Assessing the Effects of Air Pollution on All-Cause, Respiratory, and Heart-Related Mortality Using Generalized Additive Models in Mashhad, Iran

Background: Air pollution is a major public health concern associated with increased respiratory and cardiovascular mortality. This study investigates the effects of air pollution and meteorological factors on respiratory, cardiovascular, and all-cause mortality in Mashhad, Iran, using generalized additive models with cumulative lag structures. Methods: Daily mortality data from February ۱۸, ۲۰۱۷, to March ۱۹, ۲۰۲۰, were classified by cause. Air pollutants (PM۱۰, PM۲.۵, NO۲, SO۲, and CO) and meteorological data (temperature and humidity) were analyzed using quasi-Poisson GAMs, adjusting for temporal trends, weather, and day of the week. Lag effects (۰–۱۰, ۰–۲۰, and ۰–۳۰ days) were assessed for pollutant impacts on mortality. Results: Higher PM۲.۵, PM۱۰, and NO۲ levels were significantly associated with increased risks of all-cause, respiratory, and cardiovascular mortality. A ۱۰-unit increase in PM۲.۵ was associated with the highest risk for all-cause mortality at Lag ۰–۳۰ (RR = ۱.۱۸۴, P = ۰.۰۱۲). PM۲.۵ and NO۲ showed the strongest associations with respiratory mortality over ۳۰-day cumulative exposure, while PM۲.۵ (RR = ۱.۱۳۲, ۹۵% CI: ۱.۰۱۲–۱.۲۶۷) and NO۲ (RR = ۱.۰۷۴, ۹۵% CI: ۱.۰۰۶–۱.۱۴۷) also impacted cardiovascular deaths. Shorter lags revealed more immediate impacts, particularly for NO۲ and PM۲.۵ on all-cause mortality. Conclusion: These findings underscore the urgent need for strategies to reduce air pollution in Mashhad, addressing both short- and long-term health effects, particularly respiratory and cardiovascular outcomes. The results support policy interventions for improved air quality management in urban Iran.

کلیدواژه ها:

Air pollution ، Cardiovascular diseases ، Respiratory tract diseases ، Mortality