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1.
Beijing–Tianjin–Hebei region is one of the most important political, economic and cultural centers of China. The rapid development of economy in last decades has caused severe air pollution problems, which has resulted in considerable harm to local ecological environment and human health. In this study, total 671 air samples were collected from Beijing, Tianjin and Shijiazhuang (the capital city in Hebei province), one reference site and four background sites in four seasons. Particulate matters (PMs) with different sizes, elements and dissolvable ions in PMs were analyzed. Pollutant concentrations, characteristics and seasonal variations were discussed in order to describe the pollution status and the possible sources in this region. Enriched factors of K, Ca, Cr, Fe, Cu, Zn, As, Cd and Pb were all higher than 10. Concentrations of dissolvable ions were in the order of NO 3–, SO 42–>NH 4+>Cl –>Ca 2+, K +, Na +>Mg 2+, F –. NO 3–, SO 42–, NH 4+, Cl – were the most important ion pollutants in the three cities which accounted for 90.3–92.3% of total 9 ion concentrations. Ion concentrations in the PMs were in the order of PM 1>PM 1–2.5>PM 2.5–10>PM 10>TSP. More than 50% of the dissolvable ions exist in PM1 and the percentage increases to 73.9–94.8% in PM 2.5. Human activities should be the main sources of the metallic pollutants, among which coal combustion was identified as the primary one. 相似文献
2.
The results of one year's measurements (typically a two week sampling campaign in each season) of the concentrations of eight major water soluble ions, namely Na +, NH 4+, K +, Mg 2+, Ca 2+, Cl −, NO 3− and SO 42−, in atmospheric aerosols collected in three New Zealand cities (Auckland, Christchurch and Hamilton) are presented. The data has provided important information on particulate soluble ion profiles in New Zealand urban areas and revealed some useful trends.A significant correlation has been found between the average meteorological conditions in a sampling campaign and the average particulate concentrations of some of these soluble ions in the campaign. For example, average particulate NO 3− concentration in a campaign was found to correlate well with the average calm or weak wind duration percentage in the campaign, and the average concentrations of Na +, Mg 2+ and Cl − related closely to the average wind pattern and rainfall in the campaign.Significant site and seasonal variations have been observed with Hamilton having the lowest overall concentrations of all the soluble ions in the particles sampled. On average all sites had the highest particulate concentrations of Na +, Mg 2+ and Cl − in the summer but the highest particulate concentrations of NH 4+ and non-sea-salt Ca 2+ (nss-Ca 2+) in the winter. The possible sources of PM 10 mass have been deduced and in particular the relative contribution of sea salts to PM 10 mass in the cities are reported. 相似文献
3.
Two-stage aerosol samples (PM 10–2.5 and PM 2.5) were collected at a coastal rural site located in the northeastern Mediterranean, between April 2001 and 2002. A total of 562 aerosol samples were analyzed for trace elements (Fe, Ti, Mn, Ca, V, Ni, Zn, Cr) and water-soluble ions (Na +, NH 4+, K +, Mg 2+, Ca 2+, Cl −, Br −, NO 3−, SO 42−, C 2O 42− and MS −:methane sulfonate). PM 10, crustal elements, sea salt aerosols and NO 3− were mainly associated with the coarse mode whereas non-sea salt (nss)SO 42−, C 2O 42−; MS −, NH 4+, Cr and Ni were found predominantly in the fine fraction. Concentrations of aerosol species exhibited orders of magnitude change from day to day and the aerosol chemical composition is heavily affected by dust events under the influence of airflow from North Africa. During the sampling period, 11 specific mineral dust events of duration varying from 1 day to a week have been identified and their influence on the chemical composition of aerosols has been studied in detail. Ionic balance analysis performed in the coarse and fine aerosol fractions indicated anion and cation deficiency due to CO 32− and H +, respectively. A relationship between nssSO 42− and NH 4+ denoted that sulfate particles were partially neutralized (70%) by ammonium. Excess-K/BC presented two distinct ratios for winter and summer, indicating two different sources: fossil fuel burning in winter and biomass burning in summer. 相似文献
4.
