Source Apportionment And Size Distribution Of Aerosol Over Typical Areas Of Yangtze River Delta In Winter

Aerosol number concentration,PM2.5,regular pollution gas,water-soluble ions and OC,EC in Nanjing,Suzhou and Lin'an atmospheric background station from January 9 to 31,2015 were observed by wide range of particle spectrometer(WPS),KC-120H middle volume sampler,EMS system,850 professional IC ion chromatography analyzer and heat/light carbon analyzer(DRI2001A).This paper uses the ground observation data obtained three sites to analyze the source of aerosol and the aerosol size distribution characteristics of dominant factors in Linan is discussed.Besides,Characterization of aerosol size distribution and chemical composition during strong wind and stable days of a haze episode in Lin'an is analyzed.The result shows that the variation trend of PM2.5 and chemical components are similar,second generation,coal,motor vehicle emissions,dust and biomass burning were the main source of PM2.5 in Nanjing,Suzhou and Lin'an during winter.Besides,sea salt is also one of sources in Suzhou.Second generation made the most contribution to three sites,followed by vehicle and coal.The source of three sites is consistent which indicates that the pollution characteristics of the Yangtze River Delta region in winter was similar and regional pollution was obvious.Different source had different aerosol number concentration distribution.Secondary source,vehicle emissions dust and biomass burning aerosol number concentration spectrum were unimodal type distribution.Coal particle number concentration was bimodal type distribution.Surface concentration spectrum of secondary source,coal source,motor vehicle,dust and biomass burning were three peak distribution.The diurnal variation of particle number concentration were consistent with the diurnal variation of surface concentration,which displayed bimodal type distribution.On January 21,the Lin'an atmospheric background station was in the north wind at the ground,which resulted in short-term northern input-base pollution.The number concentration spectra distribution of strong wind pollution day(SWPD)was bimodal and surface concentration spectra was four-peak distribution.During January 23 to 26,stable atmospheric condition led to the local accumulation of pollutants.Number concentration spectra distribution of stable pollution days(SPD)was unimodal and surface concentration spectra was trimodal distribution.Appropriate relative humidity and number concentration of aerosol in 0.6-1 ?m were the main reasons for low visibility in SPD.PM2.5 and NO3-has significant impacts on extinction coefficient.The particle in SWPD may came from medium-range transport and gas-particles conversion,SO42-and NO3-in SPD main generated from heterogeneous reaction and homogeneous reaction respectively.Enhancement of atmospheric oxidation resulted in more generation of SOC.