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

Zhuoran He, Xuemei Wang, Zhenhao Ling, Jun Zhao, Hai Guo, Min Shao, Zhe Wang
2019 Atmospheric Chemistry and Physics  
<p><strong>Abstract.</strong> Volatile organic compounds (VOCs) are key precursors of photochemical smog. Quantitatively evaluating the contributions of VOC sources to ozone (<span class="inline-formula">O<sub>3</sub></span>) formation could provide valuable information for emissions control and photochemical pollution abatement. This study analyzed continuous measurements of VOCs during the photochemical season in 2014 at a receptor site (Heshan site, HS) in the Pearl River Delta (PRD) region,
more » ... Delta (PRD) region, where photochemical pollution has been a long-standing issue. The averaged mixing ratio of measured VOCs was <span class="inline-formula">34±3</span>&amp;thinsp;ppbv, with the largest contribution from alkanes (<span class="inline-formula">17±2</span>&amp;thinsp;ppbv, 49&amp;thinsp;%), followed by aromatics, alkenes and acetylene. The positive matrix factorization (PMF) model was applied to resolve the anthropogenic sources of VOCs, coupled with a photochemical-age-based parameterization that better considers the photochemical processing effects. Four anthropogenic emission sources were identified and quantified, with gasoline vehicular emission as the most significant contributor to the observed VOCs, followed by diesel vehicular emissions, biomass burning and solvent usage. The <span class="inline-formula">O<sub>3</sub></span> photochemical formation regime at the HS was identified as VOC-limited by a photochemical box model with the master chemical mechanism (PBM-MCM). The PBM-MCM model results also suggested that vehicular emission was the most important source to the <span class="inline-formula">O<sub>3</sub></span> formation, followed by biomass burning and solvent usage. Sensitivity analysis indicated that combined VOC and <span class="inline-formula">NO<sub><i>x</i></sub></span> emission controls would effectively reduce incremental <span class="inline-formula">O<sub>3</sub></span> formation when the ratios of VOC-to-<span class="inline-formula">NO<sub><i>x</i></sub></span> emission reductions were <span class="inline-formula"><i>&amp;gt;</i> 3.8</span> for diesel vehicular emission, <span class="inline-formula"><i>&amp;gt;</i> 4.6</span> for solvent usage, &amp;gt;&amp;thinsp;4.6 for biomass burning and 3.3 for gasoline vehicular emission. Based on the above results, a brief review of the policies regarding the control of vehicular emissions and biomass burning in the PRD region from a regional perspective were also provided in this study. It reveals that different policies have been, and continue to be, implemented and formulated and could help to alleviate the photochemical pollution in the PRD region. Nevertheless, evaluation of the cost-benefit of each policy is still needed to improve air quality.</p>
doi:10.5194/acp-19-8801-2019 fatcat:eaardivppvf6xjblsi6pfdefnq