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1.
Ten selected metals (Na, K, Fe, Zn, Pb, Mn, Cr, Co, Ni & Cd) were estimated in total suspended particulate (TSP) samples collected on glass fibre filters in urban Islamabad, Pakistan, from October 2002 to May 2003, using a high volume sampling technique. The wet digestion method (HNO3/HClO4) was used for metal analysis by the flame atomic absorption spectrophotometry (FAAS) method. Maximum mean contribution was noted for Na (1.949 μg m?3), followed by K (0.900 μg m?3), Zn (0.603 μg m?3), Fe (0.584 μg m?3) and Pb (0.214 μg m?3). The particle size determination on % volume basis for four fractions (PM< 2.5, PM2.5–10, PM10–100& PM> 100) was also carried out. PM10–100 were found to be the most abundant in the local atmosphere followed by PM2.5–10, while the respirable fraction (PM< 2.5) and giant fraction (PM> 100) showed comparable and lower levels. The trace metals were found to be mainly associated with PM< 2.5 and PM2.5–10. The influence of climatic variables on toxic trace metals and particle size fractions was also investigated statistically and it was revealed that temperature has a significant correlation with fine particle fractions and airborne trace metal levels. The source identification was carried out by Principal Component Analysis and Cluster Analysis. Four metal sources were identified: industrial (32.6%), soil-derived dust (21.9%), traffic/road dust (19.8%), and metallurgical/garbage incineration (12.4%). The metal levels were also compared with those reported for other parts around the world.  相似文献   

2.
It is now irrefutable that air pollution caused by large amounts of Total Suspended Particulates (TSP) and respiratory particulates or Particulate Matter less than 10 μm in aerodynamic diameter (PM10) has numerous undesired consequences on human health. Air quality degradation far from the African continent, in the US and in Europe, caused by high concentrations of African dust, is seen as a major threat even though most of these countries are very distant from the Sahara. Surprisingly, no estimates of TSP or PM10 levels near the Saharan dust source are available. Based on horizontal visibility observations which are reduced by the presence of dust in the atmosphere, TSP and PM10 levels are estimated throughout the year 2000 at Nouakchott-Airport, Mauritania, using relations found in the literature. It appears that concentrations of particles are significant both in terms magnitude and frequency, as the 24-hour PM10 thresholds established by the US EPA National Ambient Air Quality Standards and the EU Limits Values for Air Quality were exceeded 86 and 137 times, respectively. The average annual concentration is far above air quality standards and estimated at 159 μg m?3 for TSP and 108 μg m?3 for PM10. These very high particulate levels are likely to represent an important public health hazard and should be considered as a major environmental risk.  相似文献   

3.
Atmospheric suspended particulate matter (PM10) was sampled from the Jobos Bay estuary in Salinas and from a reference site (Fajardo) in the east coast of Puerto Rico. Salinas is a town in the south coast of Puerto Rico adjacent to a number of industries and to the only coal power plant on the island. It is important to study the air quality in this area since significant releases of metal to the environment due to energy production could represent a threat to local communities. This study evaluated the levels of PM10, metals, and arsenic to set a reference point for future environmental studies in the area. Sampling was performed for periods of 72 h between August 2002 and May 2003 using a Partisol Plus Model 2025 sequential PM10 air monitor. Seven metals were analyzed per sample (Cd, Cu, Fe, Ni, Hg, Pb and V) plus arsenic using Atomic Absorption. Average annuals levels for PM10 in Salinas were 22.9 μg/m3 versus 20.7 μg/m3 in Fajardo. All metals analyzed were significantly higher in Salinas when compared to Fajardo (reference site). Statistical analyses showed strong relationships between the metal groups (Cu and Cd) and (As and Pb) at Salinas. Good relationship was also observed for Fe and PM10. This analysis suggests two main sources for the elements: anthropogenic and metal flux from Saharan dust arriving to the island.  相似文献   

