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1.
Long-term measurements of ambient particulate matter less than 2.5 μm in diameter (PM 2.5) and its chemical compositions were performed at a rural site in Korea from December 2005 to August 2009. The average PM 2.5 concentration was 31 μg m −3 for the whole sampling period, and showed a slightly downward annual trend. The major components of PM 2.5 were organic carbon, SO 42−, NO 3−, and NH 4+, which accounted for 55 % of total PM 2.5 mass on average. For the top 10 % of PM 2.5 samples, anionic constituents and trace elements clearly increased while carbonaceous constituents and NH 4+ remained relatively constant. Both Asian dust and fog events clearly increased PM 2.5 concentrations, but affected its chemical composition differently. While trace elements significantly increased during Asian
dust events, NO 3−, NH 4+ and Cl were dramatically enhanced during fog events due to the formation of saturated or supersaturated salt solution. The
back-trajectory based model, PSCF (Potential Source Contribution Function) identified the major industrial areas in Eastern
China as the possible source areas for the high PM 2.5 concentrations at the sampling site. Using factor analysis, soil, combustion processes, non-metal manufacture, and secondary
PM 2.5 sources accounted for 77 % of the total explained variance. 相似文献
2.
The new European Council Directive (PE-CONS 3696/07) frames the inhalable (PM 10) and fine particles (PM 2.5) on priority to chemically characterize these fractions in order to understand their possible relation with health effects.
Considering this, PM 2.5 was collected during four different seasons to evaluate the relative abundance of bulk elements (Cl, S, Si, Al, Br, Cu, Fe,
Ti, Ca, K, Pb, Zn, Ni, Mn, Cr and V) and water soluble ions (F −, Cl −, NO 2
−, NO 3
−, SO 4
2−, Na +, NH 4
+, Ca 2+ and Mg 2+) over Menen, a Belgian city near the French border. The air quality over Menen is influenced by industrialized regions on
both sides of the border. The most abundant ionic species were NO 3
−, SO 4
2− and NH 4
+, and they showed distinct seasonal variation. The elevated levels of NO 3
− during spring and summer were found to be related to the larger availability of the NO x precursor. The various elemental species analyzed were distinguished into crustal and anthropogenic source categories. The
dominating elements were S and Cl in the PM 2.5 particles. The anthropogenic fraction (e.g. Zn, Pb, and Cu) shows a more scattered abundance. Furthermore, the ions and elemental
data were also processed using principal component analysis and cluster analysis to identify their sources and chemistry.
These approach identifies anthropogenic (traffic and industrial) emissions as a major source for fine particles. The variations
in the natural/anthropogenic fractions of PM 2.5 were also found to be a function of meteorological conditions as well as of long-range transport of air masses from the industrialized
regions of the continent.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
3.
This paper deals with the atmospheric concentrations of PM 5 and PM 2.5 particulate matter and its water soluble constituents along with the size distribution of ions and spatial variation at three
different residential environments in a semiarid region in India. Samples were collected from the indoors and outdoors of
urban, rural and roadside sites of Agra during October 2007–March 2008. The mean concentrations of PM 2.5 indoors and outdoors were 178 μgm −3 and 195 μgm −3 while the mean concentrations of PM 5 indoors and outdoors were 231.8 μgm −3 and 265.2 μgm −3 respectively. Out of the total aerosol mass, water soluble constituents contributed an average of 80% (33% anions, 50% cations)
in PM 5 and 70% (29% anions, 43% cations) in PM 2.5. The indoor–outdoor ratio of water soluble components suggested additional aerosol indoor sources at rural and roadside sites.
Indoor–outdoor correlations were also determined which show poor relationships among concentrations of aerosol ions at all
three sites. Univariate Pearson correlation coefficients among water soluble aerosols were determined to evaluate the relationship
between aerosol ions in indoor and outdoor air. 相似文献
4.
