Pollution's Impact On National Parks: A Worrying Trend

National parks are home to some of the most iconic landscapes and well-preserved cultural and historical sites in the US. However, air pollution and climate change remain serious threats to the health of these parks and the plants, animals, and ecosystems that live within them. Haze pollution, which consists of tiny particles and gases in the air, affects visibility in national parks, obstructing the views. On average, visitors to national parks miss out on 50 miles of scenery due to air pollution. Air pollution also poses risks to human health, especially for those exercising outdoors, children, the elderly, and those with respiratory illnesses.

Haze pollution obscures views and affects air quality

Haze pollution is a pressing issue in national parks, degrading visibility and adversely affecting the health of visitors and surrounding communities. This type of pollution is caused by particulate matter, nitrogen oxides, sulfur dioxides, and volatile organic compounds, which combine to create a hazy atmosphere that obscures views. The impact of haze pollution on visibility is significant, with visitors missing out on up to 50 miles of scenery—a distance comparable to the length of Rhode Island.

Haze pollution is not unique to any specific park, with nearly 90% of national parks affected by it. For instance, in Big Bend National Park, haze pollution can decrease visibility by up to 70% on certain days. Similarly, in Virginia's Shenandoah National Park and the Great Smoky Mountains of Tennessee and North Carolina, the average natural visual range is around 80-90 miles, but haze pollution reduces summertime visibility to a mere 12 miles.

Haze pollution poses a serious health risk to visitors, staff, and nearby residents. It contains pollutants like sulfur dioxide and ozone, which are linked to respiratory issues, heart attacks, and premature death in individuals with heart or lung disease. Additionally, haze pollution exacerbates existing health disparities, disproportionately impacting people of color and socioeconomically disadvantaged communities.

The sources of haze pollution are often located far from the parks themselves. Coal-fired power plants are a major contributor, with the U.S. EPA identifying them as responsible for over two-thirds of the sulfate particles that cause haze. Other sources include vehicles, oil and gas operations, and agricultural activities.

The Regional Haze Rule, a program under the Clean Air Act, aims to address haze pollution in national parks. However, loopholes in the rule allow states and polluters to avoid taking the necessary steps to improve air quality. Nevertheless, there have been some successes, such as the EPA's proposal to implement stricter requirements for Texas coal-fired power plants, which will significantly reduce pollution and improve visibility and health in Texas national parks.

Air pollution harms plants and animals

Air pollution has a detrimental impact on plants and animals in national parks. It stifles tree and crop growth, causing the leaves of tree species to blacken and wither. Pollution that comes through rain, snow, or fog can cause changes to the soil and water, affecting sensitive species and their habitats. For instance, acid deposition causes soils to lose calcium, an essential nutrient for animals such as snails to grow their shells. This, in turn, causes insects on the forest floor to disappear, along with the birds that feed on them.

Sulfur and nitrogen emissions from power plants, agriculture, and vehicles can also alter forest health. While acid rain is the most well-known form of sulfur and nitrogen pollution, even lower levels of these pollutants can harm trees and other plants. Sulfur pollution makes soils and waters more acidic, threatening the survival of organisms that depend on them. During the peak acid deposition years of the 1970s and 1980s, many eastern national park streams were so polluted that they killed off aquatic insects, fish, and the surrounding trees.

Additionally, nitrogen pollution causes eutrophication, leading to an overgrowth of invasive plants and algae blooms in lakes and streams, choking out other life forms. It can change the structure of a forest ecosystem, reducing biodiversity, increasing fire risk, and making lakes uninhabitable. Nitrogen deposition can also cause excess nitrogen in soils, leading plants to rely solely on their roots for nutrients, rather than symbiotic relationships with fungi. This makes them more vulnerable to stressors like drought and herbivores.

Ozone, a pervasive pollutant in parks, poses a direct threat to human and wildlife health, making breathing more difficult and putting individuals with asthma or respiratory illnesses at significant risk.

Pollution from far away can still affect national parks

Air pollution in national parks, from Yosemite to Joshua Tree and Kings Canyon, means that a hike in the 'fresh air' is not as healthy as it seems. Air pollution can travel hundreds of miles from its source, so even remote parks and distant communities are affected.

