Short-Term Associations between Daily Mortality and Fine Particulate Matter, Nitrogen Dioxide, and the Air Quality Index in Tehran, Iran

摘要

There is limited evidence for short-term associations between mortality and ambient air pollution in the Middle East, and no studies examining the association between daily mortality and the air quality index (AQI). We investigated short-term associations between non-accidental mortality and fine particulate matter (PM2.5), nitrogen dioxide (NO2), and the AQI from March 2011 through March 2014 in the megacity of Tehran, Iran. Generalized additive quasi-Poisson models were used within a distributed lag non-linear modeling framework to estimate the effects of PM2.5, N02, and AQI from lag 0 to lag of 45 days. Positive associations were found in most models, with strong evidence of effect modification by sex, age, and season. The maximum cumulative rate ratios (95% confidence interval) per inter-quartile range increment were: 1.19 (1.12,1.28) for NO2 over the previous 45 days (for males, all ages, in cooler months); 1.14 (1.07,1.21) for PM2.5 over the previous 30 days (for females, all ages, in cooler months); and 1.15 (1.08,1.22) for AQI over the previous 31 days (for females, all ages, in cooler months). The cumulative effects remained positive in multipollutant models. Overall, we found that the effects of PM2.5, NO2, and AQI on mortality in Tehran were immediate, and that they increased steadily over a period of weeks. This is the first study to report short-term association between non-accidental mortality and ambient air pollution in Iran.