Characteristic Analysis of a Muti-Day Pollution Event and Wet Removal of Aerosols

Based on an air pollution index, conventional pollution observations, surface meteorological observations and satellite remote sensing data, the relationships between air pollution, large-scale circumfluence and boundary layer meteorology associated with this event were comprehensively analyzed. Additionally, characteristics of wet removal during precipitation were investigated by Laser Precipitation Monitor data. The results showed that:1) Stable atmospheric stratification and weak winds caused by the steady and uniform high-pressure field contributed to the occurrence, development, maintainability, and reinforcement of the pollution event. The remote transport of pollutants had a significant impact on ambient air quality of Wuhan Area; 2) Wet removal of aerosols occurred during the precipitation event. For example, the washout rate of particle pollutants was the highest, following by that of NO₂, SO₂, and CO, and the washout rate of O₃ was the smallest. By comparing the parameterization of the washout rate with the average scavenging coefficient E (Scott, 1982) and that of Wuhan, it was found the E value was around 0.25 to 0.35 in Wuhan area.