Polycyclic aromatic hydrocarbons in PM2.5 in Guangzhou, southern China: Spatiotemporal patterns and emission sources

► PM2.5 samples were collected simultaneously at six different sites in Guangzhou. ► Tracer to PAH ratios were jointly used to identify sources of PAHs. ► Vehicular emissions were no longer the dominant PAH sources. ► More attention should be paid to coal combustion and biomass burning.