基于观测的我国典型地区臭氧局地化学生成及其关键前体物来源

Observation-Based Study of Local Ozone Chemical Generation and Precursor Sources in Typical Regions of China

为研究近年来我国重点区域(京津冀及周边地区、长三角地区、珠三角地区、成渝地区及汾渭平原)臭氧局地化学生成的控制因素,利用2014−2019年这些区域共8个代表性站点的夏秋季臭氧及前体物浓度数据,比较分析五大重点区域8个站点的挥发性有机物(VOCs)组成特征及其与臭氧化学生成之间关系.结果表明:①这5个重点区域的VOCs浓度主要由烷烃组成,而活性组分则以烯烃、含氧VOCs和芳香烃为主.②以泰安和成都作为郊区和城市站点的案例研究表明,环境条件发生变化(平均温度增加2℃、辐射增加20%或天然源排放增加20%)可能对当地臭氧生成量产生一定影响,但它们并不足以改变对臭氧生成控制区的判定.③通过采用VOCs来源解析技术和相对增量反应活性的方法,发现机动车尾气、工业和溶剂使用等人为源类别是影响局地臭氧化学生成的关键VOCs排放源,而在农村或郊区(如望都、泰安等站点),天然源VOCs对臭氧生成贡献很大.研究显示,实现降低各城市臭氧峰值浓度,则需要制定并实施差异化的前体物减排策略,以便根据每个城市的VOCs排放特征及其对当地臭氧生成的影响来进行有效控制;同时认为,重点控制人为源VOCs是有效控制夏季臭氧污染的关键措施.

In order to study the control factors of local ozone chemical generation in key regions of China(Beijing-Tianjin-Hebei and surrounding areas,Yangtze River Delta region,Pearl River Delta region,Chengdu-Chongqing region,and Fenhe and Weihe River Plain)in recent years,a comparative analysis was conducted on the composition of volatile organic compounds(VOCs)and their relationship with ozone chemical generation at 8 sites in five key regions using ozone and precursor concentration data from eight representative sites in these regions between 2014 and 2019.The research results indicate that:(1)The VOCs concentrations in the five key regions were mainly composed of alkanes,and the active components were mainly alkenes,oxygenated VOCs,and aromatic hydrocarbons.(2)The case studies in Taian and Chengdu as suburban and urban sites demonstrated that changes in environmental conditions(2℃increase in average temperature,a 20%increase in radiation,or a 20%increase in biogenic source emissions)may have an impact on local ozone generation.However,these factors alone were not enough to change the ozone generation control zones.(3)By using VOCs source analysis technology and Relative Incremental Reactivity method,it was found that anthropogenic sources such as vehicle exhaust,industrial operations,and solvent use were the key VOCs emission sources affecting local ozone chemical generation.In rural or suburban areas(such as Wangdu,Taian and other sites),biogenic VOCs contributed significantly to ozone generation.Therefore,in order to reduce peak concentration of ozone in cities,differentiated precursor emission reduction strategies must be implemented so as to enable effective control on the basis of each city′s VOCs emission characteristics and the impact on local ozone generation.Prioritizing the control of anthropogenic VOCs is a crucial measure for effectively controlling summer ozone pollution.