NASA Visualization Shows Air Quality Improving Across the U.S. But is the Trend Beginning to Reverse?

By Tom Yulsman | June 27, 2014 11:45 am
air quality

This animation shows significant decreases in nitrogen dioxide pollution, averaged yearly from 2005-2011, across the United States. (Source: NASA Goddard’s Scientific Visualization Studio/T. Schindler)

Despite an increasing population and ever more vehicles on the roads, air quality across the United States has improved significantly in recent years. Watch the skies clear in the animation above, which shows how levels of nitrogen dioxide pollution changed between 2005 and 2011.

The animation is based on measurements by the Ozone Monitoring Instrument on NASA’s Aura satellite.

This is clearly good news. But it’s only part of the story.

Nitrogen dioxide is one of six air pollutants regulated by the U.S. Environmental Protection Agency. It lends a yellowish-brown tinge to the skies, and it can cause respiratory problems. Nitrogen dioxide also contributes to ground-level ozone, which also cause serious health effects.

In its release of the animation and other graphics yesterday, NASA attributed the improvement in air quality to regulation, better technology, and “economic changes.” The agency didn’t specify what it meant by the latter, but I assume this means slower economic growth resulting from the financial crash in 2008.

In fact, if you watch the animation carefully, you’ll see some areas, particularly the Boston-Washington corridor, that experience a slight uptick in pollution in the last year covered. Could this increase be attributed to a pick-up in economic growth? That’s a good guess. I’ll try to find out and report back with an update.

In the meantime, there’s no question that many of us are breathing easier now, including residents of the densely populated New York metropolitan area:

air quality

Satellite monitoring has documented a 32 percent drop in nitrogen dioxide pollution over New York City between 2005-2007 (left) and 2009-2011 (right). The New York metro area has the highest population in the nation. (Source: NASA Goddard’s Scientific Visualization Studio/T. Schindler)

And people who live in Atlanta experienced an even greater improvement, with a 42 percent decrease in nitrogen dioxide pollution.

Unfortunately, the Denver metropolitan area, which I call home (I live near Boulder), has experienced much smaller improvements — a 22 percent decline in nitrogen pollution. That’s still good news. But why less so than in Atlanta and New York?

This region has seen a huge increase in drilling for oil and natural gas. And as of a year ago, oil and gas operations in Colorado were the third largest producers of nitrogen oxide pollution, according to the Denver Post.

Nitrogen oxides are not the only issue, new research published this past May shows. Here’s an excerpt from a summary by the Cooperative Institute for Research in Environmental Science at the University of Colorado:

During two days of intensive airborne measurements, oil and gas operations in Colorado’s Front Range leaked nearly three times as much methane, a greenhouse gas, as predicted based on inventory estimates, and seven times as much benzene, a regulated air toxic. Emissions of other chemicals that contribute to summertime ozone pollution were about twice as high as estimates, according to the new paper, accepted for publication in the American Geophysical Union’s Journal of Geophysical Research: Atmospheres.

Despite improvements in nitrogen pollution, the Front Range — a highly urbanized area stretching along the eastern front of the Rockies — still fails to meet federal air quality standards. To address the problem, the state’s air quality control commissioners in February “adopted tougher air pollution rules for the oil and gas industry — the first in the nation to cover methane, a gas linked to climate change,” according to the Denver Post.

I mention this just to highlight the complex tradeoffs involved in these issues. Increased reliance on natural gas has helped reduce the nation’s emissions of carbon dioxide, the greenhouse gas that is contributing the most to global warming. That’s because natural gas produces less carbon dioxide when burned than coal does.

On the other hand, the upsurge in natural gas production has clearly slowed improvements in air quality in the region where I live. Moreover, methane — a very potent greenhouse gas — is leaking from oil and gas operations to a much greater degree than expected.

So the overall picture is more complex than a simple NASA animation suggests.

  • disqus_atlq8Zmtsd

    It’s kind of interesting seeing how geographic features define a lot of the problem areas.The Tennessee Valley doesn’t have a high enough population for one to expect it to have been as much of a problem area as it was. Obviously TVA’s dependency on coal power has more than a little to do with that, but the valley being so starkly outlined shows just how much these things hang around.

    I am confident in saying that in this part of the country the installation of scrubbers at power plants is responsible for a great deal of the improvement. Perhaps “changing economic conditions” refers to financial incentives.

