    The effects of combustion phase and fuel on smoke particle emissions from a wood stove operated with three different wood fuels and from a corn stove were investigated. A single-particle mass spectrometer (aerosol time of flight mass spectrometer (ATOFMS)) was used for time- and size-resolved chemical signatures and a scanning mobility particle sizer (SMPS) was used for online mobility size distributions. Markers of particle phase organics and elemental carbon, PM1.5, and CO emissions were strongly reduced for the corn stove compared to the wood stove. This is because the more controlled fuel and air supply in the corn stove result in more complete combustion. NOx emissions and particle phase phosphates showed the opposite trend. Marker ions and particle types associated with soot and alkali salts such as potassium chloride and potassium sulfates dominated during flaming combustion and were correlated with increased exhaust temperatures and reduced CO emissions. Marker ions of hydrocarbons and oxidized organics as well as a particle cluster type with a strong organic signature were associated with reduced combustion temperature and increased CO levels, observed during start up from cold stove, addition of fuel, and combustion with reduced air supply. Two different particle types were identified in corn experiments when particles were classified according to mobility before they were measured with the ATOFMS. "Less massive" particles contained mostly ash and soot and had vacuum aerodynamic diameters that were nearly independent of mobility diameter. "More massive" particles had aerodynamic diameters that increased linearly with mobility diameter, indicating approximately spherical shapes, and were hypothesized to consist of organics.

  11. Chemical composition of ambient aerosol, ice residues and cloud droplet residues in mixed-phase clouds: single particle analysis during the Cloud and Aerosol Characterization Experiment (CLACE 6

    Directory of Open Access Journals (Sweden)

    M. Kamphus

    2009-07-01

    Full Text Available Two different single particle mass spectrometers were operated in parallel at the Swiss High Alpine Research Station Jungfraujoch (JFJ, 3580 m a.s.l. during the Cloud and Aerosol Characterization Experiment (CLACE 6 in February and March 2007. During mixed phase cloud events ice crystals from 5 μm up to 20 μm were separated from large ice aggregates, non-activated, interstitial aerosol particles and supercooled droplets using an Ice-Counterflow Virtual Impactor (Ice-CVI. During one cloud period supercooled droplets were additionally sampled and analyzed by changing the Ice-CVI setup. The small ice particles and droplets were evaporated by injection into dry air inside the Ice-CVI. The resulting ice and droplet residues (IR and DR were analyzed for size and composition by two single particle mass spectrometers: a custom-built Single Particle Laser-Ablation Time-of-Flight Mass Spectrometer (SPLAT and a commercial Aerosol Time of Flight Mass Spectrometer (ATOFMS, TSI Model 3800. During CLACE 6 the SPLAT instrument characterized 355 individual ice residues that produced a mass spectrum for at least one polarity and the ATOFMS measured 152 particles. The mass spectra were binned in classes, based on the combination of dominating substances, such as mineral dust, sulfate, potassium and elemental carbon or organic material. The derived chemical information from the ice residues is compared to the JFJ ambient aerosol that was sampled while the measurement station was out of clouds (several thousand particles analyzed by SPLAT and ATOFMS and to the composition of the residues of supercooled cloud droplets (SPLAT: 162 cloud droplet residues analyzed, ATOFMS: 1094. The measurements showed that mineral dust particles were strongly enhanced in the ice particle residues. 57% of the SPLAT spectra from ice residues were dominated by signatures from mineral compounds, and 78% of the ATOFMS spectra. Sulfate and nitrate containing particles were strongly

  12. Reprint of: A numerical investigation of fine sediment resuspension in the wave boundary layer-Uncertainties in particle inertia and hindered settling

    Science.gov (United States)

    Cheng, Zhen; Yu, Xiao; Hsu, Tian-Jian; Balachandar, S.

    2016-05-01

    The wave bottom boundary layer is a major conduit delivering fine terrestrial sediments to continental margins. Hence, studying fine sediment resuspensions in the wave boundary layer is crucial to the understanding of various components of the earth system, such as carbon cycles. By assuming the settling velocity to be a constant in each simulation, previous turbulence-resolving numerical simulations reveal the existence of three transport modes in the wave boundary layer associated with sediment availabilities. As the sediment availability and hence the sediment-induced stable stratification increases, a sequence of transport modes, namely, (I) well-mixed transport, (II) formulation of lutocline resembling a two-layer system, and (III) completely laminarized transport are observed. In general, the settling velocity is a flow variable due to hindered settling and particle inertia effects. Present numerical simulations including the particle inertia suggest that for a typical wave condition in continental shelves, the effect of particle inertia is negligible. Through additional numerical experiments, we also confirm that the particle inertia tends (up to the Stokes number St = 0.2) to attenuate flow turbulence. On the other hand, for flocs with lower gelling concentrations, the hindered settling can play a key role in sustaining a large amount of suspended sediments and results in the laminarized transport (III). For the simulation with a very significant hindered settling effect due to a low gelling concentration, results also indicate the occurrence of gelling ignition, a state in which the erosion rate is always higher than the deposition rate. A sufficient condition for the occurrence of gelling ignition is hypothesized for a range of wave intensities as a function of sediment/floc properties and erodibility parameters.

  13. On dithiothreitol (DTT) as a measure of oxidative potential for ambient particles: evidence for the importance of soluble transition metals

    OpenAIRE

    J. G. Charrier; Anastasio, C.

    2012-01-01

    The rate of consumption of dithiothreitol (DTT) is increasingly used to measure the oxidative potential of particulate matter (PM), which has been linked to the adverse health effects of PM. While several quinones are known to be very reactive in the DTT assay, it is unclear what other chemical species might contribute to the loss of DTT in PM extracts. To address this question, we quantify the rate of DTT loss from individual redox-active species that are common in ambient particulat...

  14. Occurrence of gaseous and particulate polycyclic aromatic hydrocarbons in the urban atmosphere: study of sources and ambient temperature effect on the gas/particle concentration and distribution

    Energy Technology Data Exchange (ETDEWEB)

    Tsapakis, Manolis [Environmental Chemical Processes Laboratory (ECPL), Department of Chemistry, University of Crete, EL-71409 Heraklion (Greece); Stephanou, Euripides G. [Environmental Chemical Processes Laboratory (ECPL), Department of Chemistry, University of Crete, EL-71409 Heraklion (Greece)]. E-mail: stephanou@chemistry.uoc.gr

    2005-01-01

    The presence of polycyclic aromatic hydrocarbons (PAHs) in an urban region (Heraklion, Greece) and processes that govern their atmospheric fate were studied from November 2000 until February 2002. Sixteen samples were collected, by using an artifact-free sampling device, on a monthly basis and the concentration of PAHs in gas and particulate phase was determined. The most abundant members (gas + particles) were phenanthrene (20.0 {+-} 7.0 ng m{sup -3}), fluoranthene (6.5 {+-} 1.7 ng m{sup -3}), pyrene (6.6 {+-} 2.4 ng m{sup -3}), and chrysene (3.1 {+-} 1.5 ng m{sup -3}). Total concentration (gas + particulate) of PAH ranged from 44.3 to 129.2 ng m{sup -3}, with a mean concentration of 79.3 ng m{sup -3}. Total concentration of PAHs in gas phase ranged from 31.4 to 84.7 ng m{sup -3} with non-observable seasonal variation. Conversely, maximum PAH concentrations in the particulate phase occurred during winter months. Particulate concentration varied from 11.4 to 44.9 ng m{sup -3}, with an average of 25.2 ng m{sup -3}. PAH distribution between gas and particulate phase was in agreement with the sub-cooled vapor pressure. Shift in gas/particle distribution due to difference in ambient temperature elucidated to some extent the seasonal variation of the concentration of PAHs in particles. - Capsule: Ambient PAH partitioning between gas and particle phases vary between compounds and with environmental conditions.

  15. A study of the physical, chemical, and optical properties of ambient aerosol particles in Southeast Asia during hazy and nonhazy days

    Science.gov (United States)

    See, S. W.; Balasubramanian, R.; Wang, W.

    2006-05-01

    Many Southeast Asian countries have been constantly plagued by recurring smoke haze episodes as a result of traditional slash-and-burn practices in agricultural areas to clear crop lands or uncontrolled forest fires. However, our current knowledge on the physiochemical and optical properties of ambient aerosols associated with regional haze phenomenon is still fairly limited. Therefore a comprehensive field study was carried out in Singapore from March 2001 to March 2002 under varying weather conditions to gain a better understanding of the characteristics. The physical (size distribution of mass and number concentrations), chemical (mass concentrations of chemical components: 14 ions, 24 metals, elemental carbon (EC) and organic carbon (OC)), and optical (light absorption (bap) and scattering (bsp) by particles) characteristics of ambient aerosol particles were investigated. The results are reported separately for clear and hazy days by categorizing the days as clear or hazy on the basis of visibility data. It was observed that the average concentrations of PM2.5 and most chemical components increased approximately by a factor of 2 on hazy days. Backward air trajectories together with the hot spot distributions in the region indicated that the degradation in Singapore's air quality on hazy days was attributable to large-scale forest fires in Sumatra. This visibility degradation was quantitatively measured on the basis of the light absorption and scattering by particles. As expected, scattering rather than absorption controlled atmospheric visibility, and PM2.5 particles present on hazy days were more efficient at scattering light than those found on clear days.

  16. Photocatalytic H2 Evolution Using Different Commercial TiO2 Catalysts Deposited with Finely Size-Tailored Au Nanoparticles: Critical Dependence on Au Particle Size

    Directory of Open Access Journals (Sweden)

    Ákos Kmetykó

    2014-11-01

    Full Text Available One weight percent of differently sized Au nanoparticles were deposited on two commercially available TiO2 photocatalysts: Aeroxide P25 and Kronos Vlp7000. The primary objective was to investigate the influence of the noble metal particle size and the deposition method on the photocatalytic activity. The developed synthesis method involves a simple approach for the preparation of finely-tuned Au particles through variation of the concentration of the stabilizing agent. Au was deposited on the TiO2 surface by photo- or chemical reduction, using trisodium citrate as a size-tailoring agent. The Au-TiO2 composites were synthetized by in situ reduction or by mixing the titania suspension with a previously prepared gold sol. The H2 production activities of the samples were studied in aqueous TiO2 suspensions irradiated with near-UV light in the absence of dissolved O2, with oxalic acid or methanol as the sacrificial agent. The H2 evolution rates proved to be strongly dependent on Au particle size: the highest H2 production rate was achieved when the Au particles measured ~6 nm.

  17. NMR-based metabolomics to determine acute inhalation effects of nano- and fine-sized ZnO particles in the rat lung.

    Science.gov (United States)

    Lee, Sheng-Han; Wang, Ting-Yi; Hong, Jia-Huei; Cheng, Tsun-Jen; Lin, Ching-Yu

    2016-09-01

    Zinc oxide (ZnO) particles induce acute occupational inhalation illness in humans and rats. However, the possible molecular mechanisms of ZnO particles on the respiratory system remain unclear. In this study, metabolic responses of the respiratory system of rats inhaled ZnO particles were investigated by a nuclear magnetic resonance (NMR)-based metabolomic approach. Male Sprague-Dawley rats were treated with a series of doses of nano-sized (35 nm) or fine-sized (250 nm) ZnO particles. The corresponding control groups inhaled filtered air. After 24 h, bronchoalveolar lavage fluid (BALF) and lung tissues were collected, extracted and prepared for (1)H and J-resolved NMR analysis, followed by principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA). PCA and PLSDA models from analysis of BALF and hydrophilic lung NMR spectra demonstrated that dose response trends were restricted to the 250 nm ZnO particle exposure group and were not observed in the 35 nm ZnO particle exposure group. Increased isoleucine and valine, as well as decreased acetate, trimethylamine n-oxide, taurine, glycine, formate, ascorbate and glycerophosphocholine, were recorded in the BALF of rats treated with moderate and high dose 250 nm ZnO exposures. Decreases in taurine and glucose, as well as an increase of phosphorylcholine-containing lipids and fatty acyl chains, were detected in the lung tissues from 250 nm ZnO-treated rats. These metabolic changes may be associated with cell anti-oxidation, energy metabolism, DNA damage and membrane stability. We also concluded that a metabolic approach provides more complete measurements and suggests potential molecular mechanisms of adverse effects. PMID:27245357

  18. Engineering of an MBR supernatant fouling layer by fine particles addition: a possible way to control cake compressibility.

    Science.gov (United States)

    Teychene, Benoît; Guigui, Christelle; Cabassud, Corinne

    2011-02-01

    For membrane bioreactors (MBR) applied to wastewater treatment membrane fouling is still the prevalent issue. The main limiting phenomena related to fouling is a sudden jump of the transmembrane pressure (TMP) often attributed to the collapse of the fouling layer. Among existing techniques to avoid or to delay this collapse, the addition of active particles membrane fouling reducers (polymer, resins, powdered activated carbon (PAC), zeolithe...) showed promising results. Thus the main objective of this work is to determine if fouling can be reduced by inclusion of inert particles (500 nm and inert compared to other fouling reducers) and which is the impact on filtration performances of the structuring of the fouling. Those particles were chosen for their different surface properties and their capability to form well structured layer. Results, obtained at constant pressure in dead end mode, show that the presence of particles changes foulant deposition and induces non-compressible fouling (in the range of 0.5-1 bar) and higher rejection values compared to filtration done on supernatant alone. Indeed dead end filtration tests show that whatever interactions between biofluid and particles, the addition of particles leads to better filtration performances (in terms of rejection, and fouling layer compressibility). Moreover results confirm the important role played by macromolecular compounds, during supernatant filtration, creating highly compressible and reversible fouling. In conclusion, this study done at lab-scale suggests the potential benefit to engineer fouling structure to control or to delay the collapse of the fouling layer. Finally this study offers the opportunities to enlarge the choice of membrane fouling reducers by taking into consideration their ability to form more consistent fouling (i.e. rigid, structured fouling). PMID:21232780

  19. Characterization of PM2.5 in the ambient air of Shanghai city by analyzing individual particles

    International Nuclear Information System (INIS)

    PM2.5 samples were collected simultaneously at three representative areas (central city, industrial area and clean air suburban) of Shanghai city. Their morphologies and elemental compositions were determined by scanning electron microscopy coupled with energy analysis (SEM-EDX). The particles were classified into four groups based on morphology and elemental composition. Soot aggregates and spherical fly ash particles were the two dominant types and they were identified as originating from automobile exhaust, metallurgical industry and coal combustion. The size distribution of the particles showed that most had diameters in the range of 0.2-1.4 μm. Individual particles were measured by synchrotron radiation micro-beam X-ray fluorescence (micro-SXRF) and the micro-SXRF spectra were obtained. Pattern recognition techniques, which took the micro-SXRF spectrum of a single aerosol particle as its fingerprint, were used to identify the origins of the particles. Seven source types were identified. They were: metallurgical industry, vehicle exhaust, soil dust, coal combustion, diesel exhaust, oil combustion and motorcycle exhaust. Metallurgical industry, automobile exhaust, and coal combustion were recognized to be the main pollution sources of PM2.5 in the air of Shanghai city

  20. New Directions: Questions surrounding suspended particle mass used as a surrogate for air quality and for regulatory control of ambient urban air pollution

    Science.gov (United States)

    Hoare, John L.

    2014-07-01

    The original choice of particulate matter mass (PM) as a realistic surrogate for gross air pollution has gradually evolved into routine use nowadays of epidemiologically-based estimates of the monetary and other benefits expected from regulating urban air quality. Unfortunately, the statistical associations facilitating such calculations usually are based on single indices of air pollution whereas the health effects themselves are more broadly based causally. For this and other reasons the economic benefits of control tend to be exaggerated. Primarily because of their assumed inherently inferior respirability, particles ≥10 μm are generally excluded from such considerations. Where the particles themselves are chemically heterogeneous, as in an urban context, this may be inappropriate. Clearly all air-borne particles, whether coarse or fine, are susceptible to inhalation. Hence, the possibility exists for any adhering potentially harmful semi-volatile substances to be subsequently de-sorbed in vivo thereby facilitating their transport deeper into the lungs. Consequently, this alone may be a sufficient reason for including rather than rejecting during air quality monitoring the relatively coarse 10-100 μm particle fraction, ideally in conjunction with routine estimation of the gaseous co-pollutants thereby facilitating a multi-pollutant approach apropos regulation.

  1. On dithiothreitol (DTT as a measure of oxidative potential for ambient particles: evidence for the importance of soluble ewline transition metals

    Directory of Open Access Journals (Sweden)

    J. G. Charrier

    2012-10-01

    Full Text Available The rate of consumption of dithiothreitol (DTT is increasingly used to measure the oxidative potential of particulate matter (PM, which has been linked to the adverse health effects of PM. While several quinones are known to be very reactive in the DTT assay, it is unclear what other chemical species might contribute to the loss of DTT in PM extracts. To address this question, we quantify the rate of DTT loss from individual redox-active species that are common in ambient particulate matter. While most past research has indicated that the DTT assay is not sensitive to metals, our results show that seven out of the ten transition metals tested do oxidize DTT, as do three out of the five quinones tested. While metals are less efficient at oxidizing DTT compared to the most reactive quinones, concentrations of soluble transition metals in fine particulate matter are generally much higher than those of quinones. The net result is that metals appear to dominate the DTT response for typical ambient PM2.5 samples. Based on particulate concentrations of quinones and soluble metals from the literature, and our measured DTT responses for these species, we estimate that for typical PM2.5 samples approximately 80% of DTT loss is from transition metals (especially copper and manganese, while quinones account for approximately 20%. We find a similar result for DTT loss measured in a small set of PM2.5 samples from the San Joaquin Valley of California. Because of the important contribution from metals, we also tested how the DTT assay is affected by EDTA, a chelator that is sometimes used in the assay. EDTA significantly suppresses the response from both metals and quinones; we therefore recommend that EDTA should not be included in the DTT assay.