Haze-fog conditions over northern India are associated with visibility degradation and severe attenuation of solar radiation by airborne particles with various chemical compositions. PM 2.5 samples have been collected in Delhi, India from December 2011 to November 2012 and analyzed for carbonaceous and inorganic species. PM 10 measurements were made simultaneously such that PM 10–2.5 could be estimated by difference. This study analyzes the temporal variation of PM 2.5 and carbonaceous particles (CP), focusing on identification of the primary and secondary aerosol emissions, estimations of light extinction coefficient (b ext) and the contributions by the major PM 2.5 chemical components. The annual mean concentrations of PM 2.5, organic carbon (OC), elemental carbon (EC) and PM 10–2.5 were found to be 153.6 ± 59.8, 33.5 ± 15.9, 6.9 ± 3.9 and 91.1 ± 99.9 μg m ?3, respectively. Total CP, secondary organic aerosols and major anions (e.g., SO 4 2? and NO 3 ?) maximize during the post-monsoon and winter due to fossil fuel combustion and biomass burning. PM 10–2.5 is more abundant during the pre-monsoon and post-monsoon. The OC/EC varies from 2.45 to 9.26 (mean of 5.18 ± 1.47), indicating the influence of multiple combustion sources. The b ext exhibits highest values (910 ± 280 and 1221 ± 371 Mm ?1) in post-monsoon and winter and lowest in monsoon (363 ± 110 and 457 ± 133 Mm ?1) as estimated via the original and revised IMPROVE algorithms, respectively. Organic matter (OM =1.6 × OC) accounts for ~39 % and ~48 % of the b ext, followed by (NH 4) 2SO 4 (~21 % and ~24 %) and EC (~13 % and ~10 %), according to the original and revised algorithms, respectively. The b ext estimates via the two IMPROVE versions are highly correlated (R 2 = 0.95, root mean square error = 38 % and mean bias error = 28 %) and are strongly related to visibility impairment ( r = ?0.72), mostly associated with anthropogenic rather than natural PM contributions. Therefore, reduction of CP and precursor gas emissions represents an urgent opportunity for air quality improvement across Delhi. 相似文献
5.
PM 10 samples were collected over three years at Monzenmachi, the Japan Sea coast, the Noto Peninsula, Ishikawa, Japan from January
17, 2001 to December 18, 2003, using a high volume air sampler with quartz filters. The concentrations of the water-soluble
inorganic ions in PM 10 were determined with using ion chromatography. By analyzing the characteristics of these, the evidences were found that the
Asian outflow had an obviously influence on the air quality at our study site. The results were as follows: the secondary
pollutants SO 42−, NO 3− and NH 4+ were the primary water-soluble inorganic ions at our study site. The monthly mean concentrations of SO 42−, NH 4+, NO 3− and Ca 2+ have prominent peak in spring due to the strong influence of the Asian continent outflow—these according to backward air
trajectory analysis, the maximum of which were 6.09 for nss-SO 42− in May, 2.87 for NO 3− and 0.68 μg m −3 for nss-Ca 2+ in April, respectively. Comparable to similar data reported from various points around East Asia, it had the characteristics
of a polluted coastal area at our study site. The concentration of nss-Ca 2+ in PM 10 drastically increased when the Asian dust invaded, the mean value during the Asian dust days(AD) was 0.86 μg m −3, about 4 times higher than those of normal days (NAD). Meanwhile, the mean concentrations of nss-SO 42−, NO 3− and NH 4+ in AD periods were higher than those in NAD periods which were 5.87, 1.76 and 1.82 μg m −3, respectively, it is due to the interaction between dust and secondary particles during the long-range transport of dust
storms. Finally, according to the source apportionment with positive matrix factorization (PMF) method in this study, the
major source profiles of PM 10 at our study site were categorized as (1) marine salt, (2) secondary sulfate, (3) secondary nitrate and (4) crustal source. 相似文献
6.
