AOD trends over megacities based on space monitoring using MODIS and MISR(11 page pdf, Pinhas Alpert, Olga Shvainshtein, and Pavel Kishcha, American Journal of Climate Change, Nov. 2012)

Also discussed here: Tracking Pollution from Outer Space: Team Uses NASA Satellites to Measure Pollution Hovering Over World’s Megacities(ScienceDaily, Nov. 27, 2012)

Today we review research that used three different satellite sensors to estimate atmospheric optical depth for 189 large cities world-wide over an eight year period. One big advantage of this method is that it gets away from the sometimes non standard or inconsistent pollution monitors on the earth’s surface. Another is that trends in air quality in various cities can be measured and compared using the saem equipment. While cities in Southeast Asia and Northeast USA show an improvement, the Indian subcontinent, the Middle East and Northern China show deteriorating air quality. This approach looks very promising…