The ambient air of the Monterrey Metropolitan Area (MMA) in Mexico frequently exhibits high levels of PM 10 and PM 2.5. However, no information exists on the chemical composition of coarse particles (PM c = PM 10 – PM 2.5). A monitoring campaign was conducted during the summer of 2015, during which 24-hr average PM 10 and PM 2.5 samples were collected using high-volume filter-based instruments to chemically characterize the fine and coarse fractions of the PM. The collected samples were analyzed for anions (Cl –, NO 3–, SO 42–), cations (Na +, NH 4+, K +), organic carbon (OC), elemental carbon (EC), and 35 trace elements (Al to Pb). During the campaign, the average PM 2.5 concentrations did not showed significance differences among sampling sites, whereas the average PM c concentrations did. In addition, the PM c accounted for 75% to 90% of the PM 10 across the MMA. The average contribution of the main chemical species to the total mass indicated that geological material including Ca, Fe, Si, and Al (45%) and sulfates (11%) were the principal components of PM c, whereas sulfates (54%) and organic matter (30%) were the principal components of PM 2.5. The OC-to-EC ratio for PM c ranged from 4.4 to 13, whereas that for PM 2.5 ranged from 3.97 to 6.08. The estimated contribution of Secondary Organic Aerosol (SOA) to the total mass of organic aerosol in PM 2.5 was estimated to be around 70–80%; for PM c, the contribution was lower (20–50%). The enrichment factors (EF) for most of the trace elements exhibited high values for PM 2.5 (EF: 10–1000) and low values for PM c (EF: 1–10). Given the high contribution of crustal elements and the high values of EFs, PM c is heavily influenced by soil resuspension and PM 2.5 by anthropogenic sources. Finally, the airborne particles found in the eastern region of the MMA were chemically distinguishable from those in its western region. Implications: Concentration and chemical composition patterns of fine and coarse particles can vary significantly across the MMA. Public policy solutions have to be built based on these observations. There is clear evidence that the spatial variations in the MMA’s coarse fractions are influenced by clearly recognizable primary emission sources, while fine particles exhibit a homogeneous concentration field and a clear spatial pattern of increasing secondary contributions. Important reductions in the coarse fraction can come from primary particles’ emission controls; for fine particles, control of gaseous precursors—particularly sulfur-containing species and organic compounds—should be considered. 相似文献
5.
Ambient suspended particulate (PM 2.5, PM 2.5–10, TSP) was collected from June 1998 to February 2001 in Taichung, central Taiwan. In addition, the related water-soluble ionic species (Cl −, NO 3−, SO 42−, Na +, NH 4+, K +, Mg 2+, Ca 2+) and metallic species (Fe, Zn, Pb, Ni) were also analyzed in this study. The results showed that the concentrations of particulate mass are higher in the traffic site (CCRT) than the other sampling sites in this study. Also, the fine particle (PM 2.5) concentration is the dominant species of the total suspended particles in Taichung, central Taiwan. The dominant species for PM 2.5 are sulfate and ammonium at all sampling sites during the period of 1998–2001. The results of diurnal variation at THUC sampling site are also discussed in this study. Overall, acidic and secondary aerosol (Cl −, NO 3−, SO 42− and NH 4+) is a more serious air pollutant issue in southern and central Taiwan than at several sites around the world. Therefore, ambient suspended particulate monitoring in Taichung, central Taiwan will be continuing in our following study to provide more information for the government to formulate environmental strategy. 相似文献
6.
