Story et al. Greater Yellowstone Area Air Quality Assessment Update Mark T. Story Gallatin National Forest, P.O. Box 130, Bozeman, MT 59771 (406-522-8573, [email protected])
Julie Shea Gallatin National Forest, P.O. Box 130, Bozeman, MT 59771 (406-587-6706, [email protected])
Terry Svalberg Bridger-Teton National Forest, 29 E. Fremont Lake Rd., Pinedale, WY 82941 (307-367-5797, [email protected])
Mary Hektner Yellowstone National Park, P.O. Box 168, Mammoth, WY 82190 (307-344-2151, [email protected])
George Ingersoll U.S. Geological Survey, Water Resource Division–Colorado District, MS 415, Federal Center, Denver, CO 80225 (303-236-4882 ex. 292, [email protected])
Abstract The Greater Yellowstone Area Clean Air Partnership (GYACAP) has recently completed an assessment update of air quality in the Greater Yellowstone Area (GYA). GYACAP consists of air resource program managers and specialists for the National Park Service; U.S. Forest Service; Bureau of Land Management; U.S. Fish and Wildlife Service; the Departments of Environmental Quality in Wyoming, Montana, and Idaho; and the Idaho National Engineering and Environmental Laboratory. The primary purposes of GYACAP are to serve as a technical advisory group on air quality issues to the Greater Yellowstone Coordinating Committee (GYCC), provide a forum for communicating air quality information and regulatory issues, and coordinate monitoring between states and federal agencies in the GYA. In 1999, GYACAP prepared an air quality assessment document for the GYCC for purposes of identifying air quality issues, conditions, pollution sources, and monitoring sites; summarizing known information; and advising the GYCC on air quality issues at the time. Five years later, GYACAP identi- fied the need to update the assessment with a focus on new information on the four primary air quality issues within the GYA: urban and industrial emissions, oil and gas development in southwest Wyoming, prescribed and wildfire smoke, and snowmobile emissions. This presentation will include a summary of the assessment update on the four main air quality issues in the GYA.
Purpose of the GYA air quality assessment as a technical advisory group on air quality issues update to the Greater Yellowstone Coordinating Commit- The Greater Yellowstone Area Clean Air Part- tee (GYCC), provide a forum for communicating nership (GYACAP) consists of air resource program air quality information and regulatory issues, and managers and specialists for the National Park Ser- coordinate monitoring between states and federal vice (NPS); U.S. Forest Service (USFS); Bureau of agencies in the Greater Yellowstone Area (GYA). Land Management (BLM); U.S. Fish and Wildlife The GYCC consists of park superintendents, for- Service; the Departments of Environmental Quality est supervisors, and wildlife refuge managers; it was (DEQ) in Wyoming, Montana, and Idaho; and the created to allow better communication and more Idaho National Energy and Environmental Labora- integrated management between the GYA land and tory. The primary purposes of GYACAP are to serve resource management agencies.
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The purpose of the assessment is to help GYA ho, and Gallatin County, Montana, sources, can be land managers maintain a basic understanding of transported to GYA lands. Montana has the largest air quality issues and help them address resources number of permitted stationary sources and the issues, foster partnerships, and secure funding. The highest total emissions of nitrogen oxides (NOx), assessment is not a decision document. It does not particulates (PM10), and volatile organic compounds make resource management decisions, and does not (VOCs). Idaho has the largest amount of permitted replace analysis needed at the project level to fulfill sulfur dioxide (SO2) and carbon monoxide (CO) the requirements of the National Environmental emissions (see Table 1). Policy Act (NEPA). The goal of the assessment is to The Montana sources are concentrated in the update the GYACAP (1999) air quality assessment Billings/Laurel area, where the largest concentration document with a focus on new information on the of petroleum refining and other industrial sources
Table 1. Stationary-source industrial emissions near the GYA (tons/year).
