Trend analysis of Air Quality Index criteria pollutants (CO, NO2, SO2, PM10 and O3) concentration changes in Tehran metropolis and its relationship with meteorological data, 2001-2009

Background and Aims: Air pollution is a serious threat to public health and environment. Factors contributing to air pollution have to be identified in order to reduce the corresponding effects. Meteorological data are among the noteworthy factors in determining the severity of air pollution. This study was conducted to investigate the trend of five criteria pollutants in air quality index and to find their correlation with meteorological data in Tehran metropolis during 2001- 2009. Materials and Methods: During this descriptive-analytical study, the required data were obtained from Air Quality Department of Tehran’s Municipality, the Environmental Protection Agency and also from the synoptic stations of Meteorological Organization. SPSS software was used for data analysis. The trends in concentration of studied pollutants including: CO, PM10, SO2, NO2 and O3, as well as meteorological data and their correlation were indeed considered. Results: The current study found that during the studied period, the concentration of O3 shows an increasing trend. Therefore, this pollutant could be a major factor, if not the only one, raising the index of air pollution in recent years. Another important result of this study can be cited to decrease in concentrations of CO, NO2, and SO2 during the years of present study. Conclusion: Our findings revealed that although the air quality in Tehran has improved in term of particulate matter, SO2 and NO2 during the period of study, however the concentration of ozone has increased beyond the standard. It was also possible to draw a meaningful conclusion relating to the impact of some meteorological parameters in airpollution. Keywords: Air pollution, Criteria pollutants, Meteorological data, Tehran metropoli