by Jason Dorrier, Singularity Hub
Pollution in US cities has been declining for decades now. But sometimes it takes a visual aid to drive the point home.
NASA recently released a time lapse of nitrogen oxide — one of six federally regulated pollutants — in the US from 2005 to 2011.
Nitrogen oxide is produced by cars and coal power plants, is involved in the creation of other ground-level pollutants including ozone and particulates, and can negatively impact the respiratory system. The images, collected over a six-year period from orbit by the ozone monitoring instrument (OMI) on NASA’s Aura satellite, show nitrogen oxide levels declined nationally, and in some cases dramatically.
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