National Parks Conservation Association
The Benefits and Costs of Multi Pollutant Legislation
Before the Environment and Public Works Committee
June 12, 2002
Mr. Chairman and members of the Committee, I am Don Barger, the Southeast Regional Director for the National Parks Conservation Association (NPCA). Thank you for the opportunity to testify about the national park-related benefits and costs of reducing multiple pollutants from power plants.
NPCA is America’s only private, nonprofit advocacy organization dedicated solely to protecting, preserving, and enhancing the National Park System. NPCA was founded in 1919 and today has more than 350,000 members who care deeply about the well being of our national parks. Protecting and restoring air quality in America’s national parks, including the 49 national park units defined as Class I areas by the 1977 Clean Air Act amendments, long has been one of NPCA’s top priorities.
Our nation creates and preserves national parks because of their spectacular, inspirational, scientific and historical value as pieces of America’s natural and cultural heritage. They are irreplaceable, priceless icons. Our national parks are sanctuaries sought by the American people for countless reasons and at innumerable times. Air pollution is among the most significant of the many threats our parks face. Because America’s national parks are priceless, our testimony focuses primarily on the costs air pollution levies on these national treasures that are so central to the American spirit and to our national identity.
We will begin our testimony by discussing the centrality of clean air to the purpose of many national parks. We will briefly discuss the legislative framework that governs the management and preservation of national parks, next discuss the negative impact of air pollution on the parks, and then describe the benefits of protecting the scenic values and other precious resources that comprise our parks. Finally, we will outline the impact of specific regulatory approaches on protecting the air in our national parks.
Our national parks – places where polls consistently show Americans expect to breathe clean air and be inspired by spectacular vistas – have become unfortunate laboratories for studying the impacts of air pollution on our nation’s natural and historic treasures. Americans are shocked to learn that many of our beloved national parks suffer from some of the highest levels of air pollution in the country. While visibility impairment is widespread throughout the park system, scenic views are not the only resource at risk. The same pollutants that reduce visibility also contribute to 30,000 premature human deaths each year. Acid deposition damages natural and cultural resources. Mercury deposition threatens fish and wildlife in a number of parks. Ground level ozone, or smog, threatens the health of park visitors and workers, and damages park vegetation. Finally, as the Bush Administration’s 2002 U.S. Climate Action Report concludes, global warming threatens parks in many ways, from rising sea level to melting glaciers to changes in biodiversity.
NPCA fully supports S. 556, the Clean Power Act, because it would best protect our parks. The bill requires effective, timely, and fair reductions of four key pollutants emitted by power plants – sulfur dioxide, nitrogen oxide, carbon dioxide, and mercury. The authors of S.556 recognize that significant and mandatory reductions by a date certain in these pollutants are essential elements of a responsible approach to this issue. Reductions in carbon dioxide are essential to provide certainty that new electric power plants must include controls from the beginning, rather than retrofitting years later, and to ensure that coal, a domestically abundant fuel, is burned as cleanly as possible.
In 1916, Congress created the National Park System and required the National Park Service to “conserve the scenery and the natural and historic objects and the wild life therein… and leave them unimpaired for the enjoyment of future generations.” Many national parks were established in part to offer the public access to inspirational scenic vistas and clean air, as reflected in their legislative histories:
“ The air around Lake McDonald is remarkably clear and pure…” 
“The Big Bend area is a region of inspiring scenery…”
“…the Grand Canyon of the Colorado is one of the most stupendous scenic wonders of the world…” 
“…For the purpose of protecting the scenery, the wildlife, and other natural features of the region authorized to be established as the Everglades National Park…”
Scenic vistas cannot inspire if they cannot be seen. The National Park Service must maintain the integrity of these scenic values while also ensuring that cultural, historic, and natural resources are not impaired by air pollution.
