A NASA satellite maps an invisible pollutant and its sources.
Carbon monoxide is a colorless, odorless gas that emerges from wildfires, vehicle tailpipes and other human sources. Once in the atmosphere it is one of the ingredients for ground-level ozone, a harmful pollutant that contributes to smog—sometimes thousands of miles from where the carbon monoxide originated. An instrument aboard NASA's Terra satellite called Measurements of Pollutants in the Troposphere, or MOPITT, was the first dedicated to tracking sources of carbon monoxide from space and monitoring levels across the globe. And the news is good. Satellite measurements of carbon monoxide since 2000 show that emissions have declined at a rate of one percent per year. Watch the video to see monthly changes in global carbon monoxide levels from 2000 to 2013.