Associations between ambient air pollution and mortality during a 7-year ecological time-series study.

Abstract

Air pollution remains a major public health concern, particularly in large metropolitan areas. This study aimed to evaluate the short-term association between ambient air pollution levels and non-accidental mortality in Istanbul between 2013 and 2019. In this ecological time-series study, daily mortality data were analyzed using quasi-Poisson regression models incorporating distributed lag non-linear models (DLNM) to estimate exposure-response relationships. Citywide daily mean concentrations of major air pollutants were derived from all eligible monitoring stations. Effect estimates were expressed as relative risks (RRs) with 95% confidence intervals (CIs) per 10 µg/m2 increase in particulate matter concentrations. During the 7-year period, average particulate matter levels frequently exceeded World Health Organization (WHO) guideline values. A 10 µg/m2 increase in PM10 was associated with a 1.7% increase in daily mortality (RR: 1.017; 95% CI: 1.009-1.025), while a similar increase in PM2.5 was associated with a 3.3% increase (RR: 1.033; 95% CI: 1.021-1.046). Mortality increases were more pronounced among individuals aged ≥ 65 years. Periods of consecutive high pollution were also associated with excess mortality. Short-term increases in particulate matter concentrations were associated with elevated mortality in Istanbul, particularly among older adults. These results support the relevance of WHO guideline values in the local context and highlight the importance of sustained air quality control policies.