Health impacts attributable to ambient PM2.5 and ozone pollution in major Chinese cities at seasonal-level.

Increasing ambient ozone pollution in China has caused widespread concern. It is necessary to strengthen ozone pollution control and promote PM 2.5 and ozone's coordinated management in China. This study assessed the PM 2.5 - and ozone-related health impacts of 100 major Chinese cities in fourteen seasons of 2017 (60 cities studied), 2018, 2019, and the first half of 2020. We found 6.68 × 107 disability-adjusted life years (DALYs) and 3.72 × 107 DALYs attributable to ambient PM 2.5 and ozone pollution in the 100 major cities. High PM 2.5 -related health impacts mostly appeared in winter and north, while high ozone-related mostly in summer and south. In the winter of 2019, the total PM 2.5 -related health impact of 100 major cities accounted for 98.67% of the sum of PM 2.5 - and ozone-related. The proportion in the summer of 2019 was only 23.15%. We also found a north-south differentiation of PM 2.5 - and ozone-related health impacts in spring and autumn. Taking the Yangtze River Basin as the dividing zone, PM 2.5 was generally the primary attribution of health impacts in the north in spring and autumn. To the south of the Yangtze River, ozone-related health impacts were generally dominant. The attempt to introduce seasonal population data in the health impact assessment provided a reference. Population movements relatively influenced the seasonal health impacts of developed urban agglomerations. The present study could help in the policy implementation of PM 2.5 - and ozone-related health risk prevention. [Display omitted] • PM 2.5 -related health impacts of China's major cities are assessed at the season-level. • Ozone-related health impacts of China's major cities are assessed at the season-level. • We attempt to introduce seasonal population data in health impact assessment. • We conduct a comparative analysis of health impacts at the season-city level. [ABSTRACT FROM AUTHOR]