Congress amended the Clean Air Act in 1977 to address growing concerns about pollution damaging public lands and Americans’ enjoyment of their national treasures. Recognizing that pristine air quality and scenic vistas are highly valued features of national parks, Section 169 (A) established as a national goal “the prevention of any future, and the remedying of any existing, impairment of visibility in mandatory federal Class I areas in which impairment results from man-made pollution.” Congress designated 156 areas including national parks over 6,000 acres and wilderness areas over 5,000 acres in existence on August 7, 1977 as “Class I areas,” to be afforded the greatest protection under the Clean Air Act. (Attachment 1)
The 1977 amendments also created specific programs to deal with chronic threats to park resources. They charged the Secretary of the Interior and other federal officials with the “affirmative responsibility” to protect “air quality related values” in Class I areas. These officials must participate in the Prevention of Significant Deterioration (PSD) program, part of the permitting process for new and modified air pollution sources, by determining if the emissions will have an adverse impact on park resources. The 1977 Amendments also established the Best Available Retrofit Technology program to require certain existing sources located in close proximity to a class I area to install pollution controls.
Twenty-five years after Congress established the national visibility goal to remedy existing and prevent future man-made visibility impairment in Class I areas, unnatural haze continues to shroud scenic vistas at national parks throughout the country. Emissions from outdated power plants, lacking controls required of modern facilities, contribute a large portion of the pollution hurting our parks. National Park Service photos contrast good and poor visibility in a few of America’s national parks established for their spectacular and inspirational scenery. (Attachment 2)
The National Park Service and U.S. Fish and Wildlife Service reported in December 2000 that pervasive “visibility impairment in all national parks and wilderness areas” is adversely affecting these public lands. According to the Department of the Interior, “Visibility impairment is the most ubiquitous air pollution-related problem in our national parks and refuges…parks and refuges such as Grand Canyon, Cape Romain, and Great Smoky Mountains have evidenced declining visibility…all areas monitored for visibility show frequent regional haze impairment.” The EPA reports that the mean visual range in Eastern Class I areas was 14.4 miles in 1999, compared to estimated natural visibility of 45-90 miles. In the West, the mean visual range was 48 miles for Class I areas, compared to estimated natural visibility of 120-180 miles.
Congress realized that unnatural haze was both a national and a regional problem, and revisited the problems of polluted parks in the 1990 Amendments to the Clean Air Act. Section 169B designated funds to research “sources and source regions” contributing to visibility impairment. Studies and reports verified widespread assumptions, and EPA promulgated the Regional Haze Rule in 1999. The Regional Haze Rule seeks to improve visibility by 2064 attempting to fulfill the national goal of “the prevention of any future, and the remedying of any existing” visibility impairment. EPA set decade benchmarks to ensure that the “least impaired” or clearest visibility days would suffer no degradation and the “most-impaired” or haziest days would improve.
EPA reported to Congress in November 2001 that from 1994-1998, on the clearest days, 13% of the monitored Class I areas have shown improvement while 87% have shown no change or degradation. On the haziest days, 11% have shown improvement while 89% have shown no change. Any improvement on the haziest days is still slight at best.
Emissions from power plants harm national parks throughout the country, from Acadia in Maine, to Shenandoah in Virginia, to Mammoth Cave in Kentucky, to Big Bend in Texas, to Mesa Verde in Colorado, to Canyonlands in Utah, to Mount Rainier in Washington State, to Sequoia-Kings Canyon and Joshua Tree in California. Air pollution poses one of the top threats to America’s parks.
NPCA included Great Smoky Mountains National Park in Tennessee and North Carolina and Big Bend National Park in Texas on its 2002 list of America’s Ten Most Endangered National Parks, because they represent the many national parks suffering from poor air quality. Others also recognize the threats posed by air pollution to parks and people. In a letter to President George W. Bush dated June 19, 2001, Tennessee Senator Fred Thompson wrote: “Most shocking to me is that, according to Park officials, air quality in the Smokies is so poor during the summer months that hiking our backcountry trails is more hazardous to your health than walking along (city) streets…”
Great Smoky Mountains National Park serves as an unfortunate poster child of Class I areas harmed by air pollution. The park has recorded the highest level of nitrogen deposition of any monitored site (urban or rural) in North America. Clouds blanketing the highest peaks often engulf sensitive spruce-fir forests with pH levels as low as 2.0. On average, rainwater registers five to ten times more acidic than normal rainwater. Scenic views that historically stretched for more than 77 miles in the summer and more than 113 miles during the rest of the year are reduced to 15-25 miles. Researchers have documented that at least 30 different species of plants show visible symptoms of leaf damage or reduced growth from ground-level ozone, including up to 90% of black cherry trees in locations throughout the park. On 140 days over the last four summers, the National Park Service has had to issue “unhealthful air” notices to employees and park visitors as ground-level ozone levels reached unhealthful levels. The park’s average daily ozone levels are often two times higher than those in urban areas.
