郑州市降水对大气污染物浓度的影响分析

Analysis of the influence of precipitation on air pollutants’concentration in Zhengzhou

基于2017-2020年郑州市空气质量监测数据和同期地面气象观测资料,采用数理统计方法,分析了郑州市降水对空气质量和大气污染物浓度的影响。结果表明,有降水时的空气质量等级为优和良的频率比无降水时的频率高,且降水量级越大空气质量越好。除SO_(2)外,郑州市其他大气污染物PM_(2.5)、PM_(10)、NO_(2)、O_(3)和CO在降水天气后浓度降低时次占比为42.97%~56.12%,其中PM10浓度降低最明显,CO最不明显。小时降水量越大,污染物浓度降低值越小,PM_(2.5)和PM_(10)在降雨天气后浓度降低时次占比越大,当小时降水量(R)>1 mm时,浓度降低时次占比显著高于升高时次占比,且粒径越大效果越好;SO_(2)没有明显变化规律;NO_(2)和CO变化不大。降水天气前大气污染物浓度越高,降水天气后浓度降低值的范围越大;同时浓度降低时次占比也越大(NO_(2)除外)。在小时降水量较大、大气污染物浓度较高时开展人工增雨作业,可以有效改善空气质量,特别是PM_(2.5)和PM_(10)浓度的降低最为显著。

Based on the air quality monitoring data of Zhengzhou from 2017 to 2020 and the surface meteorological observation data of the same period,the influence of precipitation on air quality and atmospheric pollutants’concentration in Zhengzhou was analyzed by using a mathematical statistics method.The results showed that the frequency of excellent and good air quality grades was higher with precipitation than without precipitation.And the higher the precipitation grade was,the better the air quality was.Except for SO_(2),the concentration of the other air pollutants PM_(2.5)、PM_(10)、NO_(2)、O_(3),and CO in Zhengzhou decreased with a proportion of 42.97%~56.12% after precipitation,among which the concentration of PM_(10) decreased most obviously,the reduction of CO concentration was least obvious.The greater the hourly rainfall was,the smaller the reduction value of pollutant concentration was,and the greater the proportion of PM_(2.5),and PM_(10) concentration reduction after the rainfall was,when the hourly rainfall(R)was>1 mm,the proportion of hourly decreasing concentration was significantly higher than that of increasing concentration,and the larger particle size was,the better the effect was.SO2 had no obvious change rule;NO2 and CO didn’t change much.The higher the concentration of air pollutants was before the precipitation,the larger the range of concentration reduction value was after the rainfall;at the same time,the greater the percentage of hourly decreasing concentration was(except for SO_(2)).When the hourly precipitation intensity was high and the concentration of air pollutants was high,artificial precipitation could effectively improve the air quality,especially for the reduction of PM_(2.5) and PM_(10) concentration.