Spatial analysis of air quality in Tehran with emphasis on particulate matter (PM2.5 and PM10)

Nowadays, the air of most of Iran cities especially high population metropolises hasn’t an optimal quality. This adverse quality is due to various pollutant resources such as automobiles, industries, heating devices, construction, and commercial activities during recent decades and there are more concerns about it. Therefore, monitoring air pollutants and studying their seasonal and spatial variations are specifically important. The present study aimed to evaluate air quality and seasonal and spatial variations of particulate matter (PM2.5 and PM10) in Tehran city. In this research, the AQI index has been used to determine the air quality of Tehran and to introduce the responsible pollutant. To investigate the variations of particulate matter (PM10 and PM2.5) in seasonal and spatial scales, the data of air pollution monitoring stations (18 stations) of Air Quality Control Company used during 2018 and 2019. Data were analyzed using Excel and SPSS software and results of statistical analysis of pollutants distribution in Temporal – spatial scales are provided and they are drawn using Arc GIS software and analytical function of inverse Distance Weighting interpolation (IDW) as maps, tables, and graphs. Based on the results, favorable and unfavorable air quality were respectively observed in 83.8 and 16.2% of days in 2018, as well as 76.4 and 23.6% of days in 2019, which can be related to the changes in rainfall rate and wind speed in the years. The maximum seasonal concentration of particulate matter (PM10 and PM2.5) relates to summer and winter respectively and the minimum seasonal concentration of both pollutants relates to spring. Results of inverse Distance Weighting interpolation (IDW) also showed that the west, south, central regions of Tehran got involved with particulate matter more than other regions.