The values we have yet to discover in our national parks may be at least as significant as those about which we already know. To the extent we allow polluted air to jeopardize those values, humanity could lose extraordinary resources that could yield enormous benefits in the future. For example, scientists announced in May 2002 discovery of organisms in a pool in Mammoth Cave that they believe may be an important anti-cancer agent. (Attachment 3) At Great Smoky Mountains National Park, only two years of study as part of the All-Taxa Biodiversity Inventory have documented 1500 species previously unknown in the park, and 250 species completely new to science. Both of these parks suffer from air pollution and acid deposition that could threaten many of these remarkable organisms.
Glacier National Park preserves more than 1 million acres of forests, alpine meadows, and lakes. Its spectacular glaciated landscape hosts one of the largest intact ecosystems in the lower 48 states.
The largest remaining glaciers at Glacier National Park in Montana are
now only about one-third the size they were in 1850, and one study estimates
that all glaciers in the park may disappear completely in 30 years. Our testimony includes two photos, one taken
in 1938 and one in 1981 of the Grinnell Glacier. By 1993, the glacier shrank about 63 per cent in area and had
receded more than half a mile since 1850.
(Attachment 4) The area of the
park covered by glaciers declined by 73 percent from 1850-1993. A regional
warming trend that some scientists believe may be related to global climate
change causes this phenomenon. Since 1900, Glacier National Park's average
summer temperatures have increased by about 1.8 degrees Fahrenheit.
Florida’s Everglades are the largest remaining subtropical wilderness in the United States. Water management and development systems have dramatically altered freshwater flow through the Everglades, with consequences ranging from contaminated freshwater aquifers to near-decimation of wood stork populations. While an unprecedented restoration effort is now underway, some scientists are concerned that the Everglades faces an even greater threat in rapidly rising seas and climate changes associated with global warming.
The sea along the Florida coast is rising today at a rate equivalent to 8-16 inches per century, a rate that is 6-10 times faster than the average rate for this area over the past 3,000 years. By 2100, the best available science indicates that south Florida seas will be approximately 20 inches higher than they were in 1990. EPA researchers estimate that the south Florida sea probably will rise 30 inches above 1990 levels by 2150. This would mean that most of Everglades National Park could essentially become an extension of Florida Bay, washing away the $7.8 billion Everglades ecosystem restoration plan that this Committee helped design.
The four national parks and preserves of south Florida are home to sixteen endangered and six threatened wildlife species. Scientists are concerned that the remaining populations of endangered species such as the Florida panther and key deer could be pushed even closer to extinction as their habitats are further limited by rising seas and sprawling human settlements.
The Energy Information Administration (EIA) of the Department of Energy released on November 9, 2001 a comprehensive official accounting of emissions changes from 1990-2000. According to the report, total U.S. carbon dioxide emissions increased by 16.8% during this period, with carbon dioxide emissions from electricity generation increasing 26.5%. Carbon dioxide comprises 82% of the greenhouse gases emitted in the United States, and power plants emit 40% of that carbon dioxide. Mandatory reductions clearly are needed to reduce the impacts we face from global warming.
Because mercury is a dangerous, persistent poison that accumulates through the food chain and can result in neurodevelopmental damage in young children and the unborn, trading to allow more mercury pollution in some places than in others is dangerous and ill advised. As a potent neurotoxin that persists in the environment and bioaccumulates in the food chain, mercury pollution demands an aggressive policy response.
Power plants are the largest uncontrolled sources of mercury deposition in the United States. National parks including Acadia, Isle Royale, and Big Bend are studying the effects of mercury contamination on fish and wildlife. Scientists at Acadia have concluded that aquatic resources are at risk from mercury contamination. Scientists at Big Bend believe that above-threshold levels of mercury may be causing reproductive failures among Peregrine Falcons – a species listed as “Endangered” following catastrophic impacts from the pesticide DDT, and de-listed in 1999. Florida has issued fish consumption advisories for water bodies found in Everglades National Park due to high levels of mercury found in largemouth bass and other species. Mammoth Cave has also been affected by a statewide fish consumption advisory due to mercury on all rivers and streams in Kentucky. Forty-one states and territories have issued fish consumption advisories due to mercury contamination.
