基于有机标志物的长沙市 PM_2.5来源解析

PM_2.5,as the key pollutant for air pollution control and management in China,holds critical scientific significance for precision pollution control strategies due to its chemical speciation characteristics and source apportionment. Continuous monitoring was performed in Changsha(a pivotal city of the triangle of Central China)during August 2021–January 2022,aiming to characterize the chemical speciation and concentration profiles of PM_2.5. The mean PM_2.5 concentration in central urban area of Changsha was(69.1 ± 44.6)μg·m^-3. Water-soluble ions dominated the composition (45.1%),followed by carbonaceous components(26.8%). Study enhances the discrimination of PM_2.5 sources by integrating key organic tracers (levoglucosan,mannosan,and cholesterol)with traditional tracers PMF modeling. It successfully attributes secondary aerosol formation to primary sources—a breakthrough achieved via the inaugural use of organic tracers in source apportionment in Changsha. Source apportionment results indicate that mobile sources,coal combustion sources,biomass burning sources,biogenic sources,cooking emissions,fugitive dust,and industrial process sources contribute 35.6%,15.1%,13.8%,12.2%,9.4%,8.1%,and 5.8% to PM_2.5 concentrations,respectively. In the central urban area of Changsha,mobile sources constitute the predominant contributor to PM_2.5 pollution. During August and September,biogenic emissions exert a notable influence,whereas from October to January of the subsequent year,pollution is significantly affected by the long-range transboundary transport of coal combustion-related air masses from northern regions and regional biomass burning within the province. Contributions from industrial process sources markedly diminish during specially controlled periods,while emissions from catering services and fugitive dust demonstrate relatively stable monthly variations.