Ambient concentrations of organic carbon (OC), elemental carbon (EC) and water soluble inorganic ionic components (WSIC) of PM 10 were studied at Giridih, Jharkhand, a sub-urban site near the Indo Gangatic Plain (IGP) of India during two consecutive winter seasons (November 2011–February 2012 and November 2012–February 2013). The abundance of carbonaceous and water soluble inorganic species of PM 10 was recorded at the study site of Giridih. During winter 2011–12, the average concentrations of PM 10, OC, EC and WSIC were 180.2?±?46.4; 37.2?±?6.2; 15.2?±?5.4 and 18.0?±?5.1 μg m ?3, respectively. Similar concentrations of PM 10, OC, EC and WSIC were also recorded during winter 2012–13. In the present case, a positive linear trend is observed between OC and EC at sampling site of Giridih indicates the coal burning, as well as dispersed coal powder and vehicular emissions may be the source of carbonaceous aerosols. The principal components analysis (PCA) also identifies the contribution of coal burning? +?soil dust, vehicular emissions?+?biomass burning and seconday aerosol to PM 10 mass concentration at the study site. Backward trajectoy and potential source contributing function (PSCF) analysis indicated that the aerosols being transported to Giridih from upwind IGP (Punjab, Haryana, Uttar Pradesh and Bihar) and surrounding region. 相似文献
7.
Beijing is one of the largest and most densely populated cities in China. PM 2.5 (fine particulates with aerodynamic diameters less than 2.5 μm) pollution has been a serious problem in Beijing in recent years. To study the temporal and spatial variations in the chemical components of PM 2.5 and to discuss the formation mechanisms of secondary particles, SO 2, NO 2, PM 2.5, and chemical components of PM 2.5 were measured at four sites in Beijing, Dingling (DL), Chegongzhuang (CG), Fangshan (FS), and Yufa (YF), over four seasons from 2012 to 2013. Fifteen chemical components, including organic carbon (OC), elemental carbon (EC), K +, NH 4 +, NO 3 ?, SO 4 2?, Cl ?, Al, Ca, Fe, Mg, Na, Pb, Si, and Zn, were selected for analysis. Overall, OC, SO 4 2?, NO 3 ?, and NH 4 + were dominant among 15 components, the annual average concentrations of which were 22.62 ± 21.86, 19.39 ± 21.06, 18.89 ± 19.82, and 13.20 ± 12.80 μg·m ?3, respectively. Compared with previous studies, the concentrations of NH 4 + were significantly higher in this study. In winter, the average concentrations of OC and EC were, respectively, 3 and 2.5 times higher than in summer, a result of coal combustion during winter. The average OC/EC ratios over the four sites were 4.9, 7.0, 8.1, and 8.4 in spring, summer, autumn, and winter, respectively. The annual average [NO 3 ?]/[SO 4 2?] ratios in DL, CG, FS, and YF were 1.01, 1.25, 1.08, and 1.12, respectively, which were significantly higher than previous studies in Beijing, indicating that the contribution ratio of mobile source increased in recent years in Beijing. Analysis of correlations between temperature and relative humidity and between SOR ([SO 4 2?]/([SO 4 2?] + [SO 2])) and NOR ([NO 3 ?]/([NO 3 ?] + [NO 2])) indicated that gas-phase oxidation reactions were the major formation mechanism of SO 4 2? in spring and summer in urban Beijing, whereas slow gas-phase oxidation reactions and heterogeneous reactions both occurred in autumn and winter. NO 3 ? was mainly formed through year-round heterogeneous reactions in urban Beijing. 相似文献
8.
Ammonia has a short residence time in the atmosphere and rapidly neutralizes acid gases that occur near its source, requiring a rapid measurement system for ammonia and particulate ammonium concentrations to better understand their sources, temporal variation of ammonia emissions, and the formation of secondary ammonium aerosols. A semi-continuous measurement system, consisting of a diffusion scrubber, a particle growth chamber, an air-liquid separator, and a fluorescent detector, was developed to determine both gaseous ammonia (NH 3) and particulate ammonium (NH 4 + ) in PM 2.5 in the ambient atmosphere of Gwangju, South Korea, during the months of March, April, July, and September of 2007. During the sampling periods, the average concentrations of ammonia and ammonium were found to be 2.33?±?1.29 μg/m 3 and 1.89?±?0.99 μg/m 3, respectively. Although the average gaseous ammonia concentration was highest in March, the particulate ammonium concentration was higher during the warmer season, reaching 2.08?±?1.07 μg/m 3 and 2.32?±?0.94 μg/m 3 in April and July, respectively, while only 1.68?±?0.61 μg/m 3 in March and 1.24?±?0.99 μg/m 3 in September. It is proposed that the higher availability of acid species during the warmer months produced a significant amount of particulate ammonium sulfate. Diurnal fluctuation of ammonia and ammonium during the warmer months showed that their peak time occurred at approximately 10:00 am. Both ammonia and ammonium concentrations were better correlated during the warmer months than during the cooler months. Further, the data suggest that the ammonia and ammonium were measured under well dispersed conditions, and multiple sources contributed to the ammonia at the sampling site. 相似文献
9.
