A Study on the Comparative Investigation of Air Quality in Tehran Metropolis Over a Five-year Period Using Air Quality Index (AQI)

Abstract

Introduction and Purpose: Air pollution is one of the major problems of megacities that seriously threatens the health of their residents. Considering this, taking some actions such as studying pollutant variations, comparing pollutants with standards, and informing the health authorities and public paly a fundamental role in developing preventive schemes. This study was targeted toward a comparative investigation of the air quality of Tehran metropolis based on Air Quality Index (AQI) over a period of five years (2011-2015). Methods: This study was a descriptive–analytic one. Firs, hourly data of four criteria pollutants were taken from the Environmental Protection Agency and Air Quality Control Company. These data were validated according to the World Health Organization (WHO) guidelines. Then, the daily AQI for the given pollutants were determined based on the available standard tables and equation. Finally, the highest value among the calculated indexes obtained from all the stations was recognized as the final index and the pollutant which was responsible for this index was introduced as the responsible pollutant of day. Results: Tehran’s air quality was shown to exceed the standards of Environmental Protection Agency of Iran (AQI>100) _ 327, 330, 343, 350, and 352 days of the year during 2011-2015 respectively. Besides, PM2.5 was found to be the main pollutant which was responsible for this condition. Conclusion: Comparing air quality of Tehran over five years demonstrated that the air quality is not in a proper condition in terms of health status; and the level of air pollution in Tehran is constantly increasing