鄂州市一次典型臭氧污染过程特征与成因分析

Characteristics and Causes of a Typical Ozone Pollution Process in Ezhou

为研究2022年9月1-14日鄂州市臭氧污染特征与成因,文章利用常规空气质量自动监测、挥发性有机物(VOCs)在线监测、OBM模型、PMF模型、后向轨迹聚类分析、最大增量反应活性法(MIR)等监测分析方法对污染过程进行综合分析。结果表明,这是一次区域性臭氧污染过程,污染程度以轻度污染为主,臭氧浓度日变化呈典型单峰型特点,13:00-16:00是臭氧浓度峰值时段。研究期间鄂州市VOCs平均浓度为19.15×10^(-9),污染阶段浓度明显高于积累阶段和稀释阶段,VOCs主要组分为烷烃、OVOCs、卤代烃。积累阶段、污染阶段和稀释阶段VOCs组分的OFP分别为48.63、89.07、45.43μg/m^(3),乙烯是对OFP贡献最大的物种。台风外围下沉气流和高温、低湿、静稳的气象条件是本次O3生成和转化的重要外部因素,本次臭氧污染以本地生成为主,同时受北方传输影响,污染阶段VOCs主要来源为工业排放(36.8%)、机动车尾气(18.3%)、化石燃料燃烧(14.9%)、溶剂使用(12.9%)、汽油挥发(9.8%)和天然源(7.3%),溶剂使用源对OFP贡献最大。

To investigate the characteristics and causes of ozone pollution in Ezhou from September 1 to 14,2022,variety of monitoring data and analysis methods were applied,including routine monitoring of ambient air quality,online monitoring of volatile organic compounds(VOCs),OBM model,PMF model,cluster analysis of air mass backward trajectory,maximum incremental reactivity method(MIR).The results showed that this was a regional ozone pollution process,and the pollution degree was mainly light pollution.O:hourly concentration showed a typical single-peak curve,and 13:00-16:00 is the peak time of ozone concentration.During the study period,the average concentration of VOCs was 19.15×10^(-9),and the concentration of vOCs in the pollution stage was significantly higher than that in the stages of accumulation and contamination.The main components of VOCs were alkanes,OVOCs,and halohydrocarbons.The OFPs of VOCs components in the stages of accumulation,pollution and contamination were 48.63,89.07,and 45.43μg/m^(3),respectively,and ethylene was the species that contributes the most to OFP.The downdraft around the typhoon and the high temperature,low humidity,and static and stable meteorological conditions were important external factors for the generation and transformation of O3.The ozone pollution was mainly caused by the local generation,and at the same time affected by the transmission in the north.The main source of VOCs in the pollution stage was industrial emission sources(36.8%),motor vehicle exhaust emission sources(18.3%),fossil fuel combustion sources(14.9%),solvent use sources(12.9%)and gasoline volatilization sources(9.8%),natural sources(7.3%),the source of solvent usage contributed the most to OFP.