To characterize atmospheric particulate matter equal or less than 2.5 μm in diameter (PM 2.5) over the Tropical Atlantic Ocean, aerosol sampling was carried out in Puerto Rico during August and September, 2006. Aerosols were analyzed by ion chromatography for water-soluble inorganic and organic ions (including Na +, NH 4 +, Mg 2+, Ca 2+, K +, Cl ?, SO 4 2?, NH 4 +, F ?, methanesulfonate (MSA), and oxalate), by inductive coupled plasma mass spectrometry (ICPMS) for trace elements (Al, Fe, Zn, Mn, Cu, Ni, V, Pb, Cr, Sb, Co, Sc, Cd), and by scanning electron microscopy for individual aerosol particle composition and morphology. The results show that the dominant cations in aerosols were Na +, (mean: 631 ng m ?3), accounting for 63.8 % of the total cation and NH 4 + (mean: 164 ng m ?3), accounting for 13.8 % of the total cation measured in this study. The main inorganic anions were Cl ? (576 ng m ?3, 54.1 %) and SO 4 2? (596 ng m ?3, 38.0 %). The main organic anion was oxalate (18 ng m ?3). Crustal enrichment factor calculations identified 62 % of the trace elements measured (Cu, Ni, V, Co, Al, Mn, Fe, Sc, and Cr) with crustal origin. Single particle analysis demonstrated that 40 % of the aerosol particles examined were Cl ? rich particles as sodium chloride from seawater and 34 % of the total particles were Si-rich particles, mainly in the form of aluminosilicates from dust material. Based on the combination of air-mass trajectories, cluster analysis and principal component analysis, the major sources of these PM 2.5 particles include marine, Saharan dust and biomass burning from West Africa; however, volcanic emissions from the Soufriere Hills in Montserrat had significant impact on aerosol composition in this region at the time of sample collection. 相似文献
10.
Secondary aerosol formation was studied at Allahabad in the Indo-Gangetic region during a field campaign called Land Campaign-II
in December 2004 (northern winter). Regional source locations of the ionic species in PM 10 were identified by using Potential Source Contribution Function (PSCF analysis). On an average, the concentration of water
soluble inorganic ions (sum of anions and cations) was 63.2 μgm −3. Amongst the water soluble ions, average NO 3− concentration was the highest (25.0 μgm −3) followed by SO 42− (15.8 μgm −3) and NH 4+ (13.8 μgm −3) concentrations. These species, contributed 87% of the total mass of water soluble species, indicating that most of the water
soluble PM 10 was composed of NH 4NO 3 and (NH 4) 2SO 4/NH 4HSO 4 or (NH 4) 3H(SO 4) 2 particles. Further, the concentrations of SO 42−, NO 3−, and NH4 + aerosols increased at high relative humidity levels up to the deliquescence point (∼63% RH) for salts of these species suggesting
that high humidity levels favor the conversion and partitioning of gaseous SO 2, NO x, and NH 3 to their aerosol phase. Additionally, lowering of ambient temperature as the winter progressed also resulted in an increase
of NO 3− and NH 4+ concentrations, probably due to the semi volatile nature of ammonium nitrate. PSCF analysis identified regions along the
Indo-Gangetic Plain (IGP) including Northern and Central Uttar Pradesh, Punjab, Haryana, Northern Pakistan, and parts of Rajasthan
as source regions of airborne nitrate. Similar source regions, along with Northeastern Madhya Pradesh were identified for
sulfate. 相似文献
11.