4.
The aim of this study is to assess the premature mortality risks caused by exposure to particulate matter with aerodynamic diameter less than 2.5???m (PM2.5) and ozone elevated concentrations for the years?2000, 2005, and 2020 in East Asia. The spatial distributions and temporal variations of PM2.5 and ozone concentrations are simulated using the Models-3 Community Multiscale Air Quality Modeling System coupled with the Regional Emission Inventory in Asia. The premature mortality risks caused by exposure to PM2.5 and ozone are calculated based on a relative risk (RR) value of 1.04 (95?% confidence interval (CI): 1.01?C1.08) for PM2.5 concentrations above the annual mean limit of 10???g?m?3 taken from the World Health Organization?CAir Quality Guideline and based on a RR value of 1.003 (95?% CI: 1.001?C1.004) for ozone concentration above 35?ppb of the SOMO35 index (the sum of ozone daily maximum 8-h mean concentrations above 35?ppb). We demonstrate one of the implications of the policy making in the area of environmental atmospheric management in East Asia by highlighting the annual premature mortalities associated with exposure to PM2.5 concentrations that just meet an annual mean concentration of 10???g?m?3, as well as ozone concentrations that have a daily zero SOMO35 index in vulnerable places. Our results point to a growing health risk that may endanger human life in East Asia. We find that the effect of PM2.5 on human health is greater than the effect of ozone for the age group of 30?years and above. We estimate the corresponding premature mortality due to the effects of both ozone and PM2.5 in East Asia for the years?2000 and 2005 to be around 316,000 and 520,000 cases, respectively. For future scenarios of the year?2020, policy succeed case, reference, and policy failed case, the estimated annual premature mortality rates are 451,000, 649,000, and 1,035,000 respectively.  相似文献   

5.
Particulate matter measurements (PM10, PM2.5) using a beta radiation attenuation monitor were performed at the Akrotiri research station (May 2003–March 2006) on the island of Crete (Greece). The mean PM10 concentration during the measuring period (05/02/03–03/09/04) was equal to 35.0?±?17.7 μg/m3 whereas the mean PM2.5 concentration (03/10/04–04/02/06) was equal to 25.4?±?16.5 μg/m3. The aerosol concentration at the Akrotiri station shows a large variability during the year. Mean concentrations of particulate matter undergo a seasonal change characterised by higher concentrations during summer [PM10, 38.7?±?10.8 μg/m3 (2003); PM2.5, 27.9?±?8.7 μg/m3 (2004) and 27.8?±?9.7 μg/m3 (2005)] and lower concentrations during winter [PM10, 28.7?±?22.5 μg/m3 (2003/2004); PM2.5, 21.0?±?13.0 μg/m3 (2004/2005) and 21.4?±?21.9 μg/m3 (2005/2006)]. Comparative measurements of the PM10 concentration between the beta radiation attenuation monitor, a standardized low volume gravimetric reference sampler and a low volume sequential particulate sampler showed that PM10 concentrations measured by the beta radiation attenuation monitor were higher than values given by the gravimetric samplers (mean ratio 1.17?±?0.11 and 1.21?±?0.08, respectively). Statistical and back trajectory analysis showed that elevated PM concentrations (PM10, 93.8?±?49.1 μg/m3; PM2.5: 102.9?±?59.9 μg/m3) are associated to desert dust events. In addition regional transport contributes significantly to the aerosol concentration levels whereas low aerosol concentrations were observed during storm episodes.  相似文献   

6.
To evaluate the potential public health impact of exposure to airborne particulate matter, concentrations of PM10 and PM2.5 were measured at 16 monitoring stations in Pearl River Delta. Epidemiological studies were collected, and meta-analysis method was used to get the exposure-response functions for health effects on mortality of residents in China. Chinese studies reported somewhat lower exposure-response coefficients as compared with studies abroad. Both Poisson model and life-table approach were used to estimate the health effects including acute effects and chronic effects. For short-term exposure, 2,700 (95% confidence interval (CI), 2,200?C3,400) premature deaths would be prevented annually if PM10 daily concentrations reduced to below World Health Organization (WHO) guideline value. Much more benefits would be gained for long-term exposure. The annual avoidable deaths would be 42,000 (95% CI, 28,000?C55,000) and 40,000 (95% CI, 23,000?C54,000) for PM10 and PM2.5, respectively, if the particulate matter annual concentrations were reduced to below WHO guideline values. And the average lifespan of residents would prolong 2.57?years for PM10 and 2.38?years for PM2.5 if reducing the PM annual concentrations. The benefits varied greatly in different areas and different manage strategies should be carried out to protect human health effectively.  相似文献   

