To study the wet removal effect of rainfall on the air pollutants in Sichuan Basin, the WRF-Chem model is adopted to simulate the changes of air pollutant concentrations before and after a rainfall episode. The results show that continuous rainfall with small-magnitude rainfall (0.3–0.5 mm h⁻¹) has an obvious effect in reducing the concentrations of PM_2.5, PM₁₀, SO₂ and NO₂ except for O₃. There is an upper limit of the impact of continuous rainfall on air pollutants. The reduction of concentrations of particulate pollutants at the level of 300–2500 m is due to its participation in the nucleation process. When rainfall occurs and vertical diffusion is not restricted, the concentration of pollutants on the ground are reduced more quickly by being transported to high altitude. In urban areas with near-surface inversion, there is an anti-correlation between concentrations and wind speed. The correlation coefficients for the concentrations of PM_2.5, PM₁₀, SO₂ and NO₂ with the wind speed are −0.85, −0.86, −0.77 and −0.82, respectively. In suburban stations with the small initial concentrations, the decrease of concentrations is mainly due to the increase of rainfall intensity, but has little relationship with the height of PBL and the wind speed. The small gradient of sea level pressure (less than 1 hPa) and the near-surface inversion in the Chengdu Plain are conducive to the accumulation of air pollutants.

为了研究降雨对四川盆地大气污染物的除湿效果，采用WRF-Chem模型模拟了降雨前后空气污染物浓度的变化。结果表明，连续降雨和小幅度降雨（0.3–0.5 mm h ^-1）对降低PM _2.5，PM ₁₀，SO ₂和NO ₂的浓度具有明显的影响，但O ₃除外。。连续降雨对空气污染物的影响有一个上限。颗粒污染物浓度降低了300–2500 m，这是由于其参与了成核过程。当发生降雨并且垂直扩散不受限制时，通过将其运输到高海拔地区，可以更快地降低地面上污染物的浓度。在近地表反演的城市地区，浓度与风速之间存在反相关关系。PM _2.5，PM ₁₀，SO ₂和NO ₂浓度的相关系数风速分别为-0.85，-0.86，-0.77和-0.82。在郊区，初始浓度较小，其浓度下降主要是由于降雨强度的增加，而与PBL高度和风速关系不大。成都平原海平面压力梯度小（小于1 hPa）和近地表反演有利于大气污染物的积累。