A Mazaheri Tehrani - MSc, Environmental Health Department, Health Faculty, Kashan University of Medical Sciences, Kashan, Iran
F Karamali - BSc, Environmental Health Department, Health Faculty, Kashan University of Medical Sciences, Kashan, Iran
E Chimehi - BSc, Environmental Health Department, Health Faculty, Kashan University of Medical Sciences, Kashan, Iran

Aims Tehran’s uncontrolled expansion, which promoted housing, public utilities, industriesand increase of vehicles caused the problem of air pollution. Necessary information about airquality in different places and different times is the first step of combating the air pollution.The purpose of this study was to investigate the annual, monthly and hourly average of 5criteria air pollutants (PM10, O3, NO2, SO2, CO) of Tehran City, Iran.Instrument & Methods The hourly concentrations of PM10, O3, NO2, SO2, CO were obtainedfrom 21 air quality-measuring stations of Tehran City, Iran, during April 2012 to March 2013.Data were presented by descriptive statistics in the form of mean and standard deviation.Findings CO concentration was not changed during the period of study. Nitrogen dioxideincreased in spring and winter. Sulfur dioxide was not changed in the first six months ofthe year but its concentration increased in winter. Trend of changes of floating particlesshowed increasing the concentration of this pollutant in May 2012 and January 2013. Ozoneconcentration increased in the warm seasons and decreased in the cold seasons.Conclusion PM10, O3, NO2, SO2 and CO has high concentrations and cold periods of the yearare more polluted than the warm periods in Tehran City, Iran.

Air Pollution; Ozone; Carbon Monoxide; Nitrogen Dioxid; Sulfur Dioxide; Tehran