7.
Despite the importance of desert dust at global and regional scales, its exact provenance is often unclear. The Taklimakan Desert in northwest China is a common source of high‐frequency regional dust storms and is also a large source of global dust production. On the basis of field observations and the determination of the fraction of aeolian dust in surface samples, we characterized the relative intensity of windblown sand/dust processes in the Taklimakan and the volume of dust emitted (PM10) during these processes. Major dust sources were degraded lands on the eastern desert margin, the Gobi and alluvial, fluvial and aeolian sediments occurring on the desert margin. These areas have high PM10 emission capacity due to high‐surface PM10 concentrations and intensive windblown sand/dust activity. Despite having intensive windblown sand activity, the central desert had lower PM10 dust emission capacity (<1·6 kg day−1 m−2 in spring, <0·08 kg day−1 m−2 in other seasons) due to lower surface PM10 fraction. The dry Taitema Lake bed was a source of potentially high dust emissions (at least 4·4–17 kg day−1 m−2 for the monitoring period) due to the intensity windblown sand/dust activities, despite low PM10 concentrations. The dry river beds on the southeastern desert margin had lower dust emission potential due to low PM10 concentrations and windblown sand/dust activity. Most dust emission sources lie in the paths of prevailing winds, leading to aeolian dust transported to and deposited in the desert hinterland or Hotan, Yutian and Minfeng areas, where wind stream convergence leads to high‐frequency dust storms. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

8.
The evaluation of the contribution of natural sources to PM10 and PM2.5 concentrations is a priority especially for the countries of European south strongly influenced by Saharan dust transport events. Daily PM2.5 concentrations and composition were monitored at an urban site at 14 m above ground level, at the National Technical University of Athens campus from February to December 2010. The typical dust constituents Si, Al, Fe, K, Ca, Mg, and Ti were determined by wavelength dispersive X-ray fluorescence spectrometry (WDXRF). Sulfur, a tracer of anthropogenic origin and major constituent of PM2.5, was determined by both WDXRF and ionic chromatography. The contribution of dust and sulfates in PM2.5 was calculated from the analytical determinations. An annual mean of 20 μg/m3 was calculated from the mean daily PM2.5 concentrations data. Twenty-two per cent of daily concentrations of PM2.5 reached or exceeded the EU annual target concentration of 25 μg/m3. The exceedances occurred during 13 short periods of 1–4 days. Back-trajectory analysis was performed for these periods in order to identify the air masses origin. From these periods, ten periods were associated to Saharan dust transport events. The most intense dust transport event occurred between February 17th and 20th and was responsible for the highest recorded PM2.5 concentration of 100 μg/m3 where the dust contribution in PM2.5 reached 96 %. The other dust transport events were less intense and corresponded to less pronounced enhancements of PM2.5 concentrations, and their contribution ranged from 15 to 39 % in PM2.5 concentrations. Air masses originated from northwest Africa while the influence of central Sahara was quite smaller.  相似文献   

9.
Widespread drought and record maximum temperatures in eastern Australia produced a large dust storm on 23 October, 2002 which traversed a large proportion of eastern Australia and engulfed communities along a 2000 km stretch of coastline from south of Sydney (NSW) to north of Mackay (Queensland). This event provided an opportunity for a study of the impacts of rural dust upon the air quality of four Australian cities. A simple model is used to predict dust concentrations, dust deposition rates and particle size characteristics of the airborne dust in the cities. The total dust load of the plume was 3.35 to 4.85 million tones, and assuming a (conservative) plume height of 1500 m, 62–90% of this dust load was deposited in-transit to the coast. It is conservatively estimated that 3.5, 12.0, 2.1 and 1.7 kilotonnes of dust were deposited during the event in Sydney, Brisbane, Gladstone and Mackay, respectively. In the South East Queensland region, this deposition is equivalent to 40% of the total annual TSP emissions for the region. The event increased TSP, PM10 and PM2.5 concentrations and reduced the visibility beyond the health and amenity guidelines in the four cities. For example, the 24-h average PM10 concentrations in Brisbane and Mackay, were 161 and 475 μg m?3 respectively, compared with the Australian national ambient air quality standard of 50 μg m?3. The 24-h average PM2.5 concentration in Brisbane was 42 μg m?3, compared with the national advisory standard of 25 μg m?3. These rural dusts significantly increased PM10/TSP ratios and decreased PM2.5/PM10 ratios, indicating that most of the particles were between PM2.5 and PM10.  相似文献   

