Analysis on the Influence of Precipitation and Wind on PM2.5 Concentration in Suzhou
In order to understand the impacts of precipitation and wind on PM2.5 concentration in Suzhou,daily data of precipitation,wind and air quality from 2018 to 2022 are used to analyse monthly variation characteristics of precipitation and PM2.5 concentration in Suzhou and the effects of daily precipitation intensity,durationwind direction and speed on PM2.5 concentration.The results indicate that precipitation has a certain wet removal effect on PM2.5.Average concentration of PM2.5 in rainy days throughout the year is 21％lower than that in non-rainy days,with the most significant effects in January,February,November and December.The magnitude and duration of daily precipitation affects its wet removal efficiency.When the magnitude of daily precipitation reaches the level of moderate rain or above,the number of samples of ρ(PM2.5)decreases more than 60％of the total number of samples,and the wet removal efficiency of precipitation significantly increases with the increase of the level.When precipitation duration exceeds 6 hours,the improvement effects on pollutant concentration is significant,with the number of samples of ρ(PM2.5)decreases more than 50％of the total number of samples.The clearance effect of different wind directions and wind speeds also varies.Southwest wind with high temperature and humidity is most likely to cause haze pollution in Suzhou in the case of low wind speed.When the northwest wind speed exceeds 4 m/s,PM2.5 concentration increases due to the southward diffusion of polluted air masses in front of the cold front.For the other three wind directions,namely,northeast,southwest,and southeast,it has an effective dry cleaning effect on pollutants when wind speed exceeds 5 m/s.
NETL
NSTL
万方数据
