南方某海滨城市臭氧污染原因解析及控制建议

Reason Analysis and Control of Ozone Pollution in a Southern Coastal City

作者于2019年7月16日-22日和10月11日-17日对S市大气中挥发性有机物(VOCs)进行连续观测,以便研究S市不同季节臭氧污染特征及臭氧污染过程的主控因素。研究表明,S市夏秋两季臭氧污染较为严重,质量浓度较高的VOCs物种有丙酮、2-丁酮、乙酸乙酯、二氯甲烷、甲苯等;等效丙烯浓度和臭氧生成潜势评估发现,苯系物为夏季臭氧生成潜势最大的VOCs类别;间/对-二甲苯与乙苯比值表明夏季气团光化学年龄较短,臭氧浓度主要受本地排放源和短距离传输的影响;结合HYSPLIT后向轨迹进一步说明了沿海城市臭氧超标主要与风速较低、气团移动较慢、以及周边城市污染物聚积有关,同时冬春季变性冷高压脊控制、夏秋季台风及副热带高压共同影响等天气形式下容易发生臭氧超标情况。控制机动车排放,控制塑胶制品行业、印刷等相关使用溶剂涂料行业的排放,以及控制周边城市的污染输送,可以缓解该地区的臭氧超标情况。

Volatile organic compounds(VOCs)in the atmosphere of City S from July 16-22,2019 and October 11-17,2019 were continuous monitored in order to study the characteristics of ozone pollution and the main controlling factors of the ozone pollution process in different seasons.Studies have shown that ozone pollution is more serious in summer and autumn in S City.VOCs species with higher mass concentration include acetone,2-butanone,ethyl acetate,methylene chloride,toluene and so on.Equivalent propylene concentration and ozone generating potential assessment found BTEX is the largest VOCs category with summer ozone formation potential,and the ratio of m/p-xylene to ethylbenzene indicates that the photochemical age of air mass is shorter in summer,and the ozone concentration is mainly affected by local emission sources and short distance transmission.Combined with the backward trajectory of HYSPLIT,it is further explained that the excessive ozone in coastal cities is mainly related to lower wind speed,slower movement of air mass,and accumulation of pollutants in surrounding cities.Ozone exceeding the standard is prone to occur under weather conditions such as the control of the denature cold high-pressure ridges in winter and spring,the combined influence of typhoons in summer and autumn,and the subtropical high.Controlling emissions from motor vehicles,plastics,printing and other related solvent-based coatings,as well as pollution transport in surrounding cities,can alleviate ozone excess in the region.