10.
The current study estimates premature mortality caused by long-term exposure to elevated concentrations of PM2.5 (particulate matter with aerodynamic diameter equal to or less than 2.5 μm) in Japan from 2006 to 2009. The premature mortality is calculated based on a relative risk of 1.04 (95 % CI, 1.01–1.08) per 10 μg?m?3 increase above the annual mean limit of 10 μg?m?3 taken from the World Health Organization Air Quality Guidelines. The spatiotemporal variations of PM2.5 are estimated based on the measurements of suspended particulate matter (SPM) (with aerodynamic diameter approximately less than 7.0 μm) at 1,843 monitors. The improvements of air quality in Japan by reducing the emissions of SPM from 2006 to 2009 could save 3,602 lives based on a reduction target of 10 μg?m?3 annual mean concentration. This finding could be a tangible benefit gained by reducing the emissions of particulate matter in Japan.  相似文献   

11.
A spatially, temporally and chemically resolved emission inventory for particulate matter and gaseous species from anthropogenic and natural sources was created for the Greater Athens Area (GAA; base year, 2007). Anthropogenic sources considered in this study include combustion (industrial, non-industrial, commercial and residential), industrial production, transportation, agriculture, waste treatment and solvent use. The annual gaseous pollutants (????x, SOx, non-methane volatile organic compounds (NMVOCs), CO and ????3) and particulate matter (PM2.5 and PM2.5?C10) emissions were derived from the UNECE/EMEP database for most source sectors (SNAP 1?C9; 50?×?50 km2) and their spatial resolution was increased using surrogate spatial datasets (land cover, population density, location and emissions of large point sources, emission weighting factors for the GAA; 1?×?1 km2). The emissions were then temporally disaggregated in order to provide hourly emissions for atmospheric pollution modelling using monthly, daily and hourly disintegration coefficients, and additionally the chemical speciation of size-segregated particles and NMVOCs emissions was performed. Emissions from agriculture (SNAP 10) and natural emissions of particulate matter from the soil (by wind erosion) and the sea surface and of biogenic gaseous pollutants from vegetation were also estimated. During 2007 the anthropogenic emissions of CO, SOx, NOx, NMVOCs, NH3, PM2.5 and PM2.5?C10 from the GAA were 151,150, 57,086, 68,008, 38,270, 2,219, 9,026 and 3,896 Mg, respectively. It was found that road transport was the major source for CO (73.3%), NMVOCs (31.6%) and NOx (35.3%) emissions in the area. Another important source for NOx emissions was other mobile sources and machinery (23.1%). Combustion for energy production and transformation industries was the major source for SOx (38.5%), industrial combustion for anthropogenic PM2.5?C10 emissions (59.5%), whereas non-industrial combustion was the major source of PM2.5 emissions (49.6%). Agriculture was the primary NH3 source in the area (72.1%). Natural vegetation was found to be an important source of VOCs in the area which accounted for approximately the 5% of total VOCs emitted from GAA on a typical winter day. The contribution of sea-salt particles to the emissions of PM2.5 was rather small, whereas the emissions of resuspended dust particles exceeded by far the emissions of PM2.5 and PM2.5?C10 from all anthropogenic sources.  相似文献   

