A Study of Airborne Selected Metals and Particle Size Distribution in Relation to Climatic Variables and their Source Identification

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}, PM_2.5–10, PM_10–100& PM_{> 100}) was also carried out. PM_10–100 were found to be the most abundant in the local atmosphere followed by PM_2.5–10, 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 PM_2.5–10. 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.     

Estimation of air quality degradation due to Saharan dust at Nouakchott, Mauritania, from horizontal visibility data

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.     

PM10 and PM2.5 Levels in the Eastern Mediterranean (Akrotiri Research Station, Crete, Greece)

Particulate matter measurements (PM₁₀, PM_2.5) 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 PM_2.5 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); PM_2.5, 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); PM_2.5, 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; PM_2.5: 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.     

辽宁西北部主要绿化树种对空气颗粒物滞留能力研究

采用洗脱法测定了辽西北地区阜新市15种常见绿化树种单位叶面积滞留粗颗粒物(TSP)及细颗粒物(PM_(2.5))的质量,分析比较了15种树种叶片去除TSP和PM_(2.5)能力以及随着空间变化的规律。结果表明:(1)不同树种单位叶面积TSP和PM_(2.5)滞留量均存在显著差异,变化范围分别为3.68~5.94g/m~2和0.47~0.92g/m~2,树种间滞留能力的差值可达2倍左右。(2)在同一个功能区不同树种滞留TSP和PM_(2.5)的差异由树冠高度(绿篱灌木乔木)和叶表面粗糙度(叶表面沟槽宽度的不同可能是沟槽宽度过宽和过窄均不利于叶片捕集颗粒物,且颗粒物滞留量随沟槽深度增加而增大)以及叶片比叶重(比叶重大的滞尘量大)等所引起。(3)在不同功能区同一树种单位叶面积滞留TSP量的排序为工业区商业交通区露天矿区清洁区,而PM_(2.5)滞留量则无明显差异。乔木中新疆杨、灌木中紫丁香的单位叶面积滞留量与单株滞留量都较高,起到明显的降尘作用,是沙尘频发的辽西北地区城市绿化树种的优先之选。     

Influence of Saharan Dust Transport Events on PM2.5 Concentrations and Composition over Athens

The evaluation of the contribution of natural sources to PM₁₀ and PM_2.5 concentrations is a priority especially for the countries of European south strongly influenced by Saharan dust transport events. Daily PM_2.5 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 PM_2.5, was determined by both WDXRF and ionic chromatography. The contribution of dust and sulfates in PM_2.5 was calculated from the analytical determinations. An annual mean of 20 μg/m³ was calculated from the mean daily PM_2.5 concentrations data. Twenty-two per cent of daily concentrations of PM_2.5 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 PM_2.5 concentration of 100 μg/m³ where the dust contribution in PM_2.5 reached 96 %. The other dust transport events were less intense and corresponded to less pronounced enhancements of PM_2.5 concentrations, and their contribution ranged from 15 to 39 % in PM_2.5 concentrations. Air masses originated from northwest Africa while the influence of central Sahara was quite smaller.     

Concentration and Sources of PM10 and its Constituents in Alsasua, Spain

Ambient concentrations of PM₁₀ were measured every fifteen minutes from November 2002 to October 2003 at Alsasua (Northern Spain) using a laser particle counter. A high volume sampler was also used to collect 24-h integrated PM₁₀ samples at a frequency of three running days per week (i.e. three consecutive PM₁₀ samples followed by five days without sampling) for gravimetric determination of PM₁₀ mass concentrations followed by chemical analysis of its chemical components. The annual mean PM₁₀ concentration obtained using the laser particle counter with gravimetric correction was 22.7 μg m^?3 (365 days), while the mean for the gravimetric samples was 29.5 μg m^?3 (134 days). A total of 94 integrated PM₁₀ samples were analyzed for 60 chemical species using a combination of inductively coupled plasma spectrometry (ICP) and ion chromatography (IC). The concentrations of the main PM₁₀ components were found to be generally in agreement with the values reported for other Spanish cities. Bilinear Positive Matrix Factorization (PMF2) was used to study the sources of PM₁₀ and its constituents. Six main sources of PM₁₀ were identified (average contribution to total PM₁₀ mass in parentheses): crustal material (35%), secondary sulfate (21%), secondary nitrate (14%), motor vehicles (12%), sea-salt aerosol (12%) and metallurgical industries (3%).     

Reductions of PM2.5 Air Concentrations and Possible Effects on Premature Mortality in Japan

The current study estimates premature mortality caused by long-term exposure to elevated concentrations of PM_2.5 (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 PM_2.5 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.     

