Assessment of meteorology vs control measures in China fine particular matter trend from 2013–2019 by an environmental meteorology index

Abstract

Abstract. A framework was developed to quantitatively assess the contribution of meteorology variations in the trend of particular matter (PM) concentrations and to separate the impacts of meteorology from the control measures in the trend, based upon an Environmental Meteorology Index (EMI). The model-based index EMI realistically reflects the role of meteorology in the trend of PM and can also be attributed into three major factors: deposition, vertical accumulation and horizontal transports. Based on the 2013–2019 PM2.5 observation data and re-analysis meteorological data in China, the contributions of meteorology and control measures in nine regions of China were assessed separately by the EMI-based framework. Monitoring network observations show that the PM2.5 concentrations have been declined about 50 % on national average and about 35 % to 53 % for various regions. It is found that the nation-wide emission control measures were the dominant factor in the declining trend of China PM2.5 concentrations, contributing to about 47 % of the PM2.5 decrease from 2013 to 2019 on the national average and 32 % to the 52 % for various regions. The meteorology has a variable and sometimes critical contribution to the year by year variations of PM2.5 concentrations, 5 % on annual average and 10–20 % for the fall-winter heavy pollution seasons.