Pollution Progress You Can See From Space
And here's the same view in the time period 2008-2010:
What changed? That would be the application of the EPA's Clean Air Interstate Rule, which made coal-fired power plants (the black dots in the images) limit emissions of sulfur dioxide, a pollutant associated with acid rain and respiratory health problems. (See NASA's Earth Observatory site for a groovy sliding image comparison device.) The satellite data confirmed that application of the rule cut SO2 emissions by nearly half.
Just last month an attempt to stymie further progress on clean air was narrowly defeated when a number of Republican senators joined all but two Democrats to quash an attempt, led by Rand Paul (R-Ky.) to block the Cross-State Air Pollution Rule, which addresses the dirty fumes that drift from one state to another. The rule will go into effect in January, 2012, contributing not only to the beauty of future satellite images but the health of 6-year olds like Peter.