[Acute effect of air pollutants (carbon monoxide and ozone) on myocardial infarction mortality in Ningbo].

Objective: To explore the effect of carbon monoxide (CO) and ozone (O(3)) in the air on the myocardial infarction mortality in Ningbo, Zhejiang province, from 2011 to 2015. Methods: The data of daily air quality surveillance and the causes of deaths in Ningbo from January 1, 2011 to December 31, 2015 were collected and the time series study using a generalized additive model was conducted to evaluate the relationship between the mortality of myocardial infarction and the air pollutants after adjustment for the long-term trend of death, weather conditions," days of the week" and other confounding factors. Results: The daily average concentrations of CO and O(3) in Ningbo during 2011-2015 were 0.90 (0.02-3.31) mg/m(3) and 82.78 (4-236) μg/m(3), respectively. A total of 5 388 myocardial infarction deaths occurred, with a daily average of 3 deaths. In single-pollutant model, an increase of 0.1 mg/m(3) in average concentration of CO could increase the risk of myocardial infarction mortality by 1.06% (95 % CI : 0.29%-1.93%) in general population, and by 1.26% (95 % CI :0.28%-2.24%) in aged people aged ≥65 years in lagged 6 days, but the influence was not significant in people aged <65 years. The influence had no significant difference in males, but it increased the risk of myocardial infarction mortality by 1.77% in females (95 % CI : 0.44%-3.13%). In multi-pollutant model, CO did remain robust after adjusting for other co-pollutants. Whereas the effect of O(3) had no significant influence. Conclusion: These findings suggested that the increased risk of daily myocardial infarction mortality was associated with the increase of CO concentration, but no such association was found for O(3) in Ningbo.