CO NOx PM10 SO2 VOCs Montana 2,066 5,501 1,330 13,541 2,591 Wyoming 1,488 3,436 78 5,127 689 Idaho 11,438 1,733 1,465 14,880 51 four primary air quality issues within the GYA. These in the Montana/Wyoming/Idaho area occurs. Pre- include urban and industrial emissions; oil and gas vailing western winds disperse these emissions pre- development in southwest Wyoming; prescribed dominantly to the east and away from the GYA. Peri- and wildfire smoke; and snowmobile emissions. odically, east winds can cause “upslope” conditions The GYACAP (1999) Air Quality Assessment that carry these emissions toward the Beartooth Document was prepared to provide the GYCC with and Absaroka Mountains on the Custer and Galla- comprehensive GYA air quality information, includ- tin national forests. These east winds, however, are ing an air quality legal framework; GYA air qual- usually associated with tight pressure gradients, and ity issues; current and potential impacts on GYA air are highly turbulent, with robust mixing heights and quality; GYA air quality monitoring and summary dispersion energy. The Wyoming stationary sources of known information; and needs and recommen- are energy generation, mining/minerals, and natural dations. This assessment is intended to be useful gas processing and transmission in the southwestern in agency planning documents, national forest plan part of the state; these will be discussed in detail later revisions, and NEPA documents; in facilitating air in this update. These industrial emissions, in combi- quality information exchange; and in providing air nation with minor sources and the extensive drill-rig quality information to the public and other agen- emissions in southwest Wyoming, are the major air cies. quality concern in the GYA. The Idaho sources are dominated by chemical and fertilizer manufactur- Urban and industrial emissions ing facilities in the Soda Springs and Pocatello areas, Urban and industrial emissions consist of a va- which can cumulatively combine with the energy-re- riety of industrial, petroleum refining, gas transmis- lated sources in southwest Wyoming. sion, agricultural processing, wood processing, min- The EPA AIRData base (EPA 2004b) was also ing, power generation, sand and gravel, and mining queried for currently listed non-attainment areas. sources. Most of these sources produce emissions These are geographic areas that have periodic vio- continuously, which can concentrate pollution in lations of National Ambient Air Quality Standards surrounding communities during inversions. The (NAAQS). The non-attainment areas in proximity
U.S. Environmental Protection Agency (EPA)’s to the GYA include Billings, Montana, for SO2, and
AIRData base (EPA 2004a) was queried for the to- Pocatello, Idaho, for PM10. No non-attainment ar- tal permitted major stationary sources of industrial eas around the GYA occur in Wyoming, as the only emissions, in 1999, for the Montana, Wyoming, and listed Wyoming non-attainment area is Sheridan (for
Idaho counties in and surrounding the GYA. Many PM10). of these emissions, particularly the Wyoming, Ida-
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Greater Yellowstone/Teton Clean Cities yellow buses runs on biodiesel and meets forthcom- Coalition ing EPA diesel emission requirements. Propane and The U.S. Department of Energy’s formal “Clean natural gas versions are being developed and will be Cities” designation for the Greater Yellowstone/ used in the future. The buses will be introduced in Teton Clean Cities Coalition (GYTCCC) occurred the GYA for mass transportation and a shuttling ser- on September 18, 2002. This event marked an im- vice. They will also play a pivotal role in the creation portant milestone in the energy and transportation of a rural tour district. Eventually, the tour district direction of the Greater Yellowstone region. After will not only be capable of moving visitors through- nearly five years of collaborative effort, the achieve- out the region, but also could be utilized to transport ments of regional public and private organizations local residents. The first “leg” of the tour district will were formally recognized when the GYTCCC be- be a shuttle service from Driggs, Idaho, to Jackson, came the only designated “Clean City” in Idaho, Wyoming, over Teton Pass. This will eliminate thou- Montana, or Wyoming. sands of private commuter vehicles (and associated This coalition is distinguished by the scope and emissions) from that stretch of highway each day. diversity of its stakeholders, including three states, More information on the Greater Yellowstone/Teton five national forests, two national parks, seven com- Clean Cities Coalition is available at