For the first time, Mammoth Cave and Great Smoky Mountains National Parks during 2002 have begun monitoring atmospheric deposition of mercury. On April 25, the Kentucky Division for Air Quality began monitoring ambient levels of mercury at Mammoth Cave. Preliminary modeling data indicates that episodic plumes of mercury many times expected background levels enter the park and can remain up to 24 hours. Mercury monitoring has been in place since 1995 in the Everglades as part of the National Atmospheric Deposition Program Mercury Monitoring Network. Everglades registers some of the highest levels of mercury deposition of any site across the country. (Attachment 5)
Visitors to national parks and wilderness areas consistently rate visibility and clear scenic vistas as one of the most important aspects of their experience. Out of Sight: Haze in our National Parks, a report published in 2000 by Clear the Air (Attachment 6) found that, given the degree to which air quality and visibility influence visitor experience in the national parks, continuing declines in visibility of park vistas could reduce visitation to these national treasures. The report also found: “increases in visibility could raise park visitation by as much as 25 percent which could yield approximately $30 million in increased fee collection and $160 million in additional concession sales. This would in turn add nearly $700 million in retail sales to the economies around the park, $53 million in local tax revenue, and create 15,896 jobs.”
Based on the public’s willingness to pay for cleaner air where they live and in national parks and wilderness areas, the report estimates the value of eliminating haze from power plants at more than $7 billion annually. The report cites studies that found that the average household in the southeast would be willing to pay $68 (in 1999 dollars) a year for a 100 percent increase in visibility in national parks in that part of the country, and $84 (in 1999 dollars) a year for a 200 percent increase in visibility. Eighty percent of respondents in a New Hampshire study said they would not accept a hazier wilderness vista in exchange for a lower electricity bill.
Recently, EPA estimated the benefits and costs of implementing the most stringent emissions-control strategy outlined by the Southern Appalachian Mountains Initiative (SAMI). This strategy, among other things, would require that all power plants be controlled to modern standards. The analysis found that this level of control would result in a $12-per-year increase in the electric bill of the average household. While not a comprehensive analysis, the study found that this SAMI strategy would reduce healthcare costs associated with respiratory illnesses such as asthma and agriculture loss from reduced tree growth. In their analysis of a strategy controlling only one pollutant– fine particulate matter (PM 2.5)– EPA estimated 8,000 fewer premature deaths and 16,000 fewer cases of acute bronchitis in children, with economic benefits ranging from $36-68 billion annually. 
At the Arlington, Virginia hearing on EPA’s proposed Best Available Retrofit Technology amendment to the Regional Haze Rule in August 2001, realtor Mary Johnson testified about a quick survey she had done on the Multiple Listing Service of listed properties near Great Smoky Mountains National Park. By comparing properties that were in every way “comparables” except for the existence of a “mountain view”, she found that the value of that view ranged around $25-$30 per square foot. If one were to assume that even 1/100th of that value would increase with improved views, the economic benefit derived would dwarf every other consideration.
The natural and cultural values protected by the National Park Service are beyond price. At what price would we sell the biodiversity of the Great Smoky Mountains, the mystery of Carlsbad Caverns or the meaning of the Statue of Liberty? However, there are many measurable direct monetary benefits produced by our parks, particularly as they relate to gateway communities adjacent to them.
National Park Service units hosted more than 275 million recreational visits in 2001.
They serve as economic anchors in many communities, providing jobs within the parks and fostering economic opportunity outside park boundaries. Occasionally, park economies actually replace declining sectors of existing rural economies, and can soften what could otherwise be a significant economic blow to declining economic opportunity in some rural communities. Enactment of S. 556 not only would improve the condition of park resources and help protect them from future impairment, it would also provide a boost to park revenues and to the many gateway communities and cities whose economies benefit from the health and beauty of our national parks. In addition, the residents of gateway communities would in many cases breathe healthier air.
A Department of Interior study cited in the report found that travel-related expenditures by visitors to national parks totaled an average of $14.55 billion (in 1996 dollars) and generated approximately 210,000 jobs. While the approximately 600 concessionaires in operation throughout the park system generated sales estimated at $650 million, the majority of revenues associated with park visitation, nine billion dollars in 1997, was spent on goods and services in communities neighboring national parks.