  2. Trajectory-based source area analysis of atmospheric fine particles, SO2, NOx and O3 for the SMEAR II station in Finland in 1996–2008

    Directory of Open Access Journals (Sweden)

    M. Kulmala

    2012-01-01

    Full Text Available Source area analysis based on combining in situ measurements of trace gas or particle concentrations and back trajectories calculated for corresponding times has proven to be a valuable approach in atmospheric research; especially in investigating air pollution episodes, but also in e.g. tracing the source areas of air masses related to high vs. low concentrations of aerosol particles of different sizes at the receptor site. A statistical trajectory method used before by Sogacheva et al. (2005 was fine-tuned to take the presumable horizontal error in calculated trajectories into account, tested with SO2 and validated by comparison against EMEP (European Monitoring and Evaluation Programme emission data. In this work we apply the improved method for characterizing the source areas of atmospheric SO2, NOx, O3 and aerosol particles of different size modes from the perspective of a Finnish measurement station located in Hyytiälä (61°51' N, 24°17' E. Our method proved useful for qualitative source area analysis of measured trace compounds. We applied it to study trends and seasonal variation in atmospheric pollutant transport during 13 yr at the SMEAR II station.

  3. Trajectory analysis of atmospheric transport of fine particles, SO2, NOx and O3 to the SMEAR II station in Finland in 1996–2008

    Directory of Open Access Journals (Sweden)

    M. Kulmala

    2013-02-01

    Full Text Available Trajectory statistical methods that combine in situ measurements of trace gas or particle concentrations and back trajectories calculated for corresponding times have proven to be a valuable approach in atmospheric research; especially in investigating air pollution episodes, but also in e.g. tracing the air mass history related to high vs. low concentrations of aerosol particles of different sizes at the receptor site. A concentration field method was fine-tuned to take the presumable horizontal error in calculated trajectories into account, tested with SO2 and validated by comparison against EMEP (European Monitoring and Evaluation Programme emission data. In this work we apply the improved method for characterizing the transport of atmospheric SO2, NOx, O3 and aerosol particles of different size modes to a Finnish measurement station located in Hyytiälä (61°51' N, 24°17' E. Our method did not reproduce the EMEP emission soures, but proved useful for qualitative analysis on where the measured compounds come from, from one measurement station point of view. We applied it to study trends and seasonal variation in atmospheric pollutant transport during 13 yr at the SMEAR II (Station for Measuring Ecosystem-Atmosphere Interactions station.

  4. The therapeutic index of locally acting inhaled drugs as a function of their fine particle mass and particle size distribution - A literature review

    NARCIS (Netherlands)

    Weda, Marjolein; Zanen, Pieter; De Boer, Anne H.; Barends, Dirk M.; Frijlink, Henderik W.

    2008-01-01

    The therapeutic index (TI) of locally acting inhaled drug products depends on a number of parameters and processes: the particle size distribution of the inhaled aerosol, the dose-efficacy response curves at the deposition sites, the amount of drug absorbed into the systemic circulation from the lun

  5. Surveillance of the short-term impact of fine particle air pollution on cardiovascular disease hospitalizations in New York State

    Directory of Open Access Journals (Sweden)

    Felton Henry D

    2009-09-01

    Full Text Available Abstract Background Studies have shown that the effects of particulate matter on health vary based on factors including the vulnerability of the population, health care practices, exposure factors, and the pollutant mix. Methods We used time-stratified case-crossover to estimate differences in the short-term impacts of PM2.5 on cardiovascular disease hospital admissions in New York State by geographic area, year, age, gender, co-morbid conditions, and area poverty rates. Results PM2.5 had a stronger impact on heart failure than other cardiovascular diagnoses, with 3.1% of heart failure admissions attributable to short-term PM2.5 exposure over background levels of 5 ug/m3. Older adults were significantly more susceptible to heart failure after short-term ambient PM2.5 exposure than younger adults. Conclusion The short-term impact of PM2.5 on cardiovascular disease admissions, and modifications of that impact, are small and difficult to measure with precision. Multi-state collaborations will be necessary to attain more precision to describe spatiotemporal differences in health impacts.

  6. Effects of salinity and particle concentration on sediment hydrodynamics and critical bed-shear-stress for erosion of fine grained sediments used in wetland restoration projects

    Science.gov (United States)

    Ghose-Hajra, M.; McCorquodale, A.; Mattson, G.; Jerolleman, D.; Filostrat, J.

    2015-03-01

    Sea-level rise, the increasing number and intensity of storms, oil and groundwater extraction, and coastal land subsidence are putting people and property at risk along Louisiana's coast, with major implications for human safety and economic health of coastal areas. A major goal towards re-establishing a healthy and sustainable coastal ecosystem has been to rebuild Louisiana's disappearing wetlands with fine grained sediments that are dredged or diverted from nearby rivers, channels and lakes to build land in open water areas. A thorough geo-hydrodynamic characterization of the deposited sediments is important in the correct design and a more realistic outcome assessment of the long-term performance measures for ongoing coastal restoration projects. This paper evaluates the effects of salinity and solid particle concentration on the re-suspension characteristics of fine-grained dredged sediments obtained from multiple geographic locations along the Gulf coast. The critical bed-shear-stress for erosion has been evaluated as a function of sedimentation time. The sediment hydrodynamic properties obtained from the laboratory testing were used in a numerical coastal sediment distribution model to aid in evaluating sediment diversions from the Mississippi River into Breton Sound and Barataria Bay.

  7. Precipitated calcium carbonate (PCC - cellulose composite fillers: Effects of PCC particle structure on the production and properties of uncoated fine paper

    Directory of Open Access Journals (Sweden)

    Paulapuro, H.

    2007-02-01

    Full Text Available This work examines the precipitation of PCC – pulp composite fillers with varying crystal habits and their effects on the papermaking properties of printing and writing paper. Colloidal (c-PCC, rhombohedral (r-PCC, and scalenohedral types (s-PCC of composite PCCs were produced and compared with commercial reference PCCs. Scanning electron micros-copy showed the c-PCC to be a high-surface-area nano-structured PCC. The rhombohedral composite was formed in clusters like a spider-web structure. Under similar experimental conditions, composite PCC was formed as individual ellipsoidal crystals and some of the particles had malformed structure, in contrast to the structured reference s-PCC. The co-precipitation and the structure of PCC significantly influence the forming, consolidation, and properties of paper, as well as its perform-ance in printing.Composite c-PCC showed the highest retention during forming. At higher filler contents, dewatering was reduced significantly with handsheets containing s- and r-PCC composite fillers. Colloidal composite hand-sheets showed the lowest tensile index and internal bond strength, while the rhombohedral composite gave the highest z-directional bond strength. Compared with the traditional reference samples containing commercial PCCs, paper with s- and r-composites had significantly higher density but similar light scattering ability. Addition of fibrillar fines to fine paper increased print rub fastness significantly in both laser and inkjet printed samples.

  8. Size-resolved source apportionment of ambient particles by positive matrix factorization at Gosan background site in East Asia

    Science.gov (United States)

    Han, J. S.; Moon, K. J.; Lee, S. J.; Kim, Y. J.; Ryu, S. Y.; Cliff, S. S.; Yi, S. M.

    2006-01-01

    Size- and time-resolved aerosol samples were collected using an eight-stage Davis rotating unit for monitoring (DRUM) sampler from 29 March to 29 May in 2002 at Gosan, Jeju Island, Korea, which is one of the representative background sites in East Asia. These samples were analyzed using synchrotron X-ray fluorescence for 3-h average concentrations of 19 elements consisting of S, Si, Al, Fe, Ca, Cl, Cu, Zn, Ti, K, Mn, Pb, Ni, V, Se, As, Rb, Cr, Br. The size-resolved data sets were then analyzed using the positive matrix factorization (PMF) technique in order to identify possible sources and estimate their contribution to particulate matter mass. PMF analysis uses the uncertainty of the measured data to provide an optimal weighting. Fifteen sources were resolved in eight size ranges (0.07~12 μm) and included continental soil, local soil, sea salt, biomass/biofuel burning, coal combustion, oil heating furnace, residual oil fired boiler, municipal incineration, nonferrous metal source, ferrous metal source, gasoline vehicle, diesel vehicle, copper smelter and volcanic emission. PMF analysis of size-resolved source contributions showed that natural sources represented by local soil, sea salt and continental soil contributed about 79% to the predicted primary particulate matter (PM) mass in the coarse size range (1.15~12 μm). On the other hand, anthropogenic sources such as coal combustion and biomass/biofuel burning contributed about 60% in the fine size range (0.56~2.5 μm). The diesel vehicle source contributed the most in the ultra-fine size range (0.07~0.56 μm) and was responsible for about 52% of the primary PM mass.

  9. Size-resolved source apportionment of ambient particles by positive matrix factorization at Gosan background site in East Asia

    Directory of Open Access Journals (Sweden)

    J. S. Han

    2006-01-01

    Full Text Available Size- and time-resolved aerosol samples were collected using an eight-stage Davis rotating unit for monitoring (DRUM sampler from 29 March to 29 May in 2002 at Gosan, Jeju Island, Korea, which is one of the representative background sites in East Asia. These samples were analyzed using synchrotron X-ray fluorescence for 3-h average concentrations of 19 elements consisting of S, Si, Al, Fe, Ca, Cl, Cu, Zn, Ti, K, Mn, Pb, Ni, V, Se, As, Rb, Cr, Br. The size-resolved data sets were then analyzed using the positive matrix factorization (PMF technique in order to identify possible sources and estimate their contribution to particulate matter mass. PMF analysis uses the uncertainty of the measured data to provide an optimal weighting. Fifteen sources were resolved in eight size ranges (0.07~12 μm and included continental soil, local soil, sea salt, biomass/biofuel burning, coal combustion, oil heating furnace, residual oil fired boiler, municipal incineration, nonferrous metal source, ferrous metal source, gasoline vehicle, diesel vehicle, copper smelter and volcanic emission. PMF analysis of size-resolved source contributions showed that natural sources represented by local soil, sea salt and continental soil contributed about 79% to the predicted primary particulate matter (PM mass in the coarse size range (1.15~12 μm. On the other hand, anthropogenic sources such as coal combustion and biomass/biofuel burning contributed about 60% in the fine size range (0.56~2.5 μm. The diesel vehicle source contributed the most in the ultra-fine size range (0.07~0.56 μm and was responsible for about 52% of the primary PM mass.

  10. Distribution of the solvent-extractable organic compounds in fine (PM1) and coarse (PM1-10) particles in urban, industrial and forest atmospheres of Northern Algeria.

    Science.gov (United States)

    Ladji, Riad; Yassaa, Noureddine; Balducci, Catia; Cecinato, Angelo; Meklati, Brahim Youcef

    2009-12-20

    The distribution of the solvent-extractable organic components in the fine (PM(1)) and coarse (PM(1-10)) fractions of airborne particulate was studied for the first time in Algeria. That was done during October 2006 concurrently in a big industrial district, a busy urban area, and a forest national park located in Algiers, Boumerdes, Blida, respectively, which are the three biggest provinces of Northern Algeria. Most of the organic matter identified in both particle size ranges consisted of n-alkanes and n-alkanoic acids, with minor contributions coming from polycyclic aromatic hydrocarbons (PAHs), nitrated polycyclic aromatic hydrocarbons (NPAHs), oxygenated PAHs, and other polar compounds (e.g., caffeine and nicotine). The potential emission sources of airborne contaminants were reconciled by combining the values of n-alkane carbon preference index (CPI) and selected diagnostic ratios of PAHs, calculated in both size ranges. The mean cumulative concentrations of PAHs reached 3.032 ng m(-3) at the Boumerdes site, urban, 80% of which (i.e. 2.246 ng m(-3)) in the PM(1) fraction, 6.462 ng m(-3) at Rouiba-Réghaia, industrial district, (5.135 ng m(-3) or 80% in PM(1)), and 0.512 ng m(-3) at Chréa, forested mountains (0.370 ng m(-3) or 72% in PM(1)). Similar patterns were shown by all organic groups, which resulted overall enriched in the fine particles at the three sites. Carcinogenic and mutagenic potencies associated to PAHs were evaluated by multiplying the concentrations of "toxic" compounds times the corresponding potency factors normalized vs. benzo(a)pyrene (BaP), and were found to be both acceptable. PMID:19837448

  11. Laboratory Investigations in Support of Carbon Dioxide-in-Water Emulsions Stabilized by Fine Particles for Ocean and Geologic Sequestration of Carbon Dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Dan Golomb; David Ryan; Eugene Barry

    2007-01-08

    Since the submission of our last Semi-annual Report, dated September 2006, the research objectives of this Co-operative Agreement shifted toward geologic sequestration of carbon dioxide. In the period September 2006-February 2007, experiments were conducted in a High-Pressure Batch Reactor (HPBR) for creating emulsions of liquid carbon dioxide (/CO{sub 2})-in-water stabilized by fine particles for geologic sequestration of CO{sub 2}. Also, emulsions were created in water of a binary mixture of liquid carbon dioxide and liquid hydrogen sulfide (/H{sub 2}S), called Acid Gas (AG). This leads to the possibility of safe disposal of AG in deep geologic formations, such as saline aquifers. The stabilizing particles included pulverized limestone (CaCO{sub 3}), unprocessed flyash, collected by an electrostatic precipitator at a local coal-fired power plant, and pulverized siderite (FeCO{sub 3}). Particle size ranged from submicron to a few micrometers. The first important finding is that /CO{sub 2} and /H{sub 2}S freely mix as a binary liquid without phase separation. The next finding is that the mixture of /CO{sub 2} and /H{sub 2}S can be emulsified in water using fine particles as emulsifying agents. Such emulsions are stable over prolonged periods, so it should not be a problem to inject an emulsion into subterranean formations. The advantage of injecting an emulsion into subterranean formations is that it is denser than the pure liquid, therefore it is likely to disperse in the bottom of the geologic formation, rather than buoying upward (called fingering). In such a fashion, the risk of the liquids escaping from the formation, and possibly re-emerging into the atmosphere, is minimized. This is especially important for H{sub 2}S, because it is a highly toxic gas. Furthermore, the emulsion may interact with the surrounding minerals, causing mineral trapping. This may lead to longer sequestration periods than injecting the pure liquids alone.

  12. Measurement of Fine Particles From Mobile and Stationary Sources, and Reducing the Air Conditioner Power Consumption in Hybrid Electric Vehicles

    OpenAIRE

    Brewer, Eli Henry

    2015-01-01

    We study the PM2.5 and ultrafine exhaust emissions from a new natural gas-fired turbine power facility to better understand air pollution in California. To characterize the emissions from new natural gas turbines, a series of tests were performed on a GE LMS100 gas turbine. These tests included PM2.5 and wet chemical tests for SO2/SO3 and NH3, as well as ultrafine (less than 100 nm in diameter) particulate matter measurements. The turbine exhaust had an average particle number concentration t...

  13. Genotoxicity, inflammation and physico-chemical properties of fine particle samples from an incineration energy plant and urban air

    DEFF Research Database (Denmark)

    Sharma, Anoop Kumar; Jensen, Keld Alstrup; Rank, Jette;

    2007-01-01

    Airborne particulate matter (PM) was sampled by use of an electrostatic sampler in an oven hall and a receiving hall in a waste-incineration energy plant, and from urban air in a heavy-traffic street and from background air in Copenhagen. PM was sampled for 1-2 weeks, four samples at each site. The......), but the distribution was completely different in the oven hall (maximum mode at about 150 nm). Also chemically, the samples from the oven hall were highly different from the other samples. PM extracts from the receiving hall, street and background air were more mutagenic than the PM extracts from the...... locations in particle size distribution, chemical composition and the resulting biological effects when A549 cells were incubated with the PM. These characteristics and observations in the oven hall indicated that the PM source was oven exhaust, which was well combusted. (c) 2007 Elsevier B.V. All rights...

  14. Synthesis of fine particles of a geometrically frustrated spin-chain system Ca3Co2O6 through a pyrophoric route and its magnetic behavior

    International Nuclear Information System (INIS)

    We report the synthesis of fine particles of a well-known geometrically frustrated spin-chain compound Ca3Co2O6 through a new route, namely, a pyrophoric method employing triethanolamine (TEA) and studied the magnetic behavior of such specimens. We find that this method of synthesis yields particles made up of rods whose diameter appears to be controllable by the fraction of TEA during synthesis. It is seen that the two well-known magnetic transitions (∼24 K and ∼8 K) remains unaffected for all TEA concentrations used. The most notable finding is that the multi-step feature in the M versus magnetic-field isotherm reported for the single crystalline form tends to smoothen out gradually with decreasing rod thickness (from about 1 μm to a few hundred nm). Further, unlike for the single crystalline form known in the literature, there is no tendency for the relaxation time (τ) to remain constant at low temperatures (<10 K) and τ remains temperature dependent up to the lowest temperature measured (1.8 K) in all the specimens. These findings suggest that the multi-step magnetization anomaly in this system may be characterized by a magnetic correlation length.

  15. Endocytosis, oxidative stress and IL-8 expression in human lung epithelial cells upon treatment with fine and ultrafine TiO2: Role of the specific surface area and of surface methylation of the particles

    International Nuclear Information System (INIS)

    Inhaled ultrafine particles show considerably stronger pulmonary inflammatory effects when tested at equal mass dose with their fine counterparts. However, the responsible mechanisms are not yet fully understood. We investigated the role of particle size and surface chemistry in initiating pro-inflammatory effects in vitro in A549 human lung epithelial cells on treatment with different model TiO2 particles. Two samples of TiO2, i.e. fine (40-300 nm) and ultrafine (20-80 nm) were tested in their native forms as well as upon surface methylation, as was confirmed by Fourier transformed infrared spectroscopy. Radical generation during cell treatment was determined by electron paramagnetic resonance with 5,5-dimethyl-1-pyrroline-N-oxide or 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl. Interleukin-8 mRNA expression/release was determined by RT-PCR and ELISA, whereas particle uptake was evaluated by transmission electron microscopy. TiO2 particles were rapidly taken up by the cells, generally as membrane bound aggregates and large intracellular aggregates in vesicles, vacuoles and lamellar bodies. Aggregate size tended to be smaller for the ultrafine samples and was also smaller for methylated fine TiO2 when compared to non-methylated fine TiO2. No particles were observed inside nuclei or any other vital organelle. Both ultrafine TiO2 samples but not their fine counterparts elicited significantly stronger oxidant generation and IL-8 release, despite their aggregation state and irrespective of their methylation. The present data indicate that ultrafine TiO2, even as aggregates/agglomerates, can trigger inflammatory responses that appear to be driven by their large surface area. Furthermore, our results indicate that these effects result from oxidants generated during particle-cell interactions through a yet to be elucidated mechanism(s)

  16. Concentrations and solubility of trace elements in fine particles at a mountain site, southern China: regional sources and cloud processing

    Science.gov (United States)

    Li, T.; Wang, Y.; Li, W. J.; Chen, J. M.; Wang, T.; Wang, W. X.

