Characteristics and Source Analysis of Carbon Aerosol Pollution in Dry Season in Kunming

To study the characteristics and sources of carbon aerosol concentration in Kunming,a southwest plateau city,117 PM_2.5samples were collected in the urban area of Kunming from November 20,2018 to March 23,2019.The mass concentration of organic carbon （OC） and elemental carbon （EC） was determined and their sources were analyzed.The results showed that the average concentration of PM_2.5 in Kunming was 72.31±26.19μg/m³,and the total carbon aerosol concentration （TC） was 38.04±18.74μg/m³,accounting for about 53%of PM_2.5.Carbon aerosols were mainly derived from organic carbon emissions,and OC accounted for approximately 75%of TC,and the average EC mass was 9.15±4.02μg/m³.The OC/EC value was 3.23.Secondary organic carbon（SOC） accounted for about 40%of organic carbon.So there were secondary organic pollutants to some extend.The ranking of carbon component concentration was:OC3>OC4>OPC>EC1>OC2>OC1>EC2>EC3,dominated by gasoline vehicle exhaust emissions,coal burning,dust and biomass combustion in Kunming.The exogenous gas mass has affected the concentration and composition of carbon aerosols in Kunming.Compared with local emission,OC3 and OP increased in southwest wind and EC1 decreased;OP increased in southerly wind and OC4 increased in northeast wind.The potential exogenous input of the carbon aerosols in Kunming mainly came from the southwest,such as Honghe,Yuxi and northern Myanmar.And some parts came from the southeast （Wenshan）and northeast （Qujing）.Biomass combustion and industrial emissions were the main sources of regional transmission.