A 2015 study by the National Parks Conservation Association (NPCA) found that the air in some of the country's most popular parks is not as fresh as one might expect and is potentially hazardous. The report rated 48 parks in three categories: levels of ozone (a lung-damaging pollutant), haziness, and the impacts of climate change on the park. The results showed that 75% of the parks had "moderate" or worse ozone pollution, according to the federal government's Air Quality Index. Four national parks—Sequoia, Kings Canyon, Joshua Tree, and Yosemite—regularly have "unhealthy" ozone levels. This means that the average hiker should reduce strenuous activity, and those with asthma should avoid these parks altogether.

The sources of air pollution in national parks are typically coal-fired power plants, cars, and industrial and agricultural emissions. Under the Regional Haze Rule, created in 1999, states are required to work with the EPA and other federal agencies to establish a plan to address air pollution in the parks. However, loopholes in the rule allow states and polluters to avoid making improvements. For example, Nebraska allowed its biggest polluter, Gerald Gentleman Station, to continue operating without basic emission controls, despite the clear damage to Badlands and Wind Cave National Parks.

The effects of air pollution in national parks are not limited to human health risks. Pollution also obscures scenic views, with smog affecting vistas in all of the parks on average by 50 miles. Additionally, air pollution harms plants and animals, weakens ecosystems, and negatively affects water quality.

To protect national parks from the detrimental effects of air pollution, swift action is needed to curb pollution and limit climate threats. Reducing air pollution and transitioning to clean energy are feasible solutions to ensure that national parks can thrive for future generations.

Climate change is a significant concern for most national parks

For instance, in California's Yosemite National Park, air pollution levels are regularly unhealthy, and climate change is already having a substantial impact. Similarly, Joshua Tree, Sequoia, Kings Canyon, and Yosemite National Parks have ozone levels that are unsafe for most visitors and park rangers. These four parks often experience unhealthy air quality for over a month each year, typically during the summer.

The sources of this pollution are varied, but they often include emissions from outdated coal plants, cars, industrial activities, and agricultural practices. Under the Regional Haze Rule, which falls under the Clean Air Act, states are required to implement plans to reduce human-caused pollution in national parks. However, loopholes in the rule allow some big polluters to avoid complying with the regulations.

The effects of climate change and pollution on national parks are not limited to air quality and human health. Haze pollution, caused by particulate matter, nitrogen oxides, sulfur dioxides, and volatile organic compounds, reduces visibility in parks. Visitors to national parks miss out on an average of 50 miles of scenery due to this pollution, which is equivalent to the length of Rhode Island.

Additionally, pollution harms the plants and animals within these protected areas. It stifles tree and crop growth, causing leaves to blacken and wither. It also contaminates water sources and changes soil and water chemistry, threatening the survival of sensitive species that depend on these habitats.

Air pollution poses a health risk to visitors

Air pollution in national parks can be just as bad as in major cities, and in some cases, worse. This is due to emissions from outdated coal plants and other sources of pollution. Of the 48 parks studied, 36 experienced "moderate" or worse ozone pollution according to the Air Quality Index developed by the Environmental Protection Agency (EPA). These levels of air pollution are risky for especially sensitive populations such as children with asthma. Four national parks—Joshua Tree, Sequoia, Kings Canyon, and Yosemite—regularly have ozone levels that are unhealthy for most visitors.

Air pollution can cause a range of health issues, including asthma attacks, tightness in the chest, and irritation in people's throats and airways. While polluted air affects everyone, those exercising outdoors, children, the elderly, and anyone with respiratory illnesses are especially at risk.

The NPCA's "Polluted Parks" report highlights the pollution-related damage in the 48 national parks required by the Clean Air Act to have the highest possible air quality. The report found that 75% of these parks have air quality that is unhealthy at times. In some cases, the parks have unsafe air for more than a month each year, usually during the summer.

The Regional Haze Rule, a program under the Clean Air Act, is responsible for protecting air quality in national parks. However, due to loopholes in the rule, states and polluters can avoid complying with it. For example, Nebraska allowed its biggest polluter, Gerald Gentleman Station, to continue operating without basic emission controls, despite the clear demonstration of damage to Badlands and Wind Cave National Parks.

The EPA has recognized the issue of air pollution in national parks and has proposed stricter requirements for certain coal-fired power plants to reduce pollution and improve community health.

Frequently asked questions