Abstract: Based on hourly meteorological and environmental observation data from Cangzhou of Hebei Province from 2014 to 2019, the influences of precipitation on atmospheric pollutant concentration were further discussed by using wind and background concentration correction method. The results show that the correction method about wind and background concentration could better remove the own diurnal variation characteristics of pollutant concentration and eliminate the influence of wind speed, and the influence of precipitation on atmospheric pollutant concentration could be acquired more accurately. Under the condition of wind force and background concentration correction, the removal effect of rainfall on PM_2.5, PM₁₀, O₃ and NO₂ was better, but for SO₂ and CO it wasn’t obvious. The removal effects of rainfall with different intensities on PM_2.5, PM₁₀ and NO₂ were better, and the removal rate increased with enhance of rainfall intensity. The removal effect of rainfall intensity less than 8.0 mm·h^-1  on O₃ was significant, while the rainfall intensity above 6.0 mm·h^-1 had removing effect on SO₂. With the duration of rainfall, the mass concentration of PM_2.5, PM₁₀, NO₂ and O₃ continuously decreased, and the removal efficiency dropped, the removal effect wasn’t obvious when the mass concentration of pollutant dropped to a certain threshold.

Key words: precipitation, air pollutant, removal capacity, wind and background concentration correction, concentration change rate

摘要： 基于2014—2019年河北沧州逐小时气象与环境监测数据，采用风力+背景浓度订正方法，进一步探讨降水对大气污染物浓度的影响。结果表明：风力+背景浓度订正方法可以较好地消除污染物浓度自身的日变化特征，并剔除了风的影响，从而更准确地获取降水对大气污染物浓度的影响。在风力+背景浓度订正条件下，降雨对PM_2.5、PM₁₀、NO₂、O₃有较好的清除作用，而对SO₂、CO的清除作用不明显。不同强度降雨对PM_2.5、PM₁₀、NO₂均具有较好的清除作用，且清除率随着雨强的增强而增大；雨强小于8.0 mm·h^-1的降雨对O₃有显著清除作用，而大于6.0 mm·h^-1的降雨对SO₂有清除作用。伴随着降雨的持续，PM_2.5、PM₁₀、NO₂、O₃质量浓度不断下降，降雨清除效率也随之降低，当污染物质量浓度降至一定阈值后降雨清除作用不明显。

关键词: 降水, 大气污染物, 清除能力, 风与背景浓度订正, 浓度变化率