Long-Term Effect of Outdoor Air Pollution on Mortality and Morbidity: A 12-Year Follow-Up Study for Metropolitan France

Background: Short-term effects of air pollution are documented more than long-term effects. Objective: We investigated 12-year impacts of ambient air pollutants on cardiovascular and respiratory morbidity and mortality at the departmental level in metropolitan France. Methods: Daily air pollution data at 2-km resolution, including concentrations of particulate matter of 10 µm or 2.5 µm in diameter or less (PM(10) and PM(2.5)), nitrogen dioxide (NO(2)), and ozone (O(3)), were accrued from the CHIMERE database for 1999 and 2000. Simultaneously, morbidity (hospitalizations) and mortality data were collected in 2012 using the ESPS (Enquête Santé et Protection Sociale/Health, Health Care and Insurance Survey) survey data and the CepiDc (Centre d’Épidémiologie sur les Causes Médicales de Décès/French Epidemiology Centre on Medical Causes of Death) database. Based on Poisson regression analyses, the long-term effect was estimated. A higher risk of all-cause mortality was observed using CépiDc database, with a relative risk of 1.024 (95% CI: 1.022, 1.026) and 1.029 (95% CI: 1.027, 1.031) for a 10 µg/m(3) increase in PM(2.5) and PM(10), respectively. Mortality due to cardiovascular and respiratory diseases likewise exhibited long-term associations with both PM(2.5) and PM(10). Using ESPS survey data, a significant risk was observed for both PM(2.5) and PM(10) in all-cause mortality and all-cause morbidity. Although a risk for higher all-cause mortality and morbidity was also present for NO(2), the cause-specific relative risk due to NO(2) was found to be lesser, as compared to PM. Nevertheless, cardiovascular and respiratory morbidity were related to NO(2), along with PM(2.5) and PM(10). However, the health effect of O(3) was seen to be substantially lower in comparison to the other pollutants. Conclusion: Our study confirmed that PM has a long-term impact on mortality and morbidity. Exposure to NO(2) and O(3) could also lead to increased health risks.