Temporal profile of PM and associated health effects in one of the most polluted cities of the world (Ahvaz, Iran) between 2009 and 2014.

Ahvaz, Iran ranks as the most polluted city of the world in terms of PM concentrations that lead to deleterious effects on its inhabitants. This study examines diurnal, weekly, monthly and annual fluctuations of PM between 2009 and 2014 in Ahvaz. Health effects of PM levels are also assessed using the World Health Organization AirQ software. Over the study period, the mean PM level in Ahvaz was 249.5 µg m, with maximum and minimum values in July (420.5 µg m) and January (154.6 µg m), respectively. The cumulative diurnal PM profile exhibits a dominant peak between 08:00-11:00 (local time) with the lowest levels in the afternoon hours. While weekend PM levels are not significantly reduced as compared to weekdays, an anthropogenic signature is instead observed diurnally on weekdays, which exhibit higher PM levels between 07:00-17:00 by an average amount of 14.2 µg m as compared to weekend days. PM has shown a steady mean-annual decline between 2009 (315.2 µg m) and 2014 (143.5 µg m). The AirQ model predicts that mortality was a health outcome for a total of 3777 individuals between 2009 and 2014 (i.e., 630 per year). The results of this study motivate more aggressive strategies in Ahvaz and similarly polluted desert cities to reduce the health effects of the enormous ambient aerosol concentrations.