Sources of ambient volatile organic compounds and their contributions to photochemical ozone formation at a site in the Pearl River Delta, southern China

► Ten sources of VOCs were identified by the PMF receptor model in the PRD region. ► In terms of mass percentage, solvent was the largest contributor, followed by vehicle emissions. ► Solvent, diesel vehicles and biomass/biofuel burning were the top three VOC contributors to O3 formation. ► Among these three sources, ethene, toluene and m/p-xylene were responsible for O3 formation. ► Biomass/biofuel burning had low uncertainty whereas gasoline evaporation showed high uncertainty.