Great Smoky Mountains National Park, the most visited national park, receives more than 9 million visitors each year. These visitors annually spend more than $618 million in the local area, supporting more than 12,000 local tourism-related jobs and close to 15,000 total jobs due to secondary effects. Similarly, the 12 national capital parks in Washington, D.C. draw more than 15 million recreational visits per year. These tourists spent $660 million in 2000, generating approximately $202 million in direct income and more than 16,000 direct and indirect jobs in the D.C. metropolitan area.
On a strictly per-acre basis, logging the 17.7 million acres of Maine timberlands is not nearly as economically productive as the 45,000 acres of mostly undeveloped land and easements that make up Acadia National Park. While each acre of private forest annually contributes $368 in direct and indirect benefits to Maine’s economy, publicly owned Acadia yields $3,400 per acre in sales of goods and services, including $1,200 in wages. In 2000 Acadia visitors spent $130 million for meals, room rentals, campsites, services, and other transactions in nearby towns, supporting 3,300 direct and indirect jobs. Total value of primary and secondary sales was $155 million, with personal income totaling $55 million. (Attachment 7)
To improve visibility, reduce smog, and restore acidified ecosystems to natural states, emissions from power plants, regardless of when they were built, must be significantly reduced.
In Great Smoky Mountains National Park, emissions from outdated power plants produce most of the pollution threatening the resources, staff, and visitors. Power plants emit 77% of the sulfur dioxide emissions that eventually form sulfate particles. In the summer, these particles contribute 73% of the yellow or grayish layers of haze hanging over the Smokies. Power plants also emit 38% of the nitrogen oxides that combine with sunlight and other compounds to create ground-level ozone or smog. There simply is no proposal that will clear the air in our parks if it fails to require the clean up of these older, grandfathered power plants. Accordingly, a provision requiring each old power plant to install modern pollution controls by its 30th birthday, or within five years of enactment, is an essential component to multi-pollutant legislation.
The Acid Rain Program established in the 1990 Amendments to the Clean Air Act set the goal of cutting sulfur emissions 10 million tons from 1980 levels. Despite reductions made to date, acid deposition continues to be a significant threat to ecosystems. 41% of lakes in the Adirondacks suffer from chronic or episodic acidification along with 15% of lakes throughout New England. According to recent studies, sulfur emissions must be reduced by an additional 80% beyond Phase II of the Acid Rain Program to bring these ecosystems from an acidic to nonacidic state in 20 to 25 years. In Great Smoky Mountains National Park, in which streams and soils have been adversely impacted by acid deposition, the average combined nitrogen and sulfur deposition continues to be at least 6 times beyond natural conditions. To restore Class I areas to their natural state and to realize the benefits Congress envisioned when it established Class I areas 25 years ago, emissions from power plants must be reduced to levels at or beyond those proposed in S. 556.
Effects-based monitoring and evaluation of Class I areas provide an appropriate measuring stick for the efficacy of pollutant-reduction strategies. Emission-based multi-pollutant strategies must be linked to specific results. A simple cap-and-trade program offers no specific protection to Class I areas as required by the Clean Air Act. Strategies must be multi-faceted, and linked to continuous and timely progress toward effect-based goals. The New Source Review (NSR) and PSD programs currently provide the only effect-based monitoring and permitting of stationary sources of sulfur and nitrogen pollution, and we’ve seen no proposal that provides effect-based monitoring and permitting in the absence of the NSR and PSD programs.
The utilities seek certainty by requesting a phased reduction schedule with no measurement of the resulting effects and no accountability for the cumulative impact of the hundreds of proposed new sources. The certainty that such a strategy would produce for our national parks is the abandonment of America’s national commitment to our descendants that we have the wisdom to create our future without destroying our past.
