Pollution Characteristics And Source Apportionment Of Atmospheric Fine Particles In Shijiazhuang

In order to analyze the mass concentration level and pollution characteristics of atmospheric particulate matter in Shijiazhuang,the atmospheric particulate matter samples were collected from June 2018 to May 2019 in Shijiazhuang in this study,and the chemical composition were analyzed including carbon composition,water-soluble ions and inorganic elements.Also,the PM_2.5 local source and the external potential source area were analyzed by using the positive definite matrix factorization method?PMF?and the backward trajectory analysis model?TrajStat?.The main conclusions were showed as follows:1)The concentration of atmospheric particulate matter showed a downward trend,and the average annual mass concentrations of PM₁,PM_2.5 and PM₁₀ from June 2018 to May 2019 decreased 0.84%,12.13%and 14.73%from year-on-year,respectively.The average concentrations of particulate matters showed a trend as winter>autumn>spring>summer.The small size particles accounted for the highest proportion in large particle size in winter,followed by summer and autumn,and lowest in spring.2)The carbon component is one of the main components in PM_2.5,and the concentration is less different between urban and suburb.The analysis of the proportion of8 carbon components in different seasons indicated that dust,coal and motor vehicle emissions,biomass burning and motor vehicle emissions were the sources of carbonaceous aerosol in spring,summer and autumn,respectively,and the sources of carbonaceous aerosols in winter was extensive and complex.The water-soluble ions concentration of Shijiazhuang accounted for 48.40%of the average mass concentrations of PM_2.5,and the secondary ions concentration accounted for 77.22%of the total measured ions concentration.Principal component analysis showed that the main sources of water-soluble ions in PM_2.5 were soil and building dust,motor vehicle emissions and coal combustion,coal and soil dust and secondary sources.During the observation periods,the average annual element concentrations of the Hebei University of Science and Technology and the Shijiazhuang Tower were 14014.34 ng·m^-3 and 13206.10 ng·m^-3,respectively.The results of inorganic element enrichment factors indicated that the elemental components of PM_2.5 in Shijiazhuang were mainly affected by human activities.3)Based on the local PM2.5 source analysis by PMF receptor model,results showed that the five main sources of PM_2.5 during the sampling periods were the vehicle emission source,the secondary source and the coal-fired hybrid source,the dust source,the industrial source and other sources.The dust source accounted for the largest proportion in spring with 33.3%.Motor vehicle emissions accounted for the largest proportion in summer with 34.4%.The secondary source and coal-fired mixed source accounted for the largest proportion in autumn and winter,respectively as 30.0%and 31.6%.4)The regional transportation pollution had a seasonal variation.The main potential source areas in spring and summer were distributed in the border between Shandong,Henan and Hebei,and the northern part of Jiangsu and Anhui Province.The contribution of daily PM_2.5 average concentrations was above 50?g·m^-3.The potential source areas in autumn were concentrated in the eastern part of Inner Mongolia,southwestern Shanxi Province,northern Hebei Province,southeastern Henan Province and northwestern Jiangsu Province,and the contribution of daily PM_2.5 average concentrations was above 90?g·m^-3.The potential pollution source areas in winter were distributed in the cities of the border between Shandong,Henan and Hebei,and the northern part of Shandong Province.The contribution of daily PM_2.5 average concentrations was above 90?g·m^-3.