12.
Former gold mining at Rodalquilar in southeastern Spain exploited a high sulphidation epithermal silicified ore deposit that contained significant enrichments in several metals/metalloids such as As, Sb, Bi, and Te. Treatment of this ore took place adjacent to the village and involved physical crushing then chemical extraction of gold using cyanide and zinc. The waste materials from this processing system, contaminated with a range of trace elements, were deposited immediately below the mine, and have been left exposed to erosion. Over the last 40 years these oxidised ferruginous tailings have not only polluted the local drainage system but also provided a point source for contaminated aeolian dust under the prevailing dry, windy climate. Chemical analyses of particulate matter mechanically resuspended from the tailings materials show enrichments in metals and metalloids due to the preferential incorporation of these elements into the inhalable size fraction (PM10). Of particular concern is the fact that these PM10 can contain >1,500 ppm As and >40 ppm Sb. Given that both As and Sb are clastogenic metalloids with proven negative health effects, and that their oxidised forms are especially toxic, such contamination levels in windblown dusts around old mine sites are highly undesirable.  相似文献   

13.
Filter-based toxicology studies are conducted to establish the biological plausibility of the well-established health impacts associated with fine particulate matter (PM2.5) exposure. Ambient PM2.5 collected on filters is extracted into solution for toxicology applications, but frequently, characterization is nonexistent or only performed on filter-based PM2.5, without consideration of compositional differences that occur during the extraction processes. To date, the impact of making associations to measured components in ambient instead of extracted PM2.5 has not been investigated. Filter-based PM2.5 was collected at locations (n?=?5) and detailed characterization of both ambient and extracted PM2.5 was performed. Alveolar macrophages (AMJ2-C11) were exposed (3, 24, and 48 h) to PM2.5 and the pro-inflammatory cytokine interleukin (IL)-6 was measured. IL-6 release differed significantly between PM2.5 collected from different locations; surprisingly, IL-6 release was highest following treatment with PM2.5 from the lowest ambient concentration location. IL-6 was negatively correlated with the sum of ambient metals analyzed, as well as with concentrations of specific constituents which have been previously associated with respiratory health effects. However, positive correlations of IL-6 with extracted concentrations indicated that the negative associations between IL-6 and ambient concentrations do not accurately represent the relationship between inflammation and PM2.5 exposure. Additionally, seven organic compounds had significant associations with IL-6 release when considering ambient concentrations, but they were not detected in the extracted solution. Basing inflammatory associations on ambient concentrations that are not necessarily representative of in vitro exposures creates misleading results; this study highlights the importance of characterizing extraction solutions to conduct accurate health impact research.  相似文献   

14.
Air pollution represents a significant fraction of the total mortality estimated by the World Health Organization (WHO) global burden of disease projec?t (GBD). The present paper discusses the characteristics of trace gases (O3, NO, NO2, and CO) and particulate matter (PM10 and PM2.5) in two Asian megacities, Delhi (India) and Beijing (China). A continuous measurement of trace gases and particulate matter are considered from 12 measuring sites in Beijing and 8 sites in Delhi. Over Beijing, the annual average of PM2.5, PM10, O3, NO2, and CO is, respectively, 85.3, 112.8, 58.7, and 53.4 μg/m3 and 1.4 mg/m3, and, respectively, over Delhi 146.5, 264.3, 24.7,and 19.8 μg/m3 and 1.73 mg/m3. From the spatial variations of pollutants, the concentrations of particulate matter and trace gases are observed to be much higher in the urban areas compared to the suburban areas. The higher average concentrations of PM10 and PM2.5 over Delhi and Beijing are observed during winter season compared with other seasons. The maximum diurnal variation of PM10 concentration is observed during winter season over Beijing and Delhi. The comparison of trace gases shows that the O3 concentrations during daytime are obviously higher compared with nighttime, and the highest diurnal variation of O3 is observed during summer. The concentrations of CO are highest during winter season, and higher concentrations are observed during nighttime compared to daytime. The O3 and CO show negative correlation over Beijing and Delhi. The negative correlation between O3 and NO2 is merely observed over Beijing, while CO and NO2 concentrations, in contrast, show positive correlation over Beijing.  相似文献   

