Urbanization, Energy, and Air Pollution in China The Challenges Ahead: Proceedings of a Symposium (2004) / Chapter Skim
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Source Apportionment of Fine-Particle Pollution in Beijing--YUANHANG ZHANG, XIANLEI ZHU, LIMIN ZENG, and WEI WANG
Source Apportionment of Fine-Particle Pollution in Beijing--YUANHANG ZHANG, XIANLEI ZHU, LIMIN ZENG, and WEI WANG
Pages 139-154
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From page 139... ...
Unfortunately, owing to rapid urbanization and industrialization, before the existing problems caused by coal combustion could be resolved, other emission sources have become increasingly important. The rapid increase in the number of vehicles in some Chinese megacities and economically developed regions, such as Beijing, Shanghai, Guangzhou, Pearl River delta, and Yangtze delta, has led to a sharp increase in concentrations of nitrogen oxides (NOx)
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From page 140... ...
The city, which has undergone rapid development since the 1980s, has high concentrations of particulate matter and poor visibility in spite of the adoption of numerous measures to control particle pollution. Measured annual mean mass concentrations of fine particles (PM10)
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. Soil dust, road dust, and wind-blown dust, which have similar profiles, were combined as fugitive dust.
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142 a 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Secondary Nitrates 775,000 226,000 a 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Secondary Sulfates 727,000 273,000 a 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 110 100 2,500 2,500 1,500 28,600 16,700 Biomass Burning 484,000 a 9.81 8.34 2.36 8.84 9.40 0.27 44.66 29.58 26.78 34.22 30.44 100 1,100 15,700 73,100 46,500 12,100 11,000 Fugitive Dust 186,800 a 3.38 1.12 0.0 0.0 0.0 0.0 0.0 93.20 27.02 66.15 93.00 84.13 31.68 28.07 30.45 157.33 42,600 16,100 Construction Dust 300,000 2001. a a a 85.03 39.96 645.31 456.66 504.17 617.05 223.01 232.61 Tang, 2,828.4 6,512.3 1,053.1 2,160 3,373 2,111 64,400 28,000 15,500 Vehicle Exhaust 390,000 365,000 1991; (µg/g)
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From page 143... ...
The source profiles of secondary sulfate and nitrate, which are formed in the atmosphere, were assumed to be ammonium sulfate and ammonium nitrate, respectively. METHODOLOGY Three approaches can be used to evaluate source contributions to airborne particles: source inventory; dispersion models; and receptor models.
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From page 144... ...
This can be expressed by the following equation: m Cik = ijSij j=1 where Cik is the concentration of chemical species i in fine particles at receptor site k; ij is the relative concentration of chemical constituent i in the fine-particle emissions from source j; and Sjk is the mass contributed to total fine particulate at receptor site k originating from source j. RESULTS AND DISCUSSION Chemical Composition of PM2.5 The complicated chemical composition of fine particles gives some clues about their sources.
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Source Contributions from Chemical Mass Balance Models Seven major sources of PM2.5 are identified by the CMB model (Figure 3) : coal combustion; vehicle exhaust; construction dust; fugitive dust; biomass
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146 URBANIZATION, ENERGY, AND AIR POLLUTION IN CHINA Pile-up dust Unpaved road dust 1.3% 2.4% Construction dust 3.7% Road dust 18.7% Stationary sources 46.1% Industrial fugitive dust 12.4% Mobile sources 15.4% FIGURE 2 Source inventory for PM2.5 in Beijing. Coal combustion 16.4% Unknown 27.5% Vehicle exhaust 5.6% Construction dust 3.3% Fugitive dust Organic matter 15.0% 18.1% Secondary sulfate Biomass burning and nitrate 4.5% 9.6% FIGURE 3 Sources of PM2.5 in Beijing identified by CMB model.
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Comparison of Results Table 2 compares the average source contributions calculated by the source inventory and CMB model. Because the source inventory only provides information on primary sources, the contributions of primary sources computed by CMB have been normalized in the last row of the table for easy comparison.
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a Coal combustion 46.1 16.4 37.8 Mobile sources 15.4 5.6 12.9 Fugitive sources 38.5 21.4 49.3 Industrial dust 12.4 NA Road dust 18.7 NA Construction dust 3.7 NA Pile-up dust 1.3 NA Unpaved road dust 2.4 NA Biomass burning NA 4.5 Secondary sulfate and nitrate NA 9.6 Organic matter NA 15.0 Unknown NA 27.5 Total 100 100 100 aNormalization of the contributions from coal combustion, mobile sources, and fugitive sources. primary sources of PM2.5 in Beijing are coal combustion and fugitive dust; mobile sources contribute a minor fraction of PM2.5.
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From page 149... ...
75 g/mµ( secondary sulfate and 100 nitrate biomass burning 60 fugitive dust contribution 45 concentration construction 50 30 Source mass vehicle exhaust 2.5 15 coal combustion PM 0 0 mass concentration CRAES CAPM BUU FIGURE 4 Source contributions at the three sampling sites in Beijing. Seasonal Variations of Source Contributions Figure 5 shows the seasonal pattern of contributions from major sources of PM2.5.
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contribution Source FIGURE
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The primary sources responsible for most of the mass concentration of PM2.5 are fugitive dust, coal combustion, and vehicle exhaust. Construction dust and biomass burning were also detected in the CMB model, but their contributions were relatively small.
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From page 152... ...
2001. PM2.5 chemical source profiles for vehicle exhaust, vegetative burning, geological material, and coal burning in northwestern Colorado during 1995.
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2002. Source apportionment of PM2.5 in the southeastern United States using solvent-extractable organic compounds as tracers.
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