NASA’s Aura satellite has now been in orbit for a decade, measuring the change in atmospheric composition around the world, and its data shows that air quality controls have been effective at reducing pollution, the agency reported (h/t Catherine Griffin at Science World Report).

“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,” says the report. “Air pollution has decreased even though population and the number of cars on the roads have increased. The shift is the result of regulations, technology improvements and economic changes.”

Air pollution down even though there are more cars on the road

The recently released data only shows changes in nitrogen dioxide, but it’s been shown to be a good proxy for the overall level air pollution in cities. Nitrogen dioxide, which is one of the common pollutants regulated by the EPA, also directly impacts human health and helps the formation of other kinds of pollution. It’s mostly emitted by cars and coal-fired power plants, so pollution levels do correlate with economic activity, but major urban areas like New York have seen their pollution levels drop even though there are more cars on the road.

pollution nyc no2 0614

pollution denver no2 0614

“While our air quality has certainly improved over the last few decades, there is still work to do – ozone and particulate matter are still problems,” said Bryan Duncan, an atmospheric scientist at NASA’s Goddard Space Flight Center.

Air pollution: “You can’t control what you don’t measure”

The improvement has been uneven, and the EPA estimates that 142 million people still live with unhealthy levels of air pollution, but that number has come down as has the severity of the pollution they have to deal with. The Aura data is also a few years out of date, displaying the average spring and summer nitrogen dioxide concentrations averaged from 2005 – 2007 compared to the average seasonal levels from 2009 – 2011, but the NASA statement didn’t give a reason for the long delay.

“You can’t control what you don’t measure,” said Russ Dickerson of the University of Maryland, College Park, and member of the NASA Air Quality Applied Sciences Team. “NASA measurements of air quality have value to the people with the authority to control emissions and develop policy.”

Dickerson is right of course, but considering how much change there was over just a couple of years you would hope we can get more up-to-date measurements for officials to use when setting policy.