15.
Suspended particulate matter (SPM) and PM2.5 in the urban and suburban atmosphere of the Kanto Plain of Japan, which includes the Tokyo metropolitan area, during the period 22–26 July 2002 were characterized. Samples of SPM and PM2.5 were collected by low-volume samplers at 6-h intervals at Suginami, Saitama, and Kisai. At all the sites, the major components of SPM and PM2.5 were organic carbon (OC), elemental carbon (EC), and sulfate. The ion balance, the size distributions of the ionic species, and the high correlation between SO4 2? and NH4 + indicated that the main chemical form of sulfate was (NH4)2SO4. The OC/EC ratios were larger in the daytime than in the nighttime. The correlation coefficients of OC, OC/EC, and SO4 2? with ozone concentrations at inland sites (Saitama, Kisai) were higher than those at the coastal site (Suginami). Bound water and hydrogen and oxygen atoms associated with OC, the amounts of which were estimated with a mass closure model, contributed substantially to the total particle mass. The chemical characteristics of the particles indicated that two mechanisms led to high concentrations of SPM and PM2.5: (i) an active photochemical process produced high concentrations of OC and sulfate, leading to a high concentration of (NH4)2SO4 in the particles and to production of secondary organic aerosols; (ii) stable meteorological conditions resulted in accumulation of primary particles, mainly emitted from vehicle exhaust, resulting in high concentrations of OC and EC.  相似文献   

16.
The Industrial Source Complex Short Term (ISCST3) model was used to discern the sources responsible for high PM10 levels in Kanpur City, a typical urban area in the Ganga basin, India. A systematic geographic information system-based emission inventory was developed for PM10 in each of 85 grids of 2?×?2 km. The total emission of PM10 was estimated at 11 t day?1 with an overall breakup as follows: (a) industrial point sources, 2.9 t day?1 (26%); (b) vehicles, 2.3 t day?1 (21%); (c) domestic fuel burning, 2.1 t day?1 (19%); (d) paved and unpaved road dust, 1.6 t day?1 (15%); and the rest as other sources. To validate the ISCST3 model and to assess air-quality status, sampling was done in summer and winter at seven sampling sites for over 85 days; PM10 levels were very high (89?C632 ??g m?3). The results show that the model-predicted concentrations are in good agreement with observed values, and the model performance was found satisfactory. The validated model was run for each source on each day of sampling. The overall source contribution to ambient air pollution was as follows: vehicular traffic (16%), domestic fuel uses (16%), paved and unpaved road dust (14%), and industries (7%). Interestingly, the largest point source (coal-based power plant) did not contribute significantly to ambient air pollution. The reason might be due to release of pollutant at high stack height. The ISCST3 model was shown to produce source apportionment results like receptor modeling that could generate source apportionment results at any desired time and space resolution.  相似文献   

17.
[目的]评价SH固化建设场地类型土的抑尘效果及其在建设场地中的适用性,为合理有效控制建设场地扬尘问题提供方法依据。[方法]以高分子材料——SH抑尘剂为研究对象,考虑建设场地扬尘来源(即建设场地类型土)、喷洒量、坡度、坡面形态、固化时间及堆土密度等因素,借助PM10及PM2.5指标评价SH抑尘剂在仅固化建设场地类型土表层条件下的抗风蚀性能及其在建设场地的适用性。[结果]SH抑尘剂可在土样颗粒间发挥联接作用,维持土体表面的完整性,有效解决洒水抑尘措施存在的缩裂问题;SH对于建设场地类型土(粉土、粉煤灰、黏性土、碎石土)均具有很好的抑尘效果,喷洒SH抑尘剂后,固化土在九级风力的吹蚀作用下不会造成PM10和PM2.5污染物;SH抑尘剂对于建筑堆土、建筑弃土及裸露地表均具有适用性,坡度、堆土密度、坡面形态不影响SH抑尘剂的渗透固化效果。从抑尘效果和施工经济角度考虑,建议施工时选取SH抑尘剂喷量1.2kg/m2,固化时间3d。[结论]SH抑尘剂可在土体表层形成抗风蚀性保护膜,实现从源头控制建设场地扬尘。  相似文献   

