益阳市大气污染特征及潜在来源分析

Study on the air pollution characteristics and potential sources in Yiyang City

该文以湖南省“大气污染防治重点城市”之一的益阳市为研究对象,分析了“十三五”期间大气环境污染物浓度变化情况,同时对后向气团轨迹、潜在污染来源进行了模拟.结果表明,益阳市“十三五”期间六项常规污染物浓度整体变化呈现向好趋势,PM_(2.5)浓度整体下降但峰值仍较高,秋冬季是益阳市PM_(2.5)污染的重点时段.O_(3)逐渐成为大气污染的重要因子,超标主要集中在4月—5月.特征雷达图显示益阳市2020年整体偏燃烧型、偏机动车型的特征.PM_(2.5)及PM_(10)、NO_(2)、CO日变化均呈现“双峰”态势,光照辐射较强的日间O_(3)与NO_(2)日变化呈现相反趋势.不同季节轨迹聚类和污染物浓度有明显的季节性差异.PM_(2.5)与PM_(10)潜在源较为相似,主要集中在湖南省东北部及湖北省东部区域,O_(3)潜在源主要分布在益阳市西部区域.

This paper takes Yiyang City,one of the“key cities for air pollution prevention and control”in Hunan Province,as the research object to analyze the changes in the concentrations of atmospheric pollutants during the“13th Five-Year Plan”period,simulate the backward air mass trajectory and potential pollution sources.The results revealed that the overall changes in the concentrations of six conventional pollutants in Yiyang City showed a positive trend during the“13th Five-Year Plan”period.The overall concentration of PM_(2.5) decreased,but its peak value remained high.Autumn and winter were the key periods for PM_(2.5) pollution in Yiyang City.O_(3) gradually became an important factor in air pollution,exceeding the prescribed upper limit mainly in April-May.The radar characteristic chart showed that the air pollutants in Yiyang City primarily manifested as burning-and motor vehicle-oriented characteristics in 2020.The daily variation of PM_(2.5),PM_(10),NO_(2),and CO all showed a“double peak”pattern.During the daytime with strong light radiation,the daily variation of O_(3) showed an opposite trend against that of NO_(2).There were obvious seasonal differences in trajectory clustering and pollutant concentration in different seasons.The potential sources of PM_(2.5) and PM_(10) were similar,mainly concentrated in the northeastern part of Hunan Province and the eastern part of Hubei Province.The potential sources of O_(3) were mainly distributed in the western part of Yiyang City.