Fortunately, certain national parks and wilderness areas have the strongest clean air protections in the country. Mandated by the Clean Air Act, the Regional Haze Rule requires federal and state agencies, as well as industry and organizations to work together to restore clear skies. The Clean Air Act’s Regional Haze Rule (RHR) is a time-tested, effective program that has resulted in real, measurable, and noticeable improvements in national park visibility and air quality.
Mammoth Cave National Park’s 52,000 acres (about twice the area of Manhattan) is home to such a diverse range of plant and animal life that the park is designated as an UNESCO Biosphere Reserve. Airborne contaminants find their way into the cave passages, affecting delicate geologic formations and subterranean ecosystems.
While the ecological integrity of the park is threatened by industrial air pollution from across the state and region, visitors also experience degraded views, and local residents suffer from asthma, bronchitis and other respiratory illnesses. Studies show that park visitation drops when air pollution is high. With 600,000 visitors per year, tourism to Mammoth Cave National Park creates $69.2 million in economic benefits for Kentucky, according to a 2021 National Park Service report.
