Spatiotemporal Distribution and Health Impacts of PM2.5 and O3 in Beijing, from 2014 to 2020

In China, fine particulate matter (PM2.5) and tropospheric ozone (O3) have become major air pollutants that threaten human health. Since 2013, the government has strengthened air pollution controls in Beijing and achieved significant effects. A spatial-temporal analysis was conducted of the distribution and health impacts of PM2.5 and O3 in Beijing, using data collected from 34 air quality monitoring sites between 2014 and 2020. In 2014, the annual average PM2.5 and seasonal (April to September) average of daily one-hourly maximum O3 concentrations (O3_max) were 92.0 μg•m-3 and 81.9 nmol•mol-1, respectively. From 2014 to 2020, annual average PM2.5 decreased at a rate of 7.5 μg•m-3. However, there was no significant difference in O3_max over the years. The concentrations of PM2.5 were highest in December and January (in winter) and lowest in August (in summer). On the contrary, O3_max was highest in June. The diurnal variations of PM2.5 were affected by meteorological conditions and emission sources, and maximum concentrations occurred between 22: 00 to 00: 00, while minimum concentrations occurred between 14: 00 to 16: 00. The concentration of O3_max showed an opposite pattern, with minimum vales occurring at 07: 00 and maximum values occurring in the afternoon. The spatial distribution of PM2.5 showed similar patterns in 2014 and 2019, with the south of Beijing exhibiting the highest concentrations, and the north the lowest. The concentration of O3_max was higher in suburban areas than in traffic areas. In terms of health impacts, 1 580 cases of cardiovascular disease and 821 of respiratory disease were attributed to PM2.5 in 2014, while 2 180 cases of respiratory disease were attributable to O3 in 2014. In 2019, mortalities attributable to PM2.5 had decreased by 50% compared to 2014. While the number of disease cases attributable to O3 were similar in 2014 and 2019. the results indicate that PM2.5 pollution in Beijing has been successfully controlled, while O3 pollution has become more severe, and was the primary air pollutant threatening human health in 2019. Therefore, the synchronous control of PM2.5 and O3 should be implemented in the future. © 2021, Science Press. All right reserved.