Physicochemical Characteristics Of PM_2.5 And Source Apportionment Of Aerosols Particle Size In Northern Of Nanjing

As the prime culprits of air pollution and smog weather, PM2.5 received widespread attention. In order to study the relationship between PM2.5 in the northern suburb of Nanjing and relative pollutants physicochemical properties, for putting forward effective countermeasures in PM2.5 pollution control. From December 2015 to December 2016, this experiment took samples of PM2.5 in the northern suburb of Nanjing for analysis, and important samples of the seriously polluted months, for exploring the correlation between relative pollutants and PM2.5. The analytical work concerning source of PM2.5 and relative pollutants has been completed, based on the analysis of atmospheric particle number concentration. The main conclusions are summarized as follows:In 2016, the annual average concentration of PM2.5 in the northern suburb of Nanjing was 56.89?g/m3, which was better than the overall trend of 2015. Throughout the four quarters of 2016, the most serious pollution occurred in the first quarter, good days less than 40%, while the air quality was full excellent in the third quarter, good days reaching 100%. Among 12 months in 2016, the lowest concentration of PM2.5 was in August, the value of which was 30.41?g/m3, and the air quality was of the most stabilization. The average concentration of PM2.5 per hour ,before and after 13 : 00,achieved the minimum value of a day.Comparing the water-soluble ions in December 2015 with which in December 2016, we found the latter decreased obviously. However, in both months, there was a significantly positive correlation between PM2.5 and SO42-?NH4+.NO3-, which are the main constituents of PM2.5.In winter in the northern suburb of Nanjing, the daily variation trend of PM2.5 in close to which of SO2, and as gaseous precursors,SO2 has a facilitated effect on the appearance of the new particles and PM2.5.In the winter of 2015, there was a significantly positive correlation between aerosol extinction coefficients and the concentration of PM2.5 in the northern suburb of Nanjing,and the correlation coefficient R2 was 0.879. Therefore, the mass concentration of PM2.5 has a significant effect on the extinction of aerosol.There factors were recognized during winter in norther of Nanjing, these were identified as local traffic emission source, secondary aerosol, remote traffic and mixed combustion emission source, heir contributions to the total n?mber concentrition of atmospheric fine particles as follows: remote traffic source (35.8%) >mixed combustion(25.5%) >secondary aerosols (21.9%) >local traffic source (21.9%).The sources of pollution are mainly concentrated in the northeast and east of the observation point.Traffic source has became the main source of pollution in Nanjing as 52.6% contribution rate.Limit motor vehicle emissions ie the primary task to control PM2.5 and other air poiiutants...