2015—2020年全国重污染天变化趋势及时空分布特征分析

2015—2020年,全国重污染发生天数、比例及城市数量整体呈逐年下降趋势。与2015年相比,2020年全国337个地级及以上城市重污染天数减少1 847 d,降幅达55.2%;重污染天数比例下降1.6个百分点;发生过重污染天气的城市数量减少60个。其中,全国细颗粒物重污染天数整体呈下降趋势,沙尘重污染天数随气象条件的差异波动变化,臭氧重污染天数呈波动上升趋势。"十四五"期间,消除重污染天气的主要对象仍是细颗粒物重污染。应将天山北坡城市群、"2+26"城市、汾渭平原及苏皖鲁豫交界地区作为"十四五"期间污染减排的重点关注区域。此外,需遏制"2+26"城市臭氧重污染上升势头。

Analysis on the Variation Trend and Spatial and Temporal Distribution Characteristics of Heavy Air Pollution Days in China from 2015 to 2020

From 2015 to 2020,the number of days,proportion and number of cities with heavy air pollution in China showed a decreasing trend year by year.Compared with 2015,the number of heavy air pollution days in China in 2020 decreased by 1847 days,a decrease of 55.2%,the proportion of heavy air pollution days decreased by 1.6 percentage points,and the number of cities with heavy air pollution decreased by 60.The days of heavy pollution of PM_2.5 in China showed a downward trend as a whole,and the days of heavy air pollution of sand and dust fluctuated with the difference of meteorological conditions.Ozone heavy pollution days had a fluctuating upward trend.During the 14th Five-Year Plan period,the main object of eliminating heavy air pollution days is still heavy pollution of PM_2.5.Urban agglomerations on the northern slope of Tianshan Mountains,"2 + 26" cities,Fenwei Plain and the border areas between Jiangsu,Anhui,Shandong and Henan should be the focus areas of pollution reduction,and it is necessary to contain the rising trend of ozone heavy pollution in "2 + 26" cities.