Drivers of alleviated PM2.5 and O3 concentrations in China from 2013 to 2020

Since 2013, the Chinese Government implemented '' Clean Air Action '' Phase I (2013-2017) and Phase II (2018-2020) consecutively to improve air quality. However, it remains unclear how these policies have impacted air quality since most studies merely focus on Phase I. In this study, we applied the Community Multiscale Air Quality (CMAQ) model to investigate variations of air quality in China during '' Clean Air Action '' Phases I and Phase II (2013-2020). Results show that PM2.5 is significantly reduced (-40%) across China except in summer. O-3 concentration also decreases, but a 3% increase is found in the Beijing-Tianjin-Hebei (BTH) region. Emission changes play a dominant role in the reduction of PM2.5 (over 95%). The contributions from meteorology and emissions to O-3 reduction are 46% and 54%, respectively. Our results suggest that a more effective emission abatement strategy should be formulated, aiming to control O-3 and PM2.5 synergistically.

Automated summary

This study used the CMAQ model to investigate air quality variations in China during the '' Clean Air Action '' Phase I and Phase II. The results show a significant reduction in PM2.5 across the country, except in summer, and a decrease in O-3 concentration, with a 3% increase found in the Beijing-Tianjin-Hebei region. Emission changes played a dominant role in PM2.5 reduction, while meteorology and emissions contributed equally to O-3 reduction.