U.S. Air Quality Has Improved. Here’s the Time-Lapse to Prove It.

Breathe a little easier, America.

National Journal
Marina Koren
June 27, 2014, 5:58 a.m.

Amer­ic­ans are breath­ing less air pol­lu­tion than be­fore.

Spe­cific­ally, they’re in­hal­ing less ni­tro­gen di­ox­ide, a gas that can cause res­pir­at­ory prob­lems, ac­cord­ing to a new time-lapse re­leased by NASA. New satel­lite im­ages show­ing con­cen­tra­tions of the gas, av­er­aged yearly between 2005 and 2011, show a re­duc­tion in air pol­lu­tion across the coun­try, es­pe­cially in ma­jor cit­ies.

Ni­tro­gen di­ox­ide, one of the six com­mon pol­lut­ants reg­u­lated by the En­vir­on­ment­al Pro­tec­tion Agency, serves as a good proxy for air pol­lu­tion in gen­er­al. The gas is pro­duced by gas­ol­ine-fueled vehicles and coal-powered plants.

The pho­tos, re­leased this week, come from the Ozone Mon­it­or­ing In­stru­ment, loc­ated aboard NASA’s Aura satel­lite, which has been in or­bit for 10 years. Blue and green de­note lower con­cen­tra­tions of ni­tro­gen di­ox­ide, while or­ange and red areas in­dic­ate high­er con­cen­tra­tions of the gas.

In 2005, pol­lu­tion built up sig­ni­fic­antly along the East Coast, from Rich­mond all the way up to Bo­ston. By 2011, there was much less, even though there were more people—and cars—in big cit­ies. From 2005 to 2007, and then again from 2009 to 2011, the level of ni­tro­gen gas de­creased by 42 per­cent in At­lanta, 32 per­cent in New York City, and 22 per­cent in Den­ver.

Ex­perts at­trib­ute the re­duc­tion in air pol­lu­tion to fed­er­al reg­u­la­tions of emis­sions, im­prove­ments in tech­no­logy, and oth­er factors. While that’s all well and good, the pic­ture is not per­fect. Ac­cord­ing to EPA, about 142 mil­lion people still live in areas in the U.S. with un­healthy levels of air pol­lu­tion.