Out of Sight: The Science and Economics of Visibility Impairment Executive Summary

Transcription

1 Abt Associates Inc. # 4800 Montgomery Lane # Bethesda, MD # Out of Sight: The Science and Economics of Visibility Impairment Executive Summary

2 Out of Sight: The Science and Economics of Visibility Impairment Executive Summary Prepared for Clean Air Task Force Boston, MA Project Manager: Dr. L. Bruce Hill Prepared by Abt Associates Inc Montgomery Lane Bethesda, MD

3 EXECUTIVE SUMMARY Introduction Visibility impairment is a basic form of air pollution, one that people can see and recognize without special instruments. It is also one of the scientifically best-understood byproducts of fossil fuel combustion. Despite this common knowledge, many people do not recognize the full costs of impaired visibility. Some people are not aware that visibility is impaired at all, incorrectly believing that the milky-white haze that blankets parts of the country is somehow a natural phenomenon associated with humidity, especially on hot summer days. In fact, visibility impairment is a major problem in the United States, with both aesthetic and economic consequences. A variety of sources contribute to the air pollutant emissions that lead to visibility impairment, including power plants, motor vehicles, wildfires and industrial processes like smelting. The largest source in many areas is power plant emissions. This report is meant to give the educated reader a basic understanding of the nature and science of visibility impairment and to provide an overview of the economic costs of visibility impairment due to sources such as power plants. Types And Causes of Visibility Impairment Visibility impairment comes in a variety of forms: intrusive plumes from local smokestacks, a dirty low-lying cloud layer, a milky haze blanketing the view in all directions. Each type of visibility impairment occurs due to the nature and source of emissions and the prevailing meteorological conditions (Malm, 1999, p. 20). With stable atmospheric conditions and large, local emission sources, plumes and layered hazes are likely to occur. When atmospheric conditions are more turbulent and emissions arrive from distant sources, a regional haze can occur. Plumes, layered haze, and regional haze differ from the clouds and fog that we might see on a rainy day, and instead are manmade impediments to visibility that federal, state, and local governments are actively trying to reduce. For regulatory purposes, the Environmental Protection Agency distinguishes between visibility impairment that is caused by one or a small group of sources, such as a the plume from a smoke stack, and visibility impairment that is caused by emissions over a wide geographic area. The distinction is made because emissions over a wide area are more diffuse and less easy to attribute to specific sources and, thus, more difficult to identify and control. Abt Associates Inc. ES-1

4 Most visibility impairment is caused by manmade air pollution, often carried by the wind hundreds of miles from where it originated. The large coal-fired electric utilities in the Ohio valley, some with stacks approaching 1000 feet tall, contribute to visibility problems over a wide area of the Eastern U.S. (Exhibit ES-1). Other contributors include motor vehicles, industrial fuel burning, manufacturing operations, and natural sources such as windblown dust, volatile organic compounds from plants, and soot from wildfires. Exhibit ES-1 National Emissions of Nitrogen Oxides and Sulfur Dioxide by Source in % 60% 50% 40% 30% 20% Nitrogen Oxides Sulfur Dioxide These emission sources contribute primary particles, which are particulates emitted directly into the air, and secondary particles, which form from gases often carried many miles from their source. Both primary 10% 0% Electric Utilities Industry Transport Other emissions and secondary formation of particles contribute to visibility impairment. Primary particles come from a variety of sources including diesel and wood combustion, and dust from industrial activities and natural sources. Secondary particles form in the atmosphere from gases emitted from power plants, cars, and a number of other sources, and are the most important in forming haze. In many areas, sulfate is the most important secondary particulate. Some particles, like sulfates and nitrates become more effective during humid conditions as they absorb water and grow (Day et al., 2000, p. 716; Sisler, 1996, p. 4-7; U.S. EPA, 1996, p. 8-44). Sulfates and nitrates can more than triple in size as relative humidity increases, thus making visibility worse during periods of high humidity, such as the humid summer months in the East (National Research Council, 1993, p. 103). However, humidity alone does not cause visibility impairment. In the eastern U.S., sulfates account for the majority of visibility impairment. In the West, sulfates and organic carbon play about equal roles. Throughout the U.S., nitrates typically account for less than 10 percent of visibility impairment in most locations. Measuring Visibility Impairment To conduct meaningful analyses of how visibility changes due to the presence of pollution in the atmosphere, there must be some standardized approach to measuring visual air quality. Visibility conditions are, therefore, commonly expressed in terms of three mathematically related metrics: visual range, light extinction, and deciviews. Standard visual range is the metric best known by the general public. It is the maximum distance at which one can identify a black object against the horizon, and is typically described in miles or kilometers. Higher visual range estimates mean better visibility. Light extinction is a somewhat better alternative than visual range because it allows one to express the relative contribution of a PM constituent to overall visibility impairment. Light extinction is the sum of the light scattering and light absorption by particles and gases in the atmosphere. Higher extinction values Abt Associates Inc. ES-2