We report on ambient atmospheric aerosols present at sea during the Atlantic–Mediterranean voyage of Oceanic II (The Scholar Ship) in spring 2008. A record was obtained of hourly PM 10, PM 2.5, and PM 1 particle size fraction concentrations and 24-h filter samples for chemical analysis which allowed for comparison between levels of crustal particles, sea spray, total carbon, and secondary inorganic aerosols. On-board monitoring was continuous from the equatorial Atlantic to the Straits of Gibraltar, across the Mediterranean to Istanbul, and back via Lisbon to the English Channel. Initially clean air in the open Atlantic registered PM 10 levels <10 μg m ?3 but became progressively polluted by increasingly coarse PM as the ship approached land. Away from major port cities, the main sources of atmospheric contamination identified were dust intrusions from North Africa (NAF), smoke plumes from biomass burning in sub-Saharan Africa and Russia, industrial sulphate clouds and other regional pollution sources transported from Europe, sea spray during rough seas, and plumes emanating from islands. Under dry NAF intrusions PM 10 daily mean levels averaged 40–60 μg m ?3 (30–40 μg m ?3 PM 2.5; c. 20 μg m ?3 PM 1), peaking briefly to >120 μg m ?3 (hourly mean) when the ship passed through curtains of higher dust concentrations amassed at the frontal edge of the dust cloud. PM 1/PM 10 ratios ranged from very low during desert dust intrusions (0.3–0.4) to very high during anthropogenic pollution plume events (0.8–1). 相似文献
7.
Ambient PM2.5 is one of the major risk factors for human health, and is not fully explained solely by mass concentration. We examined the short-term associations of cause-specific mortality (i.e., all-cause, cardiovascular, and respiratory mortality) with the 15 chemical constituents and sources of PM2.5 in four metropolitan cities of South Korea during 2014–2018. We found transition metals consistently showed significant associations with all-cause mortality, while the effects of other constituents varied across the cities and for cause of death. Carbonaceous components strongly affected the all-cause, cardiovascular, and respiratory mortality in Daejeon. Secondary inorganic aerosols, SO42? and NH4+, showed significant associations with respiratory mortality in Gwangju. We also found the sources from which species closely linked to mortality generally increased the relative mortality risks. Heavy metal markers from soil or industrial sources were significantly associated with mortality in all cities. However, several sources influenced mortality despite their marker species not being significantly associated with it. Secondary nitrate and secondary sulfate sources were linked to mortality in DJ. This could be attributed to the deep inland location, which might have facilitated formation of secondary inorganic aerosols. In addition, primary sources including mobile and coal combustion seemed to have acute impacts on respiratory mortality in Gwangju. Our findings suggest the necessity of positive matrix factorization (PMF)-based approaches for evaluating health effects of PM2.5 while considering the spatial heterogeneity in the compositions and source contributions of PM2.5. 相似文献
8.
This study investigates ammonium, nitrate, and sulfate (NH 4+, NO 3?, and SO 42?) in size-resolved particles (particularly nano (PM 0.01–0.056)/ultrafine (PM 0.01–0.1)) and NO x/SO 2 collected near a busy road and at a rural site. The average (mass) cumulative fraction of secondary inorganic aerosols (SO 42?+NO 3?+NH 4+) in nano or ultrafine particles at the roadside was found to be three to four times that at the rural site. The above three secondary inorganic aerosol species were present in similar cumulative fractions in particles of size 1–18 μm at both sites; however, dissimilar fractions were observed for Cl ?, Na +, and K +. The nitrogen ratios (NRs: NR = NO 3??N/(NO 3??N + NO 2–N)), sulfur ratios (SRs: SR = SO 42??S/(SO 42??S + SO 2–S)), dNR/D P (derivative of NR with respect to D P (particle diameter)), and dSR/D P (derivative of SR with respect to D P) at the roadside were higher than those at the rural site for nano/ultrafine particles. At both sites (particularly the roadside), the nanoparticles had significantly higher dNR/D P and dSR/D P values than differently sized particles, implying that NO 3?/SO 42? (from NO 2/SO 2 transformation or NO 3?/SO 42? deposition) were present on these particles. 相似文献
9.
