“十三五”恩施环境空气质量特征及污染来源分析

Analysis of Environmental Air Quality Characteristics and Pollution Sources in Enshi Prefecture During the 13th Five-Year Plan Period

“十三五”期间,恩施州环境空气质量逐年变好,环境空气综合指数逐年降低,环境空气优良率不断提高,“十三五”末,恩施州空气质量已达到国家二级标准。2020年,恩施州平均优良天数已达352 d,平均优良天数比例为97.6%,首要污染物为细颗粒物(PM_(2.5))。对春、夏、秋、冬不同季节的空气污染物来源进行了解析,结果发现:州城恩施市细颗粒物(PM_(2.5))组分来源贡献率最高的均为机动车尾气,年均占比为38.5%,VOCs 4个季节里来源贡献率最高的也是机动车尾气排放,年均占比为30.6%。

During the"13th Five-Year Plan"period,the ambient air quality of Enshi Prefecture has been improving year by year;the ambient air comprehensive index has been decreasing year by year,and the excellent and good rate of ambient air has been increasing.At the end of the"13th Five-Year Plan",the air quality of Enshi Prefecture has reached the national second-class standard.In 2020,the average number of good days in Enshi Prefecture reached 352,accounting for 97.6 percent.The primary pollutant is fine particulate matter(PM_(2.5)).Through the analysis of the sources of air pollutants in spring,summer,autumn and winter,it was found that the highest contribution rate of fine particulate matter(PM_(2.5))components in Enshi City was motor vehicle exhaust,accounting for 38.5%annually,and the highest contribution rate of VOCs in the four seasons was motor vehicle exhaust,accounting for 30.6%annually.