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

The Positive Matrix Factorization (PMF) receptor model and the Observation Based Model (OBM) were combined to analyze volatile organic compound (VOC) data collected at a suburban site (WQS) in the PRD region. The purposes are to estimate the VOC source apportionment and investigate the contributions of these sources and species of these sources to the O3 formation in PRD. Ten VOC sources were identified. We further applied the PMF-extracted concentrations of these 10 sources into the OBM and found 'solvent usage 1', 'diesel vehicular emissions' and 'biomass/biofuel burning' contributed most to the O3 formation at WQS. Among these three sources, higher Relative Incremental Reactivity (RIR)-weighted values of ethene, toluene and m/p-xylene indicated that they were mainly responsible for local O3 formation in the region. Sensitivity analysis revealed that the sources of 'diesel vehicular emissions', 'biomass/biofuel burning' and 'solvent usage 1' had low uncertainties whereas 'gasoline evaporation' showed the highest uncertainty. - Highlights: → 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. - Solvent usage, diesel vehicular emissions and biomass/biofuel burning were the major contributors to the photochemical O3 formation in the PRD region.