5 mean worse visibility. This is the inverse of visual range, where higher visual range estimates suggest better visibility (U.S. EPA, 1996, p. 8-56). Deciview index provides a linear scale for perceived visual changes over the entire range of conditions. On a particle-free, pristine day, the deciview index has a value of zero. For each 10 percent increase in lightextinction, the deciview index goes up by one. So, higher deciview values mean worse visibility (Exhibit ES-2). Under many scenic conditions, a change of one deciview is considered to be just perceptible by the average person. However, it is important to understand that the same amount of pollution can have dramatically different effects on visibility depending on existing conditions. Most importantly, visibility in cleaner environments is more sensitive to increases in particle concentrations than visibility in more polluted areas. Exhibit ES-2 Inverse Relationship Between Visual Range and the Deciview Index (Source: NPS-CIRA, 2000) Visual Range (km) Grand Canyon Good Day Shenandoah Good Day Shenandoah Median Day Shenandoah Bad Day Deciview Index Trends in Visibility Impairment Visibility conditions vary across the United States. Rural areas in the East generally have higher levels of impairment than most remote sites in the West. Visibility has generally worsened between the late 1940s and early 1980s, especially during the summer in the Southeast. This decline in visibility is closely matched with an increase in sulfur emissions (Malm, 1999, Figure 6.16b). Over the last decade visibility has marginally improved in some national parks, however there are clearly problem areas. In Exhibit ES-3, we present photographs to capture the range of visibility conditions at two well-known parks, Grand Canyon and Shenandoah. Abt Associates Inc. ES-3

6 In Exhibits ES-4 and ES-5, we present visibility measurements from 1988 to The National Park Service (NPS-CIRA, 2000) sorted each park's daily visibility measurements from low to high for each year, and placed them into three groups for analysis: good visibility days are the lowest 20 percent of daily measurements, mid-range days are the middle percent, and poor visibility days are those days above the 80 th percentile of the ordered data. We then plotted the annual average visibility measurement for each of these categories. To put the visibility category ranges observed at each park into perspective, we present actual photographs that represent the deciview levels for each national park for the good and poor visibility categories. Exhibit ES-3a Extreme Visibility Days at Grand Canyon National Park (Air Resource Specialists Inc., 1997, Img0010.pcd and Img0024.pcd) Excellent Visibility Day (0 deciviews) Bad Visibility Day (22 deciviews) Exhibit ES-3b Extreme Visibility Days at Shenandoah National Park (Air Resource Specialists Inc., 1999, Img0001.pcd and Img0011.pcd) Excellent Visibility Day (4 deciviews) Bad Visibility Day (44 deciviews) Abt Associates Inc. ES-4

7 Exhibit ES-4 Visibility Trends at Grand Canyon National Park, Arizona ( Photos: Air Resource Specialists Inc., 1997, Img0015.pcd and Img0023.pcd; IMPROVE data: NPS-CIRA, 2000) Grand Canyon National Park Measurements of haze (in deciviews) and its effect on visibility Deciviews Year Good Visibility Days Mid-Range Poor Visibility Days Good Visibility Day (5 deciviews) Poor Visibility Day (13 deciviews) Abt Associates Inc. ES-5

8 Exhibit ES-5 Visibility Trends at Shenandoah National Park, Virginia ( Photos: Air Resource Specialists Inc., 1999, Img0082.pcd and Img0085.pcd; IMPROVE data: NPS-CIRA, 2000) Shenandoah National Park Measurements of haze (in deciviews) and its effect on visibility Deciviews Year Good Visibility Days Mid-Range Poor Visibility Days Good Visibility Day (16 deciviews) Poor Visibility Day (33 deciviews) Abt Associates Inc. ES-6

