Contrasting emission trends between the two phases of China’s clean air actions from 2013–2020

Abstract China’s clean air actions since 2013 have led to dramatic changes in air pollutant emissions and surface air quality. Here, we investigated the trends and drivers of air pollutant emissions during the two phases of clean air actions (i.e., Phase I from 2013–2017 and Phase II from 2018–2020) in China. We estimated decreasing trends of nonmethane volatile organic compound (NMVOC) and NH3 emissions after 2017, representing the success of targeted policies for these pollutants during Phase II. However, regarding other pollutants, the emission reduction during Phase II were slowing down compared to those during Phase I. Although Phase II emphasized structural adjustment, end-of-pipe emission control measures remained the major drivers of emission reduction throughout the two phases. We thus recommend more active structural adjustment policies targeting the transition of the energy system in China.