Hi, Given that your study area Includes a small territory (just 25 sq. km) I would suggest you Lidar technology. But keep in mind that it's quite expensive.  

Thanks Levan, if lidar is going to be expensive, is it still a good idea to deploy air samplers for the study ?

Hi Arun, I would suggest you to have a look at some of the options available via the NASA Air Quality webinars. I have attached a link.

http://arset.gsfc.nasa.gov/air-quality/workshops/nasa-air-quality-remote-sensing-training

 May be useful plz go through link below

http://www.nature.com/nature/journal/v419/n6903/full/nature01091.html

You can use MODIS AOD data. To gain more information about this product, you can refer to the following  publication:

Article Investigation and validation of MODIS SST in the northern Persian Gulf