降雨对长三角区域PM2.5浓度的影响

Influence of Rainfall on PM2.5 Concentration in Yangtze River Delta Region

利用WRF-CAMx模式分析首届中国国际进口博览会(简称进博会)期间一次降雨过程对长三角地区PM2.5浓度影响,结果表明,降雨量分布区域与因降雨造成的PM2.5浓度减少量分布区域并不完全一致,湿沉降量受降雨量、PM2.5浓度和风速等多个因素共同影响。数值模拟结果表明,降雨导致浓度下降幅度排前5位的组分分别是有机气溶胶、硫酸盐、硝酸盐、铵盐和细颗粒原生气溶胶,下降幅度分别为44. 28%、16. 55%、11. 55%、9. 53%和5. 23%。结合观测资料和数值模式模拟结果可知,首届进博会期间上海本地减排和周边区域协同控制作用使PM2.5日均质量浓度降低33. 23μg/m3,因降雨引起的湿沉降作用使上海市PM2.5质量浓度降低15. 88μg/m^3。

The influence of precipitation on PM2.5 concentration in the Yangtze River Delta region was analyzed with WRF-CAMx model during the China International Import Expo in 2018. The conclusions showed that the distribution area of precipitation was not completely consistent with the distribution area of reduced PM2.5 concentration due to precipitation. Reduced PM2.5 concentration due to precipitation was correlated with precipitation,PM2.5 concentration,wind speed and et al. Numerical simulation results showed that the top five components of concentration decrease caused by precipitation were organic aerosol,sulphate,nitrate,ammonium salt and fine primary aerosol,and the decreases were 44. 28%,16. 55%,11. 55%,9. 53% and 5. 23%,respectively. Combined with observation data and numerical model simulation results,it can be known that the average daily PM2.5 concentration decreases 33. 23 μg/m^3 due to Shanghai local emission reduction strategy and reduction of external pollution transportation,15. 88 μg/m3 due to wet deposition during the Expo.