Campaigns were conducted to measure Organic Carbon (OC) and Elemental Carbon (EC) in PM2.5 during winter and summer 2003 in Beijing. Modest differences of PM2.5 and PM10 mean concentrations were observed between the winter and summer campaigns. The mean PM2.5/PM10 ratio in both seasons was around 60%, indicating PM2.5 contributed significantly to PM10. The mean concentrations of OC and EC in PM2.5 were 11.2±7.5 and 6.0±5.0μg m-3 for the winter campaign, and 9.4±2.1 and 4.3±3.0 μg m-3 for the summer campaign, respectively. Diurnal concentrations of OC and EC in PM2.5 were found high at night and low during the daytime in winter, and characterized by an obvious minimum in the summer afternoon. The mean OC/EC ratio was 1.87±0.09 for winter and Z39±0.49 for summer. The higher OC/EC ratio in summer indicates some formation of Secondary Organic Carbon (SOC). The estimated SOC was 2.8 μg m-3 for winter and 4.2μg m-3 for summer. 相似文献
12.
This study presents the chemical composition (carbonaceous and nitrogenous components) of aerosols (PM2.5 and PM10) along with stable isotopic composition (δ13C and δ15N) collected during winter and the summer months of 2015–16 to explore the possible sources of aerosols in megacity Delhi, India. The mean concentrations (mean?±?standard deviation at 1σ) of PM2.5 and PM10 were 223?±?69 µg m?3 and 328?±?65 µg m?3, respectively during winter season whereas the mean concentrations of PM2.5 and PM10 were 147?±?22 µg m?3 and 236?±?61 µg m?3, respectively during summer season. The mean value of δ13C (range: ??26.4 to ??23.4‰) and δ15N (range: 3.3 to 14.4‰) of PM2.5 were ??25.3?±?0.5‰ and 8.9?±?2.1‰, respectively during winter season whereas the mean value of δ13C (range: ??26.7 to ??25.3‰) and δ15N (range: 2.8 to 11.5‰) of PM2.5 were ??26.1?±?0.4‰ and 6.4?±?2.5‰, respectively during the summer season. Comparison of stable C and N isotopic fingerprints of major identical sources suggested that major portion of PM2.5 and PM10 at Delhi were mainly from fossil fuel combustion (FFC), biomass burning (BB) (C-3 and C-4 type vegitation), secondary aerosols (SAs) and road dust (SD). The correlation analysis of δ13C with other C (OC, TC, OC/EC and OC/WSOC) components and δ15N with other N components (TN, NH4+ and NO3?) are also support the source identification of isotopic signatures. 相似文献
13.
Airborne particulates were monitored at an urban location of middle Indo-Gangetic Plain (IGP) and subsequently analyzed for particulate diversity and mixing states. Exceptionally high particulate loadings were found both in case of coarser (PM 10: 157.5 ± 102.9 μgm ?3, n = 46) and finer particulates (PM 2.5: 92.5 ± 49.8 μgm ?3). Based on particulate morphology and elemental composition, five different clusters of particulates namely tarball, soot, sulphur-rich, aluminosilicate and mineral species were found to dominate. Soot particles (0.1–5 μm) were found to be partly coated, having voids filled by coating material without being completely engulfed. A specific type of amorphous, carbonaceous spherules was evident in wintertime fine particulates signifying emissions from biomass burning and wild fire. Traces of S, Na and Ca were found associated with carbonaceous agglomerates suggesting its metal scavenging behavior. Particle laden filters were further processed for metallic and water soluble ionic species to constitute aerosol composition. Coarser particulates were characterized with higher metallic species (9.2–17.8 %), mostly of crustal origin (Ca: 5.5 %; Fe: 1.6 %; Zn: 1.3 % and Na: 3.8 %) while PM 2.5 also revealed their association with metallic components (6.0–14.9 %) having Ca (4.6 %), Fe (0.9 %) and K (0.8 %) as principle constituents. Ca, Na and NH 4 + found to generate chloride and sulphate salts thus affecting particulate hygroscopicity. Elevated fractions of NO 3 ? and K + in PM 2.5 signified contribution of biomass burning while presence of Cl ? with carbonaceous aerosols having traces of Si and K denoted contribution of farming and burning practices. Black carbon aerosol exhibited significant seasonal variability (6.9?21.9 μgm ?3) which support larger association of carbonaceous aerosols in particle micrograph. 相似文献
14.
