en عمومى General مقاله اصیل Original Article <div style="text-align: justify;">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.<br> 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&ndash;10, 0&ndash;20, and 0&ndash;30 days) were assessed for pollutant impacts on mortality.<br> 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&ndash;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&ndash;1.267) and NO2 (RR = 1.074, 95% CI: 1.006&ndash;1.147) also impacted cardiovascular deaths. Shorter lags revealed more immediate impacts, particularly for NO2 and PM2.5 on all-cause mortality.<br> 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.</div> Air pollution, Cardiovascular diseases, Respiratory tract diseases, Mortality 1 8 http://ehemj.com/browse.php?a_code=A-10-1-426&slc_lang=en&sid=1 Nooshin Akbari Sharak akbarisn962@mums.ac.ir 100319475328460021219 100319475328460021219 No Student Research Committee, Department of Biostatistics, School of Health, Mashhad University of Medical Sciences, Mashhad, Iran Sedighe Rastaghi rastaghis971@mums.ac.ir 100319475328460021220 100319475328460021220 No Department of Biostatistics, School of Health, Mashhad University of Medical Sciences, Mashhad, Iran Maryam Salari SalariMR@mums.ac.ir 100319475328460021221 100319475328460021221 No Department of Biostatistics, School of Health, Mashhad University of Medical Sciences, Mashhad, Iran Mohammad Taghi Shakeri ShakeriMT@mums.ac.ir 100319475328460021222 100319475328460021222 Yes Correspondence to: Social Determinants of Health Research Center, Mashhad University of Medical Sciences, Mashhad, Iran Reza Esmaili r.esmaili.n@gmail.com 100319475328460021223 100319475328460021223 No Environmental Pollution Monitoring Center of Mashhad, Deputy of Services and Urban Environment, Municipality of Mashhad, Iran