Research On Spatial And Temporalvariation Characteristics Factors And Source Apportionment Of PM2.5

PM2.5, which is an important factor affecting human health, visibility and climate, is currently the primary atmospheric environmental problem faced by most cities in China. In the study, information of main gaseous pollutants and PM2.5concentrations are collected from March2013in Beijing. PM2.5concentrations are monitored and samples are collected in the summer and winter of2013in Hangzhou. By using IC, ICP-MS and TOR, the variation of PM2.5concentrations over time and space, the main factors, the chemical compositions and the source apportionment are studied in depth. The main contents and innovations are as follows:(1) The pollution levels and the spatial and temporal distribution of PM2.5in Beijing are studied, the influence of distance to road and height to ground on the PM2.5concentrations is analyzed.(2) The impact of the major gaseous pollutants and meteorological elements on PM2.5concentrations is studied. The PM2.5concentrations prediction models based on gaseous pollutants and meteorological factors are built respectively.(3) The chemical compositions of PM2.5are studied in depth, The source of PM2.5is explored by using the method of OC/EC ratio and correlation analysis.(4) The pollution component spectrum of Hangzhou is established. Kitchen fumes are added into the pollution component spectrum as a pollution source for the first time, automobile exhaust pollution is also decomposed into diesel exhaust and gasoline exhaust. PLS-CMB model is proposed by combining the Partial Least Squares Regression (PLS) and the Chemical Mass Balance (CMB) to solve the problem of collinearity. The contribution of different sources is identified quantitatively by this model.(5) Emission inventory method is used to estimate the PM2.5emissions from automobile exhaust and industrial coal. The contribution of diesel exhaust and gasoline exhaust to PM2.5is analyzed. The reason for the large difference of contribution rate between automobile exhaust and industrial coal in summer and winter is discussed.