Contributions of different anthropogenic volatile organic compound 1 sources to ozone formation at a receptor site in the Pearl River Delta 2 region and its policy implications 3

Abstract

Volatile organic compounds (VOCs) are key precursors of photochemical smog. Quantitatively 11 evaluating the contributions of VOCs sources to ozone (O3) formation could provide valuable information 12 for emissions control and photochemical pollution abatement. This study analysed the continuously 13 measured VOCs during the photochemical season in 2014 at a receptor site (Heshan site, HS) in the Pearl 14 River Delta (PRD) region, where photochemical pollution has been a long-standing issue. The averaged 15 mixing ratio of measure VOCs was 34 ± 3 ppbv, with the largest contribution from alkanes (17 ± 2 ppbv, 16 49%), followed by aromatics, alkenes, and acetylene. The positive matrix factorization (PMF) model was 17 applied to resolve the anthropogenic sources of VOCs, coupled with a photochemical-aged-based 18 parameterization that better considers the photochemical processing effects. Four anthropogenic emission 19 sources were identified and quantified, with gasoline vehicular emission as the most significant 20 contributor to the observed VOCs, followed by diesel vehicular emissions, biomass burning, and solvent 21 usage. The O3 photochemical formation regime at HS was identified as VOCs-limited by a photochemical 22 box model with the master chemical mechanism (PBM-MCM). The PBM-MCM model results also 23 suggested that vehicular emission was the most important source to the O3 formation, followed by 24 biomass burning and solvent usage. Sensitivity analysis indicated that in order to prevent the increment 25 Atmos. Chem. Phys. Discuss., https://doi.org/10.5194/acp-2018-1293 Manuscript under review for journal Atmos. Chem. Phys. Discussion started: 11 February 2019 c © Author(s) 2019. CC BY 4.0 License.