Temporal profiles of ambient air pollutants and associated health outcomes in two polluted cities of the Middle East.

Dust storms and particulate matters had been increased due to climate change in the Middle East. On the other hand, urbanization and industrialization raised levels of gaseous air pollutants in all big cities. In the current study, air pollution information collected from Environmental Protection Agency of Khuzestan and Tehran containing hourly O 3 , NO 2 , CO, SO 2 , PM 10 and PM 2.5 concentrations between 2014 and 2015. This study evaluated the air quality of these two cities by Air Quality Index (AQI). As a result, mean concentrations of O 3 , NO 2 , PM 10 and PM 2.5 were higher in Ahvaz than Tehran while Tehran was more pollutant in terms of CO and SO 2 . Diurnal variations of O 3 in weekend were the only trend located above weekday variations along the daytimes. Hourly variations of all pollutants changed with a wider range of concentrations in Ahvaz. Diurnal peaks of all pollutants showed their highest level on Monday as the busiest day in mega city, Tehran with the exception of SO 2 . PM 2.5 was the worst and limiting pollutant for both cities. Accordingly, winter was the most polluted season by 77 and 33 μg m -3 in Ahvaz and Tehran, respectively. Number of clean days was significantly lower in Ahvaz (no-day) than mega city, Tehran (<17 days). The number of unhealthy days was also presented significantly higher in Ahvaz (>186 days). Although, annual PM 2.5 concentrations were more in Ahvaz, the higher at-risk population in Tehran caused more health endpoints in the capital of Iran. Consequently, both cities should have their own especial pattern to control air pollution and attributed health damages.