南京大气颗粒物化学组分的粒径分布和来源解析OA北大核心CSTPCD

The size distribution of the chemical components of particulate matter in the atmosphere is closely related to its source,formation process,environment,and health effects.There are relatively few studies on the characteristics of the particle size distribution of particulate matter in different seasons and the contribution of different sources to coarse and fine particulate matter.Size-resolved aerosol samples were collected in Nanjing during December 2022(winter)and August 2023(summer).Samples of coarse and fine particulate matter(PM2.1-10,PM2.1)were further analyzed for their carbonaceous compositions and water-soluble inorganic ions.The size distributions and seasonal variations of all the species were characterized.The potential sources of aerosols were quantified using the positive matrix factorization(PMF)model.The results showed that organic carbon(OC),elemental carbon(EC),and water-soluble organic carbon(WSOC)had bimodal distributions in both seasons.Both SO42-and NO3-showed a bimodal distribution during the warm and cold seasons.NH4+exhibited a unimodal distribution,peaking at 0.43-0.65 μm in both seasons.Regarding the seasonal variation,the concentrations of the main chemical species were higher in winter,with the exception of Na+and SO42-.Markers of crustal materials,such as Ca2+and Mg2+,were mainly found in the coarse mode during summer and winter.Finally,four emission sources were resolved using the PMF model.The results showed that secondary aerosols and biomass burning were the dominant sources of PM2.1,accounting for 65.7%and 61.0%in winter and summer,respectively.Biomass burning and secondary nitrate dominated PM2.1 pollution in winter,while secondary sulfate was a major source in summer.For PM2.1-10,traffic emissions were a major source in winter,with a share of 41.8%.In contrast,biomass burning and secondary nitrate were the main sources of PM2.1-10 in the summer,contributing approximately 43.9%of the PM2.1-10 masses.This study investigated the characteristics of the particle size distribution,seasonal variations,and sources of the chemical components of particulate matter,which can provide a scientific basis for the effective prevention and control of air pollution.