Size-segregated aerosol particles were collected using a high volume MOUDI sampler at a coastal urban site in Xiamen Bay, China, from March 2018 to June 2020 to examine the seasonal characteristics of aerosol and water-soluble inorganic ions (WSIIs) and the dry deposition of nitrogen species. During the study period, the annual average concentrations of PM1, PM2.5, PM10, and TSP were 14.8?±?5.6, 21.1?±?9.0, 35.4?±?14.2 μg m?3, and 45.2?±?21.3 μg m?3, respectively. The seasonal variations of aerosol concentrations were impacted by the monsoon with the lowest value in summer and the higher values in other seasons. For WSIIs, the annual average concentrations were 6.3?±?3.3, 2.1?±?1.2, 3.3?±?1.5, and 1.6?±?0.8 μg m?3 in PM1, PM1-2.5, PM2.5–10, and PM>10, respectively. In addition, pronounced seasonal variations of WSIIs in PM1 and PM1-2.5 were observed, with the highest concentration in spring-winter and the lowest in summer. The size distribution showed that SO42?, NH4+ and K+ were consistently present in the submicron particles while Ca2+, Mg2+, Na+ and Cl? mainly accumulated in the size range of 2.5–10 μm, reflecting their different dominant sources. In spring, fall and winter, a bimodal distribution of NO3? was observed with one peak at 2.5–10 μm and another peak at 0.44–1 μm. In summer, however, the fine mode peak disappeared, likely due to the unfavorable conditions for the formation of NH4NO3. For NH4+ and SO42?, their dominant peak at 0.25–0.44 μm in summer and fall shifted to 0.44–1 μm in spring and winter. Although the concentration of NO3–N was lower than NH4–N, the dry deposition flux of NO3–N (35.77?±?24.49 μmol N m?2 d?1) was much higher than that of NH4–N (10.95?±?11.89 μmol N m?2 d?1), mainly due to the larger deposition velocities of NO3–N. The contribution of sea-salt particles to the total particulate inorganic N deposition was estimated to be 23.9—52.8%. Dry deposition of particulate inorganic N accounted for 0.95% of other terrestrial N influxes. The annual total N deposition can create a new productivity of 3.55 mgC m?2 d?1, accounting for 1.3–4.7% of the primary productivity in Xiamen Bay. In light of these results, atmospheric N deposition could have a significant influence on biogeochemistry cycle of nutrients with respect to projected increase of anthropogenic emissions from mobile sources in coastal region. 相似文献
15.
Using a single drop experiment, the uptake of NO 3 radicals on aqueous solutions of the dye Alizarin Red S and NaCl was measured at 293 K. Uptake coefficients in the range
(1.7–3.1) ⋅ 10 − 3 were measured on Alizarin Red S solutions. The uptake coefficients measured on NaCl solutions were in the range of (1.1–2.0)
⋅ 10 −3 depending on the salt concentration. Both experiments lead to a consistent result for the mass accommodation coefficient
of α NO3 = (4.2 − 1.7+2.2)⋅ 10 −3.
The product H( Dl kCl− II) 0.5 for the NO 3 radical was determined to be (1.9 ± 0.2) M atm − 1 cm s −0.5 M −0.5 s −0.5 by fitting the uptake data for the NaCl solutions to the so-called resistance model.
The yield of the chemical NO 3 radical source was characterized using UV-VIS and FT-IR spectroscopy. The amount of gas-phase NO 3 radicals measured at elevated humidities was less than expected. Instead, a rise of the gas-phase HNO 3 concentration was found indicating a conversion of gas-phase NO 3 radicals to gas-phase HNO 3 on the moist reactor walls. 相似文献
16.