Evidence of Long-Range Transport of Pollutants from the Size-Fractionated Ionic Composition of Aerosols in the Jeju Island of Korea

The ionic composition of total suspended particulate (TSP) and fine (PM_2.5) fractions was investigated from an 1,100 site in the middle of Mt. Halla in Jeju Island, Korea from March to November 2006. The sum concentrations of cation and anion species in TSP fraction were 205 ± 170 and 183 ± 164 neq m^?3, respectively, while those for PM_2.5 as 118 ± 129 and 88.5 ± 89.3 neq m^?3, respectively. In TSP, the concentration of the major ions changed in the order of SO₄ ^2? > NH₄ ⁺ > Ca²⁺ > Na⁺ > NO₃ ^? > Mg²⁺ > K⁺ > Cl^?, while its PM_2.5 counterpart as NH₄ ⁺ > SO₄ ^2? > Ca²⁺ > NO₃ ^? > Na⁺ > Mg²⁺ > K⁺ > Cl^?. Inspection of the temporal variabilities of ionic components indicated that most ions peaked in spring or fall months. The back trajectory analysis showed that the atmospheric composition of the major ionic species was affected fairly sensitively by long-range transport from China under the favorable meteorological conditions. In contrast, the lowest ionic concentration levels were seen most abundantly, when air masses passed from South Sea. Hence, the analysis of ionic concentration data suggests that their distributions are controlled by the combined effects of various source processes including the most prominent Chinese origin and the meteorological condition favorable for such transport.     

A Study of PM2.5 and PM2.5-Associated Polycyclic Aromatic Hydrocarbons at an Urban Site in the Po Valley (Bologna, Italy)

PM_2.5 and PAHs bound to PM_2.5 were investigated in downtown Bologna, from January to June 2003, in order to determine the burden of the fine fraction in the aerosol of a typical urban environment of the Po Valley, a critical area in Northern Italy in terms of atmospheric pollution. The sampling campaign was divided into three parts: a winter sub-campaign, an intermediate campaign where PM_2.5 and PM₁₀ were simultaneously sampled and which identified PM_2.5 as the major component of PM₁₀, and a summer sub-campaign. Critical concentrations of both PM_2.5 and PAHs were observed in winter time; for example, in January 2003 the mean value for the 24-h average PM_2.5 concentration was 58 μg/m³, much higher than the annual arithmetic mean of 15 μg/m³ established by the US ambient air quality standard (NAAQS). Correspondingly, the mean value for benzo[a]pyrene (BAP) in PM_2.5 was 1.79 ng/m³, again higher than the annual mean of 1 ng/m³, required by European regulations for BAP in PM₁₀. In summer time the BAP concentration considerably decreases to 0.10 ng/m³ as the likely effect of photolysis and dilution on a higher boundary layer; PM_2.5 decreases too, but the mean concentration (22 μg/m³) is still higher than the NAAQS value. Further analysis included TEM microscopy of collected particles and correlations between PM_2.5, PAHs and gases (benzene, O₃, CO, NO₂, SO₂). All these observations identified on-road mobile sources as the main source of emissions and, in general, of the poor air quality level in the city of Bologna.     

Characterization of Elemental Species in PM2.5 Samples Collected in Four Cities of Northeast China

A monitoring program of particulate matter was conducted at eight sampling sites in four highly industrialized cities (Shenyang, Anshan, Fushun, and Jinzhou) of Liaoning Province in Northeast China to identify the major potential sources of ambient PM_2.5. A total of 814 PM_2.5 and PM_2.5–10 samples were collected between 2004 and 2005. All PM samples were collected simultaneously in four cities and analyzed gravimetrically for mass concentrations. A sum of 16 elemental species concentrations in the PM samples were determined using inductively coupled plasma atomic emission spectroscopy. Annual means of PM_2.5 concentrations ranged from 65.0 to 222.0 μg m^?3 in all the eight sampling sites, and the spatial and seasonal variations were discussed. Enrichment factors were calculated, and Cr, Cu, Zn, As, Cd, and Pb will be pollution-derived elements. Site-to-site comparisons of PM_2.5 species in each city were examined using coefficient of divergence, revealing that the two sites in each city are similar in elemental species. Principle component analysis was used for preliminary source analysis of PM_2.5. Three or four factors in each city were isolated, and similar sources (crustal source, coal combustion, vehicle exhaust, iron making, or some other metallurgical activities) were identified at four cities.     