Experience with the cap and trade system established in the 1990 Clean Air Act Amendments indicates the potentially devastating impacts of a national emissions cap without clear and enforceable protections against local hotspots. While emissions nationwide have been reduced, emissions affecting a number of Class I areas have increased. Due to the use of emission reduction credits under the national trading program, the Tennessee Valley Authority emitted approximately 700,000 tons of sulfur dioxide last year, 300,000 tons above their Phase II allocation. As a result of this and other factors, visibility in and around Great Smoky Mountains National Park remains consistently impaired. A similar situation exists in Florida where power plants increased their sulfur emissions from 1995-2000. (Attachment 8)
In order for federal land managers to meet their affirmative responsibility to protect the air quality related values of these precious resources, effect-based analyses as prescribed in the PSD program are necessary for any proposed sources which might individually or cumulatively adversely impact the area, regardless of distance. The Administration’s proposal to draw 50 kilometer or even 100-kilometer circles around Class I areas would provide less protection than proper implementation of the current Clean Air Act. While it would provide limited effect-based analysis within those zones, such a proposal would also create “free-fire zones” outside those circles, allowing large sources to proliferate without regard to their individual or cumulative impacts on Class I areas, impacts now analyzed in the PSD program. A cap and trade program instituted in lieu of the current effect-based programs of the Clean Air Act cannot protect Class I areas from existing or future adverse effects.
Our national parks have been called the best idea America ever had. That may become particularly true as we seek to control not just the amounts, but also the effects of air pollution. America’s parks are the measuring sticks by which the effectiveness of any national pollution control policy can be judged. If we clean up the air in our parks, we will clean up the air in our neighborhoods. If we save our parks, they may very well save us.
Enactment of S. 556 provides a critical step to protect America’s national parks. Our national parks and wilderness areas deserve and demand the protection that S. 556 will provide; the American public expects no less.
A May 2001 poll showed that nearly eight out of ten Virginians (77%) believed older power plants should meet modern pollution control standards. In a 1996 survey, 84% of visitors at Great Smoky Mountains National Park responded that scenic views are “extremely important.” The National Park Service conducted similar studies in the mid 1980’s, surveying visitors at five parks on the importance of various park features to their recreational experience. At all five parks – Grand Canyon, Mount Rainier, Everglades, Mesa Verde and Great Smoky Mountains--“clean, clear air” ranked among the top four valued features. A 1998 survey of Tennessee residents showed that 75% of the citizens wanted new rules to control emissions from power plants, while 85% thought that all plants should be required to meet the same standards regardless of when they were built. From the same survey, 69% of Tennesseans were willing to pay at least $12/year more on their electric bills, including some who were willing to pay up to $240/year more, to reduce air pollution from electricity generation.
We are eager to work with the Committee to fulfill the vision of the Clean Air Act to protect and restore air quality in America’s national parks. We must work together to meet the goals of the 1977 Clean Air Act Amendments to prevent future impairment and remedy existing visibility impairment in all Class I areas.
While we greatly appreciate the opportunity to appear before you today, we are compelled to note that the last oversight hearing specifically to address impacts of air pollution on national park units was held 17 years ago in May 1985 by the House Subcommittee on National Parks and Recreation. That hearing, chaired by the late Rep. Bruce Vento of Minnesota, focused on the damage acid rain, regional haze, and ozone were causing in national parks. An oversight hearing to provide a comprehensive update from scientists, park officials, and others concerning the range of pollutants and their impacts in national parks would be useful as Congress considers changes in the Clean Air Act. We respectfully request that this Committee schedule a hearing in the near future dedicated to impacts of air pollution on America’s national parks.
Thank you for inviting NPCA to appear before you today and for considering our views.
1: National Park Service, Class I areas.
2: National Park Service, Good and poor visibility days in selected national parks.
3: Environmental News Service, “Mammoth Cave Bioprospecting Produces Potential Cancer Drug,” May 21, 2002.
4: USGS, photos of the Grinnell glacier in Glacier National Park in 1938 and 1981.
5: National Atmospheric Deposition Program: Mercury Deposition Network map showing mercury advisories and deposition at sites across the country, with the Everglades registering the highest levels.
6: Clear the Air, Out of Sight: Haze in our National Parks, August 2000.
7: W. Kent Olson, “Acadia’s green 45,000 acres,” Bangor Daily News, April 24, 2002.
8: U.S. PIRG, Florida’s Top Ten: Power Plants that increased emissions, 1995-2000.
 Abt Associates, The Particulate-Related Health Benefits of Reducing Power Plant Emissions, October 2000. For a quick reference to the key findings of the Abt Associates study, see Clear the Air, Death, Disease, & Dirty Power: Mortality and Health Damage Due to Air Pollution from Power Plants, October 2000, p.3; http://cta.policy.net/fact/mortality/mortalitylowres.pdf.
 U.S. Department of State, U.S. Climate Action Report 2002, Washington, D.C., May 2002, http://www.epa.gov/globalwarming/impacts/parks/index.html.
