MODIS AOT product for the duration of 2007 – 2011 was downloaded from NASA website, from which the AOT physical value was extracted at the selected pixels where the 12 PCD stations are located. The hourly PCD PM10 data also collected from 12 PCD stations for the same duration. AOT MODIS data which has the same acquiring date and time with the measurement date and time of PM10 stations were selected to make yearly and monthly groups of matching pairs