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 18, 2017, to March 19, 2020, were classified by cause. Air pollutants (PM10, PM2.5, NO2 , SO2 , 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 (0–10, 0–20, and 0–30 days) were assessed for pollutant impacts on mortality. Results: Higher PM2.5, PM10, and NO2 levels were significantly associated with increased risks of all-cause, respiratory, and cardiovascular mortality. A 10-unit increase in PM2.5 was associated with the highest risk for all-cause mortality at Lag 0–30 (RR=1.184, P=0.012). PM2.5 and NO2 showed the strongest associations with respiratory mortality over 30-day cumulative exposure, while PM2.5 (RR=1.132, 95% CI: 1.012–1.267) and NO2 (RR=1.074, 95% CI: 1.006–1.147) also impacted cardiovascular deaths. Shorter lags revealed more immediate impacts, particularly for NO2 and PM2.5 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.
Sharak et al. (Tue,) studied this question.