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

摘要

A framework was developed to quantitatively assess the contribution of meteorology variations to the trend of fine particular matter (PM 2.5 ) concentrations and to separate the impacts of meteorology from the control measures in the trend, based upon the Environmental Meteorology Index (EMI). The model-based EMI realistically reflects the role of meteorology in the trend of PM 2.5 and is explicitly attributed to three major factors: deposition, vertical accumulation and horizontal transports. Based on the 2013–2019 PM 2.5 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 PM 2.5 concentrations have declined by about 50?% on the national average and by about 35?% to 53?% for various regions. It is found that the nationwide emission control measures were the dominant factor in the declining trend of China PM 2.5 concentrations, contributing about 47?% of the PM 2.5 decrease from 2013 to 2019 on the national average and 32?% to 52?% for various regions. The meteorology has a variable and sometimes critical contribution to the year-by-year variations of PM 2.5 concentrations, 5?% on the annual average and 10?%–20?% for the fall–winter heavy pollution seasons.