    2015-08-01

    The concentrations and solubility of twelve trace elements in PM2.5 at Mt. Lushan, southern China, were investigated during the summer of 2011 and the spring of 2012. The average PM2.5 mass was 55.2 ± 20.1 μg m-3 during the observation period. Temporal variations of all trace elements including total and water-soluble fractions with several dust storm spikes in total fractions of Al and Fe were observed. The enrichment factor (EF) values were 1 order of magnitude higher for the water-soluble fractions versus the total fractions of trace elements. Four major emission sources, namely nonferrous metal mining and smelting (for Cr, As, Ba and parts of Zn), coal combustion (for Pb, Zn, Se, Cu and Mn), crustal materials (for Al and Fe) and municipal solid waste incineration (for Cd and Mo), were classified by principal component analysis (PCA). Trajectory cluster analysis and the potential source contribution function (PSCF) consistently identified the Yangtze River delta (YRD), the Pearl River delta (PRD), and the neighbouring provinces of Mt. Lushan as the major source regions and transport pathways for anthropogenic elements. Northern China was identified as a major source region for crustal elements. It should be noted that apart from the YRD, the area around Mt. Lushan has become the most significant contributor to the solubility of most trace elements. Element solubility can be partially determined by emission sources. However, enhanced solubility of trace elements corresponding to increased concentrations of sulfate after the occurrence of cloud events indicated significant effects of cloud processing on aerosol element dissolution. Metal particles mixed with sulfate in cloud droplet residues were further investigated through transmission electron microscopy (TEM) analysis. Irreversible alteration of particle morphology by cloud processing was confirmed to be highly responsible for the enhancement of trace element solubility. The findings from this study imply an

  17. Characteristics and Influence of Biosmoke on the Fine-Particle Ionic Composition Measured in Asian Outflow during the Transport and Chemical Evolution Over the Pacific (TRACE-P) Experiment

    Science.gov (United States)

    Ma, Y.; Weber, R. J.; Lee, Y.-N.; Orsini, D. A.; Maxwell-Meier, K.; Thornton, D. C.; Bandy, A. R.; Clarke, A. D.; Blake, D. R.; Sachse, G. W.

    2003-01-01

    We investigate the sources, prevalence, and fine-particle inorganic composition of biosmoke over the western Pacific Ocean between 24 February and 10 April 2001. The analysis is based on highly time-resolved airborne measurements of gaseous and fine- particle inorganic chemical composition made during the NASA Transport and Chemical Evolution over the Pacific (TRACE-P) experiment. At latitudes below approximately 25 deg. N, relatively pure biomass burning plumes of enhanced fine-particle potassium, nitrate, ammonium, light-absorbing aerosols, and CO concentrations were observed in plumes that back trajectories and satellite fire map data suggest originated from biomass burning in southeast Asia. Fine-particle water-soluble potassium (K+) is confirmed to be a unique biosmoke tracer, and its prevalence throughout the experiment indicates that approximately 20% of the TRACE-P Asian outflow plumes were influenced, to some extent, by biomass or biofuel burning emissions. At latitudes above 25 deg. N, highly mixed urban/industrial and biosmoke plumes, indicated by SO(sup 2, sub 4) and K+, were observed in 5 out of 53 plumes. Most plumes were found in the Yellow Sea and generally were associated with much higher fine-particle loadings than plumes lacking a biosmoke influence. The air mass back trajectories of these mixed plumes generally pass through the latitude range of between 34 deg. and 40 deg. N on the eastern China coast, a region that includes the large urban centers of Beijing and Tianjin. A lack of biomass burning emissions based on fire maps and high correlations between K+ and pollution tracers (e.g., S(sup 2, sub 4) suggest biofuel sources. Ratios of fine-particle potassium to sulfate are used to provide an estimate of relative contributions of biosmoke emissions to the mixed Asian plumes. The ratio is highly correlated with fine-particle volume (r(sup 2) = 0.85) and predicts that for the most polluted plume encounter in TRACE-P, approximately 60% of the

  18. SOUTHERN FINE PARTICULATE MONITORING PROJECT

    Energy Technology Data Exchange (ETDEWEB)

    Unknown

    2002-04-01

    This quarterly report presents results and analysis of continuous onsite ambient fine particulate data at the North Birmingham sampling site during the January-March, 2002 study period. The continuous data include PM{sub 2.5} mass concentrations measured by TEOM, particle sulfate using the R&P 8400S monitor, particle size distributions measured by SMPS and APS monitors, and PM{sub 2.5} light scattering extinction coefficient as measured by nephelometer. Some instrumental issues were noted with the upgrade of the APS model 3320 are described in the report, as well as preliminary performance indications for the upgraded instrument. During the quarter preliminary data analysis and modeling studies were conducted to test the potential of the North Birmingham site data for source attribution analyses. Our initial assessment has continued to be optimistic in this regard due to the location of the site relative to several important classes of local and midrange emission sources. We anticipate that these analyses will provide good separations of the effects of major source classes and spatial source clusters, and will provide useful information relevant to PM{sub 2.5} implementation strategies.

  19. Chemical fractionation of arsenic and heavy metals in fine particle matter and its implications for risk assessment: A case study in Nanjing, China

    Science.gov (United States)

    Li, Huiming; Wang, Jinhua; Wang, Qin'geng; Qian, Xin; Qian, Yu; Yang, Meng; Li, Fengying; Lu, Hao; Wang, Cheng

    2015-02-01

    A four-step sequential extraction procedure was used to study the chemical fractionation of As and heavy metals (Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn) in fine particulate matter (PM2.5) collected from Nanjing, China. The mass concentrations of most PM2.5 samples exceeded the 24 h standard (75 μg/m3) recommended by the new national ambient air quality standard of China. The most abundant elements were Fe, Zn and Pb, while As and Cd were present at the lowest concentrations. As, Cd, Cu, Mn, Pb and Zn were mostly present in the two mobile fractions, including the soluble and exchangeable fraction (F1), and carbonates, oxides and reducible fraction (F2). Fe had the highest proportion present in the residual fraction (F4). Relatively high proportions of the metals Ni and Cr were present in the oxidizable and sulfidic fraction (F3). High proportions of Zn, As and Cu and lower proportions of Cd, Cr and Fe were present in the potentially mobile phases. The enrichment factor, contamination factor and risk assessment code were calculated to analyze the main sources and assess the environmental risks of the metals in PM2.5. The carcinogenic risks of As, Cd, Ni and Pb were all lower than the accepted criterion of 10-6, whereas the carcinogenic risks of Cr for children and As and Cr for adults were higher than 10-6. The non-carcinogenic health risk of As and heavy metals because of PM2.5 exposure for children and adults were lower than but close to the safe level of 1.

  20. Imaging the fine-scale structure of the cellular actin cytoskeleton by Single Particle Tracking and Atomic Force Microscopy

    Science.gov (United States)

    Mustata, Gina-Mirela

    It has been proposed that diffusion in the plasma membrane of eukaryotic cells it is compartmentalized due to the interaction with the underlying actin-based membrane skeleton that comes into close proximity to the lipid bilayer. The cytoskeleton is a dynamic structure that maintains cell shape, enables cell motion, and plays important roles in both intra-cellular transport and cellular division. We show here the evidence of plasma membrane compartmentalization using Single Particle Tracking (SPT) and Atomic Force Microscopy (AFM) imaging. SPT of Quantum dot labeled lipid in the plasma membrane of live normal rat kidney cells show compartments ranging from 325 nm to 391 nm depending on the sampling time. Using AFM imaging of live NRK cell in the presence of phalloidin, the membrane compartmentalization it is visible with the average size of the compartments of 325 +/- 10 nm (the main peak is centered at 260 nm). Further, the underlying membrane skeleton in fixed cells was directly imaged after partial removal of the plasma membrane to reveal size of the membrane skeleton meshwork of 339 +/- 10 nm. A new method of measuring the characteristics of the actin meshwork was proposed. Probing the local compliance of the plasma membrane through the deflection of a soft AFM cantilever we can expect that the stiffness of the membrane will be higher at locations directly above a cortical actin. This new method provided information about the structure of the skeletal meshwork of neuronal cell body predicting an average compartment size of about 132 nm. This was confirmed through SPT of QD-lipid incorporated into the neuronal cell membrane.

  1. Concentrations and solubility of trace elements in fine particles at a mountain site, southern China: regional sources and cloud processing

    Directory of Open Access Journals (Sweden)

    T. Li

    2015-05-01

    Full Text Available The concentrations and solubility of twelve trace elements in PM2.5 at Mt. Lushan, southern China, were investigated during the summer of 2011 and the spring of 2012. The average PM2.5 mass was 55.2 ± 20.1 μg m-3 during the observation period. Temporal variations of all trace elements including total and water-soluble fractions with several dust storm spikes for total fraction Al and Fe were observed. The enrichment factor (EF values were one order of magnitude higher for the water-soluble fractions vs. the total fractions of trace elements. Four major emission sources were classified by principal component analysis (PCA, namely nonferrous metal mining and smelting (for Cr, As, Ba and parts of Zn, coal combustion (for Pb, Zn, Se, Cu and Mn, crustal materials (for Al and Fe and municipal solid waste incineration (for Cd and Mo. Trajectory cluster analysis and the potential source contribution function (PSCF consistently identified the Yangtze River Delta (YRD, the Pearl River Delta (PRD and parts of Hunan and Jiangxi as the major source regions and pathways for anthropogenic elements, while northern China was identified for crustal elements. In contrast, the local Jiangxi area has become the most significant contributor to the solubility of most trace elements, apart from the YRD with severe air pollution. In addition, the solubility alteration of trace elements in cloud events was investigated and transmission electron microscopy (TEM analysis indicated that the irreversible alteration of particle morphology by cloud processing was highly responsible for the enhancement of element solubility. Our work implies an important role of regional anthropogenic pollution and cloud processing in the evolution of trace element solubility during transport.

  2. Exposure to genotoxins present in ambient air in Bangkok, Thailand - particle associated polycyclic aromatic hydrocarbons and biomarkers

    DEFF Research Database (Denmark)

    Ruchirawat, Mathuros; Mahidol, Chulabhorn; Tangjarukij, Chanthana;

    2002-01-01

    officers were divided into a high exposure group (traffic police) and low exposure (office duty). Particulate matter was collected using personal pumps (2 l/min) and the eight carcinogenic PAHs were analysed by standard procedures. The traffic police was exposed to a 20-fold higher level of total PAHs than...... the office group. Lower biomarker levels were observed during the period when the traffic police officers were wearing a simple facemask, indicating that these masks protect against particle-associated PAHs. No statistically significant correlations were observed between biomarker levels and the level...... of individual PAHs or total PAH. Our data show, that people in Bangkok, who spend most of the day outside air-conditioned offices, are exposed to high levels of genotoxic PAHs. However, for people who spend their working day in offices, the exposure is similar to people living in other metropolitan...

  3. 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.

  4. 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.

  5. Trajectory analysis of atmospheric transport of fine particles, SO2, NOx and O3 to the SMEAR II station in Finland in 1996–2008

    OpenAIRE

    M. Kulmala; Junninen, H.; Dal Maso, M.; Hulkkonen, M.; L. Riuttanen

    2013-01-01

    Trajectory statistical methods that combine in situ measurements of trace gas or particle concentrations and back trajectories calculated for corresponding times have proven to be a valuable approach in atmospheric research; especially in investigating air pollution episodes, but also in e.g. tracing the air mass history related to high vs. low concentrations of aerosol particles of different sizes at the receptor site. A concentration field method was fine-tuned to take the presumable horizo...

  6. Online determination of levoglucosan in ambient aerosols with Particle-into-Liquid Sampler – High-Performance Anion-Exchange Chromatography – Mass Spectrometry (PILS–HPAEC–MS

    Directory of Open Access Journals (Sweden)

    K. Saarnio

    2013-06-01

    Full Text Available Biomass burning, such as domestic heating, agricultural, and wild open-land fires, has a significant influence on the atmosphere at the global and, especially, at the local scale. Levoglucosan has been shown to be a good tracer for biomass burning emissions in atmospheric particulate matter and several analytical techniques have been presented for the determination of levoglucosan from filter samples. In this paper, a novel combination of a Particle-into-Liquid Sampler (PILS to a high-performance anion-exchange chromatograph (HPAEC with the detection by a mass spectrometer (MS is presented for the online analysis of levoglucosan in ambient particles. The PILS–HPAEC–MS technique enables a fast online analysis of levoglucosan from the particulate samples. The method was tested at an urban background station in Helsinki, Finland, in winter 2011. A comparison with simultaneous levoglucosan measurements from filter samples by the HPAEC–MS was performed and it showed a good agreement between the online and offline methods. Additionally, the online levoglucosan data were compared with the biomass burning tracer fragments measured by a High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS. As there were no local biomass burning sources close to the measurement station, online levoglucosan measurements revealed that most of the particles from biomass burning were either regionally distributed or long-range transported in the urban background of Helsinki. The average levoglucosan concentrations were relatively low (average 0.083 μg m−3 during the measurement campaign. The highest concentration peak measured for levoglucosan (1.4 μg m−3 seemed to originate from biomass burning in Eastern Europe, likely in Estonia, that was transported to Helsinki.

  7. Online determination of levoglucosan in ambient aerosols with particle-into-liquid sampler – high-performance anion-exchange chromatography – mass spectrometry (PILS–HPAEC–MS

    Directory of Open Access Journals (Sweden)

    K. Saarnio

    2013-10-01

    Full Text Available Biomass burning, such as domestic heating, agricultural, and wild open-land fires, has a significant influence on the atmosphere at the global and, especially, at the local scale. Levoglucosan has been shown to be a good tracer for biomass burning emissions in atmospheric particulate matter, and several analytical techniques have been presented for the determination of levoglucosan from filter samples. In this paper, a novel combination of a particle-into-liquid sampler (PILS to a high-performance anion-exchange chromatograph (HPAEC with the detection by a mass spectrometer (MS is presented for the online analysis of levoglucosan in ambient particles. The PILS–HPAEC–MS technique enables a fast online analysis of levoglucosan from the particulate samples. The method was tested at an urban background station in Helsinki, Finland, in winter 2011. A comparison with simultaneous levoglucosan measurements from filter samples by the HPAEC–MS was performed and it showed a good agreement between the online and offline methods. Additionally, the online levoglucosan data were compared with the biomass burning tracer fragments measured by a high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS. As there were no local biomass burning sources close to the measurement station, online levoglucosan measurements revealed that most of the particles from biomass burning were either regionally distributed or long-range transported in the urban background of Helsinki. The average levoglucosan concentrations were relatively low (average 0.083 μg m−3 during the measurement campaign. The highest concentration peak measured for levoglucosan (1.4 μg m−3 seemed to originate from biomass burning in the Baltic countries, likely in Estonia, that was transported to Helsinki.

  8. Online determination of levoglucosan in ambient aerosols with particle-into-liquid sampler - high-performance anion-exchange chromatography - mass spectrometry (PILS-HPAEC-MS)

    Science.gov (United States)

    Saarnio, K.; Teinilä, K.; Saarikoski, S.; Carbone, S.; Gilardoni, S.; Timonen, H.; Aurela, M.; Hillamo, R.

    2013-10-01

    Biomass burning, such as domestic heating, agricultural, and wild open-land fires, has a significant influence on the atmosphere at the global and, especially, at the local scale. Levoglucosan has been shown to be a good tracer for biomass burning emissions in atmospheric particulate matter, and several analytical techniques have been presented for the determination of levoglucosan from filter samples. In this paper, a novel combination of a particle-into-liquid sampler (PILS) to a high-performance anion-exchange chromatograph (HPAEC) with the detection by a mass spectrometer (MS) is presented for the online analysis of levoglucosan in ambient particles. The PILS-HPAEC-MS technique enables a fast online analysis of levoglucosan from the particulate samples. The method was tested at an urban background station in Helsinki, Finland, in winter 2011. A comparison with simultaneous levoglucosan measurements from filter samples by the HPAEC-MS was performed and it showed a good agreement between the online and offline methods. Additionally, the online levoglucosan data were compared with the biomass burning tracer fragments measured by a high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS). As there were no local biomass burning sources close to the measurement station, online levoglucosan measurements revealed that most of the particles from biomass burning were either regionally distributed or long-range transported in the urban background of Helsinki. The average levoglucosan concentrations were relatively low (average 0.083 μg m-3) during the measurement campaign. The highest concentration peak measured for levoglucosan (1.4 μg m-3) seemed to originate from biomass burning in the Baltic countries, likely in Estonia, that was transported to Helsinki.

  9. Effectiveness of street sweeping and washing for controlling ambient TSP

    Science.gov (United States)

    Chang, Yu-Min; Chou, Chih-Mei; Su, Kuo-Tung; Tseng, Chao-Heng

    Effectiveness of street sweeping and washing (S/W) for controlling ambient "total suspended particles (TSP)" was evaluated by TSP measurements and determining silt load from active traffic streets. A modified regenerative-air vacuum sweeper (RAVS) and a washer were used in this study. The sweeper made a pass followed by the washer. The S/W efficiencies (η,η) were obtained based on the experimental data of silt loading and TSP. It was found that the direct impact of sweeping on ambient TSP emissions was short-lived lasting no more than 3-4 h. When a vacuum sweeper and a washer, respectively, did a good job collecting or cleaning the visible fine particles on roads, the method of S/W tested in this work was effective at removing the sources of the road dust particles. This paper concludes that street sweeping followed by washing was found to offer a measurable reduction in TSP emission potentials. Typically, the reduction efficiency of ambient TSP is up to 30%. Finally, correlated with η (based on silt loading), a useful equation is proposed to estimate the S/W efficiency, η (based on TSP) with a standard error of ±20%. It seems feasible to predict the reduction efficiency of ambient TSP controlled by the regenerative-air vacuum sweeper and washer used in this work for engineering applications. Effects of traffic volume and wind velocity on the S/W efficiencies are also discussed in the paper.