Aerosol particles in the developing world; a comparison between New Delhi in India and Beijing in China

In developing countries, aerosol particles damage the health of hundreds of millions of people. Migration from the country side to megacities increases emissions and exposure to particles. Some countries have started to limit emissions based on particulate mass, but this may increase particle number concentrations. In this study we discuss some earlier measurements carried out in the developing world and compare results from one-week measurement campaigns concerning the particle number size distribution and PM₁₀ mass concentrations in New Delhi, India and Beijing, China. Our results show that submicron particle concentrations are high in both places. The average PM₁₀ concentration was 360 μg/m³ in New Delhi and 120 μg/m³ in Beijing. The corresponding total particle number concentrations in the size range 3–800 nm were 63 000 cm^?3 and 35 000 cm^?3. Number and mass concentrations and their characteristics showed significantly different behaviour between these two locations, which stresses the importance of long-term simultaneous measurements of both quantities in different types of megacities.     

Evaluation of Premature Mortality Caused by Exposure to PM2.5 and Ozone in East Asia: 2000, 2005, 2020

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 (PM_2.5) and ozone elevated concentrations for the years?2000, 2005, and 2020 in East Asia. The spatial distributions and temporal variations of PM_2.5 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 PM_2.5 and ozone are calculated based on a relative risk (RR) value of 1.04 (95?% confidence interval (CI): 1.01?C1.08) for PM_2.5 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 PM_2.5 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 PM_2.5 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 PM_2.5 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.     

Concentration Of Trace Elements in Airborne PM10 from Jobos Bay National Estuary, Puerto Rico

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.     

FIELD OBSERVATIONS OF WINDBLOWN SAND AND DUST IN THE TAKIMAKAN DESERT,NW CHINA,AND INSIGHTS INTO MODERN DUST SOURCES

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.     

SH抑尘剂固化建设场地类型土的抗风蚀性能

[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。     

A Comparison of Trace Gases and Particulate Matter over Beijing (China) and Delhi (India)

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 PM_2.5) 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 PM_2.5, 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 PM_2.5 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.     

Atmospheric Emission Inventory for Natural and Anthropogenic Sources and Spatial Emission Mapping for the Greater Athens Area

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 (PM_2.5 and PM_2.5?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, PM_2.5 and PM_2.5?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 PM_2.5?C10 emissions (59.5%), whereas non-industrial combustion was the major source of PM_2.5 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 PM_2.5 was rather small, whereas the emissions of resuspended dust particles exceeded by far the emissions of PM_2.5 and PM_2.5?C10 from all anthropogenic sources.     

GIS-Based Emission Inventory, Dispersion Modeling, and Assessment for Source Contributions of Particulate Matter in an Urban Environment

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.     

Physical and Chemical Properties of a Winter-Time Yellow Sand Event in Northeast Asia

The long range transport of mineral dust such as Yellow Sand (YS) is not restricted to the springtime periods in Northeast Asia. A YS phenomenon was observed during 25～27 January 1999, which was a remarkably distinctive episode in the occurrence time and intensity that had ever been observed in the wintertime in Korea. This YS event had a bi-modal temporal structure with the daily average concentrations of 210～349 µg m^?3. The long-lasted second one followed the first arriving short and strong dust pulse. The dominant ion components were SO₄ ^2?, NO₃ ^?, Ca²⁺ and Na⁺ with the concentration of 11.3, 7.6, 6.1 and 4.2 µg m^?3, respectively during the passage of YS, compared to the corresponding concentrations of 4.1, 4.6, 0.4, and 1.2 µg m^?3 after the passage of YS (AYS) over Korea. The mode diameter of these compounds of YS was around 4 µm, compared to 0.4～0.9 µm of AYS. Concentrations of SO₄ ^2? and NO₃ ^? were found to be highly correlated with that of Ca²⁺ in the coarse mode during the YS event, whereas they were well correlated with NH₄ ⁺ during the non-YS period.     

A study of the gaseous and particulate pollutants in the environment of a thermal power plant project area

Observations on gaseous and particulate pollutants were undertaken at four locations in the region of a thermal power plant (TPP), which is under construction at Tuticorin, south India. The predicted concentrations Of SO₂ due to the emissions from the TPP and its possible impact on the inhabitants and climate in the downwind region were evaluated. Also, the predicted concentrations downwind of a Petrochemical Industrial Complex (PIC) located in the vicinity of the TPP were computed and compared with the measured concentrations. The predicted maximum concentration of SO₂ at 6 km downwind of TPP is about 530 μg m^?3 under most favourable wind conditions. The anticipated increase in SO₂ due to the thermal power plant under construction may therefore be substantial. The predicted concentrations Of SO₂, at a distance of 1.8 km downwind of the PIC, varied between 34 and 216 μg m^?3 for wind directions ranging from 70 to 90° and for Pasquill stability category C. The plume would be over the observational site when the wind direction is 80°. The maximum measured concentration was 23 ug m^?3. The discrepancy was due to the rapid fluctuations in the wind direction during the observational period over a wide range from 20 to 90°.