Estimating PM10 and PM2.5 in Tehran mega city using MODIS data of Terra and Aqua satellites

Air pollution is a major problem in urban life and populated cities. The important issue to contrast and reduce this problem is to estimate the level of air pollution. We can use satellite sensors according to their application for this act. The suitable sensor is MODIS that is aboard the Terra and Aqua satellites. MODIS is the best choice for estimating the level of air pollution especially aerosols, because of its numerous spectrum channels, narrow spectral bands, complete daily coverage of the earth, free of charge and availability of data. In this study, we use 20 air quality stations of Tehran for a period of 85 days (25 Sep to 19 Dec 2012) thatmeasures air pollution hourly. These stations are scattered in Tehran irregularly, in some areas, it has high density, and in some areas, there is no station for measurement. Thus, satellites are good supplements for measuring pollution, due to their spatial and temporal coverage of earth. According to this issue, in this study, we evaluated estimation accuracy of PM10 and PM2.5 mass concentration using MOD04 and MYD04 products. Results show that there is a linear relationship between aerosol optical depth and PM10 and PM2.5 (that are measured at ground stations). Results show good correlation (R) 0.67 to 0.81 between satellite data and ground data. AOD act better in estimating PM10 than PM2.5 mass concentration.