  • John Barba

    Is the total planet benefiting or did we just reassign air pollution to China and other developing nations?

    The latest United Nations projections indicate that world population will nearly stabilize at just above 10 billion persons after 2062.

    • disqus_atlq8Zmtsd

      I believe that worldwide pollution output is supposed to peak in the next couple years before trending downwards due to continuing infrastructure improvements in fledgling industrial powers.

      So I think pollution is still trending upwards, but the US getting their act together is responsible for keeping the rate of increase under control.

      • PhotoMaineAC

        You “believe” pollution output is supposed to peak when?

        And why do you believe this? TV?

        • disqus_atlq8Zmtsd

          As in, “I remember reading published work projecting worldwide pollution based on numerous factors including industrialization, population growth, and improved use of mitigation technology. I think (believe) that the peak year was 2017.”

    • Tom Yulsman

      John, I think you make a good point. We’ve outsourced a huge amount of industrial capacity to China. So our insatiable consumerism contributes mightily to their air pollution.

      Even so, the contribution of the Clean Air Act and revisions to cleaner skies is undeniable. And perhaps our example will eventually inspire China and other industrializing nations to do something about their own pollution problems.

      • PhotoMaineAC

        Stop buying stuff made in China!

        • Tom Yulsman

          That would basically mean stopping buying stuff. Almost everything.

      • John Barba

        I think our clean air standards just helped manufacturers rationalize the move to China. The Chinese will begin to address pollution when the cost of polluting exceeds the cost of not polluting. I think they beginning to see signs of this now in relation to increasing health care costs from work related illnesses’, especially in the recycling sectors.

    • PhotoMaineAC

      Fukushima is still leaking RADIATION!

      • Tom Yulsman

        What does Fukushima leaking radiation have to do with air pollution improving in the United States?

  • PhotoMaineAC

    So how many chemicals have been sprayed from airplanes, in order to reduce this “one single gas”?

    More smoke and mirrors please…….

    As far as the population goes, get rid of the Republicans and Democrats and the Earth will be a happy place to live.

    Without all of the Dis-Ease!

    • Buddy199

      Are you referring to the govt. chem trail program?

      • Tom Yulsman

        I’ll let this go — for now.

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  • Stephen Davies

    I think new fuel economy standards and the move by Detroit toward more fuel-efficient vehicles has had a big impact.

    I’m glad nitrogen dioxide levels are generally decreasing, but for me, there’s too much of a “good news” angle to this story, tempered somewhat by the observation that in the DC-Baltimore area, there was a “slight uptick” in pollution. Also, given the fact that our air standards, especially for ozone, are severely outdated given what we know about health effects, I wouldn’t say we’re anywhere where we need to be.

    The focus in air quality stories is almost always on the big sources — cars, trucks, factories. But the simple act of lawn care — mowing, blowing, trimming, edging — contributes enormous amounts of nitrogen and volatile organic compounds. In the greater Washington, D.C., area, the metropolitan Washington Council of Governments estimates that lawn care is in the top 5 in both categories — — with 52.2 tons per day — yes, Tons per Day — of VOC’s and 10.6 tons/day of NOx.

    So, there’s something we can all do — switch to push mowers or get an electric mulching mower, get rid of your gas leaf blower (or any leaf blower), mulch your leaves, compost, plant native plants. Just stop spending so much time using gas and oil to turn your lawn into a putting green.

    I’m going to check on the ground-level ozone numbers and see if there’s been a comparable drop.



ImaGeo is a visual blog focusing on the intersection of imagery, imagination and Earth. It focuses on spectacular visuals related to the science of our planet, with an emphasis (although not an exclusive one) on the unfolding Anthropocene Epoch.

About Tom Yulsman

Tom Yulsman is Director of the Center for Environmental Journalism and a Professor of Journalism at the University of Colorado, Boulder. He also continues to work as a science and environmental journalist with more than 30 years of experience producing content for major publications. His work has appeared in the New York Times, Washington Post, Audubon, Climate Central, Columbia Journalism Review, Discover, Nieman Reports, and many other publications. He has held a variety of editorial positions over the years, including a stint as editor-in-chief of Earth magazine. Yulsman has written one book: Origins: the Quest for Our Cosmic Roots, published by the Institute of Physics in 2003.


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