Abstract
China's rapid industrialization and urbanization have led to poor air quality, and air pollution has caused great concern among the Chinese public. Most analyses of air pollution trends in China are based on model simulations or satellite data. Studies using field observation data and focusing on the latest data from environmental monitoring stations covering the whole country to assess the latest trends of different pollutants in different regions are relatively rare. The State Council of China promulgated the toughest-ever Air Pollution Prevention and Control Action Plan (Action Plan) in 2013. This led to a major improvement in air quality. We use the hourly Air Quality Index (AQI) and mass concentrations of PM2.5, PM10, CO, NO2, O3, and SO2 in 362 cities from 2015 to 2019, obtained from the Ministry of Ecology and Environment, to study their temporal and spatial changes and assess the effectiveness of the policy on the atmospheric environment since its promulgation and implementation. We found that the national and regional air quality in China continues to improve, with PM2.5, PM10, AQI, CO, and SO2 exhibiting negative trends. However, O3 and NO2 pollution is an urgent problem that needs to be solved and the current control strategy for PM2.5 will only partially reduce the PM2.5 pollution in the western region. Although the implementation of "Action Plan" measures has effectively improved air quality, China's air pollution is still serious and far from the WHO standard. Implementing measures for continuous and effective emissions control is still a top priority.