 The National Park System Organic Act of 1916 (16 USC § 1).
 16 USC § 410d.
 42 USC § 7491 (a)(2).
 42 USC § 7475.
 National Park Service Air Resources Division and U.S. Fish and Wildlife Service Air Quality Branch, Technical Information in Support of the Department of the Interior’s Request for a Rule to Restore and Protect Air Quality Related Values, December 2000, p.1-1.
 U.S. Department of the Interior to U.S. Environmental Protection Agency, Docket No. A-2000-28, September 17, 2001.
, U.S. Environmental Protection Agency, Latest Findings on National Air Quality: 2000 Status and Trends, September 2001, p.19.
 National Park Service, 2002 Air Quality Issues at Great Smoky Mountains National Park, Tennessee/North Carolina, 2002.
 US EPA website, www.epa.gov/globalwarming/impacts/mountains/index.html.
 US Geological Survey, http://nrmsc.usgs.gov/research/glacier_retreat.htm
 U.S. Department of State, U.S. Climate Action Report 2002, Washington, D.C., May 2002, http://www.epa.gov/globalwarming/impacts/coastal/cs_ever2.html
 U.S. Department of State, U.S. Climate Action Report 2002, Washington, D.C., May 2002, http://www.epa.gov/globalwarming/publications/car/index.html.
 U.S. Department of Energy, Energy Information Administration, Emissions of Greenhouse Gases in the United States 2000, http://www.eia.doe.gov/oiaf/1605/ggrpt/summary/pdf/0573(2000es).pdf
 SAMI was a voluntary 10-year consortium of state and federal agencies, business, utilities, and public interests which met to study problems faced in Class I areas in the eight Southern Appalachian states, and to seek consensus on solutions to those problems. SAMI’s final written report is due in August 2002.
 U.S. Environmental Protection Agency, National Park Service, and U.S. Forest Service, Impacts of the SAMI Strategies: An Independent Analysis of the Benefits and Economic Impacts, April 2002.
 National Park Service, Public Use Statistics Office, National Park Service Statistical Abstract 2001.
 Clean Air Task Force for Clear the Air, Out of Sight: Haze in Our National Parks, August 29, 2000.
 Department of Park, Recreation and Tourism Resources, Michigan State University, Economic Impacts of Great Smoky Mt. National Park Visitors on Local Region, 1997-2000, February 2002.
 Department of Park, Recreation and Tourism Resources, Michigan State University, Economic Impacts of National Parks on Gateway Communities; Summary of MGM2 Shortform Analyses, January 2002, pp.7-16. MGM2 is the National Park Service’s Money Generation Model version two, used to estimate park visitor impacts on local economies in terms of contribution to sales, income, and jobs. Model documentation and economic impact reports for individual parks may be found at the MGM2 website: http://www.prr.msu.edu/mgm2/mgm2toc.htm.
 W. Kent Olson, “Acadia’s green 45,000 acres,” Bangor Daily News, April 24, 2002.
 Driscoll, C.T., G.B. Lawrence, A.J. Bulger, T.J. Butler, C.S. Cronan, C. Eagar, K.F. Lambert, G.E. Likens, J.L. Stoddard, K.C. Weathers. 2001. Acid Rain Revisited: Advances in scientific understanding since the passage of the 1970 and 1990 Clean Air Act Amendments. Hubbard Brook Research Foundation. Science Links Publication. Vol. 1, no.1.
National Park Service to SAMI, Proposed Air Quality Benchmarks at Great Smoky Mountains and Shenandoah National Parks, November 7, 2001.
 US PIRG Education Fund, Darkening Skies, Trends Toward Increasing Power Plant Emissions. http://floridapirg.org/reports/darkeningskies/darkeningskiespdf.pdf. Chart at http://floridapirg.org/reports/darkeningskies/floridatopten.pdf
 The Tarrance Group, statewide poll conducted for the League of Conservation Voters Education Fund,
May 6-8, 2001, p. 10.
 Great Smoky Mountains Natural History Association and the National Park Service, Great Smoky Mountains National Park Management Folio #2: Air Quality, 1997, p. 2.
 House Committee on Interior and Insular Affairs, Subcommittee on National Parks and Recreation, Impacts of Air Pollution on National Park Units, Serial No. 99-10, May 20-21, 1985, 586 pp.