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 (PM10 and PM2.5 ), nitrogen dioxide (NO₂), and ozone (O₃), 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/m³ increase in PM2.5 and PM10 , respectively. Mortality due to cardiovascular and respiratory diseases likewise exhibited long-term associations with both PM2.5 and PM10 . Using ESPS survey data, a significant risk was observed for both PM2.5 and PM10 in all-cause mortality and all-cause morbidity. Although a risk for higher all-cause mortality and morbidity was also present for NO₂, the cause-specific relative risk due to NO₂ was found to be lesser, as compared to PM. Nevertheless, cardiovascular and respiratory morbidity were related to NO₂, along with PM2.5 and PM10 . However, the health effect of O₃ 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 NO₂ and O₃ could also lead to increased health risks.