Source Apportionment Of PM_2.5 In Atmosphere In Changchun Using Pmf And PCA/APCS Methods

In recent years, regional atmospheric pollution incidents occurred frequently in China. Primary pollutants of most prominent pollution incidents are PM_2.5 and PM₁₀. And the scope of atmospheric pollution is increasing, the public concern is increasing. With a deep understanding of the harm of atmospheric particulate matters, many countries and regions carried out the related research, in order to better understand and grasp the regularity of atmospheric particulate matter pollution. Since 2014, Ministry of environmental protection issued some work notices, required that municipalities, the provincial capital cities（except Lhasa） and specifically-designed cities in the state plan to complete the first phase of source apportionment studies, say clearly preliminarily the main sources of urban atmospheric particulate matter, in order to meet the urgent needs of the current prevention and control of particulate matter.This study counts and analyzes spatial and temporal distribution characteristics of PM_2.5 in the atmosphere in Changchun, according to hourly concentration data of PM_2.5 in 2014 provided by the Environmental Monitoring Center. This study uses chemical composition data of 45 organic film samples taked in Changchun in the four seasons of 2014 to explore the concentration of PM_2.5 in Changchun City, and uses PMF and PCA/APCS methods to source apportionment by Enrichment Factor Analysis and Correlation Analysis as auxiliary. Finally, suggestions and measures of PM_2.5 pollution control in atmospheric environment in Changchun are proposed based on the results of this study.This study obtains the following main conclusions:（1） The annual average of PM_2.5 concentration is 65.57μg/m3 in 2014 in Changchun, the PM_2.5 concentration in the city center is significantly higher than that in the surrounding area, eastern pollution is higher than that of the west, pollution of the north is higher than that of the south. The PM_2.5 concentration in October is highest. Overall, the change of season hourly PM_2.5 concentrations shows a double peak valley type distribution.（2） Silicon is the most abundant inorganic elements in PM_2.5, the average concentration of silicon is 1.2632μg/m3. The top five content elements in inorganic elements are earth crust elements. The total content of NO3-,SO42- and NH4+ account for 67.8% of water soluble ions, this indicates that the secondary photochemical pollution is more serious.（3） There are seven main sources of PM_2.5 in 2014 in Changchun by PMF method, they are coal dust（22.3%）, soil dust（18.5%）, biomass burning dust（18.0%）, secondary particulates（14.3%）, industrial dust（13.5%）, vehicle exhaust dust（8.5%） and construction dust（4.9%）.（4） There are six main sources of PM_2.5 in 2014 in Changchun by PCA/APCS method, they are soil dust（34.37%）, vehicle exhaust dust（28.15%）, coal dust（25.52%）, industrial dust（5.95%）, secondary particulates（4.23%） and smelting dust（1.79%）.（5） On the whole, results of PMF method and PCA/APCS method on categories of pollution sources are roughly same. Judging from the number of factors, PMF method gets more categories of pollution sources, they are more representative of the actual situation in Changchun. Judging from the contribution rate of various factors, somethe contribution rates of PCA/APCS method are different from the actual situation in Changchun. By comparison results of PMF method are more reasonable and practical, results of PCA/APCS method can provide support and supplement to PMF analytic results.（6） According to the conclusions of the study, in order to improve the atmospheric environment in Changchun City, suggestions are proposed including reasonable allocation and adjusting energy structure, expanding the central heating and promoting the use of high quality coal, increasing the surrounding green area and the water spraying is carried out regularly on the road, strengthening governance of vehicle exhaust and promoting health way to travel, strengthening the management on the construction site, reducing the straw burning and advocating for comprehensive utilization of straw.