  10. In-situ ambient quantification of monoterpenes, sesquiterpenes, and related oxygenated compounds during BEARPEX 2007: implications for gas- and particle-phase chemistry

    Science.gov (United States)

    Bouvier-Brown, N. C.; Goldstein, A. H.; Gilman, J. B.; Kuster, W. C.; de Gouw, J. A.

    2009-08-01

    We quantified ambient mixing ratios of 9 monoterpenes, 6 sesquiterpenes, methyl chavicol, the oxygenated terpene linalool, and nopinone using an in-situ gas chromatograph with a quadrupole mass spectrometer (GC-MS). These measurements were a part of the 2007 Biosphere Effects on AeRosols and Photochemistry EXperiment (BEARPEX) at Blodgett Forest, a ponderosa pine forest in the Sierra Nevada Mountains of California. To our knowledge, these observations represent the first direct in-situ ambient quantification of the sesquiterpenes α-bergamotene, longifolene, α-farnesene, and β-farnesene. From average diurnal mixing ratio profiles, we show that α-farnesene emissions are dependent mainly on temperature whereas α-bergamotene and β-farnesene emissions are temperature- and light-dependent. The amount of sesquiterpene mass quantified above the canopy was small (averaging a total of 3.3 ppt during the day), but nevertheless these compounds contributed 7.6% to the overall ozone-olefin loss rate above the canopy. Assuming that the monoterpene-to-sesquiterpene emission rate in the canopy is similar to that observed in branch enclosure studies at the site during comparable weather conditions, and the average yield of aerosol mass from these sesquiterpenes is 10-50%, the amount of sesquiterpene mass reacted within the Blodgett Forest canopy alone accounts for 6-32% of the total organic aerosol mass measured during BEARPEX. The oxygenated monoterpene linalool was also quantified for the first time at Blodgett Forest. The linalool mass contribution was small (9.9 ppt and 0.74 ppt within and above the canopy, respectively), but it contributed 1.1% to the total ozone-olefin loss rate above the canopy. Reactive and semi-volatile compounds, especially sesquiterpenes, significantly impact the gas- and particle-phase chemistry of the atmosphere at Blodgett Forest and should be included in both biogenic volatile organic carbon emission and atmospheric chemistry models.

  11. In-situ ambient quantification of monoterpenes, sesquiterpenes, and related oxygenated compounds during BEARPEX 2007 – implications for gas- and particle-phase chemistry

    Directory of Open Access Journals (Sweden)

    N. C. Bouvier-Brown

    2009-04-01

    Full Text Available We quantified ambient mixing ratios of 9 monoterpenes, 6 sesquiterpenes, methyl chavicol, the oxygenated terpene linalool, and nopinone using an in-situ gas chromatograph with a quadrupole mass spectrometer (GC-MS. These measurements were a part of the 2007 Biosphere Effects on AeRosols and Photochemistry EXperiment (BEARPEX at Blodgett Forest, a ponderosa pine forest in the Sierra Nevada Mountains of California. To our knowledge, these observations represent the first direct in-situ ambient quantification of the sesquiterpenes α-bergamotene, longifolene, α-farnesene, and β-farnesene. From average diurnal mixing ratio profiles, we show that α-farnesene emissions are dependent mainly on temperature whereas α-bergamotene and β-farnesene emissions are temperature- and light-dependent. The amount of sesquiterpene mass quantified above the canopy was small (averaging a total of 3.3 ppt during the day, but nevertheless these compounds contributed 8.5% to the overall ozone reactivity above the canopy. Assuming that the monoterpene-to-sesquiterpene emission rate in the canopy is similar to that observed in branch enclosure studies at the site during comparable weather conditions, and the average yield of aerosol mass from these sesquiterpenes is 10–50%, the amount of sesquiterpene mass reacted within the Blodgett Forest canopy alone accounts for 8–38% of the total organic aerosol mass measured during BEARPEX. The oxygenated monoterpene linalool was also quantified for the first time at Blodgett Forest. The linalool mass contribution was small (9.9 ppt and 0.74 ppt within and above the canopy, respectively, but it contributed 1.2% to the total ozone reactivity above the canopy. Reactive and semi-volatile compounds, especially sesquiterpenes, significantly impact the gas- and particle-phase chemistry of the atmosphere at Blodgett Forest and should be included in both biogenic volatile organic carbon emission and atmospheric chemistry models.

  12. In-situ ambient quantification of monoterpenes, sesquiterpenes, and related oxygenated compounds during BEARPEX 2007: implications for gas- and particle-phase chemistry

    Directory of Open Access Journals (Sweden)

    N. C. Bouvier-Brown

    2009-08-01

    Full Text Available We quantified ambient mixing ratios of 9 monoterpenes, 6 sesquiterpenes, methyl chavicol, the oxygenated terpene linalool, and nopinone using an in-situ gas chromatograph with a quadrupole mass spectrometer (GC-MS. These measurements were a part of the 2007 Biosphere Effects on AeRosols and Photochemistry EXperiment (BEARPEX at Blodgett Forest, a ponderosa pine forest in the Sierra Nevada Mountains of California. To our knowledge, these observations represent the first direct in-situ ambient quantification of the sesquiterpenes α-bergamotene, longifolene, α-farnesene, and β-farnesene. From average diurnal mixing ratio profiles, we show that α-farnesene emissions are dependent mainly on temperature whereas α-bergamotene and β-farnesene emissions are temperature- and light-dependent. The amount of sesquiterpene mass quantified above the canopy was small (averaging a total of 3.3 ppt during the day, but nevertheless these compounds contributed 7.6% to the overall ozone-olefin loss rate above the canopy. Assuming that the monoterpene-to-sesquiterpene emission rate in the canopy is similar to that observed in branch enclosure studies at the site during comparable weather conditions, and the average yield of aerosol mass from these sesquiterpenes is 10–50%, the amount of sesquiterpene mass reacted within the Blodgett Forest canopy alone accounts for 6–32% of the total organic aerosol mass measured during BEARPEX. The oxygenated monoterpene linalool was also quantified for the first time at Blodgett Forest. The linalool mass contribution was small (9.9 ppt and 0.74 ppt within and above the canopy, respectively, but it contributed 1.1% to the total ozone-olefin loss rate above the canopy. Reactive and semi-volatile compounds, especially sesquiterpenes, significantly impact the gas- and particle-phase chemistry of the atmosphere at Blodgett Forest and should be included in both biogenic volatile organic carbon emission and atmospheric chemistry

  13. Ambient Space and Ambient Sensation

    DEFF Research Database (Denmark)

    Schmidt, Ulrik

    The ambient is the aesthetic production of the sensation of being surrounded. As a concept, 'ambient' is mostly used in relation to the music genre 'ambient music' and Brian Eno's idea of environmental background music. However, the production of ambient sensations must be regarded as a central...... aspect of the aesthetization of modern culture in general, from architecture, transport and urbanized lifeforms to film, sound art, installation art and digital environments. This presentation will discuss the key aspects of ambient aesthetization, including issues such as objectlessness...

  14. Consequences of Developmental Exposure to Concentrated Ambient Ultrafine Particle Air Pollution Combined with the Adult Paraquat and Maneb Model of the Parkinson’s Disease Phenotype in Male Mice

    OpenAIRE

    Allen, Joshua L.; Liu, Xiufang; Weston, Douglas; Conrad, Katherine; Oberdörster, Günter; Cory-Slechta, Deborah A.

    2014-01-01

    Current evidence suggests suceptibility of both the substantia nigra and striatum to exposure to components of air pollution. Further, air pollution has been associated with increased risk of PD diagnsosis in humans or PD-like pathology in animals. This study examined whether exposure of mice to concentrated ambient ultrafine particles (CAPS;

  15. Receptor modelling of fine particles in southern England using CMB including comparison with AMS-PMF factors

    Science.gov (United States)

    Yin, J.; Cumberland, S. A.; Harrison, R. M.; Allan, J.; Young, D. E.; Williams, P. I.; Coe, H.

    2015-02-01

    PM2.5 was collected during a winter campaign at two southern England sites, urban background North Kensington (NK) and rural Harwell (HAR), in January-February 2012. Multiple organic and inorganic source tracers were analysed and used in a Chemical Mass Balance (CMB) model, which apportioned seven separate primary sources, that explained on average 53% (NK) and 56% (HAR) of the organic carbon (OC), including traffic, woodsmoke, food cooking, coal combustion, vegetative detritus, natural gas and dust/soil. With the addition of source tracers for secondary biogenic aerosol at the NK site, 79% of organic carbon was accounted for. Secondary biogenic sources were represented by oxidation products of α-pinene and isoprene, but only the former made a substantial contribution to OC. Particle source contribution estimates for PM2.5 mass were obtained by the conversion of the OC estimates and combining with inorganic components ammonium nitrate, ammonium sulfate and sea salt. Good mass closure was achieved with 81% (92% with the addition of the secondary biogenic source) and 83% of the PM2.5 mass explained at NK and HAR respectively, with the remainder being secondary organic matter. While the most important sources of OC are vehicle exhaust (21 and 16%) and woodsmoke (15 and 28%) at NK and HAR respectively, food cooking emissions are also significant, particularly at the urban NK site (11% of OC), in addition to the secondary biogenic source, only measured at NK, which represented about 26%. In comparison, the major source components for PM2.5 at NK and HAR are inorganic ammonium salts (51 and 56%), vehicle exhaust emissions (8 and 6%), secondary biogenic (10% measured at NK only), woodsmoke (4 and 7%) and sea salt (7 and 8%), whereas food cooking (4 and 1%) showed relatively smaller contributions to PM2.5. Results from the CMB model were compared with source contribution estimates derived from the AMS-PMF method. The overall mass of organic matter accounted for is rather

  16. Biological activities of organic compounds adsorbed onto ambient air particles: comparison between the cities of Teplice and Prague during the summer and winter seasons 2000-2001

    Energy Technology Data Exchange (ETDEWEB)

    Binkova, Blanka; Cerna, Milena; Pastorkova, Anna; Jelinek, Richard; Benes, Ivan; Novak, Jiri; Sram, Radim J

    2003-04-09

    The capital of the Czech Republic, Prague, appears today to be one of the most polluted residential areas in the country, whereas air pollution in the Northern Bohemia region (the former 'Black Triangle Region') has substantially decreased during the last decade, especially with respect to the gaseous pollutant SO{sub 2}. This study evaluated the biological activities of complex mixtures of organic compounds adsorbed onto ambient air particles (PM10) collected during the summer and winter seasons of 2000-2001 at three monitoring sites - Teplice (TP), Prague-Smichov (PRG-SM) (city centre) and Prague-Libus (PRG-LB) (suburban area). The following short-term in vitro assays with strikingly different endpoints were used: a bacterial mutagenicity test using the Salmonella typhimurium tester strain TA98 and YG1041, an acellular assay (CT DNA) combined with {sup 32}P-postlabelling to evaluate DNA adduct-forming potency and the chick embryotoxicity screening test (CHEST). The results of the mutagenicity test with the YG1041 strain, the acellular genotoxicity (DNA adducts) and the embryotoxicity tests responded to the amount of eight carcinogenic polycyclic aromatic hydrocarbons (PAHs) analysed in the EOM (dichloromethane extractable organic matter) samples tested. Nevertheless, the biological effects of the EOM did not differ between locations. The highest biological activity of the ambient air in terms of organic compounds associated with particles (per unit volume of air) was seen in the Prague city centre during both summer and winter seasons. At this location, B[a]P concentration ranged from 0.1 to 8.9 ng/m{sup 3} (mean 0.3 and 3.6 ng/m{sup 3} for summer and winter seasons, respectively), 13 PAHs ranged from 11 to 343 ng/m{sup 3} (mean 52 and 160 ng/m{sup 3} for summer and winter seasons, respectively). Generally, using in vitro tests, higher ambient air activity was found in the winter season as compared with the summer season at all three monitoring sites

  17. Transport, biomass burning, and in-situ formation contribute to fine particle concentrations at a remote site near Grand Teton National Park

    Science.gov (United States)

    Schurman, M. I.; Lee, T.; Desyaterik, Y.; Schichtel, B. A.; Kreidenweis, S. M.; Collett, J. L.

    2015-07-01

    Ecosystem health and visibility degradation due to fine-mode atmospheric particles have been documented in remote areas and motivate particle characterization that can inform mitigation strategies. This study explores submicron (PM1) particle size, composition, and source apportionment at Grand Teton National Park using High-Resolution Time-of-Flight Aerosol Mass Spectrometer data with Positive Matrix Factorization and MODIS fire information. Particulate mass averages 2.08 μg/m3 (max = 21.91 μg/m3) of which 75.0% is organic; PMF-derived Low-Volatility Oxygenated Organic Aerosol (LV-OOA) averages 61.1% of PM1 (or 1.05 μg/m3), with sporadic but higher-concentration biomass burning (BBOA) events contributing another 13.9%. Sulfate (12.5%), ammonium (8.7%), and nitrate (3.8%) are generally low in mass. Ammonium and sulfate have correlated time-series and association with transport from northern Utah and the Snake River Valley. A regionally disperse and/or in situ photochemical LV-OOA source is suggested by 1) afternoon concentration enhancement not correlated with upslope winds, anthropogenic NOx, or ammonium sulfate, 2) smaller particle size, higher polydispersity, and lower levels of oxidation during the day and in comparison to a biomass burning plume inferred to have traveled ∼480 km, and 3) lower degree of oxidation than is usually observed in transported urban plumes and alpine sites with transported anthropogenic OA. CHN fragment spectra suggest organic nitrogen in the form of nitriles and/or pyridines during the day, with the addition of amine fragments at night. Fires near Boise, ID may be the source of a high-concentration biomass-burning event on August 15-16, 2011 associated with SW winds (upslope from the Snake River Valley) and increased sulfate, ammonium, nitrate, and CHN and CHON fragments (nominally, amines and organonitrates). Comparison to limited historical data suggests that the amounts and sources of organics and inorganics presented here

  18. Particulate composition characteristics under different ambient air quality conditions.

    Science.gov (United States)

    Tsai, Jiun-Horng; Chang, Lisa Tzu-Chi; Huang, Yao-Sheng; Chiang, Hung-Lung

    2011-07-01

    Particulate compositions including elemental carbon (EC), organic carbon (OC), water-soluble ionic species, and elemental compositions were investigated during the period from 2004 to 2006 in southern Taiwan. The correlation between the pollutant standard index (PSI) of ambient air quality and the various particle compositions was also addressed in this study. PSI revealed a correlation with fine (r = 0.74) and coarse (r = 0.80) particulate matter (PM). PSI manifested a significant correlation with the amount of analyzed ionic species (r approximately 0.80) in coarse and fine particles and a moderate correlation with carbon content (r = 0.63) in fine particles; however, it showed no correlation with elemental content. Although the ambient air quality ranged from good to moderate, the ionic species including chloride (Cl-), nitrate (NO3-), sulfate (SO4(2-)), sodium (Na+), ammonium (NH4+), magnesium (Mg2+), and calcium (Ca2+) increased significantly (1.5-3.7 times for Daliao and 1.8-6.9 times for Tzouying) in coarse PM. For fine particles, NO3-, SO4(2-), NH4+, and potassium (K+) also increased significantly (1.3-2.4 times for Daliao and 2.8-9.6 times for Tzouying) when the air quality went from good to moderate. For meteorological parameters, temperature evidenced a slightly negative correlation with PM concentration and PSI value, which implied a high PM concentration in the low-temperature condition. This reflects the high frequency of PM episodes in winter and spring in southern Taiwan. In addition, the mixing height increase from 980 to 1450 m corresponds to the air quality condition changing from unhealthy to good. PMID:21850835

  19. Different immunomodulatory effects associated with sub-micrometer particles in ambient air from rural, urban and industrial areas

    International Nuclear Information System (INIS)

    Immunomodulatory effects of chemicals adsorbed to particles with aerodynamic diameter below 0.49 μm (PM0.5) collected in winter 2001 at three sampling points (industrial area [LPIn], traffic-influenced urban area [LPCi], and control area [LPCo]) of La Plata, Argentina, were investigated. The sampling of particulate matter was carried out with high-volume collectors using cascade impactors. PM0.5-adsorbed compounds were hexane-extracted by accelerated solvent extraction. For immunological investigations, human peripheral blood lymphocytes were activated by phytohemagglutinin and exposed to dimethyl-sulfoxide dilutions of PM0.5-extracts for 24 h. Vitality/proliferation was quantified using MTT, released interferon-γ (IFN-γ) and interleukin-4 (IL-4) by ELISA. Cytokine production but not vitality/proliferation was significantly suppressed by all of the highest extract concentrations. Generally, suppression of IFN-γ by PM0.5-extracts was stronger than those of IL-4. Based on administered mass of PM0.5, all extracts suppressed IFN-γ production nearly uniform. Contrary, LPCi-extracts exerted maximum IFN-γ suppression based either on air volume or regarding PM0.5-adsorbed PAH. Also the ranking of PM0.5-associated effects on IL-4 production differs in dependence of the chosen reference points, either mass or [μg/ml] or air volume [m3/ml] related dust quantities in cell culture. Based on the corresponding air volume, LPCi-extracts inhibited IL-4 production to the maximum extend, whereas suppression of IL-4 was comparable based on concentrations. This indicates that not only the disparate PM0.5-masses in air cause varying impacts, but also that disparities in PM0.5-adsorbed chemicals provoke different effects on immune responses and shifts in the regulatory balance that might have implications for allergy and cancer development

  20. Comparison of sources of urban ambient particle bound PAHs between non-heating seasons 2009 and 2012 in Belgrade, Serbia

    Directory of Open Access Journals (Sweden)

    Cvetković Anka

    2015-01-01

    Full Text Available Exposure to increased cconcentrations of polycyclic aromatic hydrocarbons (PAHs is associated with adverse health problems and specifically with carcinogenic and mutagenic effects. The major PAH sources outdoors are: stationary sources from industry (power plants, incineration, local industry and domestic sources as the residential heating, burning and pyrolysis of coal, oil, gas, garbage, wood, or other organic substances mobile emissions (diesel and petrol engines, biomass burning and agricultural activities (e.g., open burning of brushwood, straw, stubble. The aim of this study was to assess potential differences in particle-bound PAH levels and source contribution between summer 2009 and 2012 sampling campaigns done at same location in Belgrade urban area. The sampling location is considered representative for a mix of residential, business and industrial areas of New Belgrade, an urban area that has been under rapid development. The average concentrations of PM10 are slightly higher in summer 2012 than in 2009. PM-bound PAH follow the same trend as the PM indicating an increasing strength of PAH sources relative to all PM sources. Appling Positive Matrix Factorization, three potential sources of PAHs in the atmosphere were distinguished: (1 stationary sources, (2 traffic (diesel and gasoline vehicle exhaust and (3 local open burning sources (OBS. The analysis confirmed higher contribution of traffic and lower of OBS in summer 2012 than in 2009, reflecting higher traffic volumes and absence of or lower local OBS emissions due to burning wood, grass and domestic waste in 2012. [Projekat Ministarstva nauke Republike Srbije, br. III41028

  1. Development of an Optical system for the determination of concentration of fine particulate material

    International Nuclear Information System (INIS)

    We have developed a new system of passive recollection of fine particulate material present in ambient air. Preliminary measurements under field conditions show the success of the new design with an increased collection efficiency. In addition, we have used a simple optical system as an alternative to the regular gravimetric technique for the determination of particle concentration. Laboratory tests of the optical method display good correlation with standard mass measurements. (Author)

  2. Regular Changes in the Fine Structure of Histograms Revealed in the Experiments with Collimators which Isolate Beams of Alpha-Particles Flying at Certain Directions

    Directory of Open Access Journals (Sweden)

    Shnoll S. E.

