Source apportionment of PM2.5 in urban Shanghai based PMF and PSCF model

Source apportionment of PM2.5 in urban Shanghai based PMF and PSCF modelMengfei Zhao, Guangli Xiu*, Ting Qiao State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemicals Processes, East China University of Science and Technology, Shanghai, China*Corresponding author: xiugl@ecust.edu.cnAbstract: In the study, we analyzed chemical compositions of PM2.5 collected in urban Shanghai from July 2013 to August 2014. Based on the analyzed species, seven major sources of PM2.5 identified from Positive Matrix Factorization (PMF) model included sulfate and ammonium dominant, nitrate dominant, coal combustion, biomass burning, Cu and Ni smelt industry, marine aerosols and mineral dust. The annual contribution of secondary sources (sulfate, ammonium and nitrate dominant) was similar to primary sources. As for secondary sources, sulfate and ammonium dominant was much higher than nitrate dominant, while nitrate dominant which represented mobile source played more important roles on haze days. Potential Source Contribution Function (PSCF) model was used to investigate the distribution area of each area. The result showed that secondary sources were relatively concentrated, mainly from the surroundings of Shanghai. Most primary sources were affected by regional transports. The source of coal combustion was located in the Northwest, and marine aerosols were from the ocean. The Yangtze River Delta (YRD) region and Pearl River Delta (PRD) region were major source areas of biomass burning and Cu and Ni smelt industry, respectively. In addition, Liquid water content (LWC) in PM2.5 was calculated by a thermodynamic model (AIM-IV). LWC showed positive correlations with nitrate dominant and sulfate and ammonium dominant (r=0.64 and 0.49, p<0.01). The correlation between LWC and nitrate dominant was more significant during heavy haze episodes.