To mitigate the serious levels of air pollution in China, the State Council of China issued the Air Pollution Prevention and Control Action Plan (APPCAP) in 2013. This policy is a milestone in air quality control in China. We aimed to evaluate the effects of the APPCAP on long-term air quality management and the related health impacts in China. We did an analysis of national air quality monitoring and mortality data to estimate the health impact of the APPCAP from 2013 to 2017 in 74 key cities in China. Changes in mortality and in years of life lost (YLL), an indicator that considers life expectancy at death, were calculated to assess the health impact of air quality management during the 5-year period. Between 2013 and 2017, annual average concentrations of PM2·5 decreased by 33·3% (95% CI 16·3-50·3), PM10 by 27·8% (8·0-47·5), sulphur dioxide by 54·1% (28·2-80·0), and carbon monoxide by 28·2% (3·1-53·3) in the 74 key cities. However, no significant change was seen in annual average concentrations of nitrogen dioxide (9·7% reduction; 95% CI -23·0 to 42·4) or ozone (20·4% increase; -30·1 to 71·0). In 2017, as a result of substantial improvements in air quality, there were 47 240 (95% CI 25 870-69 990) fewer deaths and 710 020 (420 230-1 025 460) fewer YLL in the 74 key cities in China than in 2013. Substantial reductions in mortality and YLL related to control of ambient air pollution were achieved from 2013 to 2017 in China, indicating appreciable effectiveness of China's APPCAP. However, emissions control efforts for ozone and nitrogen dioxide should be strengthened in the future. National Natural Science Foundation of China and the National Key Research and Development Program of China.

Importance: Air pollution is increasingly recognized as an important environmental risk factor for mental health. However, epidemiologic evidence on long-term exposure to low levels of air pollutants with incident depression and anxiety is still very limited.Objectives: To investigate the association of long-term joint exposure to multiple air pollutants with incident depression and anxiety.Design, Setting, and Participants: This prospective, population-based cohort study used data from the UK Biobank. The participants were recruited between March 13, 2006, and October 1, 2010, and included individuals who had never been diagnosed with depression or anxiety at baseline and had full information on exposure and covariates. Data were analyzed from May 1 to October 10, 2022.Exposures: Annual mean air pollution concentrations of particulate matter (PM) with aerodynamic diameter of 2.5 μm or less (PM_2.5) and PM with aerodynamic diameter between 2.5 μm and 10 μm (PM_2.5-10). Nitrogen dioxide (NO₂) and nitric oxide (NO) were estimated for each participant’s residential address using the land use regression model, and joint exposure to air pollution reflected by air pollution score was calculated by principal components analysis.Main Outcomes and Measures: Incidence of diagnosed depression (F32-F33) and anxiety (F40-F48) were ascertained with International Statistical Classification of Diseases and Related Health Problems, Tenth Revision codes.Results: During a median (IQR) follow-up of 10.9 (10.1-11.6) years, among 389 185 participants (mean [SD] age, 56.7 [8.1] years, 205 855 female individuals [52.9%]), a total of 13 131 and 15 835 patients were diagnosed with depression and anxiety, respectively. The median (IQR) concentration of pollutants was as follows: PM_2.5, 9.9 (9.3-10.6) μg/m³; PM_2.5-10, 6.1 (5.8-6.6) μg/m³; NO₂, 26.0 (21.3-31.1) μg/m³; and NO, 15.9 (11.6-20.6) μg/m³. Long-term estimated exposure to multiple air pollutants was associated with increased risk of depression and anxiety, and the exposure-response curves were nonlinear, with steeper slopes at lower concentrations and plateauing trends at higher exposure. The hazard ratios (HRs) and 95% CIs for depression and anxiety were 1.16 (95% CI, 1.09-1.23; P < .001) and 1.11 (95% CI, 1.05-1.17; P < .001) in the highest quartile compared with the lowest quartile of air pollution score, respectively. Similar trends were shown for PM_2.5, NO₂, and NO. Subgroup analysis showed the association between PM_2.5 and anxiety tended to be higher in male individuals than in female individuals (quartile 4: male individuals, 1.18; 95% CI, 1.08-1.29; female individuals, 1.07; 95% CI, 1.00-1.14; P = .009).Conclusions and Relevance: Study results suggest that estimates of long-term exposure to multiple air pollutants was associated with increased risk of depression and anxiety. The nonlinear associations may have important implications for policy making in air pollution control. Reductions in joint exposure to multiple air pollutants may alleviate the disease burden of depression and anxiety.