    2009-04-01

    Full Text Available As was shown in the works of 1951–1983, the fine structure of distributions of the re- sults of measurements of processes of diverse nature is not casual. The changes in the shape of histograms corresponding to the distributions were called “macroscopic fluctu- ations”. The universal character of the phenomenon and its independence of the nature of the process studied were demonstrated for various processes: biochemical and chem- ical reactions, movement of latex particles in the electric field, proton transverse relax- ation in the inhomogeneous magnetic field, discharge in the neon-tube RC-generator and radioactive decay of various - and -isotopes. Since 1982, the main object chosen to study macroscopic fluctuations has been -decay. The choice was based on the pro- cess being a priori independent of trivial factors and the possibility to conduct continu- ous long-term automatic measurements while storing the results in a computer archive (database. Started in 1982, these measurements have been carrying on, as unceasingly as possible, until now. Since July 2000, the measurements are conducted using devices designed by one of the coauthors of this review, I. A. Rubinstein. Application of these devices (especially, detectors with collimators which isolate beams of -particles fly- ing at certain directions, along with the use of Edwin Pozharsky’s computer program, which eases histogram comparing by the expert, has allowed us to reveal a number of fundamentally new regularities. In the review, we describe these regularities, device constructions, and the methods of measurement and analysis of the results obtained.

  3. Emissions of Greenhouse Gases and Fine Particles (PM2.5) from Wildland Fires in the United States from 2003 to 2011

    Science.gov (United States)

    Huang, S.; Larkin, N. K.; Raffuse, S. M.

    2013-12-01

    Wildland fires not only affect adjacent communities, but also produce smoke that can travel long distances and significantly impact downwind communities, alter weather patterns, and contribute to global climate change. As air quality standards have tightened, smoke from wildland fires has faced greater scrutiny from the air quality management community. Wildland fire emissions in the United States from 2003 to 2011 were estimated using the SmartFire2 system and the BlueSky Smoke Modeling Framework. Based on various sources of observational fire activity data, including ground-based incident reports and satellite-derived fire perimeters, fire information was reconciled and passed through a chain of models that estimate fuel loading, fuel consumption, and smoke emissions. While the spatial and temporal distributions of prescribed fires follow a stable pattern, wildfires are difficult to predict and their effects vary greatly from fire to fire. We analyzed the area burned and the emissions of select greenhouse gases (carbon dioxide and methane) and fine particles (PM2.5) from the model outputs to characterize long-term temporal and spatial variations. We will present these results, discuss factors that cause variability and uncertainty, and make comparisons to typical global modeling methods.

  4. STB-HO, a novel mica fine particle, inhibits the teratoma-forming ability of human embryonic stem cells after in vivo transplantation.

    Science.gov (United States)

    Choi, Soon Won; Shin, Tae-Hoon; Uddin, Md Hafiz; Shin, Ji-Hee; Kang, Tae-Wook; Lee, Byung-Chul; Kim, Hyung-Sik; Seo, Yoojin; Shams, Sulaiman; Jung, Yeon-Kwon; Kang, Kyung-Sun

    2016-01-19

    Although pluripotent stem cell (PSC) therapy has advantages for clinical applications because of the self-renewal and multi-lineage differentiation abilities of PSCs, it also has disadvantages in terms of the potential for PSCs to undergo malignant transformation or unexpected differentiation. The prevention of teratoma formation is the largest hurdle of all. Despite intensive studies that have investigated ways to block teratomas, such methods have yet to be further developed for clinical use. Here, a new approach has focused on exerting anti-tumorigenic effects using a novel mica fine particle (MFP) designated STB-HO. Treatment with STB-HO regulated pluripotency- and apoptosis-related genes in differentiating human embryonic stem (hES) cells, while there is no effects in undifferentiated hES cells. In particular, STB-HO blocked the anti-apoptotic gene BIRC5 and activated p53, p21 and the pro-apoptotic proteins Bim, Puma and p-Bad during early spontaneous differentiation. Moreover, STB-HO-pretreated differentiating hES cells did not give rise to teratomas following in vivo stem cell transplantation. Our in vitro and in vivo results suggest a method for teratoma prevention in the context of PSC-derived cell transplantation. This novel MFP could break through the limitations of PSC therapy. PMID:26646796

  5. Contribution of woodsmoke and motor vehicle emissions to ambient aerosol mutagenicity

    International Nuclear Information System (INIS)

    A multiple linear regression form of receptor modeling has been used to determine the sources of the mutagenicity of fine-particle ambient aerosol samples collected during the winter in a residential area of Albuquerque, NM. Virtually all the mutagenicity (Salmonella typhimurium TA98 + S9) could be accounted for by woodsmoke and motor vehicle emissions. Woodsmoke was found to be the greater contributor to the average ambient concentrations of both extractable organ is and mutagenicity. The mutagenic potency (revertants per microgram) of extractable organics traced to motor vehicles, however, was 3 times greater than that with a woodsmoke origin. The results were confirmed by 14C measurements

  6. Technical comments on EPA`s proposed revisions to the National Ambient Air Quality Standard for particulate matter

    Energy Technology Data Exchange (ETDEWEB)

    Lipfert, F.W.

    1997-03-01

    The US Environmental Protection Agency (EPA) has proposed new ambient air quality standards specifically for fine particulate matter, regulating concentrations of particles with median aerodynamic diameters less than 2.5 {mu}m (PM{sub 2.5}). Two new standards have been proposed: a maximum 24-hr concentration that is intended to protect against acute health effects, and an annual concentration limit that is intended to protect against longer-term health effects. EPA has also proposed a slight relaxation of the 24-hr standard for inhalable particles (PM{sub 10}), by allowing additional exceedances each year. Fine particles are currently being indirectly controlled by means of regulations for PM{sub 10} and TSP, under the Clean Air Act of 1970 and subsequent amendments. Although routine monitoring of PM{sub 2.5} is rare and data are sparse, the available data indicate that ambient concentrations have been declining at about 6% per year under existing regulations.

  7. Det ambiente

    DEFF Research Database (Denmark)

    Schmidt, Ulrik

    Om begrebet "det ambiente", der beskriver, hvad der sker, når vi fornemmer baggrundsmusikkens diskrete beats, betragter udsigten gennem panoramavinduet eller tager 3D-brillerne på og læner os tilbage i biografsædet. Bogen analyserer, hvorfan ambiente oplevelser skabes, og hvilke konsekvenser det...

  8. Ambient Sensors

    OpenAIRE

    Börner, Dirk; Specht, Marcus

    2014-01-01

    This software sketches comprise two custom-built ambient sensors, i.e. a noise and a movement sensor. Both sensors measure an ambient value and process the values to a color gradient (green > yellow > red). The sensors were built using the Processing 1.5.1 development environment. Available under the GNU LGPL licence version 3 or higher.

  9. Ambient Sensors

    NARCIS (Netherlands)

    Börner, Dirk; Specht, Marcus

    2014-01-01

    This software sketches comprise two custom-built ambient sensors, i.e. a noise and a movement sensor. Both sensors measure an ambient value and process the values to a color gradient (green > yellow > red). The sensors were built using the Processing 1.5.1 development environment. Available under th

  10. 颗粒细度与粉煤灰-水泥胶凝体系韧性关系研究%Research on relationship between particle fineness and toughness of fly ash- cement

    Institute of Scientific and Technical Information of China (English)

    袁晓露; 周世华

    2013-01-01

    为了弄清水泥与粉煤灰颗粒细度对水泥石韧性的影响,利用灰色关联理论,试验研究了水泥和粉煤灰颗粒细度与粉煤灰-水泥胶凝体系韧性间的关系。试验结果表明,影响粉煤灰-水泥体系韧性的因素排序为:粉煤灰颗粒细度>水泥颗粒细度>水泥与粉煤灰颗粒细度之差。适当增大粉煤灰的比表面积以及水泥与粉煤灰间比表面积的差异、降低水泥的比表面积,对于提高粉煤灰-水泥体系的韧性是有利的。%In order to study the influence of fineness of cement and fly ash on toughness of cement stone, we used grey correla-tion analysis to study the correlation between the particle fineness of cement and fly ash and the toughness of fly-ash cement. The results showed that the factors influencing the toughness of fly-ash cement the most is particle fineness of fly ash, followed by particle fineness of cement and the difference of particle fineness between cement and fly ash. Toughness of fly ash cement can be improved by increasing the specific surface area of fly ash and the difference of specific surface areas between cement and fly ash, and reducing the specific surface area of cement properly.

  11. Det Ambiente

    DEFF Research Database (Denmark)

    Schmidt, Ulrik

    Det ambiente er iscenesættelsen af en karakteristisk sanseoplevelse, der er kendetegnet ved fornemmelsen af at være omgivet. I dag bliver begrebet om det ambiente mest anvendt i forbindelse med musikgenren ’ambient musik’. Det ambiente er dog ikke essentielt knyttet til det musikalske, men må...... forstås som et betydeligt bredere fænomen i den moderne æstetiske kultur, der spiller en væsentlig rolle i oplevelsen af moderne transportformer, arkitektur, film, lydkunst, installationskunst og digitale multimedieiscenesættelser. En forståelse af det ambiente er derfor centralt for forståelsen af en...... moderne æstetiseret oplevelseskultur i almindelighed. Da det ambiente ikke hidtil har været gjort til genstand for en mere indgående teoretisk behandling, er der dog stor usikkerhed omkring, hvad fænomenet overhovedet indebærer. Hovedformålet med Det ambiente – Sansning, medialisering, omgivelse er derfor...

  12. Effect of particle size on the flux pinning properties of YBa2Cu3O7–δ thin films containing fine Y2O3 nanoprecipitates

    Science.gov (United States)

    Yamasaki, H.

    2016-06-01

    The magnetic-field angle dependence of the critical current density, J c(H, θ), was measured at various temperatures in co-evaporated YBa2Cu3O7–δ (YBCO) thin films. The YBCO films showed volcano-shaped J c(θ) peaks around H//ab, and J c(θ) peaks around H//c were not observed. Film A, deposited at a lower temperature than the commercial standard film B, showed lower J c values at high temperatures (T ≥ 60 K) compared with film B, although film A showed higher J c at T = 20 K. Plan-view transmission electron microscope observations revealed that films A and B contained a high density of fine Y2O3 nanoprecipitates. The modes in the distribution of their cross-sectional areas are 10–20 nm2 in film A and 20–30 nm2 in film B. Because of the smaller particle size, film A showed lower J c at high temperatures owing to the smaller elementary pinning force, f p, but showed higher J c at 20 K where the temperature-dependent coherence length ξ ab (T) was short (∼2 nm) and comparable with the radius of Y2O3 nanoparticles. Film A showed anisotropic scaling behavior at T = 70–80 K, and the T dependence of J c followed ∼(1 ‑ T/T c) m (1 + T/T c)2 (m ≈ 2.5), which was expected from a simple flux-pinning model.

  13. Knock Resistance and Fine Particle Emissions for Several Biomass-Derived Oxygenates in a Direct-Injection Spark-Ignition Engine

    Energy Technology Data Exchange (ETDEWEB)

    Ratcliff, Matthew A.; Burton, Jonathan; Sindler, Petr; Christensen, Earl; Fouts, Lisa; Chupka, Gina M.; McCormick, Robert L.

    2016-04-01

    Several high octane number oxygenates that could be derived from biomass were blended with gasoline and examined for performance properties and their impact on knock resistance and fine particle emissions in a single cylinder direct-injection spark-ignition engine. The oxygenates included ethanol, isobutanol, anisole, 4-methylanisole, 2-phenylethanol, 2,5-dimethyl furan, and 2,4-xylenol. These were blended into a summertime blendstock for oxygenate blending at levels ranging from 10 to 50 percent by volume. The base gasoline, its blends with p-xylene and p-cymene, and high-octane racing gasoline were tested as controls. Relevant gasoline properties including research octane number (RON), motor octane number, distillation curve, and vapor pressure were measured. Detailed hydrocarbon analysis was used to estimate heat of vaporization and particulate matter index (PMI). Experiments were conducted to measure knock-limited spark advance and particulate matter (PM) emissions. The results show a range of knock resistances that correlate well with RON. Molecules with relatively low boiling point and high vapor pressure had little effect on PM emissions. In contrast, the aromatic oxygenates caused significant increases in PM emissions (factors of 2 to 5) relative to the base gasoline. Thus, any effect of their oxygen atom on increasing local air-fuel ratio was outweighed by their low vapor pressure and high double-bond equivalent values. For most fuels and oxygenate blend components, PMI was a good predictor of PM emissions. However, the high boiling point, low vapor pressure oxygenates 2-phenylethanol and 2,4-xylenol produced lower PM emissions than predicted by PMI. This was likely because they did not fully evaporate and combust, and instead were swept into the lube oil.

  14. Quantification of environmentally persistent free radicals and reactive oxygen species in atmospheric aerosol particles

    OpenAIRE

    Arangio, Andrea M.; Tong, Haijie; Socorro, Joanna; Pöschl, Ulrich; Shiraiwa, Manabu

    2016-01-01

    Fine particulate matter plays a central role in adverse health effects of air pollution. Inhalation and deposition of aerosol particles in the respiratory tract can lead to the release of reactive oxygen species (ROS), which may cause oxidative stress. In this study, we have detected and quantified a wide range of particle-associated radicals using electron paramagnetic resonance (EPR) spectroscopy. Ambient particle samples were collected using a cascade impactor at a semi-urban site in centr...

  15. La intervención del derecho penal en materia de bioseguridad: la criminalización de la actividad empresarial biotecnológica de liberación intencional en el ambiente con fines comerciales y de comercialización de productos biotech

    OpenAIRE

    Tanus Job e Meira, Bruno

    2009-01-01

    [ES] El objetivo general del presente trabajo reside en analizar el sistema de control del riesgo biotecnológico relativo a las principales actividades por las cuales se utilizan las empresas biotech en el ámbito agroalimentario, es decir, las conductas de liberación en el ambiente con fines comerciales, así como la comercialización de “organismos modificados genéticamente” (OMGs) y sus derivados. Tales actividades son consideradas como las más importantes en el ámbito mercantil y, efectivame...

  16. Ambient Gestures

    OpenAIRE

    Karam, Maria; Hare, Jonathon; Lewis, Paul; schraefel, m.c.

    2006-01-01

    We present Ambient Gestures, a novel gesture-based system designed to support ubiquitous ‘in the environment’ interactions with everyday computing technology. Hand gestures and audio feedback allow users to control computer applications without reliance on a graphical user interface, and without having to switch from the context of a non-computer task to the context of the computer. The Ambient Gestures system is composed of a vision recognition software application, a set of gestures to be p...

  17. DIAGNOSTICO AMBIENTAL Y VALORACIÓN DE LOS RECURSOS PARA FINES TURÍSTICOS DE LOS ECOSISTEMAS DE MANGLAR EN LA BAHÍA DE BANDERAS, MÉXICO

    OpenAIRE

    Cruz Romero Bartolo; Luis Fernando González Guevara; Carmen Navarro Rodríguez

    2013-01-01

    Mediante una “Lista de chequeo” se establece el diagnóstico ambiental de los sistemas estuarinos de la Bahía de Banderas: El Salado, Boca Negra – Boca de Tomates y El Quelele; y se identifican los principales factores de presión ambiental en cada sistema. Los elementos ambientales considerados fueron el suelo, agua, aire, flora, fauna y paisaje. Los resultados indican que el paisaje de estos sistemas, ha perdido su calidad original y las principales causas han sido el cambio de uso de suelo y...

  18. DIAGNOSTICO AMBIENTAL Y VALORACIÓN DE LOS RECURSOS PARA FINES TURÍSTICOS DE LOS ECOSISTEMAS DE MANGLAR EN LA BAHÍA DE BANDERAS, MÉXICO.

    OpenAIRE

    Cruz Romero Bartolo; Luis Fernando González Guevara; Carmen Navarro Rodríguez

    2013-01-01

    Mediante una “Lista de chequeo” se establece el diagnóstico ambiental de los sistemas estuarinos de la Bahía de Banderas: El Salado, Boca Negra – Boca de Tomates y El Quelele; y se identifican los principales factores de presión ambiental en cada sistema. Los elementos ambientales considerados fueron el suelo, agua, aire, flora, fauna y paisaje. Los resultados indican que el paisaje de estos sistemas, ha perdido su calidad original y las principales causas han sido el cambio de uso de suelo y...

