Air Pollution Haze in Our National Parks

Case Overview

The 1977 Clean Air Act set a national goal of cleaning up dirty air in major national parks and wilderness areas. Decades later, only a small handful of states have submitted legally required plans to comply. The result: power plant and factory emissions continue to obscure views of beloved landmarks in national parks across the country including Shenandoah, Great Smoky Mountains, Glacier, Big Bend, Acadia, Sequoia, and Yosemite.

On October 21, 2008, Earthjustice filed suit on behalf of Environmental Defense Fund and National Parks Conservation Association over the U.S. Environmental Protection Agency’s failure to enforce deadlines for the states to adopt these clean air plans. The Clean Air Act required states to submit enforceable plans to EPA by last December to clean up hazy skies in parks and wilderness areas. As of June 2008, only six had submitted plans, according to EPA sources. The Earthjustice letter gave notice of intent to sue EPA unless the agency enforces the deadline against delinquent states within 60 days.

According to the National Park Service, human-caused air pollution reduces visibility in most national parks throughout the country. Average visual range—the farthest a person can see on a given day—in most of the western United States is now about one-half to two-thirds of what it would be without man-made air pollution (about 140 miles). In most of the east, the average visual range is about one-fifth of what it would be under natural conditions (about 90 miles).

Earthjustice is suing EPA on behalf of conservation groups.

Case Updates

November 18, 2021 Press Release

Colorado Could Lead Nation in Fighting Air Pollution, But Isn’t

National Parks Conservation Association, Sierra Club, and Earthjustice call for improvements on Colorado’s regional haze plan to better protect air quality and public health

November 20, 2020 Press Release: Victory

Regional Haze Plan Calls for Earlier Retirement for Colorado Coal-Fired Power Plants

Proposal by Sierra Club and National Parks Conservation Association will reduce greenhouse gas emissions and other pollutants, improving public health and visibility at national parks

Split view of clear and hazy days in Shenandoah National Park.
August 23, 2019 Press Release: Victory

Smog Standard Too Weak To Protect Forests, Court Rules

Court rejects polluters’ claims that standards are too protective