The water-soluble ions in fine (PM <2.5) and coarse (PM 2.5−10) atmospheric aerosols collected in Christchurch during winter 2001, spring 2000 and summer 2001, and in Auckland during winter 2001 have been studied in terms of coarse–fine and day–night differences. Although the chemical characteristics of the coarse particles were similar in both cities, those of the fine particles collected in the Christchurch winter were significantly different, as manifested by higher concentrations of nss-K +, nss-Cl −, nss-Ca 2+, nss-SO 42−, NO 3− and NH 4+. It was found that nighttime PM 10 and nss-K + concentrations were much higher than their daytime concentrations in the Christchurch winter but a clear day–night difference was not apparent in the Auckland winter. Moreover, in the winter, sea-salt ions did not show a day–night difference; however, nss-SO 42− had opposite day–night variation in the two cities. An ion balance calculation has shown that in most samples, coarse particles can be neutral or alkaline, however, fine particles can be neutral or acidic. The possibility of ammonium salts existing in the fine particles collected in the Christchurch winter is discussed and it is concluded that a variety of ammonium salts were present. Equivalent ratios suggest that the fine particles may be significantly aged in the Christchurch winter.The evidence from our soluble ion study strongly suggests that wood and coal burning and secondary aerosols make a significant contribution to fine particulate mass in the Christchurch atmosphere. Thus, home-heating, a sheltered geographic location and relatively calm atmospheric condition are thought to be the major causes for the serious atmospheric particulate pollution in the Christchurch winter. 相似文献
10.
AbstractTo determine the sources of particulate matter less than 2.5?μm (PM 2.5 in different ambient atmospheres (urban, roadside, industrial, and rural sites), the chemical components of PM 2.5 such as ions (Cl -, NO 3-, SO 42-, NH 4+, Na +, K +, Ca 2+, and Mg 2+), carbonaceous species, and elements (Al, As, Ba, Cd, Cu, Fe, Mn, Ni, Pb, Se, V, and Zn) were measured. The average mass concentrations of PM 2.5 at the urban, roadside, industrial, and rural sites were 31.5?±?14.8, 31.6?±?22.3, 31.4?±?16.0, and 25.8?±?12.4?μg/m 3, respectively. Except for secondary ammonium sulfate and ammonium nitrate, the model results showed that the traffic source (i.e., the sum of gasoline and diesel vehicle sources) was the most dominant source of PM 2.5 (17.1%) followed by biomass burning (13.8%) at the urban site. The major primary sources of PM 2.5 were consistent with the site characteristics (diesel vehicle source at the roadside site, coal-fired plants at the industrial site, and biomass burning at the rural site). Seasonal data from the urban site suggested that ammonium sulfate and ammonium nitrate were the most dominant sources of PM 2.5 during all seasons. Further, the contribution of road dust source to PM 2.5 increased during spring and fall seasons. We conclude that the determination of the major PM 2.5 sources is useful for establishing efficient control strategies for PM 2.5 in different regions and seasons. 相似文献
11.
