Effect of short-term exposure to PM₁₀ on mortality of cardiovascular diseases in Nanjing

Background Studies on the relationship between PM₁₀ pollution and population health have been widely reported. Most studies only focus on the death risks of respiratory and circulatory diseases, rather than specific cardiovascular diseases which also deserve concern, linked to PM₁₀ pollution.

Objective This study explores the effect of short-term exposure to PM₁₀ on mortality of cardiovascular diseases in Nanjing.

Methods Daily deaths from cardiovascular diseases, daily average concentrations of air pollutantsincluding coarse particles (PM₁₀), sulfur dioxide (SO₂), nitrogen dioxide (NO₂), carbon monoxide (CO), ozone (O₃), and fine particles (PM_2.5), and meteorological factors (including temperature and relative humidity) from January 1, 2014 to December 31, 2018 in Nanjing were collected to analyze the relationship between season-specific (cold season:October to next March; warm season:April to September) PM₁₀ concentration and daily cardiovascular mortality by time-series analysis, and the effect sizes in different gender, age, and educational level groups.

Results The average concentrations of PM₁₀, SO₂, NO₂, CO, O₃, and PM_2.5 were (91.6±52.2) μg·m^-3, (17.7±9.9) μg·m^-3, (45.5±18.6) μg·m^-3, (0.9±0.3) mg·m^-3, (100.8±49.1) μg·m^-3, and (52.5±34.7) μg·m^-3, respectively. The results of PM₁₀, NO₂, and PM_2.5 exceeded the national class Ⅱ limits. For each 10 μg·m^-3 increase in PM₁₀ concentration at annual level, the mortality risks of cardiovascular diseases, hypertension, acute myocardial infarction, and other ischemic heart diseases increased by 0.88% (95% CI:0.58%-1.18%), 1.74% (95% CI:0.96%-2.52%), 0.97% (95% CI:0.46%-1.49%) and 0.79% (95% CI:0.33%-1.25%). At annual and cold season levels, for each 10 μg·m^-3 increase in PM₁₀ concentration, the total mortality risks of cardiovascular diseases in women were higher than that in men; the risks in residents over age of 65 increased by 0.99% (95% CI:0.67%-1.31%) and 0.94% (95% CI:0.58%-1.31%) respectively; the risks in residents under high school education increased by 0.96%(95% CI:0.62%-1.29%) and 0.86% (95% CI:0.47%-1.24%) respectively. There was no significant effect of PM₁₀ in warm season on mortality of cardiovascular diseases.

Conclusion Short-term exposure to PM₁₀ increases the mortality risks of cardiovascular diseases, hypertension, acute myocardial infarction, and other ischemic heart diseases.