Objective To estimate the exposure-response relationship between daily circulatory disease mortality and daily particulate matter with an aerodynamic diameter ≤2.5 μm (PM_2.5) concentration in Shanghai, and analyze the excess mortality of circulatory diseases attributed to exposure to PM_2.5.

Methods The information about the daily PM_2.5 concentration and the incidence data of circulatory disease death in Shanghai from 2013 to 2020 were collected. The trends of daily PM_2.5 concentration and circulatory mortality were analyzed by using the auto-regressive integrated moving average model. The risk of premature death due to short-term exposure to PM_2.5 was investigated by using the generalized additive model of Poisson distribution. The excess circulatory disease mortality was calculated by using acute health risk assessment model for short-term exposure to air pollution.

Results During the study period a total of 398400 deaths due to circulatory diseases occurred in Shanghai, accounting for 40.27% of total recorded deaths, and the median number of daily deaths attributed to circulatory disease was 131. Atmospheric PM_2.5 concentrations in Shanghai exhibited a general decline, with the median daily atmospheric PM_2.5 concentration decreasing by 48.98% from 2013 to 2020. Both daily circulatory disease mortality and daily PM_2.5 concentration exhibited clear seasonal patterns, with peak in winter and valley in summer, and there was a significant positive correlation between these two variables on a seasonal basis. The risk for death from circulatory diseases was observed to rise by 0.22% for per 10 μg/m³ increase in PM_2.5 concentration (95% confidential interval: 0.02%−0.42%). The risk for mortality from circulatory diseases associated with PM_2.5 exposure was found to increase in individuals aged 45−65 years compared with those in other age groups. During the study period, the atmospheric PM_2.5 concentration in 67.80% of the days exceeded the limit recommended by World Health Organization (WHO) (25 μg/m³) in Shanghai. During the study period, there were 4 910 excess circulatory disease death cases attributed to exceeded PM_2.5 level.

Conclusion Elevated atmospheric PM_2.5 concentrations are associated with an increased risk of excess mortality from circulatory diseases. From 2013 to 2020, the annual excess mortality attributed to exposure to PM_2.5 declined in Shanghai, indicating a significant public health achievement in air pollution prevention and control. However, the highly exceeded PM_2.5 concentration based on WHO recommendation in Shanghai during the study period highlighted the need for continuous improvement of air pollution control and disease prevention.