Animal feeding operations (AFOs) produce particulate matter (PM) and gaseous pollutants. Investigation of the chemical composition of PM 2.5 inside and in the local vicinity of AFOs can help to understand the impact of the AFO emissions on ambient secondary PM formation. This study was conducted on a commercial egg production farm in North Carolina. Samples of PM 2.5 were collected from five stations, with one located in an egg production house and the other four located in the vicinity of the farm along four wind directions. The major ions of NH 4+, Na +, K +, SO 42?, Cl ?, and NO 3? were analyzed using ion chromatography (IC). In the house, the mostly abundant ions were SO 42?, Cl ?, and K +. At ambient stations, SO 42?, and NH 4+ were the two most abundant ions. In the house, NH 4+, SO 42?, and NO 3? accounted for only 10% of the PM 2.5 mass; at ambient locations, NH 4+, SO 42?, and NO 3? accounted for 36–41% of the PM 2.5 mass. In the house, NH 4+ had small seasonal variations indicating that gas-phase NH 3 was not the only major force driving its gas–particle partitioning. At the ambient stations, NH 4+ had the highest concentrations in summer. In the house, K +, Na +, and Cl ? were highly correlated with each other. In ambient locations, SO 42? and NH 4+ had a strong correlation, whereas in the house, SO 42? and NH 4+ had a very weak correlation. Ambient temperature and solar radiation were positively correlated with NH 4+ and SO 42?. This study suggests that secondary PM formation inside the animal house was not an important source of PM 2.5. In the vicinity, NH 3 emissions had greater impact on PM 2.5 formation. ImplicationsThe chemical composition of PM 2.5 inside and in the local vicinity of AFOs showed the impact of the AFO emissions on ambient secondary PM 2.5 formation, and the fate and transport of air pollutants associated with AFOs. The results may help to manage in-house animal facility air quality, and to develop regional air quality control strategies and policies, especially in animal agriculture-concentrated areas. 相似文献
12.
Interest in the role and contribution of fungi to atmospheric aerosols and processes grows in the past decade. Substantial data or information such as fungal mass or carbon loading to ambient aerosols is however still lacking. This study aimed to quantify the specific organic carbon content (OC per spore) of eleven fungal species commonly found airborne in the subtropics, and estimated their contribution to organic carbon in aerosols. The specific OC contents showed a size-dependent relationship ( r = 0.64, p < 0.05) and ranged from 3.6 to 201.0 pg carbon per spore or yeast cell, giving an average of 6.0 pg carbon per spore (RSD 51%) for spore or cell size less than 10 μm. In accounting for natural variations in the composition and abundance of fungal population, weighted-average carbon content for field samples was adopted using the laboratory determined specific OC values. An average of 5.97 pg carbon per spore (RSD 3.8%) was enumerated from 28 field samples collected at the university campus. The mean fungal OC concentration was 3.7, 6.0 and 9.7 ng m ?3 in PM 2.5, PM 2.5–10 and PM 10, respectively. These corresponded to 0.1%, 1.2% and 0.2% of the total OC in PM 2.5, PM 2.5–10 and PM 10, respectively. In the study period, rain provided periods with low total OC but high fungal prevalence and fungi contributed 7–32% OC in PM 2.5–10 or 2.4–7.1% OC in PM 10. More extensive studies are deserved to better understand the spatial-, temporal- and episodic dependency on the fungal OC contribution to the atmospheric aerosols. 相似文献
13.
This study investigates the water-soluble ionic constituents (Na +, K +, NH 4 +, Ca 2+, Mg 2+, Cl ?, NO 3 ?, SO 4 2?) associated to PM 2.5 particle fraction at two urban sites in the city of Thessaloniki, northern Greece, an urban traffic site (UT) and urban background site (UB). Ionic constituents represent a significant fraction of PM 2.5 mass (29.6 at UT and 41.5 % at UB). The contribution of marine aerosol was low (<1.5 %). Secondary inorganic aerosols (SIA) represent a significant fraction of PM 2.5 mass contributing to 26.9?±?12.4 % and 39.2?±?13.2 % at UT and UB sites, respectively. Nitrate and sulfate are fully neutralized by ammonium under the existing conditions. The ionic constituents were evaluated in relation to their spatial and temporal variation, their gaseous precursors, meteorological conditions, local and long-range transport. 相似文献
14.
