长沙市大气污染特征的气象条件分析

Analysis of meteorological conditions of air pollution characteristics in Changsha City

本文利用长沙市2015—2019年长沙市空气质量数据,分析长沙市大气污染的时空分布特征。结果表明:(1)2015—2019年,长沙市大气首要污染物为PM_(2.5)、O_(3)、PM_(10)、NO_(2)四种,其中PM_(2.5)和O_(3)两者占比超过85%,4月和10月首要污染物的占比发生转折;O_(3)浓度逐年上升,其他污染物浓度不同程度下降。(2)PM_(2.5)、PM_(10)、NO_(2)浓度的季(月)变化相似,由高到低为:冬季、秋季、春季、夏季,冬季显著高于其他季节;1—7月下降,8月上升,9月下降,10—12月上升;PM_(2.5)、PM_(10)浓度1月最大,NO_(2)浓度12月最大。O_(3)浓度由高到低为:夏季、春季、秋季、冬季,9月浓度最高。各污染物浓度日变化特征明显。(3)空间分布上,PM_(2.5)、PM_(10)、NO_(2)呈“中部高南北低”的分布特征;O_(3)的浓度呈单低值中心分布,火车新站为显著低值中心,首要污染物的浓度分布受城市的产业布局影响大。(4)O_(3)已经成为长沙市当前的主要污染物之一,未来需加强PM_(2.5)和O_(3)的协同治理。

Based on the air quality data of Changsha city from 2015 to 2019,this paper analyzes the spatial and temporal distribution characteristics of primary atmosphere pollutants in Changsha city.The results indicate that,(1)From 2015 to 2019,the primary pollutant in Changsha urban area were PM_(2.5),O_(3),PM_(10) and NO_(2),of which PM_(2.5) and O_(3) accounted for more than 85%of the total,and the proportion of pollutants changed in April and October.The concentration of O_(3) increased year by year,while the concentration of other pollutants decreased in various degrees.(2)Seasonal(monthly)changes in PM_(2.5),PM_(10),NO_(2) concentrations were similar,from high to low in seasons as:winter,autumn,spring,summer.Concentrations in winter is significantly higher than in other seasons.Concentraions decreased from January to July,increased in August,decreased in September and increased from October to December.The seasonal order of O_(3) concentration is:summer,spring,autumn,winter,and the concentration is the highest in September.The daily variation of pollutant concentrations are obvious.(3)In terms of spatial distribution,the concentrations of PM_(2.5),PM_(10) and NO_(2) were higher in central section and lower in northern and southern section.The concentration of O_(3) is distributed as a single low value center,and the railway station is a significant low value center.The concentration distribution of primary pollutants is greatly affected by the industrial layout of the city.(4)The O_(3) had become one of the major pollutants,in the future,collaborative governance of PM_(2.5) and O_(3) should be strengthened.