Nature World: You may not have noticed, but if you've been living in a major US city for the past decade, your quality of air has actually been improving. New Images out from NASA satellites show this significant reduction in air pollution levels in a series of striking photographs released this week.
"After ten years in orbit, the Ozone Monitoring Instrument (OMI) on NASA's Aura satellite has been in orbit sufficiently long to show that people in major U.S. cities are breathing less nitrogen dioxide - a yellow-brown...