To better understand the influence of sources and atmospheric processing on aerosol chemical composition, we collected atmospheric particles in Sapporo, northern Japan during spring and early summer 2005 under the air mass transport conditions from Siberia, China and surrounding seas. The aerosols were analyzed for inorganic ions, organic carbon (OC), elemental carbon (EC), water-soluble organic carbon (WSOC), and the major water-soluble organic compound classes (i.e., dicarboxylic acids and sugars). SO 42? is the most abundant inorganic constituent (average 44% of the identified inorganic ion mass) followed by NH 4+ (21%) and NO 3? (13%). Concentrations of OC, EC, and WSOC ranged from 2.0–16, 0.24–2.9, and 0.80–7.9 μg m ?3 with a mean of 7.4, 1.0, and 3.1 μg m ?3, respectively. High OC/EC ratios (range: 3.6–19, mean: 8.7) were obtained, however WSOC/OC ratios (0.23–0.69, 0.44) do not show any significant diurnal changes. These results suggest that the Sapporo aerosols were already aged, but were not seriously affected by local photochemical processes. Identified water-soluble organic compounds (diacids + sugars) account for <10% of WSOC. Based on some marker species and air mass back trajectory analyses, and using stable carbon isotopic compositions of shorter-chain diacids (i.e., C 2–C 4) as photochemical aging factor of organic aerosols, the present study suggests that a fraction of WSOC in OC is most likely influenced by aerosol aging, although the OC loading in aerosols may be more influenced by their sources and source regions. 相似文献
15.
The characteristics of ambient aerosols, affected by solar radiation, relative humidity, wind speed, wind direction, and gas–aerosol interaction, changed rapidly at different spatial and temporal scales. In Taipei Basin, dense traffic emissions and sufficient solar radiation for typical summer days favored the formation of secondary aerosols. In winter, the air quality in Taipei Basin was usually affected by the Asian continental outflows due to the long-range transport of pollutants carried by the winter monsoon. The conventional filter-based method needs a long time for collecting aerosols and analyzing compositions, which cannot provide high time-resolution data to investigate aerosol sources, atmospheric transformation processes, and health effects. In this work, the in situ ion chromatograph (IC) system was developed to provide 15-min time-resolution data of nine soluble inorganic species (Cl −, NO 2−, NO 3−, SO 42−, Na +, NH 4+, K +, Mg 2+ and Ca 2+). Over 89% of all particles larger than approximately 0.056 μm were collected by the in situ IC system. The in situ IC system is estimated to have a limit of detection lower than 0.3 μg m −3 for the various ambient ionic components. Depending on the hourly measurements, the pollutant events with high aerosol concentrations in Taipei Basin were associated with the local traffic emission in rush hour, the accumulation of pollutants in the stagnant atmosphere, the emission of industrial pollutants from the nearby factories, the photochemical secondary aerosol formation, and the long-range transport of pollutants from Asian outflows. 相似文献
16.
Fine particulate matter (PM 2.5) was sampled at 5 Spanish locations during the European Community Respiratory Health Survey II (ECRHS II). In an attempt to identify and quantify PM 2.5 sources, source contribution analysis by principal component analysis (PCA) was performed on five datasets containing elemental composition of PM 2.5 analysed by ED-XRF. A total of 4–5 factors were identified at each site, three of them being common to all sites (interpreted as traffic, mineral and secondary aerosols) whereas industrial sources were site-specific. Sea-salt was identified as independent source at all coastal locations except for Barcelona (where it was clustered with secondary aerosols). Despite their typically dominant coarse grain-size distribution, mineral and marine aerosols were clearly observed in PM 2.5. Multi-linear regression analysis (MLRA) was applied to the data, showing that traffic was the main source of PM 2.5 at the five sites (39–53% of PM 2.5, 5.1–12.0 μg m −3), while regional-scale secondary aerosols accounted for 14–34% of PM 2.5 (2.6–4.5 μg m −3), mineral matter for 13–31% (2.4–4.6 μg m −3) and sea-salt made up 3–7% of the PM 2.5 mass (0.4–1.3 μg m −3). Consequently, despite regional and climatic variability throughout Spain, the same four main PM 2.5 emission sources were identified at all the study sites and the differences between the relative contributions of each of these sources varied at most 20%. This would corroborate PM 2.5 as a useful parameter for health studies and environmental policy-making, owing to the fact that it is not as subject to the influence of micro-sitting as other parameters such as PM 10. African dust inputs were observed in the mineral source, adding on average 4–11 μg m −3 to the PM 2.5 daily mean during dust outbreaks. On average, levels of Al, Si, Ti and Fe during African episodes were higher by a factor of 2–8 with respect to non-African days, whereas levels of local pollutants (absorption coefficient, S, Pb, Cl) showed smaller variations (factor of 0.5–2). 相似文献
17.
