Air Pollution And The National Parks

The national parks are a good place to gain understanding of the effects of air pollution on the environment. The parks are small and contained, and many have been well studied over many decades. Although national parks are set aside from the rest of the landscape, they do not exist in isolation: Traffic, noise, and air and water pollution invade them no matter where they are. Most air pollution in national parks comes from outside park boundaries, and some of the greatest jewels of the park system are positioned near urban areas, power plants, and industrial complexes.

Shenandoah National Park, located in Virginia, is near a well-developed region. The park straddles a beautiful section of the Blue

Ridge Mountains, delighting its visitors with cool forests, deep canyons, lovely waterfalls, and expansive views of the rugged landscape. In 1886, those views inspired naturalist George Freeman Pollock to write, "To say that I was carried away is to put it mildly. I raved, I shouted." Since then, the average summer visibility has dropped from 90 miles (145 km) to less than 20 miles (30 km). Winds bring in coal smoke from an expanding number of coal-fired power plants in Virginia and the Ohio Valley. Once inside park boundaries, the pollutants are trapped by the tall mountains and deep valleys. At times, the smog in the Shenandoah is worse than in some major industrial cities.

Shenandoah National Park is designated as deserving of the highest protection afforded by the Clean Air Act. Since the act's passage, visibility has improved, but the situation is still bad. In 1996, only 31% of summer days had "good" visibility of over 30 miles (50 km). Ozone levels are high enough that sensitive plants are being injured;

Shenandoah National Park has much lower visibility than it once did. (DavidR. Frazier/ Photo Researchers)

weakened plants are more vulnerable to other problems such as invasions by insects. The ozone is so bad that health standards are being violated. Adverse health effects from air pollution are possible on employees and park visitors.

Some parks are far removed from development, yet they are still polluted. This is true of Yellowstone National Park, where the primary source of pollution is park visitors. In the winter, snowmobiles emit toxic air pollutants, such as the VOCs benzene and toluene, plus CO and methane. Winter inversions trap pollutants, further impacting air quality. Substantial air pollution levels have been measured, even in remote park locations. Summer days are not pollutant-free either; cars and motor homes create ground-level ozone and other air pollutants.

Some national parks endure pollution from both inside and outside their boundaries. The most popular destination in Yosemite National Park in California is the majestic Yosemite Valley, where granite domes and cliffs carved by glaciers are adorned with cascading waterfalls. Yet, on summer weekends, visitors jam thousands of cars and motor homes into the valley's small space, which becomes filled with smoke from campfires and the occasional wildfire. Yosemite lies adjacent to California's San Joaquin Valley, which contains tremendous sources of agricultural and motor vehicle pollution. Pesticides and other chemicals from the San Joaquin Valley waft into the park, causing problems for aquatic and terrestrial organisms. Ozone damages plant species, including the unique and important ponderosa pine (Pinus ponderosa). Nitrogen pollutants injure the native plants that have evolved under nitrogen-poor conditions and favors nonnative, nitrogen-tolerant species. Visibility in the park suffers; even in the photo of Half Dome on the National Park Service brochure, the mountain seems to be mired in haze.

Renewable Energy 101

Renewable Energy 101

Renewable energy is energy that is generated from sunlight, rain, tides, geothermal heat and wind. These sources are naturally and constantly replenished, which is why they are deemed as renewable. The usage of renewable energy sources is very important when considering the sustainability of the existing energy usage of the world. While there is currently an abundance of non-renewable energy sources, such as nuclear fuels, these energy sources are depleting. In addition to being a non-renewable supply, the non-renewable energy sources release emissions into the air, which has an adverse effect on the environment.

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