9 The Economics of Visibility Visibility is a commodity that cannot be bought or sold. This makes it difficult to measure what it is worth to people. Economists have taken on the challenge to devise ways of measuring the value of various types of environmental improvements, such as the improvements in visibility. One approach is to examine the economic impact of a reduction in park visitation, and an alternative approach is to directly estimate people's willingness to pay for improved visibility. Visibility Impairment and Park Visitation One approach is to measure the affect poor air quality has on a person s decision to recreate. If, because of poor visibility, a person decides to shorten their visit to a particular park, or go to another recreation site altogether, the economic impacts will be felt in the way of lost revenue at the recreation site (park fees, lodging, concessions) and lost revenue in the communities close to the site (gas, food, lodging, concessions, additional tourist attractions). While visibility degradation is likely to affect most types of outdoor recreation to one degree or another, the impacts of impaired visibility are perhaps most pronounced at national parks. It has consistently been shown that American vacationers believe that one of the leading attributes of a desirable travel destination is beautiful scenery and clean, clear air. In fact, the National Park Service (NPS, 1988) has conducted a number of studies that have examined the importance of clean air as a park feature. Park visitors perceive different degrees of visibility impairment, with hazy days detracting from their enjoyment of the park. Consistently among visitors' top priorities when visiting national parks are clear air and unobstructed views. When confronted with poor visibility at their destination, travelers shorten their stay or go elsewhere. Tourism is a big industry in the U.S., supplying a significant number of jobs. The parks employ approximately 21,000 permanent and seasonal employees (NPS, 2000), and there are over 600 concessionaires in operation throughout the national park system providing visitors with lodging, transportation, food, shops and recreational services. In 1997, the NPS collected $122.2 million in recreation fee revenue, and concessions earned $650 million (U.S. Department of the Interior, 1988). One study, conducted by the Department of the Interior, measured the state and national economic impacts associated with all travel related expenditures (Peacock et al., 1998). The study estimated that travel related expenditures by visitors to National Parks generated an average of $14.55 billion (1996$) in annual output and approximately 210,000 jobs. Including all lands managed by the Department of the Interior, the study found annual economic impacts increased to $35 billion (1996$) and 500,000 jobs. To measure the impact tourism has on communities adjacent to or near national parks, the NPS developed the Money Generation Model (MGM) to generate quick and inexpensive benefit estimates (NPS, 1998). The model estimates three types of economic benefits generated by park visitors: 1) income to local businesses; 2) increases in local area tax revenues; and 3) new jobs. We use MGM to demonstrate the potential impact on the local communities of seven popular destinations located through out the country: Acadia National Park, Big Bend National Park, Grand Canyon National Park, Great Smoky Mountains National Park, Indian Dunes National Lakeshore, Mt. Rainier National Park, and Shenandoah National Park. We considered two scenarios for each park. In the first scenario, we assumed that visibility improves enough to increase visitation at the park by 10 percent. In the second scenario, we assumed that visibility improves enough to increase visitation at the park by 25 percent. For these changes in visitor activity at each of these parks, there are potentially large positive benefits to be gained (Exhibit ES-6). However, the benefits Abt Associates Inc. ES-7

10 are very rough estimates. The change in visitation is hypothetical, and the MGM is a simple model that provides only rough estimates of economic benefits. Exhibit ES-6a Sales Increase Near Park Due to an Increase in Park Visitation % Increase in Visitation 25% Increase in Visitation 250 Sales Benefit (millions 1999$) Acadia Big Bend Grand Canyon Great Smoky Indiana Dunes Mt. Rainier Shenandoah National Park Exhibit ES-6b Tax Revenue Increase Near Park Due to an Increase in Park Visitation 25 10% Increase in Visitation 25% Increase in Visitation Tax Revenue Benefit (millions 1999$) Acadia Big Bend Grand Canyon Great Smoky Indiana Dunes Mt. Rainier Shenandoah National Park Abt Associates Inc. ES-8

