摘要
通过2015—2018年常州市逐时的PM_(2.5)、PM_(10)数据及降水资料,研究降水对大气颗粒物的湿清除特征、雨后PM_(2.5)的增长速度及PM_(2.5)低浓度持续时间规律。结果表明:(1)对PM_(2.5)和PM_(10)有正清除作用的降水量占比分别为79.9%和82.7%。降水对PM_(2.5)和PM_(10)的湿清除量分别占PM_(2.5)和PM_(10)年均值的1.6%和1.9%。冬季和春季颗粒物的湿清除总量较大,夏季和秋季较小。(2)降水强度和雨前颗粒物浓度均较低时,降水过程易导致颗粒物浓度不降反升。(3)雨后PM_(2.5)增长速度的月度变化规律呈“U”形分布。1月雨后PM_(2.5)小于75μg/m^(3)的持续时间较短(13.4 h),4—10月则大于30 h。(4)总体上,随着雨后PM_(2.5)升高,PM_(2.5)小于75μg/m^(3)的持续时间缩短,PM_(2.5)增长速度加大。当雨后PM_(2.5)>50μg/m^(3)时,PM_(2.5)增至75μg/m^(3)以上仅需7~11 h。雨后PM_(2.5)>45μg/m^(3)时,PM_(2.5)易快速反弹。
The characteristics of wet scavenging on atmospheric particulate matter,the growth rate and the duration of low concentration of PM_(2.5)after rain periods were analyzed by using the hourly data of PM_(2.5),PM_(10)and precipitation in Changzhou from 2015 to 2018.The results showed that:(1)the average percentage of positive precipitation,which could alleviate particulate matter concentration,were 79.9%and 82.7%for PM_(2.5)and PM_(10).The influences of wet scavenging by precipitation on annual average concentration of PM_(2.5)and PM_(10)were 1.6%and 1.9%,respectively.The amounts of particulate matter by wet scavenging in winter and spring were higher than those of summer and autumn.(2)When the precipitation intensity and the particulate matter concentration before the precipitation were both low,the wet scavenging had a greater chance for negative effect.(3)The monthly variation of growth rate of PM_(2.5)after precipitation was“U”-shaped.PM_(2.5)after precipitation could easily rose to 75μg/m^(3) in January with an average of 13.4 h period,and it was more than 30 h from April to October.(4)Overall,the higher of the PM_(2.5)after precipitation,the shorter of the duration below 75μg/m^(3),and the greater of the growth rate of PM_(2.5).When PM_(2.5)was larger than 50μg/m^(3) after precipitation,it could increase to more than 75μg/m^(3) in only 7-11 h.If PM_(2.5)was larger than 45μg/m^(3) after precipitation,PM_(2.5)was more likely to rebound quickly.
作者
何涛
彭燕
雷正翠
HE Tao;PENG Yan;LEI Zhengcui(Changzhou Environmental Monitoring Center of Jiangsu Province,Changzhou Jiangsu 213001;Chang zhou Meteorological Bureau of Jiangsu Province,Changzhou Jiangsu 213022)
出处
《环境污染与防治》
CAS
CSCD
北大核心
2021年第9期1114-1117,1123,共5页
Environmental Pollution & Control
基金
国家自然科学基金青年科学基金项目(No.21607016)
常州市科技局应用基础研究计划项目(No.CJ20180039)
江苏省常州环境监测中心培新项目(No.201806-PX)。
关键词
大气污染
有效降水
湿清除
雨后PM_(2.5)
增长
降水强度
atmospheric pollution
effective precipitation
wet scavenging
increase of PM_(2.5)after rain
precipitation intensity
