Abstract
Volatile organic compounds (VOCs) were monitored online at three photochemical assessment monitoring stations (MDS, WQS and HGS) in the Pearl River Delta region during the summer of 2016. Measured levels of VOCs at the MDS, WQS and HGS sites were 34.78, 8.54 and 8.47 ppbv, respectively, with aromatics and alkenes as major ozone precursors and aromatics as major precursors to secondary organic aerosol (SOA). The positive matrix factorization (PMF) model revealed that VOCs at the sites mainly came from vehicle exhaust, petrochemical industry, and solvent use. Vehicle exhaust and industrial processes losses contributed most to ozone formation potentials (OFP) of VOCs, while industrial processes losses contributed most to SOA formation potentials of VOCs. Potential source contribution function (PSCF) analysis revealed a north-south distribution for source regions of aromatics occurring at MDS with emission sources in Guangzhou mainly centered in the Guangzhou central districts, and source regions of aromatics at WQS showed an east-west distribution across Huizhou, Dongguan and east of Guangzhou, while that at HGS showed a south-north distribution across Guangzhou, Foshan, Zhaoqing and Yangjiang. This study demonstrates that multi-point high time resolution data can help resolve emission sources and locate emission areas of important ozone and SOA precursors.
Highlights
Previous studies demonstrated that in these megacities O3 formation is largely Volatile organic compounds (VOCs)-limited and the increase in anthropogenic emissions of VOCs is an important reason for the deteriorating O3 pollution
For the coordinated prevention and control of O3 and PM2.5 prevention, it is critical to determine which are the most important precursors to O3 and secondary organic aerosol (SOA) among the hundreds of VOC species occurring in the ambient [6,7,10], and, what are the major sources and emission areas of these precursors
Three sites (MDS, WQS and HGS; Figure 1) among Photochemical Assessment Monitoring Stations (PAMS) in the Pearl River Delta (PRD) region are selected in this study
Summary
Previous studies demonstrated that in these megacities O3 formation is largely VOC-limited and the increase in anthropogenic emissions of VOCs is an important reason for the deteriorating O3 pollution. Many VOCs, like aromatic hydrocarbons and biogenic VOCs, are precursors of SOA [6,7], which shares 20–70% mass concentrations of PM2.5 in ambient air [8,9]. For the coordinated prevention and control of O3 and PM2.5 prevention, it is critical to determine which are the most important precursors to O3 and SOA among the hundreds of VOC species occurring in the ambient [6,7,10], and, what are the major sources and emission areas of these precursors
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