NOX It Off!

Thanks to stricter emissions rules, one foul gas is on the downswing.

Illustrated by: NASA Goddard's Scientific Visualization Studio/T. Schindler

The red in the map on the left shows how much nitrogen dioxide pollution wafted over the Northeast in 2005. On the right is 2011. Cars and coal-fired power plants emit NO2 into the air, where the brown-yellow gas can cause respiratory problems and react with other atmospheric substances to form ground-level ozone and particulate matter. So what happened in those six years? Stricter NO2 standards and improvements in technology both helped clear the air—despite increases in population, electricity consumption, and numbers of cars on the road. About 147 million Americans, however, still live in areas with high levels of air pollution.

This week, the Supreme Court began deliberating over whether the U.S. Environmental Protection Agency can issue its new mercury standards for power plants, which would also help curb particulate matter and save of an estimated $90 billion in annual health costs. If the standards are put in place, imagine the map NASA could create a half decade from now on those pollutants. Suddenly, the future looks more rosy than red.


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