11 Exhibit ES-6c Local Job Increase Near Park Due to an Increase in Park Visitation % Increase in Visitation 25% Increase in Visitation Jobs Created Acadia Big Bend Grand Canyon Great Smoky National Park Indiana Dunes Mt. Rainier Shenandoah The Non-Market Value of Visibility Another approach to value visibility is to survey people and ask their willingness to pay for better visibility. The most common method is known as the contingent valuation (CV) method. CV studies present people with a series of photographs of the same location at different visibility levels, and ask what they would be willing to pay each year to have visibility improve. While CV studies are still controversial because of their hypothetical nature, there has been much progress in designing studies to minimize the pitfalls and to maximize the likelihood that subjects clearly understand what it is they are being asked to value and that their answers will reflect their true willingness to pay. CV studies have considered two broad measures of visibility benefits: recreational and residential. Recreational visibility refers to people's willingness to pay for visibility improvement at national parks and wilderness areas, and residential visibility refers to people's willingness to pay for visibility improvement around their home. A number of researchers have looked at these visibility measures, and the results of their work are useful when estimating the impact of a regulatory action aimed at visibility improvement. The value of visibility improvements due to a particular policy scenario has been a regular component of regulatory impact analyses for years. In each analysis, the policy-specific relationship between the amount of improvement in visibility and the average value households place on that improvement has been estimated, resulting in a range of benefit results. Exhibit ES-7 displays various recreational and residential visibility benefit totals that have been estimated for significant air quality policies over the last decade. While the results show a number of cases where there are substantial benefits, the results are not easily comparable since the geographic coverage and policy emphasis have varied from analysis to analysis. For example, the Section 812 Retrospective and Prospective Analyses measured visibility changes over the entire nation, while the Section 126 and NO x SIP Call Analyses only estimated visibility changes over a portion of the nation. In another Abt Associates Inc. ES-9

12 instance, the Haze Rule was specifically designed to improve visibility and has relatively large visibility benefits, while the Tier 2 Rule is not focused on visibility improvement and the benefits are relatively small. Exhibit ES-7 Visibility Benefits from Different Policy Analyses 7000 Benefits (millions 1999$) Prospective 812 Retrospective Haze Rule Ozone/PM NAAQS Tier 2 NAPAP/Title IV Navajo NOx SIP Call Section 126 [ National ] [ Regional ] Policy Analysis Recreational Benefits Residential Benefits Power Plant Emissions and Visibility Benefits A series of legislative, regulatory and legal options are being considered to decrease sulfur dioxide (SO 2 ) and nitrogen oxide (NO x ) emissions from power plants in the United States. Although power plant emissions are currently regulated, and further reductions are required, power plant emissions still contribute to visibility impairment. In this hypothetical example, we estimate what visibility impairment would be in 2007 with the status quo policy, and what it would be if we were to shift to a policy that eliminates power plant emissions. To give a rough idea of the impact EGU emissions have on a National Park with significant visibility problems, we used WinHaze, a visual air quality model, to generate photographs of a poor visibility day for the status-quo and no-egu scenarios in Great Smoky Mountains National Park (Exhibit ES-8). We estimated the monetary value for two broad categories of visibility benefits: (1) changes in residential visibility i.e., the visibility in and around the locations where people live; and (2) changes in recreational visibility at Class I areas i.e., visibility at Class I national parks and wilderness areas. Abt Associates Inc. ES-10

13 The results of the analysis estimate that status-quo EGU emissions in the year 2007 will cost the United States $3.4 billion (1999$) in foregone residential visibility benefits and $4.3 billion (1999$) in foregone recreational visibility benefits (Exhibits ES-9 and ES-10). In total, EGU emissions will cost the United States $7.7 billion in foregone total visibility benefits. Of course, the full extent of these foregone benefits will never be realized because EGU emissions will never be completely eliminated. These foregone visibility benefit totals, however, reflect the potential for substantial visibility-related benefits if EGUs were to reduce emissions beyond current levels. Exhibit ES-8 WinHaze Split-Image of a Poor Visibility Day at Great Smoky Mountains National Park for the Status Quo and No-EGU Scenarios Status Quo (visual range=20km) No-EGU (visual range=43km) Abt Associates Inc. ES-11

