Regional Haze: EPA's Proposal to Improve Visibility in National Parks and Wilderness Areas

James E. McCarthy, John E. Blodgeu, and Larry B. Parker
Environment and Natural Resources Policy Division

Robert Meltz
American Law Division

Updated July 9, 1998

97-1010 ENR

Contents

Abstract
Summary
Introduction
I. Nature of the Problem
II. Efforts to Address the Problem

Prevention of Significant Deterioration
1977 Amendments to the Clean Air Act
Implementation
1990 Amendments
National Academy of Sciences Report
Grand Canyon Visibility Transport Commission

III. The Proposed Rule

SIP Revisions
BART
Reasonable Further Progress
Regional Cooperation

IV. The Rule in Context

Related EPA Programs
Costs
Benefits

V. Issues

Concern over potential impacts
Choice of Methodology
What Constitutes "Reasonable Further Progress".
Grand Canyon Commision Recommendations
Federal-State Issues

Conclusion

List of Figures

Figure 1. (49K) Median Summer Visibility for Suburban/Non-urban Areas:1974-1976, Displayed Using the Deciview Scale

 

Summary

On July 31, 1997, the Environmental Protection Agency proposed a new regulatory program to reduce "regional haze." The proposed program would require the states to develop and implement long-term strategies to attain a congressionally mandated goal of remedying the impairment of visibility in national parks and wilderness areas resulting from man-made air pollution.

Regional haze results from the presence of small particles, generally ranging in size from 0.1 to 1.0 micrometers in diameter, in the air. These particles absorb and scatter sunlight, with the effect of reducing contrasts, washing out colors, and making distant objects indistinct or invisible. Because of this pollution, the current visual range in the East is only about 20 miles, about one-fifth of the range one could expect in the absence of air pollution. In the West, visibility is better, ranging up to 90 miles, but even there it is only half to two-thirds of its natural range.

Contributors to the regional haze problem include sulfates from fossil-fueled power plants and smelters; nitrates and organic matter from the same sources, as well as from cars and trucks; elemental carbon from forest fires, prescribed burns, and diesel engines; and soil dust from unpaved roads, construction, and agriculture. Because of their small size, the particles tend to remain suspended for long periods of time and to travel long distances. Thus, addressing the problem will require planning on a regional basis, and will involve measures in all 50 states.

The proposed regulations would require the states to develop plans to improve visibility by one "deciview' (a measure of visibility) every 10 to 15 years. As a first step, the states would be required to review major stationary sources of pollution to identify those potentially subject to Best Available Retrofit Technology (BART), as required in Section 169A of the Clean Air Act.

The proposed rule was open to public comment until December 5, 1997. Since then, EPA has been reviewing the comments it received and deciding what to include in the final regulation. At least five groups of issues have arisen: 1) the potential impacts on various economic sectors (with special concern for the continued use of prescribed burning in agriculture and forestry); 2) the choice of methodology (i.e., "deciviews"), and whether improvement should be measured in terms of emission reductions or visibility improvement; 3) what constitutes reasonable further progress, as required by the Act -- in particular whether a goal of one deciview improvement is sufficiently ambitious, or appropriate for all regions; 4) whether EPA paid sufficient attention to the work of the Grand Canyon Visibility Transport Commission, which completed a five-year study of the visibility issue and made recommendations in June 1996; and 5) federal-state issues, including the respective powers of federal land managers and state governments. Congress has also expressed concern that the regional haze rule not be implemented in advance of the schedule for new standards on fine particulates; in P.L. 105-178, enacted June 9, 1998, Congress addressed this issue, by stipulating that plans implementing the regional haze rule be submitted on the same schedule as those for PM25 nonattainment areas.

Introduction

On July 31, 1997, the Environmental Protection Agency proposed a new regulatory program to improve visibility in the nation's national parks and wilderness areas. This "regional haze" program uses the authority of Section 169A of the Clean Air Act, first granted the Agency in 1977, and reinforced by Section 1 69B in the Act's 1990 amendments.

This report provides background concerning the regional haze program and the issues that have been raised concerning the proposed rule. The report is divided into five sections. Section I discusses the nature of the visibility problem and the sources of regional haze. Section II provides a brief history of legislative and regulatory attempts to address the problem. Section III discusses the proposed rule. Section IV places the rule in context, discussing how it relates to other EPA initiatives, including revision of the air quality standards for ozone and particulates and the acid rain program, and providing a brief discussion of benefits and costs. Section V discusses five sets of issues that have been raised since the rule was proposed.

A formal public comment period on the proposed rule ended December 5, 1997. Since then, EPA has been reviewing the comments received and deciding what to include in the final regulation. Promulgation is not expected before late summer 1998. The rule would then be implemented over a multi-year period.

EPA faces significant choices in finalizing the regulations, with potential impacts on a variety of economic sectors and regions. States will have decisions to make, too, once the rule is final. As a result, the Congress is likely to retain an interest in the program and its implementation.

I. Nature of the Problem

Impairment of visibility due to air pollution occurs throughout the United States. According to the National Academy of Sciences,

the average visual range in most of the western United States, including national parks and wilderness areas, is 100-150 km (about 60-100 miles), or about one-half to two-thirds of the natural visual range that would exist in the absence of air pollution.... In most of the East, including parklands. the average visual range is less than 30 km (about 20 miles), or about one-fifth of thc natural visual range.1

This reduction in visibility is caused by the presence of small particles, generally ranging in size from 0.1 to 1.0 micrometers in diameter in the air. Such particles absorb and scatter sun light. Th doing so, they reduce contrasts, wash out colors, and make distant objects indistinct or invisible. Especially in national parks and wilderness areas, but more generally in any area dependent on tourism, a reduction in visibility vitiates the experience sought by visitors and reduces the economic value of assets related to tourist services.2

Some of the particles that create this reduction in visibility are emitted directly to the atmosphere. Others form as a result of atmospheric reactions involving gaseous precursors. Whatever their source, they tend to remain suspended for long periods of time and to travel long distances, creating a widespread problem known as regional haze.

The primary causes of regional haze are sulfates, organic matter, elemental carbon (soot), nitrates, and soil dust. As noted in the National Academy of Sciences report:

The major cause of reduced visibility in the East is sulfate particles, formed principally from sulfur dioxide (SO2) emitted by coal combustion in electric utility boilers. In the West, the other four particle types play a relatively greater role than in the East. The causes and severity of visibility impairment vary over time and from one place to another, depending on meteorological conditions, sunlight, and the size and proximity of emission sources.3

Humidity also plays a role. Because moisture in the air can facilitate the formation of fine particles in atmospheric reactions, visibility in the East would generally be less than that in the arid West, even in the absence of air pollution. Estimates of the natural visual range in the East are on the order of 90-100 miles, versus 140-150 miles in the West. Because of pollution, however, the current visual range in the East is only one-fifth of the natural range, whereas in the West it is half to two-thirds what it would otherwise be.

ENDNOTES

1Committee on Haze in National Parks and Wilderness Areas, National Research Council, National Academy of Sciences, Protecting Visibility in National Parks and Wilderness Areas (Washington: National Academy Press, 1993), p.1. Hereafter cited as NAS Report.

2 There may also be health benefits related to the reduction of fine particle pollution, but the proposed regulations are aimed primarily at improving welfare, not health.

3 NAS Report, p. 2.