18.
Morphometric and compositional studies have been performed on both PM10–2.5 and PM2.5 aerosol collected in the city of Prato, Italy. Chemical analysis has been carried out using PIXE technique and factor analysis was applied for the source apportionment process. Industrial emissions, vehicular traffic as well as crustal dust and marine aerosol were the sources identified. SEM-EDS analysis has been employed to individually characterize particles collected during a week of the sampling campaign. The morphometric study, performed on 43,671 particles, revealed that, for both the fine and coarse fraction, about 2/3 of particles display a high roundness coefficient, 1/3 of them a medium value, while only a small number of particles (from silicates and organics) exhibits a low roundness coefficient. Similarly, particles with small surface area represent the greater portion in both fractions. Particles classified as organics, metals and oxides, chlorides, carbonates, phosphates, sulphates and silicates have been detected in the PM10–2.5 while in the PM2.5 chlorides and phosphates are lacking. Silicates are about the same percentage, by concentration number, in the coarse and fine fraction (20.7% and 20.5% respectively) showing that this material, at least one fifth of the total PM, might be the result of crustal erosion and anthropic activities. The purpose of this work has been that of providing a contribution to the study of particulate matter and took an effort for relating morphometric and compositional features of urban aerosol collected in a medium size industrial city.  相似文献   

19.
Samples of airborne particulate matter (PM2.5) were collected at a site in Lahore, Pakistan from November 2005 to January 2006. A total of 129 samples were collected using an Andersen Reference Ambient Air Sampler 2.5-400 sampler and analyzed for major ions, trace metals, and organic and elemental carbon concentrations. The data set was then analyzed by positive matrix factorization (PMF) to identify the possible sources of the atmospheric PM collected in this urban area. Six factors reproduced the PM2.5 sample compositions with meaningful physical interpretation of the resolved factors. The sources included secondary PM, diesel emissions, biomass burning, coal combustion, two-stroke vehicle exhaust, and industrial sources. Diesel and two-stroke vehicles contributed about 36%, biomass burning about 15%, and coal combustion sources around 13% of the PM2.5 mass. Nearly two thirds of the PM2.5 mass is carbonaceous material. Secondary particles contributed about 30% of PM2.5 mass. The conditional probability function (CPF) was then used to help identify likely locations of the sources present in this area. CPF analysis point to the east and northeast, which are directions of urban and industrial areas located across the border near Amritsar, India as the most probable source for high PM2.5 concentration from diesel and two-stroke vehicles exhaust in Lahore. Analysis of those days within three different ranges of PM2.5 concentration shows that most of the measured high PM2.5 mass concentrations were driven by diesel and two-stroke vehicle emissions including the associated primary sulfate. The use of the potential source contribution function (PSCF) to find the source locations of regionally transported particles is inapplicable in situations when high PM2.5 concentrations are dominated by local sources and local meteorology.  相似文献   

20.
西安市地表灰尘中重金属污染水平与健康风险评价   总被引：4，自引：0，他引：4  
在西安市三环内采集58个地表灰尘样品,分析了其中重金属含量,利用单因子污染指数法和污染负荷指数法对西安市地表灰尘中重金属污染进行了评价,应用美国环境保护部(US EPA)人体暴露风险评价模型对人群暴露地表灰尘中重金属的健康风险进行了分析。结果表明,地表灰尘中Zn、Pb、Cu、Cr、Ni、As、Co和Mn的平均含量分别为231.0、145.4、59.4、213.0、48.7、9.8、12.6和417.0 mg kg~(-1),其中Zn、Pb、Cu、Cr和Ni的含量是陕西省土壤元素背景值的1.7~6.8倍。地表灰尘中Zn、Cr和Pb达到了重度污染,Cu处于中度污染,Ni、Co、As和Mn为轻度或无污染。人群暴露地表灰尘中重金属的主要途径是手-口直接摄入,且儿童大于成人。西安市及其不同功能区地表灰尘中重金属的非致癌风险均低于风险阈值,8种重金属不存在明显非致癌危害。Cr、Co、As和Ni的致癌风险在可接受范围内。  相似文献   

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