Press Release Jul 28, 2015

National Parks Plagued by Significant Air Pollution Impacts, Finds New Analysis

Majority of Parks Experience Days Risky for Vulnerable Visitors; Four Parks Regularly Unsafe for Most People

WASHINGTON – A new analysis, released today by National Parks Conservation Association, shows that every one of the 48 national parks with the greatest Clean Air Act protections are plagued by significant air pollution problems and climate change impacts. In fact, air quality in parks can be as bad – or worse – than in some major cities due to emissions from outdated coal plants and other sources of pollution.

Of the 48 parks studied, 36 at times experienced “moderate” or worse ozone pollution according to the Air Quality Index developed by the Environmental Protection Agency. These levels of air pollution are risky for especially sensitive populations such as children who have asthma (roughly one out of every ten children in the United States). Even more troubling, four parks—Joshua Tree, Sequoia, Kings Canyon, and Yosemite National Parks—regularly had ozone levels that are known to be unhealthy for most park visitors.

“As Americans flock to our national parks this summer to enjoy the great outdoors, they expect and deserve to find clean, healthy air. Sadly that is not always the case,” said Ulla Reeves, manager of NPCA’s Clean Air Campaign. “Our parks remain under threat from air pollution, harming visitors’ health, reducing visibility, and driving the impacts of climate change.”


Polluted Parks: How Dirty Air is Harming America’s National Parks

“Polluted Parks” graded the pollution-related damage in the 48 national parks required by the Clean Air Act to have the highest possible air quality.

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The analysis – “Polluted Parks” – graded the pollution-related damage in the 48 national parks required by the Clean Air Act to have the best possible air quality. The report highlights 12 parks across the nation that earned a D or lower in at least one of three categories – threat to public health, hazy skies, and impacts from climate change.

Key Findings:

  • 75% of the 48 iconic national parks have air quality that’s unhealthy at times.
  • Four parks—Joshua Tree, Sequoia, Kings Canyon, and Yosemite National Parks—regularly have air that’s known to be unhealthy for most park visitors and rangers. In some cases, the parks have unsafe air for more than a month each year, usually during the summer.
  • Haze pollution limits how far you can see in 100% of the national parks. On average, visitors miss out on 50 miles of scenery—a distance equivalent to the length of Rhode Island.
  • 90% of our national parks are currently experiencing extreme weather that scientists link to climate-changing air pollution: They are hotter, wetter, or drier than they were for most of the past century.

The Regional Haze Rule is the program under the Clean Air Act responsible for protecting air quality in our parks. But due to loopholes in the rule, states and polluters can game the system to avoid cleaning up. For example, Nebraska opted to allow its biggest polluter, Gerald Gentleman Station, to continue operating without basic emission controls, despite a clear demonstration of damage to Badlands and Wind Cave National Parks. If the Regional Haze Rule is not improved, in 50 years just 10 percent of national parks required to have clean air will actually have it.

“Fortunately, this is one of those rare problems with a simple solution,” said Reeves. “With a stroke of the pen, the President can close the loopholes and make common sense revisions to ensure that states and the Environmental Protection Agency are poised in the coming years to restore dozens of our most treasured national parks to clear, healthy air.”

The Obama Administration is expected to revise the Regional Haze Rule before the end of its term. The NPCA analysis recommends that changes must include setting park-centered targets for reducing pollution impacting parks for the next decade, as well as closing loopholes that allow some polluters to escape the rule’s requirements and greater accountability for states to reduce pollution within their borders.


About National Parks Conservation Association

Since 1919, the nonpartisan National Parks Conservation Association has been the leading voice in safeguarding our national parks. NPCA and its more than one million supporters work together to protect and preserve our nation’s natural, historical, and cultural heritage for future generations. For more information, visit

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