Visibility
Great Smoky Mountains National Park, an example of one area with haze
Clear Day
Hazy Day
One of the most basic forms of air pollution - haze - degrades visibility in many American cities and scenic areas. Haze is caused when sunlight encounters tiny pollution particles in the air, which reduce the clarity and color of what we see, and particularly during humid conditions. Since 1988 the federal government has been monitoring visibility in national parks and wilderness areas, for example, in the Great Smoky Mountains National Park as illustrated at right. In 1999, EPA announced a major effort to improve air quality in national parks and wilderness areas.
This Web site describes visibility impairment caused by air pollution in the United States, and EPA's activities to address the problem.
Basic Information - The basics of visibility and haze.
Regional Haze Program - Improving visibility in national parks and wilderness areas.
Regional Planning Organizations - Addressing visibility impairment from a regional perspective.
Visibility in Parks and Wilderness Areas - Pollutants, photos, trends, and real-time images.
Regulatory Actions - Actions EPA is taking to combat haze and improve visibility.