  19. Anne Fine

    Directory of Open Access Journals (Sweden)

    Philip Gaydon

    2015-04-01

    Full Text Available An interview with Anne Fine with an introduction and aside on the role of children’s literature in our lives and development, and our adult perceptions of the suitability of childhood reading material.Since graduating from Warwick in 1968 with a BA in Politics and History, Anne Fine has written over fifty books for children and eight for adults, won the Carnegie Medal twice (for Goggle-Eyes in 1989 and Flour Babies in 1992, been a highly commended runner-up three times (for Bill’s New Frock in 1989, The Tulip Touch in 1996, and Up on Cloud Nine in 2002, been shortlisted for the Hans Christian Andersen Award (the highest recognition available to a writer or illustrator of children’s books, 1998, undertaken the positon of Children’s Laureate (2001-2003, and been awarded an OBE for her services to literature (2003. Warwick presented Fine with an Honorary Doctorate in 2005.Philip Gaydon’s interview with Anne Fine was recorded as part of the ‘Voices of the University’ oral history project, co-ordinated by Warwick’s Institute of Advanced Study.

  20. Emission factors of fine particles, carbonaceous aerosols and traces gases from road vehicles: Recent tests in an urban tunnel in the Pearl River Delta, China

    Science.gov (United States)

    Zhang, Yanli; Wang, Xinming; Li, Guanghui; Yang, Weiqiang; Huang, Zhonghui; Zhang, Zhou; Huang, Xinyu; Deng, Wei; Liu, Tengyu; Huang, Zuzhao; Zhang, Zhanyi

    2015-12-01

    Motor vehicles contribute primarily and secondarily to air quality problems due to fine particle (PM2.5) and ozone (O3) pollution in China's megacities. Characterizing vehicle emission with the rapid change of vehicle numbers and fleet compositions is vital for both bottom-up emission survey and top-down source apportioning. To obtain emission factors (EFs) of PM2.5, carbonaceous aerosols and trace gases for road vehicles, in urban Guangzhou we conducted a field campaign in 2014 in the Zhujiang Tunnel, a heavily burdened tunnel with about 40,000 motor vehicles passing through each of its two separated bores per day. PM2.5 and volatile organic compounds (VOCs) were sampled for offline analysis while trace gases including SO2, NOx and CO were measured online and in situ. An eddy covariance system with an integrated 3-D sonic anemometer was also adopted to measure CO2 and winds inside the tunnel. We recorded an average fleet composition of 61% light-duty gasoline vehicles (LDVs) + 12% heavy-duty diesel vehicles (HDVs) + 27% liquefied petroleum gas vehicles (LPGVs), and EFs of 82.7 ± 28.3, 19.3 ± 4.7 and 13.3 ± 3.3 mg veh-1 km-1, respectively, for PM2.5, organic carbon (OC) and elemental carbon (EC). These EFs were respectively 23.4%, 18.3% and 72.3% lower when compared to that measured in the same tunnel in 2004. EFs of PM2.5, OC and EC were higher at night time (148 ± 126, 29 ± 24 and 21 ± 18 mg veh-1 km-1, respectively) due to significantly elevated fractions of HDVs in the traffic fleets. An average ratio of OC to EC 1.45 from this tunnel study was much higher than that of ∼0.5 in previous tunnel studies. The EFs of SO2, NOx, CO, CO2 and NMHCs for road traffic were also obtained from our tunnel tests, and they were 20.7 ± 2.9, (1.29 ± 0.2)E+03, (3.10 ± 0.68)E+03, (3.90 ± 0.49)E+05, and 448 ± 39 mg veh-1 km-1, respectively.

  1. Regulating drug release behavior and kinetics from matrix tablets based on fine particle-sized ethyl cellulose ether derivatives: an in vitro and in vivo evaluation.

    Science.gov (United States)

    Shah, Kifayat Ullah; Khan, Gul Majid

    2012-01-01

    The design and fabrication of sustained/controlled release dosage forms, employing new excipients capable of extending/controlling the release of drugs from the dosage forms over prolonged periods, has worked well in achieving optimally enhanced therapeutic levels of the drugs. In this sense, the objective of this study was to investigate the suitability of selected cellulose ether derivatives for use in direct compression (DC) and as efficient drug release controlling agents. Controlled release matrix tablets of ciprofloxacin were prepared at different drug-to-polymer (D : P) ratios by direct compression using a fine particle sized ethylcellulose ether derivative (ETHOCEL Standard Premium 7FP) as rate controlling polymer. The tablets obtained were evaluated for various physico-chemical characteristics and in-vitro drug release studies were conducted in phosphate buffer (pH 7.4) using PharmaTest dissolution apparatus at constant temperature of 37 °C ± 0.1. Similarity factor f(2) was employed to the release profiles of test formulations and were compared with marketed ciprofloxacin conventional tablets. Drug release mechanism and the kinetics involved were investigated by fitting the release profile data to various kinetic models. It was found that with increasing the proportion of ethylcellulose ether derivative in the matrix, the drug release was significantly extended up to 24 hours. The tablets exhibited zero order or nearly zero order drug transport mechanism. In vivo drug release performance of the developed controlled release tablets and reference conventional tablets containing ciprofloxacin were determined in rabbit serum according to randomized two-way crossover study design using High Performance Liquid Chromatography. Several bioavailability parameters of both the test tablets and conventional tablets including C(max⁡), T(max⁡) and AUC(0-t) were compared which showed an optimized C(max⁡) and T(max⁡) (P < 0.05). A good correlation was obtained

  2. Regulating Drug Release Behavior and Kinetics from Matrix Tablets Based on Fine Particle-Sized Ethyl Cellulose Ether Derivatives: An In Vitro and In Vivo Evaluation

    Directory of Open Access Journals (Sweden)

    Kifayat Ullah Shah

    2012-01-01

    Full Text Available The design and fabrication of sustained/controlled release dosage forms, employing new excipients capable of extending/controlling the release of drugs from the dosage forms over prolonged periods, has worked well in achieving optimally enhanced therapeutic levels of the drugs. In this sense, the objective of this study was to investigate the suitability of selected cellulose ether derivatives for use in direct compression (DC and as efficient drug release controlling agents. Controlled release matrix tablets of ciprofloxacin were prepared at different drug-to-polymer (D : P ratios by direct compression using a fine particle sized ethylcellulose ether derivative (ETHOCEL Standard Premium 7FP as rate controlling polymer. The tablets obtained were evaluated for various physico-chemical characteristics and in-vitro drug release studies were conducted in phosphate buffer (pH 7.4 using PharmaTest dissolution apparatus at constant temperature of 37∘C±0.1. Similarity factor 2 was employed to the release profiles of test formulations and were compared with marketed ciprofloxacin conventional tablets. Drug release mechanism and the kinetics involved were investigated by fitting the release profile data to various kinetic models. It was found that with increasing the proportion of ethylcellulose ether derivative in the matrix, the drug release was significantly extended up to 24 hours. The tablets exhibited zero order or nearly zero order drug transport mechanism. In vivo drug release performance of the developed controlled release tablets and reference conventional tablets containing ciprofloxacin were determined in rabbit serum according to randomized two-way crossover study design using High Performance Liquid Chromatography. Several bioavailability parameters of both the test tablets and conventional tablets including max, max and AUC0- were compared which showed an optimized max and max (<0.05. A good correlation was obtained between in vitro

  3. Fish oil and olive oil supplements attenuate the adverse cardiovascular effects of concentrated ambient air pollution particles exposure in healthy middle-aged adult human volunteers

    Science.gov (United States)

    Exposure to ambient levels of air pollution increases cardiovascular morbidity and mortality. Advanced age is among the factors associated with susceptibility to the adverse effects of air pollution. Dietary fatty acid supplementation has been shown to decrease cardiovascular ris...

  4. Toxicity of Ambient Particulate Matter (PM10) I. Acute toxicity study in asthmatic mice following 3-day exposure to ultrafine and fine ammonium bisulfate, a model compound for secondary aerosol fraction of PM10

    NARCIS (Netherlands)

    Cassee FR; Dormans JAMA; Loveren H van; Bree L van; Rombout PJA; LEO; LPI

    1998-01-01

    Presented here is the first in a series of 3-day inhalation studies aimed to generate data on the health effects of inhaled ultrafine and fine ammonium bisulfate aerosols as model compound for the secondary fraction of particulate matter (PM10). Epidemiologic studies identified asthmatics as a risk

  5. Toxicity of Ambient Particulate Matter II. Acute toxicity study in asthmatic mice following 3-day exposure to fine ammonium ferrosulfate, a model compound for secondary aerosol of PM10

    NARCIS (Netherlands)

    Cassee FR; Dormans JAMA; Loveren H van; Bree L van; Rombout PJA; LEO; LPI

    1998-01-01

    In this second report on acute inhalation studies with model compounds for secondary particulate matter, results are presented of a study with fine ammonium ferrosulfate aerosol in asthmatic animals. We hypothesised that an aerosol with a transitional metal could produce enhanced symptoms of asthma.

  6. Mass concentration and ion composition of coarse and fine particles in an urban area in Beirut: effect of calcium carbonate on the absorption of nitric and sulfuric acids and the depletion of chloride

    Science.gov (United States)

    Kouyoumdjian, H.; Saliba, N. A.

    2006-05-01

    Levels of coarse (PM10-2.5) and fine (PM2.5) particles were determined between February 2004 and January 2005 in the city of Beirut, Lebanon. While low PM mass concentrations were measured in the rainy season, elevated levels were detected during sand storms originating from Arabian desert and/or Africa. Using ATR-FTIR and IC, it was shown that nitrate, sulfate, carbonate and chloride were the main anionic constituents of the coarse particles, whereas sulfate was mostly predominant in the fine particles in the form of (NH4)2SO4. Ammonium nitrate was not expected to be important because the medium was defined as ammonium poor. In parallel, the cations Ca2+ and Na+ dominated in the coarse, and NH4+, Ca2+ and Na+ in the fine particles. Coarse nitrate and sulfate ions resulted from the respective reactions of nitric and sulfuric acid with a relatively high amount of calcium carbonate. Both CaCO3 and Ca(NO3)2 crystals identified by ATR-FTIR in the coarse particles were found to be resistant to soaking in water for 24 h but became water soluble when they were formed in the fine particles suggesting, thereby, different growth and adsorption phenomena. The seasonal variational study showed that nitrate and sulfate ion concentrations increased in the summer due to the enhancement of photochemical reactions which facilitated the conversion of NO2 and SO2 gases into NO3- and SO42-, respectively. While nitrate was mainly due to local heavy traffic, sulfates were due to local and long-range transport phenomena. Using the air mass trajectory HYSPLIT model, it was found that the increase in the sulfate concentration correlated with wind vectors coming from Eastern and Central Europe. Chloride levels, on the other hand, were high when wind originated from the sea and low during sand storms. In addition to sea salt, elevated levels of chloride were also attributed to waste mass burning in proximity to the site. In comparison to other neighboring Mediterranean countries, relatively

  7. Mass concentration and ion composition of coarse and fine particles in an urban area in Beirut: effect of calcium carbonate on the absorption of nitric and sulfuric acids and the depletion of chloride

    Directory of Open Access Journals (Sweden)

    H. Kouyoumdjian

    2006-01-01

    Full Text Available Levels of coarse (PM10-2.5 and fine (PM2.5 particles were determined between February 2004 and January 2005 in the city of Beirut, Lebanon. While low PM mass concentrations were measured in the rainy season, elevated levels were detected during sand storms originating from Arabian desert and/or Africa. Using ATR-FTIR and IC, it was shown that nitrate, sulfate, carbonate and chloride were the main anionic constituents of the coarse particles, whereas sulfate was mostly predominant in the fine particles in the form of (NH42SO4. Ammonium nitrate was not expected to be important because the medium was defined as ammonium poor. In parallel, the cations Ca2+ and Na+ dominated in the coarse, and NH4+, Ca2+ and Na+ in the fine particles. Coarse nitrate and sulfate ions resulted from the respective reactions of nitric and sulfuric acid with a relatively high amount of calcium carbonate. Both CaCO3 and Ca(NO32 crystals identified by ATR-FTIR in the coarse particles were found to be resistant to soaking in water for 24 h but became water soluble when they were formed in the fine particles suggesting, thereby, different growth and adsorption phenomena. The seasonal variational study showed that nitrate and sulfate ion concentrations increased in the summer due to the enhancement of photochemical reactions which facilitated the conversion of NO2 and SO2 gases into NO3- and SO42-, respectively. While nitrate was mainly due to local heavy traffic, sulfates were due to local and long-range transport phenomena. Using the air mass trajectory HYSPLIT model, it was found that the increase in the sulfate concentration correlated with wind vectors coming from Eastern and Central Europe. Chloride levels, on the other hand, were high when wind originated from the sea and low during sand storms. In addition to sea salt, elevated levels of chloride were also attributed to waste mass burning in proximity to the site. In comparison to other neighboring Mediterranean

  8. Relationship between the Particulate Matter Concentrations in the Indoor and Ambient Air of the Tehran Children Hospital in 2007

    OpenAIRE

    Soheila Rezaei; Kazem Naddafi; Hossain Jabbari; Masoud Yonesian; Arsalan Jamshidi; Abdolmohamad Sadat; Alireza Raygan Shirazinejad

    2013-01-01

    Background and Objectives: In recent years exposure to fine airborne particles has been identified as an important factor affecting human health. Epidemiological studies have showed that the aerosol laden air can be an agent for microorganisms’ dispersion. Ignoring internal sources, ambient air quality significantly affects indoor air quality. Since people spend most of their times in the indoor spaces and little data are available on the general understanding of the indoor air quality, the...

  9. Ambient intelligence

    OpenAIRE

    Sanders, David; Gegov, Alexander

    2006-01-01

    This paper considers some history and the state of the art of Ambient Intelligence and from that seeks to identify new topics and future work. Ubiquitous computing, communications, human-centric computer interaction, embedded systems, context awareness, adaptive systems and distributed device networks are considered.

  10. Ambient intelligence

    CERN Document Server

    Weber, W; Aarts, E

    2005-01-01

    Addresses ambient intelligence used to support human contacts and accompany an individual''s path through the complicated modern world, from applications that are imminent, since they use essentially existing technologies, to ambitious ideas whose realization is still far away, due to major unsolved technical challenges.

  11. THE BIMODAL DISTRIBUTION: DEVELOPMENT OF THE CONCEPT OF FINE AND COARSE PARTICLES AS SEPARATE AND DISTINCT COMPONENTS OF AIRBORNE PARTICULATE MATTER

    Science.gov (United States)

    In the early 1970s, it was understood that combustion particles were formed mostly in sizes below 1 um diameter, and windblown dust was suspended in sizes mostly above 1 um diameter. However, particle size distribution was thought of as a single mode. Particles were thought to f...

  12. Fine chemistry

    International Nuclear Information System (INIS)

    The 1988 progress report of the Fine Chemistry laboratory (Polytechnic School, France) is presented. The research programs are centered on the renewal of the organic chemistry most important reactions and on the invention of new, highly efficient and highly selective reactions, by applying low cost reagents and solvents. An important research domain concerns the study and fabrication of new catalysts. They are obtained by means of the reactive sputtering of the metals and metal oxydes thin films. The Monte Carlo simulations of the long-range electrostatic interaction in a clay and the obtention of acrylamides from anhydrous or acrylic ester are summarized. Moreover, the results obtained in the field of catalysis are also given. The published papers and the congress communications are included

  13. Ambient intelligence

    CERN Document Server

    Basten, Twan; de Groot, Harmke

    2007-01-01

    ""This book is truly an eye-opener as it is the first book that relates the dream scenarios of Ambient Intelligence quantitatively to the technical challenges and requirements of the huge distributed and interoperable embedded systems needed to implement AmI systems in the real world. This book is strongly recommended to a wide spectrum of engineers interested to embark in this rapidly emerging and fascinating technology."" (From the foreword by Hugo De Man, Professor K.U. Leuven and Senior Research Fellow IMEC)

  14. Waste Utilization as Fine Coconut Fiber for Core and Wood Waste Bayur to The Face Layer of The Physical and Mechanical Properties of Particle Board Produced

    Directory of Open Access Journals (Sweden)

    Sahadi Didi Ismanto

    2014-01-01

    Full Text Available This study aims to determine the effect of wood particle bayur comparison to the outer layer of coconut husk particle board smooth the physical and mechanical properties of the resulting particle board . The design used was completely randomized design ( CRD with 5 treatments with 3 replications for each treatment used is the use of wood particles bayur as the outer layer of particle board and refined coconut fiber as a core that is 80 % : 20 % , 70 % : 30 % , 60 % : 40 % , 50 % : 50 % , 40 % : 60 % observational data physical and mechanical properties were analyzed using analysis of variance if significantly different then performed with a further test of Duncan's New Multiple Range Test ( DMNRT at the 5% significance level . Observations made on the physical properties of particle board include : water content , water absorption and thickness expansion. The mechanical properties of particle board : strength broken , the pressure parallel and bonding strength. Based on the research that has been carried out showed that the utilization of wood waste bayur as the outer layer of particle board on a percentage varying significantly different effect on strength broken , water content , water absorption , expansion of thick , strength pressure bonding parallel to the internal surface . The results show the percentage of particle board with wood bayur with delicate coconut husk ( 40:60 is the best board with a water content of 6.11% , water absorption 20.56 % 10.93 % thicker expansion, density of 0.84 % , bonding strength of 56.90 kg / cm 2 pressure and parallel fiber determination 146.65 kg /cm 2.

  15. DIAGNOSTICO AMBIENTAL Y VALORACIÓN DE LOS RECURSOS PARA FINES TURÍSTICOS DE LOS ECOSISTEMAS DE MANGLAR EN LA BAHÍA DE BANDERAS, MÉXICO.

    Directory of Open Access Journals (Sweden)

    Cruz Romero Bartolo

    2013-06-01

    Full Text Available Mediante una “Lista de chequeo” se establece el diagnóstico ambiental de los sistemas estuarinos de la Bahía de Banderas: El Salado, Boca Negra – Boca de Tomates y El Quelele; y se identifican los principales factores de presión ambiental en cada sistema. Los elementos ambientales considerados fueron el suelo, agua, aire, flora, fauna y paisaje. Los resultados indican que el paisaje de estos sistemas, ha perdido su calidad original y las principales causas han sido el cambio de uso de suelo y el desarrollo urbano y turístico mal planeado. Respecto a la valoración de los recursos (naturales y artificiales, con potencial turístico para cada sistema, se determinó bajo la metodología de “Inventario de recursos”; propuesta por Leno (1993. La valoración de recursos en los tres sistemas estuarinos El Salado, Boca Negra – Boca de Tomates y El Quelele; nos muestra que todos los recursos potenciales se encuentran en conjunto lo cual les otorga un valor más elevado respecto a la metodología utilizada, esto no limita las áreas solo al avistamiento y visita de los recursos con mayor jerarquía como las aves, cangrejos, flora, canales navegables, torres de observación y senderos elevados. Al contrario, se considera que el conjunto de todos los recursos con potencial turístico son susceptibles de aprovechamiento bajo esquemas de sustentabilidad mediante programas de turismo asociado a la naturaleza.

