黄冈市大气挥发性有机物污染特征、来源及对臭氧生成的影响

基于黄冈市城区大气挥发性有机物（VOCs）离线采样数据和常规空气污染物、气象在线监测数据，分析了黄冈市大气VOC组分和体积分数特征，并利用正交矩阵因子分解（PMF）模型和耦合MCM机制的光化学反应箱式模型（PBM-MCM）分别分析了臭氧（O₃）污染高发期VOCs的来源及臭氧生成敏感性.结果表明，φ（TVOCs）平均值为（21.57±3.13）×10^-9，且呈现出冬春高、夏秋低的季节性特征，其中烷烃（49.9%）和烯烃（16.4%）的占比最大.PMF解析结果显示黄冈市大气VOCs主要来源为：燃料燃烧源（27.8%）、机动车排放源（19.9%）、溶剂使用源（15.7%）、工业卤代烃排放源（12.1%）、化工企业排放源（10.5%）、自然源（7.8%）和柴油车排放源（6.2%）.在人为源中，溶剂使用、燃料燃烧和化工企业排放的VOCs对大气环境中O₃生成的贡献较大，贡献了O₃生成的60.9%，故对O₃污染防控应优先管控这3种人为源.通过相对增量反应性（RIR）和经验动力学方法（EKMA）曲线分析，观测期间黄冈市O₃生成处于VOCs控制区，且间/对-二甲苯、乙烯、1-丁烯和甲苯等VOCs对O₃生成比较敏感，应重点削减以上VOCs的排放.

Characteristics, Sources, and Contributions to Ozone Formation of Ambient Volatile Organic Compounds in Huanggang, China

Based on the offline sampling data of volatile organic compounds (VOCs) and the simultaneous online measurements of conventional gaseous air pollutants and meteorological parameters in urban Huanggang, the volume fractions and component characteristics of VOCs were analyzed. The sources and ozone (O₃) formation sensitivity of VOCs during severe ozone pollution episodes were analyzed using the positive matrix factorization (PMF) model and the photochemical box model coupled with master chemical mechanism (PBM-MCM), respectively. The results revealed that the average volume fractions of total volatile organic compounds were (21.57±3.13)×10^-9, with higher volume fractions in winter and spring compared to those in summer and autumn. Among these, alkanes (49.9%) and alkenes (16.4%) accounted for the highest proportion. The PMF analysis results showed that fuel combustion (27.8%), vehicle emission (19.9%), solvent use (15.7%), industrial halogenated hydrocarbon emission (12.1%), chemical enterprise emission (10.5%), natural sources (7.8%), and diesel vehicle emission (6.2%) were the main sources of VOC emissions. Anthropogenic VOCs emitted by solvent use, fuel combustion, and chemical enterprises contributed significantly (60.9% in total) to generating O₃, which indicates that these three types of anthropogenic sources should be controlled first when it comes to preventing and controlling ozone pollution. Further, the relative incremental reactivity (RIR) and empirical kinetic method approach (EKMA) revealed that O₃ formation was in a VOCs-limited regime during the observation period in Huanggang, China. Furthermore, O₃ formation was more sensitive to m-xylene, p-xylene, ethylene, 1-butene, and toluene; therefore, reducing these VOCs should be prioritized.