Visibility and Regional Haze

November 3, 2016 - In response to the D.C. Circuit's remand of the CSAPR Phase 2 SO2 emissions budgets, EPA proposed to remove Texas from the CSAPR SO2 and annual NOX trading programs. The proposal includes a discussion of the relationship between this proposed action and the determination that CSAPR participation meets the Regional Haze Rule's criteria to qualify as an alternative to BART.

Visibility and Regional Haze

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.

Regulatory Actions and Guidance Documents