USA TODAY(one of the largest newspapers in USA) has reported a research work published by AJCC (Vol.1 No.3 September 2012).
Below please read the news:
http://www.usatoday.com/story/news/nation/2012/11/15/megacity-smog-satellites/1707761/
For the original information on the research work:
AOD Trends over Megacities Based on Space Monitoring Using MODIS and MISR