  16. Tracking Petroleum Refinery Emission Events Using Lanthanum and Lanthanides as Elemental Markers for Fine Particulate Matter

    Science.gov (United States)

    Kulkarni, P.; Chellam, S.; Fraser, M. P.

    2007-12-01

    This presentation reports the development and application of an analytical method to quantify the rare earth elements (REEs) in atmospheric particulate matter and emissions of catalyst material from the petroleum refining industry. Inductively coupled plasma - mass spectrometry following high temperature/high pressure microwave digestion has been used to study the REE composition of several fresh and spent catalysts used in fluidized-bed catalytic cracking (FCC) units in petroleum refineries as well as in ambient atmospheric fine particulate matter collected in Houston, TX. The results show that the routine emissions from local FCC units in Houston contribute a constant and low amount to ambient PM2.5 of ~0.1 micrograms per cubic meter. However, a significant (33 - 106 fold) increase in the contributions of FCC emissions to PM2.5 is quantified during an upset emission event compared with background levels associated with routine operation. The impact of emissions from the local refinery that reported the emission event was tracked to a site approximately 50 km downwind from the source, illustrating the potential exposure of humans over a large geographical area through the long-range transport of atmospheric fine particles as well as the power of elemental signatures to understand the sources of fine particles.

  17. Indirect estimation of absorption properties for fine aerosol particles using AATSR observations: a case study of wildfires in Russia in 2010

    Science.gov (United States)

    Rodriguez, E.; Kolmonen, P.; Virtanen, T. H.; Sogacheva, L.; Sundstrom, A.-M.; de Leeuw, G.

    2015-08-01

    The Advanced Along-Track Scanning Radiometer (AATSR) on board the ENVISAT satellite is used to study aerosol properties. The retrieval of aerosol properties from satellite data is based on the optimized fit of simulated and measured reflectances at the top of the atmosphere (TOA). The simulations are made using a radiative transfer model with a variety of representative aerosol properties. The retrieval process utilizes a combination of four aerosol components, each of which is defined by their (lognormal) size distribution and a complex refractive index: a weakly and a strongly absorbing fine-mode component, coarse mode sea salt aerosol and coarse mode desert dust aerosol). These components are externally mixed to provide the aerosol model which in turn is used to calculate the aerosol optical depth (AOD). In the AATSR aerosol retrieval algorithm, the mixing of these components is decided by minimizing the error function given by the sum of the differences between measured and calculated path radiances at 3-4 wavelengths, where the path radiances are varied by varying the aerosol component mixing ratios. The continuous variation of the fine-mode components allows for the continuous variation of the fine-mode aerosol absorption. Assuming that the correct aerosol model (i.e. the correct mixing fractions of the four components) is selected during the retrieval process, also other aerosol properties could be computed such as the single scattering albedo (SSA). Implications of this assumption regarding the ratio of the weakly/strongly absorbing fine-mode fraction are investigated in this paper by evaluating the validity of the SSA thus obtained. The SSA is indirectly estimated for aerosol plumes with moderate-to-high AOD resulting from wildfires in 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

  18. Monitoring pool-tail fines

    Science.gov (United States)

    Bunte, K.; Potyondy, J. P.; Abt, S. R.; Swingle, K. W.

    2010-12-01

    Fine sediment deposited in pool-tail areas of mountain streams is often measured to monitor changes in the supply of fines (e.g., by dam removal, bank erosion, or watershed effects including fires and road building) or to assess the status and trend of aquatic ecosystems. Grid counts, pebble counts, and volumetric bedmaterial samples are typically used to quantify pool-tail fines. Grid-count results exhibit a high degree of variability not only among streams and among operators, but also among crews performing a nearly identical procedure (Roper et al. 2010). Variability is even larger when diverse methods are employed, each of which quantifies fines in a different way: grid counts visually count surface fines on small patches within the pool-tail area, pebble counts pick up and tally surface particles along (riffle) transects, and volumetric samples sieve out fines from small-scale bulk samples; and even when delimited to pool-tail areas, individual methods focus on different sampling locales. Two main questions were analyzed: 1) Do pool-tail fines exhibit patterns of spatial variability and are some grid count schemes more likely to provide accurate results than others. 2) How and why does the percentage of fines vary among grid counts, pebble counts, and volumetric samples. In a field study, grids were placed at 7 locales in two rows across the wetted width of 10 pool tails in a 14-m wide 3rd order coarse gravel-bed mountain stream with banks, sometimes interrupted by a secondary peak of fines within the central half of the wetted width. Among the five sampling schemes tested, grid counts covering the wetted width with 7 locales produced the highest accuracy and the least variability among the pools of the reach. Pebble counts between the two waterlines indicated 2-3 times more fines than grid counts, likely because grid counts did not extend exactly up to the waterline. However, when confined to the central 50% of the wetted width, grid counts indicated 1.2 and

  19. Formation of fine palladium particles from palladium sulfate aqueous solution by gamma-ray irradiation as observed by electronic absorption spectroscopy and dynamic light scattering

    International Nuclear Information System (INIS)

    To find a way of probing the coagulation of metal particles formed by the irradiation of metallic ion solution without surfactant, palladium sulfate aqueous solution was irradiated with gamma rays (11.2kGy/h, 10kGy) and turbidity change of the solution after irradiation was followed by optical density at 700nm using a UV-visible spectrophotometer. The particle diameter distribution was monitored by dynamic light scattering. The results indicate that the turbidity decreased monotonously, and that there are major peaks in the distributions, one with diameters in the 400-800nm region and the other with diameters in the 1500-2500nm. The density of the particles seems to be smaller than that of bulk palladium metal. Similar experiments were carried out on palladium-silver sulfate solution. (author)

  20. Wood-fired oven with particle precipitator for the reduction of fine dust emissions; Chemineeanlage mit Partikelabscheider zur Minderung der Feinstaubemission

    Energy Technology Data Exchange (ETDEWEB)

    Brenn, J.; Rauch, S.; Schmatloch, V. [Swiss Federal Laboratories for Materials Testing and Research (EMPA), Duebendorf (Switzerland); Rueegg, P. [Rueegg Cheminee AG, Zumikon (Switzerland)

    2005-07-01

    This illustrated final report for the Swiss Federal Office of Energy (SFOE) discusses the development of a particle-separator for small wood-fired ovens. The device was implemented without major changes to the oven. The functioning of the system is described. Further improvements to the electrode and the electronic control unit are expected to lead to a high level of reliability. The results of measurements made on-site are presented and discussed. These show that the aims of the project regarding particle separation were reached. The construction of the fireplace is illustrated and the results of the measurements made are presented in graphical form.

  1. Catalyst Chemical State during CO Oxidation Reaction on Cu(111) Studied with Ambient-Pressure X-ray Photoelectron Spectroscopy and Near Edge X-ray Adsorption Fine Structure Spectroscopy.

    Science.gov (United States)

    Eren, Baran; Heine, Christian; Bluhm, Hendrik; Somorjai, Gabor A; Salmeron, Miquel

    2015-09-01

    The chemical structure of a Cu(111) model catalyst during the CO oxidation reaction in the CO+O2 pressure range of 10-300 mTorr at 298-413 K was studied in situ using surface sensitive X-ray photoelectron and adsorption spectroscopy techniques [X-ray photoelectron spectroscopy (XPS) and near edge X-ray adsorption fine structure spectroscopy (NEXAFS)]. For O2:CO partial pressure ratios below 1:3, the surface is covered by chemisorbed O and by a thin (∼1 nm) Cu2O layer, which covers completely the surface for ratios above 1:3 between 333 and 413 K. The Cu2O film increases in thickness and exceeds the escape depth (∼3-4 nm) of the XPS and NEXAFS photoelectrons used for analysis at 413 K. No CuO formation was detected under the reaction conditions used in this work. The main reaction intermediate was found to be CO2(δ-), with a coverage that correlates with the amount of Cu2O, suggesting that this phase is the most active for CO oxidation. PMID:26275662

  2. Detectors for alpha particles and X-rays operating in ambient air in pulse counting mode and/or with gas amplification

    CERN Document Server

    Charpak, Georges; Breuil, P; Peskov, Vladimir

    2008-01-01

    Ionization chambers working in ambient air in current detection mode are widely used in several applications such as smoke detection, dosimetry, therapeutic beam monitoring and cetera. The aim of this work was to investigate if gaseous detectors can operate in ambient air in pulse counting mode as well as with gas amplification. . To investigate the feasibility of this method two types of open- end gaseous detectors were build and successfully tested. The first one was a single wire or multiwire cylindrical geometry detector operating in pulse mode at a gas gain of 1. The second type alpha detector was an innovative GEM-like detector with resistive electrodes operating in air in avalanche mode at high gas gains (up to 10E4). A detailed comparison between these two detectors is given as well as comparison with the commercially available alpha detectors. The main advantages of gaseous detectors operating in air in a pulse detection mode are their simplicity, low cost and high sensitivity. One of the possible ap...

  3. Vascular and lung function related to ultrafine and fine particles exposure assessed by personal and indoor monitoring: a cross-sectional study

    DEFF Research Database (Denmark)

    Olsen, Yulia; Karottki, Dorina Gabriela; Jensen, Ditte Marie; Bekö, Gabriel; Kjeldsen, Birthe Uldahl; Clausen, Geo; Hersoug, Lars-Georg; Holst, Gitte Juel; Wierzbicka, Aneta; Sigsgaard, Torben; Linneberg, Allan; Møller, Peter; Loft, Steffen

    2014-01-01

    -related effects. Methods: Associations between vascular and lung function, inflammation markers and exposure in terms of particle number concentration (PNC; d = 10-300 nm) were studied in a cross-sectional design with personal and home indoor monitoring in the Western Copenhagen Area, Denmark. During 48-h, PNC...

  4. Effect of 2-propenyltrimethylsilane and magnetic field effect on photochemical Fe/Co fine particle formation from a ternary gaseous mixture

    Czech Academy of Sciences Publication Activity Database

    Morita, H.; Hattori, K.; Šubrt, Jan

    2011-01-01

    Roč. 218, č. 1 (2011), s. 111-116. ISSN 1010-6030 Institutional research plan: CEZ:AV0Z40320502 Keywords : gas phase photochemical reaction * aerosol particle * magnetic field effect * iron pentacarbonyl * cobalt tricarbonyl nitrosyl Subject RIV: CA - Inorganic Chemistry Impact factor: 2.421, year: 2011

  5. Raman Microspectroscopy of Exhaled Breath Condensate and Urine in Workers Exposed to Fine and Nano TiO2 Particles: a Cross-sectional Study

    Czech Academy of Sciences Publication Activity Database

    Pelclová, D.; Barošová, H.; Kukutschová, J.; Ždímal, Vladimír; Navrátil, Tomáš; Felclová, Z.; Vlčková, Š.; Schwarz, Jaroslav; Zíková, Naděžda; Kačer, P.; Komarc, M.; Běláček, J.; Zakharov, S.

    2015-01-01

    Roč. 9, č. 3 (2015), s. 036008. ISSN 1752-7155 R&D Projects: GA ČR(CZ) GBP503/12/G147 Institutional support: RVO:67985858 ; RVO:61388955 Keywords : nano particles * TiO2 * titanium Subject RIV: DN - Health Impact of the Environment Quality; CG - Electrochemistry (UFCH-W) Impact factor: 4.631, year: 2014

  6. Production of De-asphalted Oil and Fine Asphalt Particles by Supercritical Extraction%超临界流体萃取制备脱沥青油与沥青微粒

    Institute of Scientific and Technical Information of China (English)

    赵锁奇; 许志明; 王仁安

    2003-01-01

    A continuous three-stage supercritical fluid extraction (SFE) process with a capacity of 1.0 kg·h-1 was setup to extract petroleum residue by pentane to obtain more oil for further upgrading. A discharging system integrated to the bottom of the extractor was used to recover solvent as gas while asphalt was obtained as fine particles. The influence of operating conditions on the yield and quality of extracts, i.e., deasphalted oil (DAO) and resin, was studied in the range of temperature 150-220℃, pressure of 4.0-6.0 MPa and the mass ratio of solvent to oil feed (S/O) 2.5-5.0. The particle size distribution, apparent forms and the packing density, which vary with operating pressure, were measured. The particle structures were observed by SEM as well. With the modification to conventional processes, furnace can be eliminated for solvent recovery from asphalt phase, so as to reduce energy consumption.

  7. Fluidized-bed gasification of biomass: Conversion of fine carabon particles in the freeboard; Biomassevergasung in der Wirbelschicht: Umsatz von feinen Kohlenstoffpartikeln im Freeboard

    Energy Technology Data Exchange (ETDEWEB)

    Miccio, F. [Ist. Ricerche sulla Combustione-CNR, Napoli (Italy); Moersch, O.; Spliethoff, H.; Hein, K.R.G. [Stuttgart Univ. (Germany). Inst. fuer Verfahrenstechnik und Dampfkesselwesen

    1998-09-01

    The conversion of carbon particles in gasification processes was investigated in a fluidized-bed reactor of the Institute of Chemical Engineering and Steam Boiler Technology of Stuttgart University. This reactor is heated electrically to process temperature, and freeboard coal particles can be sampled using an isokinetic probe. The fuel used in the experiments consisted of beech wood chips. The temperature and air rating, i.e. the main parameters of the process, were varied in order to investigate their influence on product gas quality and carbon conversion. The conversion rate is influenced to a significant extent by grain disintegration and discharge of carbon particles. In gasification conditions, a further conversion process takes place in the freeboard. (orig.) [Deutsch] In dieser Arbeit wird die Umsetzung von Kohlenstoffpartikeln unter Vergasungsbedingungen untersucht. Die Versuche wurden an einem Wirbelschichtreaktor des Instituts fuer Verfahrenstechnik und Dampfkesselwesen der Universitaet Stuttgart durchgefuehrt. Dieser Reaktor wird elektrisch auf Prozesstemperatur beheizt. Mit Hilfe einer isokinetischen Sonde koennen Proben von Kohlenstoffpartikeln im Freeboard genommen werden. Als Brennstoff wurden zerkleinerte Buchenholz-Hackschnitzel eingesetzt. Variiert wurden als Hauptparameter des Prozesses Temperatur und Luftzahl. Untersucht wurde der Einfluss dieser Parameter auf die Qualitaet des Produktgases und die Umsetzung des Kohlenstoffes. Kornzersetzungs- und Austragsvorgaenge von Kohlenstoffpartikeln spielen eine wichtige Rolle fuer den Kohlenstoffumsatz. Unter Vergasungsbedingungen findet im Freeboard eine weitere Umsetzung der Partikel statt. (orig.)

  8. Exposure to ambient concentrations of particulate air pollution does not influence vascular function or inflammatory pathways in young healthy individuals

    DEFF Research Database (Denmark)

    Bräuner, E. V.; Møller, P.; Barregård, L.;

    2008-01-01

    semialdehyde in plasma. Results: No statistically significant differences were observed on microvascular function or the biomarkers after exposure to particle rich or particle filtered air. Conclusion: This study indicates that exposure to air pollution particles at outdoor concentrations is not associated......Background: Particulate air pollution is associated with increased risk of cardiovascular events although the involved mechanisms are poorly understood. The objective of the present study was to investigate the effects of controlled exposure to ambient air fine and ultrafine particles on......: 11600 +/- 5600 per cm(3), mass concentrations: 13.8 +/- 7.4 mu g/m(3) and 10.5 +/- 4.8 mu g/m(3) for PM10-2.5 and PM2.5, respectively) or particle filtered (NC: 555 +/- 1053 per cm(3)) air collected above a busy street. Microvascular function was assessed non-invasively by measuring digital peripheral...

  9. Calculation of particle and quark masses solely using the fine structure constant alpha, the nucleon/electron mass ratio beta and the electron mass

    International Nuclear Information System (INIS)

    A surprisingly simple relationship for particle and quark masses is given as m = x*y*me. Thereby y = 1 and x = 1/α, β and β/α for a hypothetic mass m0, the nucleon and the Higgs boson. With y = 4/3 instead y = 1 one obtains the masses of the strange-, charm-, and top quark, with x = β/α and y = 2/π the Z boson and with the π-2 fold thereof the W boson. The aforementioned m0 is the building block for calculating, as integer multiples, all other meson- and baryon masses with better than 2 % accuracy.