Samples of airborne PM 2.5 particles in Guangzhou urban area were collected during the autumn of 2006 and the spring of 2007. The morphologies and elemental
compositions of individual particles were determined by Scanning Electron Microscopy coupled with Energy Dispersive X-ray
Spectrometer (SEM-EDX). The obtained images were further analyzed for size distribution by an image analysis system. Based
on the morphology, particles in PM 2.5 were classified into four groups: soot aggregates, minerals, fly ash and others. The amount of soot aggregates and minerals
were higher than that of fly ashes. The distributions of particles by number and size in two seasons were bimodal with 90%
less than 1.0 μm in diameter. The primary peak from the autumn samples was in the size range of 0.4 ~ 0.5 μm, and 0.3 ~ 0.4 μm
for the spring samples. More soot aggregates (36.1%) and minerals (61.5%) were found than fly ash (2.4%) in autumn, but soot
aggregates (89.9%) was the dominant particle type in spring. The size distribution of particles according to the volume was
generally opposite to that according to the number. Particles less than 1.0 μm were as high as 89.5% in number but contributed
only 18.9% in volume, indicating that fine particles contributed relatively little in volume although existing in large numbers. 相似文献
17.
This study elucidates the characteristics of ambient PM 2.5 (fine) and PM 1 (submicron) samples collected between July 2009 and June 2010 in Raipur, India, in terms of water soluble ions, i.e. Na +, NH 4 + , K +, Mg 2+, Ca 2+, Cl ?, NO 3 ? and SO 4 2? . The total number of PM 2.5 and PM 1 samples collected with eight stage cascade impactor was 120. Annual mean concentrations of PM 2.5 and PM 1 were 150.9?±?78.6 μg/m 3 and 72.5?±?39.0 μg/m 3, respectively. The higher particulate matter (PM) mass concentrations during the winter season are essentially due to the increase of biomass burning and temperature inversion. Out of above 8 ions, the most abundant ions were SO 4 2? , NO 3 ? and NH 4 + for both PM 2.5 and PM 1 aerosols; their average concentrations were 7.86?±?5.86 μg/m 3, 3.12?±?2.63 μg/m 3 and 1.94?±?1.28 μg/m 3 for PM 2.5, and 5.61?±?3.79 μg/m 3, 1.81?±?1.21 μg/m 3 and 1.26?±?0.88 μg/m 3 for PM 1, respectively. The major secondary species SO 4 2? , NO 3 ? and NH 4 + accounted for 5.81%, 1.88% and 1.40% of the total mass of PM 2.5 and 11.10%, 2.68%, and 2.48% of the total mass of PM 1, respectively. The source identification was conducted for the ionic species in PM 2.5 and PM 1 aerosols. The results are discussed by the way of correlations and principal component analysis. Spearman correlation indicated that Cl ? and K + in PM 2.5 and PM 1 can be originated from similar type of sources. Principal component analysis reveals that there are two major sources (anthropogenic and natural such as soil derived particles) for PM 2.5 and PM 1 fractions. 相似文献
18.
A study has been carried out on water soluble ions, trace elements, as well as PM 2.5 and PM 2.5–10 elemental and organic carbon samples collected daily from Central Taiwan over a one year period in 2005. A source apportionment
study was performed, employing a Gaussian trajectory transfer coefficient model (GTx) to the results from 141 sets of PM 2.5 and PM 2.5–10 samples. Two different types of PM 10 episodes, local pollution (LOP) and Asian dust storm (ADS) were observed in this study. The results revealed that relative
high concentrations of secondary aerosols (NO 3−, SO 42− and NH 4+) and the elements Cu, Zn, Cd, Pb and As were observed in PM 2.5 during LOP periods. However, sea salt species (Na + and Cl −) and crustal elements (e.g., Al, Fe, Mg, K, Ca and Ti) of PM 2.5–10 showed a sharp increase during ADS periods. Anthropogenic source metals, Cu, Zn, Cd, Pb and As, as well as coarse nitrate
also increased with ADS episodes. Moreover, reconstruction of aerosol compositions revealed that soil of PM 2.5–10 elevated approximately 12–14% in ADS periods than LOP and Clear periods. A significantly high ratio of non-sea salt sulfate
to elemental carbon (NSS-SO 42−/EC) of PM 2.5–10 during ADS periods was associated with higher concentrations of non-sea-salt sulfates from the industrial regions of China.
