Risk assessment on ambient ozone exposure-related circulation system mortality among residents in Fuzhou city

  Objective  To investigate the effect of ambient ozone (O₃) exposure on mortality risk of circulatory diseases among residents in Fuzhou city.

  Methods  We collected three sets of daily data for Fuzhou city from January 1, 2015 to December 31, 2018: 1) average concentration of O₃ maximum in 8 hours (O_3-8h), particulate matter < 2.5 μm in aerodynamic diameter (PM_2.5), particulate matter < 10 μm in aerodynamic diameter (PM₁₀), nitrogen dioxide (NO₂), sulfur dioxide (SO₂); 2) average ambient temperature, humidity, atmospheric pressure; and 3) the number of deaths due to circulatory system diseases in Fuzhou city. The correlation between O_3-8h and circulatory system mortality was analyzed using generalized additive model (GAM). Based on a health risk model for short-term O₃ exposure, the excess circulatory death associated with O_3-8h among the residents in Fuzhou city was evaluated.

  Results  During 2015 – 2018 for the city, the average daily concentration of O_3-8h was 86.77 ± 34.13 ug/m³; the average mortality rate of circulatory disease was 2.015‰; and the daily number of circulatory disease death was 11.30 ± 3.99 and the daily number of death due to ischemic heart disease and cerebrovascular disease were 2.75 ± 1.83 and 4.87 ± 2.39, respectively. Based on the single pollutant model, a 10 μg/m³ increase in O_3-8h concentration is correlated with a lag day 2 increment of 0.89% (95% confident interval 95% CI: 0.33% – 1.46%) for circulatory mortality and 1.49% (95% CI: 0.66% – 2.32%) for cerebrovascular mortality. The estimated overall excess mortality contributed to ambient O₃ exposure is 118 (95% CI: 44 – 191) for circulatory diseases and 81 (95% CI: 36 – 126) for cerebrovascular diseases among the residents in Fuzhou city during the 4-year period.

  Conclusion  Short-term exposure to ambient ozone could increase mortality risk due to circulatory and cerebrovascular diseases.