hello. im SYAFIQA AND I'M new here. wanna ask some question. actually im doing a research. which is pm10 concentration using modis image. the problem that im having is with the algorithms. i have found some of the algorithms to extract pm10.. but the algorithms need the value of AOT. which is oerosol optical thickness or aerosol optical depth. i have ask mr devin. how to extract aod in image. he told me to download the mod04. i already download it. but while georeferencing, there's a lot processing option that i need to select. i dontknow which one is suitable in extracting the value of aod in image,.... but i just pick mass concentration, and optical depth land and ocean. can someone know in this thing help me how to process the mod04 in extracting the value of AOT/AOD?..