Chemical composition and source identification of PM2.5 in the suburb of Shenzhen, China

In this study, PM2.5 has been measured in the suburb of Shenzhen. The mean mass concentration of PM2.5 was 101.6 ± 27.5 μg m− 3 in winter and 32.7 ± 19.7 μg m− 3 in summer. The high PM2.5 concentration level is probably due to the serious emissions from the Pearl River Delta where Shenzhen is located. The sum contribution of water-soluble ions was an average of 53.1 ± 7.6% in winter and 56.3 ± 15.2% in summer, while the sum contribution of polycyclic aromatic hydrocarbons was an average of 7.5 ± 1.4% in winter and 20.5 ± 7.0% in summer. Obvious seasonal variations of PM2.5 and chemical composition were partly because of the different origins of air mass reaching Shenzhen. SO42 −, NH4+ and NO3− were the major water-soluble ions and fluorene and pyrene were the major polycyclic aromatic hydrocarbons in PM2.5. Additionally, six factors including combustion emission factor, fresh sea-salt factor, secondary nitrate factor, airborne dust factor, secondary aerosol factor and aged sea-salt factor were identified by EPA positive matrix factorization.