| According to the China Environmental Quality Status Report issued by the State Environmental Protection Ministry, environment air quality of our country is good on the whole, but the pollution of some cities is still heavier, especially some provinces and cities with faster economic development. Because of the influence of such factors as climate, topography, urban layout, it's very difficult to deal with environment air pollution. Atmospheric particulates and its control have attracted more and more attention, because it is complex, harmful and can be the carrier of other dangerous substances. The source apportionment of atmospheric particulates cannot only qualitatively understand pollution characteristics of the atmospheric particulates, but can also quantitatively calculate the contributions of various emission sources to the atmospheric particulates. The result of source apportionment study can be taken as the scientific basis of treating environmental air particulates pollution. And different measures are adopted to manage different emission sources.Longyan city is located in the west of Fujian province. The valley slope of Longyan city is from south to east. The east valley is higher. The valley terrain seriously impacts the flow of the lower atmosphere in the urban area, making the pollution in the lower atmosphere of Longyan city more serious. The air contaminant PM10 cannot be diluted and diffused because of the temperature inversion in winter, which results in PMio accumulated easily in urban areas. As a result, the concentration of pollutant in winter is higher than that in other seasons. According to receptor samples collected in four monitoring spots which represent different functional areas (Longyan Teachers College, Longyan college, Environment Monitoring Station of Longyan and University of Western Fujian), and the study of the distributive characters of atmospheric particulates in time and space in Longyan city, the elements concentration of atmospheric particulates samples collected in different functional areas is obviously different in different places. Industrial and mechanical manufacturing areas (Longyan Teachers College and University of Western Fujian) are higher in the quantity of particulates than downtown and living areas (Environment Monitoring Station of Longyan). The concentration of elements such as Mg, Al, K, Ca, Fe, Zn and Ni varies greatly from season according to different tendencies, while the amount of other elements does not change very much.At present, atmospheric particulate pollution of Longyan city is serious. The study on source apportionment to atmospheric particulates PM10 of Longyan city adopts the CMB, FA and PMF models, which is helpful for effectively controlling particulate pollution and improving the air quality. The results by CMB model show that:for the first samples, the sources with bigger contribution to PM10 sample of Longyan city are urban fugitive dust and road dust; for the second, urban comprehensive fugitive dust and motor vehicle exhaust dust are the major contribution to PM10; for the third, the main sources of PM10 sampled in Longyan city are urban comprehensive fugitive dust, soil dust and motor vehicle exhaust dust; for annual samples, the main sources of atmospheric particulates PM10 are coal-burnt dust, soil dust, urban comprehensive fugitive dust and road dust. The results by FA model show that:for the first samples, PM10 of Longyan city mainly comes from soil dust and urban comprehensive fugitive dust; for the second, soil dust, urban comprehensive fugitive dust and road dust are the largest contribution to PM10 of Longyan city; for the third, the main sources of PM10 of Longyan city are soil dust, road dust, coal-burnt dust and urban comprehensive fugitive dust; for the annual samples, the main sources of atmospheric particulates PM10 are:soil dust, urban comprehensive fugitive dust, road dust and motor vehicle exhaust dust. The results by PMF model show that:for the first samples, the main sources of PM10 of Longyan city are construction cement dust and coal-burnt dust; for the second, coal-burnt dust, motor vehicle exhaust dust, construction cement dust and soil dust are the largest contribution to PM10; for the third samples, the main sources of PM10 are soil dust, biomass-burnt and waste-burnt dust, and urban comprehensive fugitive dust; for annual samples, the main sources of atmospheric particulates PM10 of Longyan city are:coal-burnt dust, construction cement dust, motor vehicle exhaust dust, iron and steel industry dust. The PMF sources apportionment program designed via Visual Basic 6.0 can satisfy the need of calculation, and the calculation result is consistent with the reality. The CMB model is more mature and more widely used than PMF model and FA model. With both receptor component spectrums and source component spectrum known, the source apportionment result by CMB model is more efficient. According to the correlation between the receptor components and the characteristics of source components, the source types and contribution rate can be deduced by the FA model, even though the receptor profile is known and the source profile is unknown. The PMF model is similar to the FA model. The type of emissions sources is inferred by PMF, when the receptor profile is known but the source profile unknown, combined with calculation result, the EV and the characteristics of source components. The advantage of PMF model to FA model is that nonnegative source profile and contribution rate can be obtained by PMF model. And the results of source apportionment are more meaningful and more consistent with the actual situation.According to the PM10 monitoring results and source apportionment results of Longyan city, the author has designed a results-displaying system based on GIS. This system can visually show distribution rule, pollution, pollutants sources of PM10 of Longyan city, and conveniently generate the map of contaminant distribution, special charts of each index and isoline layers. Stacking these layers selectively and orderly, the comprehensive information of different layers can be displayed in one map. Meanwhile, the sources apportionment results calculated by different sources apportionment methods to the samples collected during different sampling period are showed comparatively. |
