成都市2017年夏季大气VOCs污染特征、臭氧生成潜势及来源分析

为评估成都市2017年夏季（6-8月）开展的臭氧防治行动措施对空气质量的改善效果，采用在线监测系统对成都市环境空气中VOCs物种进行监测，对比分析VOCs污染特征、OFP（臭氧生成潜势），并利用PMF（正矩阵因子法）模型对VOCs主要来源进行解析.结果表明:2017年8月$φ$（VOCs）平均值为31.85×10-9，比2016年同期下降了32%，其中，$φ$（芳香烃）和$φ$（卤代烃）平均值下降最为明显.$φ$（VOCs）日变化呈双峰型，分别在每日09:00和23:00左右达峰值，臭氧防治行动期间$φ$（VOCs）月均小时值低于2016年同期.VOCs的OFP敏感性物种以烯烃为主，占总VOCs OFP贡献的48%.2017年8月成都市OFP为61.89×10-9，比2016年同期下降44%.VOCs源解析结果发现，2017年8月油气挥发源、有机溶剂使用源、工业源、生物质燃烧源等排放占比均有所下降，而机动车排放源和天然源的排放占比增加.研究显示，成都市2017年夏季臭氧防治行动对成都市大气VOCs排放有明显的控制效果. 

Analyses of Pollution Characteristics, Ozone Formation Potential and Sources of VOCs Atmosphere in Chengdu City in Summer 2017

In order to evaluate the air quality improvement during the Ozone Control Action in Chengdu City in summer 2017, on-line monitoring systems were used to monitor atmosphere volatile organic compounds (VOCs) in the ambient air of Chengdu City. The pollution characteristics of VOCs and ozone formation potential were compared and analyzed. In addition, the Positive Matrix Factorization (PMF) model was utilized to analyze the main sources of VOCs. The results indicated that the VOCs volume fraction was 31.85×10^-9 in August 2017, which decreased by 32% compared to the same period in 2016, especially the concentration of aromatic hydrocarbon and halogenated hydrocarbon declined dramatically. The daily change of VOCs shows a bimodal pattern, peaking at 09:00 and 23:00, respectively. Furthermore, the average hourly volume fraction of VOCs is lower than that of the same period of last year during the Ozone Control Action. The majority of VOCs'' OFP sensitive species is alkenes, accounting for 48% of the total OFP of VOCs. The OFP of VOCs is 61.89×10^-9 in August 2017, falling down 44% compared to the same period in 2016. VOCs source analyses by PMF model showed that the emissions of fuel volatile, solvent evaporation, industrial sources and biomass burning declined, while the ratio of emissions of vehicle and natural resources increased in the summer of 2017. Overall, the ozone control action of Chengdu City in the summer of 2017 had a significant effect on the control of atmospheric VOCs emissions.