Analysis of the meteorological impact on PM2.5 pollution in Changchun based on KZ filter and WRF-CMAQ

During the “13th Five Year Plan” period, the nationwide mean concentration of PM2.5 in 2020 decreased by 28.8% compared to that in 2015. Exploring the relative impact of anthropogenic emission control and meteorological conditions to the reduction in PM2.5 concentration is a key step in further ensuring the accuracy of plans for the control of atmospheric environmental problems. In this study, the KZ filter and WRF-CMAQ model were used to quantitatively evaluate the relative impact of anthropogenic emission control and meteorological conditions to the decline in PM2.5 concentration. The KZ filter results show that the changes in PM2.5 concentration in Changchun were mainly caused by the short-term (45.95%–54.74%) and seasonal (31.62%–42.65%) fluctuations of pollution precursor emissions and meteorological conditions, and the average decline rate for the PM2.5 concentration after meteorological adjustment (3.36) is lower than that of the original data (3.74). Based on the KZ filter results, the relative impact proportions of meteorological conditions and anthropogenic emission control to the decline in PM2.5 concentration in Changchun are 11.36% and 88.64%, respectively, while the numerical simulation results of the WRF-CMAQ model show values of 14.79% and 85.21%, respectively. The results of both methods indicate that, although both meteorological conditions and anthropogenic emission control are conducive to the improvement of the atmospheric environment, anthropogenic emission control played a major role in the decline in PM2.5 in Changchun from 2015 to 2020, and the impact of meteorological conditions is relatively limited.