  10. Research on Processing Method of Fine Particle Content Uprush in Raw Coal%原煤中细粒煤含量突增的处理方法研究

    Institute of Scientific and Technical Information of China (English)

    许强

    2015-01-01

    The fine particle content bump up leads to the phenomenon of which system can not run normally in coal mine,so the equipment,process flow and coal quality in coal preparation plant are analyzed and researched,and finds the reason for fine coal content uprush in raw coal is that the quantity of waste rock bump up as passing through faults in mining processing.Because waste rock friction and collision forms high ash fine mud,surface area of fine grained material is large,the medium of adhesion is more,it is difficult to removal from sculping screen.So the medi-um consumption increases in the system,which leads to the separation density instability,affects the normal produc-tion.In the case of ensuring the normal operation of all equipment,increases the lower sieve seam of desliming sieve, effectively solves the production problems,the end system returns to normal operation,reduces the medium consump-tion,restores the normal production.%针对矿井出煤中细颗粒含量突增,导致系统不能正常运行的现象,对选煤厂设备、工艺流程和煤质进行了分析研究,发现原煤中细粒级物料含量增加,原因是矿井过断层时在开采过程中矸石量突增。由于矸石摩擦、碰撞后形成高灰细泥,细粒级物料表面积大,黏附的介质多,在脱介筛上难以脱除,因此,系统介耗增大,导致末系统分选密度不稳定,影响正常生产。在保证各设备正常运行的情况下,通过增大脱泥筛下层筛缝尺寸,有效解决了这一生产问题,末系统恢复正常运行,降低了介耗,恢复正常生产。

  11. The influence of design and fuel parameters on the particle emissions from wood pellets combustion. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Wiinikka, Henrik; Gebart, Rikard [Energy Technology Centre, Piteaa (Sweden)

    2005-02-01

    Combustion of solid biomass under fixed bed conditions is a common technique to generate heat and power in both small and large scale grate furnaces (domestic boilers, stoves, district heating plants). Unfortunately, combustion of biomass will generate particle emissions containing both large fly ash particles and fine particles that consist of fly ash and soot. The large fly ash particles have been produced from fusion of non-volatile ash-forming species in burning char particle. The inorganic fine particles have been produced from nucleation of volatilised ash elements (K, Na, S, Cl and Zn). If the combustion is incomplete, soot particles are also produced from secondary reaction of tar. The particles in the fine fraction grows by coagulation and coalescence to a particle diameter around 0.1 pm. Since the smallest particles are very hard to collect in ordinary cleaning devices they contribute to the ambient air pollution. Furthermore, fine airborne particles have been correlated to adverse effects on the human health. It is therefore essential to minimize particle formation from the combustion process and thereby reduce the emissions of particulates to the ambient air. The aim with this project is to study particle emissions from small scale combustion of wood pellets and to investigate the impact of different operating, construction and fuel parameters on the amount and characteristic of the combustion generated particles. To address these issues, experiments were carried out in a 10 kW updraft fired wood pellets reactor that has been custom designed for systematic investigations of particle emissions. In the flue gas stack, particle emissions were sampled on a filter. The particle mass and number size distributions were analysed by a low pressure cascade impactor and a SMPS (Scanning Electron Mobility Particle Sizer). The results showed that the temperature and the flow pattern in the combustion zone affect the particle emissions. Increasing combustion

  12. Effects of solubility of urban air fine and coarse particles on cytotoxic and inflammatory responses in RAW 264.7 macrophage cell line

    International Nuclear Information System (INIS)

    We investigated the inflammatory and cytotoxic activities of the water-soluble and -insoluble as well as organic-solvent-soluble and -insoluble fractions of urban air fine (PM2.5-0.2) and coarse (PM10-2.5) particulate samples. The samples were collected with a high volume cascade impactor (HVCI) in 7-week sampling campaigns of selected seasons in six European cities. Mouse macrophage cells (RAW 264.7) were exposed to the samples for 24 h. The production of nitric oxide (NO) and proinflammatory cytokines (TNFα, IL-6), and cytotoxicity (MTT-test, apoptosis, cell cycle) were measured. The inflammatory and cytotoxic responses in both size ranges were mostly associated with the insoluble particulate fractions. However, both the water- and organic-solvent-soluble particulate fractions induced TNFα production and apoptosis and had some other cytotoxic effects. Soil-derived water-soluble and -insoluble components of the chemical PM2.5-0.2 mass closure had consistent positive correlations with the responses, while the correlations were negative with the secondary inorganic anions (NO3-, NH4+, non-sea-salt SO42-) and particulate organic matter (POM). With the PM10-2.5 samples, sea salt and soluble soil components correlated positively with the induced toxic responses. In this size range, a possible underestimation of the insoluble, soil-related compounds containing Si and Ca, and biological components of POM, increased uncertainties in the evaluation of associations of the mass closure components with the responses. It is concluded that insoluble components of the complex urban air particulate mixture exert the highest inflammatory and cytotoxic activities in the macrophage cell line but, at the same time, they may operate as carriers for active water- and lipid-soluble components

  13. Online determination of levoglucosan in ambient aerosols with particle-into-liquid sampler – high-performance anion-exchange chromatography – mass spectrometry (PILS–HPAEC–MS)

    OpenAIRE

    Saarnio, K.; K. Teinilä; Saarikoski, S.; Carbone, S.; Gilardoni, S.; Timonen, H.; M. Aurela; R. Hillamo

    2013-01-01

    Biomass burning, such as domestic heating, agricultural, and wild open-land fires, has a significant influence on the atmosphere at the global and, especially, at the local scale. Levoglucosan has been shown to be a good tracer for biomass burning emissions in atmospheric particulate matter, and several analytical techniques have been presented for the determination of levoglucosan from filter samples. In this paper, a novel combination of a particle-into-liquid sampler (PIL...

  14. Biological activities of organic compounds adsorbed onto ambient air particles: comparison between the cities of Teplice and Prague during the summer and winter seasons 2000-2001

    Czech Academy of Sciences Publication Activity Database

    Binková, Blanka; Černá, M.; Pastorková, A.; Jelínek, R.; Beneš, I.; Novák, J.; Šrám, Radim

    2003-01-01

    Roč. 525, - (2003), s. 43-59. ISSN 0027-5107 R&D Projects: GA MŽP SI/340/2/00 Grant ostatní: GA-(XE) IC QLRT-2000-00091 Institutional research plan: CEZ:AV0Z5039906 Keywords : Air pollution * air particles (PM10) * polycyclic aromatic compounds Subject RIV: DN - Health Impact of the Environment Quality Impact factor: 3.433, year: 2003

  15. Particle-Associated Ambient Benzo[a]pyrene and Levels of Urinary 1-Hydroxypyrene in a Non-occupationally Exposed Population of Adults and Children in Lanzhou, China.

    Science.gov (United States)

    Yu, Yunjiang; Wang, Qiong; Li, Liangzhong; Liu, Zien; Sun, Peng; Zhang, Yanping; Lin, Haipeng; Xiang, Mingdeng; Li, Hui; Lin, Bigui

    2016-03-01

    Concentrations of benzo[a]pyrene (B[a]P) in ambient air from different areas in Lanzhou city in northwest of China, and its metabolite 1-hydroxypyrene (1-OHP) in the urine of resident children and adults were determined by using gas chromatography/mass spectrometry and high performance liquid chromatography. Results showed that the atmospheric environmental concentration of B[a]P varied significantly from one part of the city to another with levels of 150 ng/m(3) in the industrial area of Xigu and 73.8 ng/m(3) in the agricultural area of Yuzhong. The geometric mean urinary 1-OHP concentration was 0.42 µmol/mol-creatinine, with a range of means between 0.067 and 2.05 for the various population sub-groups. The non-occupationally exposed populations' age, gender and area of residence were the major factors that influenced urinary 1-OHP levels. The health risks of B[a]P for adults and children in Xigu and for children in Yuzhong exceeded the acceptable level (1 × 10(-4)) of the US Environmental Protection Agency. PMID:26841792

  16. Analysis system of submicron particle tracks in the fine-grained nuclear emulsion by a combination of hard x-ray and optical microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Naka, T., E-mail: naka@flab.phys.nagoya-u.ac.jp [Kobayashi-Maskawa Institute for the Origin of Particles and the Universe, Nagoya University, Aichi 464-8602 (Japan); Institute for Advanced Research, Nagoya University, Aichi 464-8602 (Japan); Asada, T.; Yoshimoto, M.; Katsuragawa, T.; Tawara, Y.; Umemoto, A. [Department of Physics, Graduated School of Science, Nagoya University, Nagoya 464-8602 (Japan); Suzuki, Y.; Terada, Y.; Takeuchi, A.; Uesugi, K. [Japan Synchrotron Radiation Research Institute (JASRI), SPring-8, Hyogo 679-5198 (Japan); Kimura, M. [Kobayashi-Maskawa Institute for the Origin of Particles and the Universe, Nagoya University, Aichi 464-8602 (Japan)

    2015-07-15

    Analyses of nuclear emulsion detectors that can detect and identify charged particles or radiation as tracks have typically utilized optical microscope systems because the targets have lengths from several μm to more than 1000 μm. For recent new nuclear emulsion detectors that can detect tracks of submicron length or less, the current readout systems are insufficient due to their poor resolution. In this study, we developed a new system and method using an optical microscope system for rough candidate selection and the hard X-ray microscope system at SPring-8 for high-precision analysis with a resolution of better than 70 nm resolution. Furthermore, we demonstrated the analysis of submicron-length tracks with a matching efficiency of more than 99% and position accuracy of better than 5 μm. This system is now running semi-automatically.

  17. Analysis system of submicron particle tracks in the fine-grained nuclear emulsion by a combination of hard x-ray and optical microscopy

    International Nuclear Information System (INIS)

    Analyses of nuclear emulsion detectors that can detect and identify charged particles or radiation as tracks have typically utilized optical microscope systems because the targets have lengths from several μm to more than 1000 μm. For recent new nuclear emulsion detectors that can detect tracks of submicron length or less, the current readout systems are insufficient due to their poor resolution. In this study, we developed a new system and method using an optical microscope system for rough candidate selection and the hard X-ray microscope system at SPring-8 for high-precision analysis with a resolution of better than 70 nm resolution. Furthermore, we demonstrated the analysis of submicron-length tracks with a matching efficiency of more than 99% and position accuracy of better than 5 μm. This system is now running semi-automatically

  18. Source apportionment of fine particles and its chemical components over the Yangtze River Delta, China during a heavy haze pollution episode

    Science.gov (United States)

    Li, L.; An, J. Y.; Zhou, M.; Yan, R. S.; Huang, C.; Lu, Q.; Lin, L.; Wang, Y. J.; Tao, S. K.; Qiao, L. P.; Zhu, S. H.; Chen, C. H.

    2015-12-01

    contributors to organic carbon. Results show that the Yangtze River Delta region should focus on the joint pollution control of industrial processing, combustion emissions, mobile source emissions, and fugitive dust. Regional transport of air pollution among the cities are prominent, and the implementation of regional joint prevention and control of air pollution will help to alleviate fine particulate matter concentrations under heavy pollution case significantly.

  19. Apportioned contributions of PM2.5 fine aerosol particles over the Maldives (northern Indian Ocean) from local sources vs long-range transport.

    Science.gov (United States)

    Budhavant, Krishnakant; Andersson, August; Bosch, Carme; Kruså, Martin; Murthaza, Ahmed; Zahid; Gustafsson, Örjan

    2015-12-01

    Urban-like plumes of gases and particulate matter originating from the South Asian region are frequently observed over the Indian Ocean, especially during the dry winter period. However, in addition to the strong sources on mainland South Asia, there are also local Maldivian emissions. The local contributions to the load of fine particulate matter (PM2.5) in the Maldivian capital Malé was assessed using the well-established Maldives Climate Observatory at Hanimaadhoo (MCOH) to represent local background, recording the long-range transported component for a full-year synoptic campaign at both sites in 2013. The year-round levels in both Malé and MCOH are strongly influenced by the seasonality of the monsoon cycle, including precipitation patterns and air-mass transport pathways, with lower levels during the wet summer season. The annual-average PM2.5 levels in Malé are higher (avg. 19 μg/m3) than at MCOH (avg. 13 μg/m3) with the difference being the largest during the summer, when local emissions play a larger role. The 24-h World Health Organization (WHO) PM2.5 health guideline was surpassed for the weeklong collections in 71% of the cases in Malé and in 74% of the cases for Hanimaadhoo. This study shows that in the dry/winter season 90±11% of PM2.5 levels in Malé could be from long-range transport with only 8±11% from local emissions while in the wet/monsoon season the relative contributions are about equal. The concentrations of organic carbon (OC) and elemental carbon (EC) showed similar seasonal patterns as bulk mass PM2.5. The relative contribution of total carbonaceous matter to bulk mass PM2.5 was 17% in Malé and 13% at MCOH, suggesting larger contributions from incomplete combustion practices in the Malé local region. PMID:26196071

  20. Cake properties in ultrafiltration of TiO2 fine particles combined with HA: in situ measurement of cake thickness by fluid dynamic gauging and CFD calculation of imposed shear stress for cake controlling.

    Science.gov (United States)

    Du, Xing; Qu, Fangshu; Liang, Heng; Li, Kai; Chang, Haiqing; Li, Guibai

    2016-05-01

    In this study, the cake buildup of TiO2 fine particles in the presence of humid acid (HA) and cake layer controlling during ultrafiltration (UF) were investigated. Specifically, we measured the cake thickness using fluid dynamic gauging (FDG) method under various solution conditions, including TiO2 concentration (0.1-0.5 g/L), HA concentration (0-5 mg/L, total organic carbon (TOC)), and pH values (e.g., 4, 6 and 10), and calculated the shear stress distribution induced by stirring using computational fluid dynamics (CFD) to analyze the cake layer controlling conditions, including the operation flux (50-200 L m(-2) h(-1)) and TiO2 concentration (0.1-0.5 g/L). It was found that lower TiO2/HA concentration ratio could lead to exceedingly severe membrane fouling because of the formation of a relatively denser cake layer by filling the voids of cake layer with HA, and pH was essential for cake layer formation owing to the net repulsion between particles. Additionally, it was observed that shear stress was rewarding for mitigating cake growth under lower operation flux as a result of sufficient back-transport forces, and exhibited an excellent performance on cake layer controlling in lower TiO2 concentrations due to slight interaction forces on the vicinity of membrane. PMID:26810663

  1. Aerobyologic monitoring in urban and extra urban areas : analysis of airborne fungal particle concentration; Indagini aerobiologiche in ambiente urbano ed extraurbano componente fungina aerodiffusa

    Energy Technology Data Exchange (ETDEWEB)

    Bari, A. [ENEA, Saluggia (Italy). Centro Ricerche Energia; Caramiello, R.; Fossa, V.; Potenza, A. [Turin Univ. (Italy), Dip. di Biologia Vegetale

    1995-12-01

    In the environmental monitoring studies carried out by ENEA (Italian Agency for New Technologies, Energy and the Environment) a research about air quality of Turin and Saluggia (VC) has started in collaboration with the University of Turin. This research concerns the study of pollen and airborne fungal particle concentrations in the atmosphere. In the last few years the interest in airborne spores and hyphal fragments has increased. Indeed these particles play a very important role in allergic reactions, in several other human diseases, and in plant pathology. The incidence and the risk of infections by airborne fungal spores are correlated to the general climate and to the local micro climatic conditions; a complete aerosporological knowledge can be in many cases a useful indicator for infection risks. In this study the concentrations of airborne fungal spores in two different stations (urban station, Turin; and rural station, Saluggia (VC)) has been evaluated and compared, only for the year 1992, in order to verify the influence of climatic conditions and of floristic and vegetational aspects. In order to establish the correlations between the climate and the airborne fungal data, the results of aerosporogical analysis, relative to the Turin station, are reported. This investigation cover a six year period, three of which under standard climatic conditions and three with considerable peculiarities. A comparative evaluation of the efficiency in the collection of aerobiological particles (pollen and spores) by natural traps (mosses) has been attempted in Saluggia. The results obtained by this palinological analysis have been compared with the composition of the local flora and the data monitored by a spore-trap (volumetric pollen trap) positioned on the roof of a building in the ENEA Research Center of Saluggia.

  2. Exposure of chronic obstructive pulmonary disease patients to particulate matter: relationships between personal and ambient air concentrations.

    Science.gov (United States)

    Ebelt, S T; Petkau, A J; Vedal, S; Fisher, T V; Brauer, M

    2000-07-01

    Mot time-series studies of particulate air pollution and acute health outcomes assess exposure of the study population using fixed-site outdoor measurements. To address the issue of exposure misclassification, we evaluate the relationship between ambient particle concentrations and personal exposures of a population expected to be at risk of particle health effects. Sampling was conducted within the Vancouver metropolitan area during April-September 1998. Sixteen subjects (non-smoking, ages 54-86) with physician-diagnosed chronic obstructive pulmonary disease (COPD) wore personal PM2.5 monitors for seven 24-hr periods, randomly spaced approximately 1.5 weeks apart. Time-activity logs and dwelling characteristics data were also obtained for each subject. Daily 24-hr ambient PM10 and PM2.5 concentrations were measured at five fixed sites spaced throughout the study region. SO4(2-), which is found almost exclusively in the fine particle fraction and which does not have major indoor sources, was measured in all PM2.5 samples as an indicator of accumulation mode particulate matter of ambient origin. The mean personal and ambient PM2.5 concentrations were 18 micrograms/m3 and 11 micrograms/m3, respectively. In analyses relating personal and ambient measurements, ambient concentrations were expressed either as an average of the values obtained from five ambient monitoring sites for each day of personal sampling, or as the concentration obtained at the ambient site closest to each subject's home. The mean personal to ambient concentration ratio of all samples was 1.75 (range = 0.24 to 10.60) for PM2.5, and 0.75 (range = 0.09 to 1.42) for SO4(2-). Regression analyses were conducted for each subject separately and on pooled data. The median correlation (Pearson's r) between personal and average ambient PM2.5 concentrations was 0.48 (range = -0.68 to 0.83). Using SO4(2-) as the exposure metric, the median r between personal and average ambient concentrations was 0.96 (range

  3. Quality of skin as a barrier to ultra-fine particles. Contribution of the IBA group to the NANODERM EU-5 project in 2003-2004

    International Nuclear Information System (INIS)

    Complete text of publication follows. Micronised titanium-, zinc- or silicon-oxide is a widely used physical photoprotective agent as a component of various cosmetic products. Due to the small particle size (down to 15 nm) it is supposed, that the particles may pass through the uppermost horny skin layer, and penetrate into deeper vital skin layers. However, only a few experiments have been carried out on its penetration through the human epidermal barrier and its possible biological effects in vivo and in vitro, using the tape stripping method which has no lateral and limited depth resolution. A consortium consisting of 12 European universities and scientific institutes has been established under the leadership of the Fakultat fuer Physik und Geowissenchaft Universitat Leipzig, whose goal is to get quantitative information on the penetration of ultrafine particles in all strata of skin, on their penetration pathways as well as on their impact on human health [1]. The IBA group of the Atomki takes part in this project as a subcontractor of the Department of Dermatology, University of Debrecen, Hungary. Ion microscopy, electron microscopy and autoradiography are used to trace the penetration of the nanoparticles into the skin layers, molecular and cell-biological methods are applied to assess the skin response and activation of dermal cells. The IBA group of the Atomki takes part in WP3: Ion Microscopy Work Package together with five other nuclear microprobe laboratories. The participants provide quantitative elemental composition in all strata of skin with detection limits of about 1 μg/g and lateral resolution of 1-2 μm by applying various ion beam analytical techniques. Samples investigated by ion microscopy are 14-16 μm thick cryo-fixed freeze-dried sections of porcine and human