14 Exhibit ES-9 State-Level Residential Visibility Benefits State Monetary Benefits (1999$) State Monetary Benefits (1999$) Alabama $74 Nebraska $149 Arizona $35 Nevada $5 Arkansas $8 New Hampshire $19 California $61 New Jersey $25 Colorado $14 New Mexico $139 Connecticut $56 New York $4 Delaware $9 North Carolina $4 District of Columbia $17 North Dakota $270 Florida $208 Ohio $183 Georgia $123 Oklahoma $33 Idaho $46 Oregon $8 Illinois $3 Pennsylvania $230 Indiana $190 Rhode Island $16 Iowa $114 South Carolina $66 Kansas $28 South Dakota $8 Kentucky $71 Tennessee $95 Louisiana $37 Texas $170 Maine $93 Utah $6 Maryland $124 Vermont $132 Massachusetts $17 Virginia $10 Michigan $167 Washington $27 Minnesota $47 West Virginia $81 Mississippi $93 Wisconsin $29 Missouri $38 Wyoming $2 Montana $3 TOTAL $3,385 Abt Associates Inc. ES-12

15 Exhibit ES-10 State-Level Recreational Visibility Benefits State Benefits (millions 1999$) State Benefits (millions 1999$) Alabama $2.1 North Dakota $16.8 Arkansas $1.6 New Hampshire $6.0 Arizona $293.3 New Mexico $20.6 California $218.7 Nevada $0.1 Colorado $152.6 Oregon $10.0 Florida $58.6 South Dakota $95.0 Idaho $5.8 Tennessee $1,839.2 Kentucky $147.8 Texas $44.4 Maine $327.8 Utah $142.3 Michigan $20.6 Virginia $128.3 Minnesota $97.2 Vermont $0.6 Missouri $2.3 Washington $263.8 Montana $69.4 West Virginia $4.4 North Carolina $6.8 Wyoming $277.7 References Air Resource Specialists Inc Grand Canyon National Park Arizona: IMPROVE Monitoring Network Permanent Photographic Archive , Slide Spectrum. September. Prepared for the IMPROVE program, NPS Contract #CX Fort Collins, CO. Air Resource Specialists Inc Shenandoah National Park Virginia: IMPROVE Monitoring Network Permanent Photographic Archive , Slide Spectrum. Prepared for the IMPROVE program, NPS Contract #CX Fort Collins, CO. Day, D.E., W.C. Malm and S.M. Kreidenweis Aerosol light scattering measurements as a function of relative humidity. J Air Waste Manag Assoc. Vol. 50(5): Malm, W.C Introduction to Visibility. Cooperative Institute for Research in the Atmosphere (CIRA). Fort Collins, CO. Cooperative Agreement. May. National Park Service Air Quality in the National Parks. National Park Service, Air Quality Division. Denver, Colorado. Natural Resources Programs, Natural Resources Report National Park Service The Money Generation Model. Executable dated March 4. National Park Service, Public Use Statistics Office. Abt Associates Inc. ES-13

16 National Park Service Recreation Visits May. National Park Service, Public Use Statistics Office. National Park Service (NPS) and the Cooperative Institute for Research in the Atmosphere (CIRA) IMPROVE Data Available at FTP Site. Downloaded May 28. National Park Service, Air Resources Division - Cooperative Institute for Research in the Atmosphere, Colorado State University. Fort Collins, CO. National Research Council Protecting visibility in national parks and wilderness areas. National Academy Press: Washington, DC. Peacock, B., C. Killingsworth and B. Simon State and National Economic Impacts Associated with Travel Related Expenditures by Recreational Visitors to Lands Managed by the U.S. Department of the Interior. U.S. Department of the Interior. January 16. Sisler, J.F Spatial and Seasonal Patterns and Long Term Variability of the Composition of the Haze in the United States: An Analysis of Data from the IMPROVE Network. Colorado State University, Cooperative Institute for Research in the Atmosphere. Fort Collins, CO. July. U.S. Department of the Interior Recreational Fee Demonstration Program, Volume I Overview and Summary. Progress Report to Congress. January 31. U.S. EPA Air Quality Criteria for Particulate Matter. Volume II. U.S. EPA, Office of Research and Development. Washington, DC. EPA-/600/P-95/001bF. April. Abt Associates Inc. ES-14

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