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

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.