| Although air pollution can have significant and direct negative effects on public health and the environment, it has been recognized that air pollution is also having a significant negative impact on our aesthetic enjoyment of the United States' national parks and wilderness areas. Increased amounts of air pollution cause haze that has decreased visibility in the east from 90 miles to 15-25 miles and in the west from 140 miles to 35-90 miles. Haze is caused when tiny particles of air pollution absorb and scatter sunlight, reducing the color and clarity of the view. Different types of particulate pollution have different effects on visibility. The particles that cause haze can come from a variety of sources, including ordinary dust kicked up from unpaved roads and tilled fields and soot from fuel combustion of all sorts. The particles that are responsible for haze not only cause reduced visibility but can pose health hazards and environmental hazards beyond visibility as well.
To address the problem of visibility and the related environmental and health effects of visibility impairing pollutants, which affect among others 280 million annual visitors to our national parks and wilderness areas, in 1999 the Environmental Protection Agency (EPA) announced the Regional Haze Rule (RHR), which represents a concerted effort to improve the visibility in 156 national parks and wilderness areas. Recognizing that haze can be spread over wide areas, the EPA assigns each state, whether or not it contains national parks or wilderness areas, to one of five multi-state regional planning organizations. The regional planning organizations work in conjunction with the EPA and other federal agencies to reduce the types of air pollution that cause decreased visibility. The EPA also funds the efforts of the regional planning organizations in improving visibility and addressing related issues.
The RHR requires states that contribute to visibility impairment in national parks and wilderness areas to submit implementation plans (called "state implementation plans" or SIPs) setting out how they intend to reduce the air pollutants that cause haze. SIPs must contain a description of the long-term strategies that will be employed to monitor and reduce haze, a state inventory of the emissions that cause haze, and plans for applying the Best Available Retrofit Technology (BART) to pollution sources. The BART for any given pollution source is determined on a case-specific basis, taking into consideration the costs of compliance with air pollution reduction requirements, environmental impacts of compliance apart from the effect on air quality, existing pollution control technologies already in use by the source, the remaining useful life of the source, and the amount of visibility improvement that can reasonably be expected from employing the chosen technology. States may also choose, as an alternative to determining the BART for each specific source, to set a state-wide cap on visibility-related emissions and implement an emissions trading program such as the one in place for reducing acid rain.
To determine visibility goals, states must estimate natural visibility impairment and establish baseline conditions for the 20 percent best- and worst-visibility days using visibility monitoring data collected between 2002 and 2004. That information is used to set visibility progress goals. States must periodically report on their degree of success in meeting progress goals. States are expected to fully implement their visibility improvement plans by different years depending on whether they are currently meeting national air quality standards regarding particulate matter pollution and the methods that they choose to reduce visibility-impairing pollution. Copyright 2010 LexisNexis, a division of Reed Elsevier Inc. |