The frequency, strength and sources of long-range transport (LRT) episodes of fine particles (PM 2.5) were studied in southern Finland using air quality monitoring results, backward air mass trajectories, remote sensing of fire hot spots, transport and dispersion modelling of smoke and chemical analysis of particle samples (black carbon, monosaccharide anhydrides, oxalate, succinate, malonate, SO 42?, NO 3?, K + and NH 4+). At an urban background site in Helsinki, the daily WHO guideline value (24-h PM 2.5 mean 25 μg m ?3) was exceeded during 1–7 LRT episodes per year in 1999–2007. The 24-h mean maximum concentrations varied between 25 and 49 μg m ?3 during the episodes, which was 3–6 times higher than the local mean concentration (8.7 μg m ?3) in 1999–2007. The highest particle concentrations (max. 1-h mean 163 μg m ?3) and the longest episodes (max. 9 days) were mainly caused by the emissions from open biomass burning, especially during springs and late-summers in 2002 and 2006. During the period 2001–2007, the satellite remote sensing of active fire hot spots and transport and dispersion modelling of smoke indicated that approximately half of the episodes were caused partly by the emissions from wildfires and/or agricultural waste burning in fields in Eastern Europe, especially in Russia, Belarus and Ukraine. Other episodes were mainly caused by the LRT of ordinary anthropogenic pollutants, e.g. from energy production, traffic, industry and wood combustion. During those ‘other episodes’, air masses also arrived from Eastern Europe, including Poland. The highest concentrations of biomass-burning tracers, such as monosaccharide anhydrides (levoglucosan + mannosan + galactosan) and K +, were observed during open biomass-burning episodes, but quite high values were also measured during some winter episodes due to wood combustion emissions. Our results indicate that open biomass burning in Eastern Europe causes high fine particle concentration peaks in large areas of Europe almost every year. 相似文献
18.
Continuous measurement of PM 10, PM 2.5 and carbon (organic, elemental composition) concentrations, and samples of PM 10 and PM 2.5 collected on a polycarbonate membrane filter (Nuclepore ®, pore size: 0.8 μm), were carried out during a period from December 1998 to January 1999 at Shinjuku in Tokyo in order to investigate the chemical characterization of particles in winter-night smog within a large area of the Japan Kanto Plain including the Tokyo Metropolitan area. These were measured using an ambient particulate monitor (tapered element oscillating microbalance—TEOM) and a carbon particulate monitor. Elemental compositions in the filter samples of PM 10 and PM 2.5 were determined by means of particle-induced X-ray emission (PIXE) analysis. Ionic species (anion: F −, Cl −, NO 3−, SO 42− and C 2O 42−; cation: Na +, NH 4+, K +, Ca 2+ and Mg 2+) in the filter samples were analyzed by ion chromatography. The temporal variation patterns of PM 2.5 were similar to those of PM 10 and carbon. PM 2.5 made up 90% of the PM 10 at a high concentration, and 70% at a low concentration. Concentrations of 22 elements in both the PM 10 and PM 2.5 samples were consistently determined by PIXE, and Na, Mg, Al, Si, S, Cl, K, Ca, Fe, Zn and Pb were found to be the major components. Among these S and Cl were the most dominant elements of the PM 2.5 and PM 10 at high concentrations. Ionic species were mainly composed of Cl −, NO 3−, SO 42− and NH 4+. The component proportion of carbon, the other elements (total amount of measured elements other than S and Cl) and secondary-formed particles of PM 2.5 was similar to that of PM 10. The major component was carbon particles at a low concentration and secondary-formed particles at a high concentration. The proportion of NH 4NO 3 and NH 4Cl plus HCl in secondary-formed particles at a high concentration, in particular, was as high as 90%. 相似文献
19.
