| Atmospheric pollution is one of the main increasingly environmental problems, which needed to be resolved nowadays. Especially in recent years, with the rapid vehicle increasing, air pollution problems have gradually changed from traditional coal smoke pollution to soot and complex photochemical pollution. PM2.5, as one participant of many photochemical reactions, promoted the occurrence of urban photochemical reaction. And most of finer particle can directly access to the human lungs, then deposited in the alveoli and finally involved in the blood circulation. So for the environment and human health, the pollution of PM2.5 seems to be particularly prominent in the particulate matter. Changchun city as one of the country’s major grain producing areas and the base part of major industrial development in Jilin province, the increasingly and widespread frequent haze phenomenon in recent years were concerned by people. Therefore, the study of the mass concentration distribution, physical-chemical properties and the source of the particulate matter pollution can provide a scientific basis and theoretical support for the prevention and control of the air pollution. In this study, sampling time was from December 2013 to November 2014, a total of a whole year. The sampling location was at Jilin Agricultural University campus and PM2.5, PM10 and TSP samples were collected at the same time. Besides the determination and analysis of mass concentration of particulate matter, chemical methods, scanning electron microscopy(SEM) and X-ray diffraction(XRD) methods were also used to analyze the chemical composition of atmospheric particles, morphology and mineral composition. The results showed that mass concentration of particulate matter in the atmosphere had a certain regularity change with time. Higher concentration of particulate matter appeared in the autumn and winter while the minimum one appeared in summer throughout the whole year. The concentration of particulate matter in heating period was significantly higher than the concentration in the non-heating period. Meanwhile PM2.5 was the most important part of PM10 in heating period. According to the measured percentage of each month for each year of water-soluble ionic concentrations, it can be seen that SO42-, NO3- and NH4+ were the important part of the water-soluble ions and the main product of coal burning and vehicle exhaust. PM2.5 was mainly consisted of a chain of soot aggregates, coal-fired spherical particles and secondary particle pollution, massive and flaky mineral particles and other types of microscopic particles. The mineral composition in four seasons were as follows: kaolinite, quartz, muscovite, feldspar, rectorite, pyroxene and vermiculite were concluded in spring. Gibbsite, montmorillonite, feldspar, quartz, pyroxene, muscovite, hematite, vermiculite and chlorite were concluded in summer. Smectite, kaolinite, gibbsite, goethite, feldspar, chlorite, quartz and muscovite were concluded in autumn. Smectite, quartz, feldspar, β-Fe2O3·H2O, calcite, dolomite, vermiculite and chlorite were concluded in winter. Finally, SPSS statistical analysis software was used to perform the principal component analysis(PCA) on PM2.5 pollution. Analytical results showed that there are three main sources of pollution. According to the comprehensive analysis of influence, they are: car exhaust/fly ash; dust soil/biomass, building and cement dust. |
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