Source apportionment analysis showed that 39% of PM 10, 25% of PM 2.5, 50% of PM 2.5–10, 42% of sulfate and 30% of nitrate were attributable to the long range transport during ADS periods, respectively. 相似文献
19.
The contribution of emissions from agricultural facilities is rapidly becoming a major concern for local and regional air
quality. Characterization of particle properties such as physical size distribution and chemical composition can be valuable
in understanding the processes contributing to emissions and ultimate fate of particulate matter from agricultural facilities.
A measurement campaign was conducted at an Iowa, deep-pit, three-barn swine finishing facility to characterize near-source
ambient particulate matter. Size-specific mass concentrations were determined using minivol samplers, with additional size
distribution information obtain using optical particle counters. Particulate composition was determined via ion chromatographic
analysis of the collected filters. A thermal-CO 2 elemental/organic carbon analyzer measured particulate carbon. The chemical composition and size distribution of sub-micron
particles were determined via real-time aerosol mass spectrometry. Primary particulate was not found to be a major emission
from the examined facility, with filter-based impactor samples showing average near-source increases (~15–50 m) in ambient
PM 10 of 5.8 ± 2.9 μg m −3 above background levels. PM 2.5 also showed contribution attributable to the facility (1.7 ± 1.1 μg m −3). Optical particle counter analysis of the numerical size distributions showed bimodal distributions for both the upwind
and downwind conditions, with maximums around 2.5 μm and below the minimum quantified diameter of 0.3 μm. The distributions
showed increased numbers of coarse particles (PM 10) during periods when wind transport came from the barns, but the differences were not statistically significant at the 95%
confidence level. The PM 10 aerosols showed statistically increased concentrations of sulfate, nitrate, ammonium, calcium, organic carbon, and elemental
carbon when the samplers were downwind from the pig barns. Organic carbon was the major constituent of the barn-impacted particulate
matter in both sub-micron (54%) and coarse size (20%) ranges. The AMS PM 1 chemical speciation showed similar species increases, with the exception of and Ca +2, the latter not quantified by the AMS. 相似文献
20.
In this study, 123 PM2.5 filter samples were collected in Wuhan, Hubei province from December 2014 to November 2015. Water- soluble inorganic ions (WSIIs), elemental carbon (EC), organic carbon (OC) and inorganic elements were measured. Source apportionment and back trajectory was investigated by the positive matrix factorization (PMF) model and the hybrid single particle lagrangian integrated trajectory (HYSPLIT) model, respectively. The annual PM2.5 concentration was 80.5?±?38.2 μg/m3, with higher PM2.5 in winter and lower in summer. WSIIs, OC, EC, as well as elements contributed 46.8%, 14.8%, 6.7% and 8% to PM2.5 mass concentration, respectively. SO42?, NO3? and NH4+ were the dominant components, accounting for 40.2% of PM2.5 concentrations. S, K, Cl, Ba, Fe, Ca and I were the main inorganic elements, and accounted for 65.2% of the elemental composition. The ratio of NO3?/SO42? was 0.86?±?0.72, indicating that stationary sources play dominant role on PM2.5 concentration. The ratio of OC/EC was 2.9?±?1.4, suggesting the existence of secondary organic carbon (SOC). Five sources were identified using PMF model, which included secondary inorganic aerosols (SIA), coal combustion, industry, vehicle emission, fugitive dust. SIA, coal combustion, as well as industry were the dominant contributors to PM2.5 pollution, accounting for 34.7%, 20.5%, 19.6%, respectively. 相似文献
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