The concentrations of PM 2.5−10, PM 2.5 and associated water-soluble inorganic species (WSIS) were determined in a coastal site of the metropolitan region of Rio de Janeiro, Southeastern Brazil, from October 1998 to September 1999 ( n=50). Samples were dissolved in water and analyzed for major inorganic ions. The mean (± standard deviation; median) concentrations of PM 2.5−10 and PM 2.5 were, respectively, 26 (± 16; 21) μg m −3 and 17 (± 13; 14) μg m −3. Their mean concentrations were 1.7–1.8 times higher in dry season (May–October) than in rainy season (November–April). The WSIS comprised, respectively, 34% and 28% of the PM 2.5−10 and PM 2.5 masses. Chloride, Na + and Mg 2+ were the predominant ions in PM 2.5−10, indicating a significant influence of sea-salt aerosols. In PM 2.5, SO 42− (∼97% nss-SO 42−) and NH 4+ were the most abundant ions and their equivalent concentration ratio (SO 42−/NH 4+ ∼1.0) suggests that they were present as (NH 4) 2SO 4 particles. The mean concentration of (NH 4) 2SO 4 was 3.4 μg m −3. The mean equivalent PM 2.5 NO 3− concentration was eight times smaller than those of SO 42− and NH 4+. The PM 2.5 NO 3− concentration in dry season was three times higher than in rainy season, probably due to reaction of NaCl (sea salt) with HNO 3 as a result of higher levels of NO y during the dry season and/or reduced volatilization of NH 4NO 3 due to lower wintertime temperature. Chloride depletion was observed in both size ranges, although more pronouncely in PM 2.5. 相似文献
20.
The present study investigated the comprehensive chemical composition [organic carbon (OC), elemental carbon (EC), water-soluble inorganic ionic components (WSICs), and major & trace elements] of particulate matter (PM 2.5) and scrutinized their emission sources for urban region of Delhi. The 135 PM 2.5 samples were collected from January 2013 to December 2014 and analyzed for chemical constituents for source apportionment study. The average concentration of PM 2.5 was recorded as 121.9 ± 93.2 μg m ?3 (range 25.1–429.8 μg m ?3), whereas the total concentration of trace elements (Na, Ca, Mg, Al, S, Cl, K, Cr, Si, Ti, As, Br, Pb, Fe, Zn, and Mn) was accounted for ~17% of PM 2.5. Strong seasonal variation was observed in PM 2.5 mass concentration and its chemical composition with maxima during winter and minima during monsoon seasons. The chemical composition of the PM 2.5 was reconstructed using IMPROVE equation, which was observed to be in good agreement with the gravimetric mass. Source apportionment of PM 2.5 was carried out using the following three different receptor models: principal component analysis with absolute principal component scores (PCA/APCS), which identified five major sources; UNMIX which identified four major sources; and positive matrix factorization (PMF), which explored seven major sources. The applied models were able to identify the major sources contributing to the PM 2.5 and re-confirmed that secondary aerosols (SAs), soil/road dust (SD), vehicular emissions (VEs), biomass burning (BB), fossil fuel combustion (FFC), and industrial emission (IE) were dominant contributors to PM 2.5 in Delhi. The influences of local and regional sources were also explored using 5-day backward air mass trajectory analysis, cluster analysis, and potential source contribution function (PSCF). Cluster and PSCF results indicated that local as well as long-transported PM 2.5 from the north-west India and Pakistan were mostly pertinent. 相似文献
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