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

► Comprehensive study on atmospheric PM2.5 in the suburb of Shenzhen in recent years. ► SO42 −, NH4+ and NO3− were the major WSIs in PM2.5. ► Fluorene and pyrene were the major PAHs in PM2.5. ► Five factors in PM2.5 were identified by pmf.