晋中市夏季典型臭氧污染事件中VOCs化学特征与来源分析
- Chemical Characteristics and Source Analysis of VOCs in Typical Summer Ozone Pollution Events in Jinzhong
- 基金项目：省级自然科学基金,国家自然科学基金面上项目
- 摘要：本研究基于2022年6月15-30日晋中市一次典型臭氧（O3）污染过程，深入分析了不同污染阶段（污染前期、中期、后期）O3及其前体挥发性有机污染物（VOCs）变化。通过计算臭氧生成潜势（OFP）和OH自由基的消耗速率（LOH），评估了VOCs活性并识别关键活性组分和物种，运用正定矩阵因子分析（PMF）研究其来源贡献。结果表明，O3污染中期主要受高温、低湿、风速小等恶劣气象条件作用，叠加VOCs浓度升高的影响；OVOCs、烯烃和芳香烃是晋中市O3生成贡献较大的组分；乙醛、乙烯、丙醛和异戊二烯对LOH和OFP贡献突出，是防治关注的关键活性物种；PMF揭示了焦化源、溶剂使用、机动车排放、LPG & NG和生物源5个主要排放来源，其中焦化源是晋中市O3污染期VOCs控制的重点；后向轨迹揭示O3污染过程中西南方向气团中VOCs体积分数明显高于其他方向气团，故需针对上述VOCs展开区域范围联防联控。
- Abstract：This study meticulously analyzed the variations in ozone (O3) and its precursor volatile organic compounds (VOCs) during different phases of a typical pollution event in Jinzhong from June 15 to 30, 2022. By quantifying the ozone formation potential (OFP) and the consumption rate of OH radicals (LOH), the activity of VOCs was assessed, pinpointing critical active components and species. The analysis utilized Positive Matrix Factorization (PMF) to determine the source contributions of these pollutants. The findings revealed that the peak of the O3 pollution was predominantly influenced by severe meteorological conditions such as high temperatures, low humidity, and minimal wind speeds, coupled with an increase in VOC concentrations. Oxygenated VOCs (OVOCs), olefins, and aromatic hydrocarbons were identified as significant contributors to ozone production in Jinzhong. Notably, acetaldehyde, ethylene, propanal and isoprene were significant to both LOH and OFP, marking them as critical targets for pollution control strategies. PMF analysis highlighted five principal emission sources: coking activities, solvent usage, vehicle emissions, LPG & NG emissions, and biological sources, with coking activities being a pivotal focus for VOC management during the ozone pollution period. Backward trajectory analysis indicated that air masses from the southwest had a notably higher VOC content compared to other directions, suggesting the need for a regional cooperative approach to pollution prevention and control focusing on these key VOCs.
