Objective To assess the effects of exposure to ambient ozone on human mortality in Nantong, China.

Methods A descriptive analysis was performed on daily data about air pollution, meteorological factors and mortality in Nantong from 2017 to 2020. Uni-pollutant and multi-pollutant generalized linear models were used to analyze the relationships between ambient ozone changes and deaths from non-accidental, respiratory, and circulatory causes as well as the lag effects.

Results The eight-hour average ozone mass concentration (O₃-8 h) in the ambient showed significant exposure-response relationships with the death tolls from non-accidental, respiratory, and circulatory causes (P < 0.05). The effect was highest for the deaths from respiratory diseases, with the maximum effect occurring at lag 1, increasing the number of deaths by 1.40% (95% CI: 0.97%-1.84%) for every 1 μg/m³ increase in O₃-8 h. When PM_2.5, nitrogen dioxide(NO₂), and sulfur dioxide(SO₂) were included in the multi-pollutant model, the O₃-8 h showed a higher effect on the deaths from respiratory diseases from 2017 to 2020 (P < 0.05).

Conclusion Ozone exposure was closely related to an increase in the risk of non-accidental death among people in Nantong from 2017 to 2020, which mainly increased the risk of death from respiratory diseases, without significant association with the risk of excess death from circulatory diseases.