武威市城区季节性复合大气污染特征及来源解析

Analysis of Seasonal Composite Air Pollution Characteristics and Sources in Urban Areas of Wuwei City

近年来,武威市城区环境空气质量总体向好发展,但随着社会经济发展,空气质量受季节性气候变化和外源污染物释放影响较明显。分析了“十三五”期间武威市环境空气质量特征,同时对城区夏、冬两季可吸入颗粒物(PM_(10))来源进行了解析。结果表明:武威市城区空气质量总体趋好,2016~2020年连续5年优良天数超过320 d,平均优良率达到90%;轻度污染天数略有增加,由2016年的17 d增加至2020年的38 d;重污染天数连年减少。冬季城区主要污染源为生物质燃烧源,贡献率23.35%;其次为城市扬尘、土壤尘、餐饮油烟尘、燃煤尘,贡献率在10%左右;机动车尾气尘、建筑水泥尘、道路扬尘等最少,均低于5%。夏季城区主要污染源为城市扬尘、建筑水泥尘、土壤尘,贡献率在20%左右;其次为机动车尾气尘、道路扬尘、餐饮油烟尘等,贡献率在5%~10%之间;其他源类贡献值较少。

In recent years,the environmental air quality of the urban area of Wuwei City has been steadily developing,and it has developed in good development.However,with the socio-economic development,air quality is more significantly affected by seasonal climate change and the release of exogenous pollutants.This paper analyzes the ambient air quality characteristics of Wuwei City during the"13th Five-Year Plan"period,and analyzes the sources of PM_(10) in urban areas in summer and winter.The results indicate that the air quality in Wuwei City is generally better.The five consecutive years of excellent days in 2016~2020 exceeded 320 days,with an average excellent rate of 90%;light pollution days increased slightly,from 17 days in 2016 to 38 days in 2020;the number of days of heavy pollution has been reduced year after year.The main source of pollution in urban areas in winter is biomass combustion sources,with a contribution rate of 23.35%,followed by urban dust,soil dust,restaurant fume dust and coal-fired dust,with a contribution rate of about 10%;motor vehicle exhaust dust,construction cement dust,road dust and other least are all less than 5%.The main sources of pollution in urban areas in summer are urban dust,construction cement dust,soil dust,with a contribution rate of about 20%,followed by motor vehicle exhaust dust,road dust,restaurant fume dust,etc.,with a contribution rate between 5%and 10%;other source categories contribute less value.