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USFS, NPS, BLM, Wyoming DEQ, and energy de- The final results of the modeling analyses will be velopment companies. available in early 2006. The Wyoming DEQ will con- Natural gas development is active in the Jonah II tinue to update the emissions inventory and model- and Pinedale Anticline natural gas fields. Proposed ing to evaluate cumulative NO2 incrementation on a new developments include the Jonah Infill, Pinedale periodic basis. Anticline Infill, South Piney coalbed methane, Ri- verton Dome gas, and Atlantic Rim gas. Additional Monitoring development is likely north of the Pinedale Anticline Wyoming historically has required significant in the Daniel area. air quality monitoring of industrial activity. The Wy- oming DEQ is furthering this legacy by expanding Wyoming DEQ air resource management monitoring statewide, including in the Upper Green In response to the rapidly changing oil and gas River Basin, in collaboration with industry. Since the development in the Upper Green River Basin, the fall of 2004, industry and the Wyoming DEQ have Wyoming DEQ is implementing multiple air re- funded monitoring stations established in the Jonah source management strategies: Field, near Boulder, near Daniel, and in Pinedale. Monitoring stations are also being planned near Permitting and compliance Wamsutter, South Pass, Murphy Ridge, and in the The Wyoming DEQ has a program to ensure Wyoming Range. The monitors are being strategical- that all oil and gas production units are permitted ly placed to assess actual ambient air quality impacts and that Best Available Control Technology (BACT) and also will serve as reality checks for modeling as- is utilized to control or eliminate emissions. To guide sumptions. oil and gas producers through the New Source Re- The Wyoming DEQ is increasing staffing and view (NSR) permitting process, the Wyoming DEQ funding to expand upon and implement multiple developed the Oil & Gas Production Facilities Chap- air resource management strategies. The additional ter 6, Section 2: Permitting Guidance. To address the staffing and funding have been requested for the increased activity and emission levels within the Jo- 2006–2007 budget, in addition to long-term funding nah and Pinedale Anticline gas fields, the emission from industry to directly support monitoring and control requirements and permitting process were modeling. Increased staffing in the Upper Green Riv- revised, effective July 28, 2004, with the result that er Basin is also occurring as a direct result of mitiga- more emissions are being controlled earlier in the life tion commitments by industry in records of decision of the well for single-well facilities, and controlled for environmental assessments and environmental on startup of all wells at multiple-well or drill pad fa- impact statements. cilities (WYDEQ 2004). Operators within the Jonah and Pinedale Anticline gas fields also must comply Air quality monitoring programs and with permits issued by the Wyoming DEQ for all well budgets in the Bridger-Teton and completions and re-completions, which emphasize Shoshone national forests the implementation of flareless completion technol- The southwest Wyoming gas development ac- ogy. In addition, the Wyoming DEQ is evaluating the tivity is directly upwind of the Wind River Range, permitting of drill-rig engines. which contains two Class I and one Class II wilder- ness areas (the Bridger and Fitzpatrick wilderness Emissions inventory and modeling areas and Popo Agie Wilderness Area, respectively); The Wyoming DEQ has undertaken an exten- about 2,000 lakes; sensitive wilderness and air qual- sive analysis and modeling study designed to obtain ity values; and high levels of wilderness recreation the best possible estimate of the cumulative NO2 use. The USFS is mandated by the Clean Air Act PSD increment consumption from sources impact- and the Wilderness Act to protect AQRVs, includ- ing southwestern Wyoming. The analysis focuses on ing visibility, in Class I wilderness areas. Air quality the Bridger and Fitzpatrick wilderness areas, which monitoring within the Bridger-Teton and Shoshone are federally designated Class I areas, along with the national forests’ Class I areas has been ongoing since surrounding Class II areas. The preliminary results the early 1980s. The current program consists of the of the modeling analyses indicate that the allowable following:
NO2 Class I and Class II increment levels and the • National Atmospheric Deposition Pro-
NO2 ambient air quality standard are not threatened. gram (NADP): Monitoring at Gypsum Creek
162 Greater Yellowstone Public Lands Proceedings 163 Story et al.
(Bridger-Teton National Forest) and South designed to reduce fuels in a contiguous area over Pass (Shoshone National Forest). a landscape) and pile burns (discrete piles of slash • Interagency Monitoring for Protected Vi- from timber harvest and/or thinning from fuel treat- sual Environments (IMPROVE): An aerosol ment projects). Prescribed burns are designed to monitor and an optical monitor (transmis- reduce the size, frequency, and intensity of wildland someter) located near Pinedale (above Fre- fires and improve fire control, increase predictability mont Lake) and at Dead Indian Pass north- of fire effects, and allow for smoke emissions man- west of Cody. agement. • Long-term lakes: Benchmark monitoring The SIS (smoke impact spreadsheet) model (Air at five “long-term” lakes (Hobbs, Black Joe, Sciences 2003) was used to estimate smoke particu-
Deep, Ross and Lower Saddlebag) in the late emissions (PM2.5) in the GYA. The SIS model uses Bridger, Fitzpatrick, and Popo Agie wilder- the FOFEM5 fire effects model (Reinhardt 2003), ness areas in the Wind River Range, sampled the CONSUME fuel consumption and particulate three times a year, and at another lake very emission generation model, and the CALPUFF dis- sensitive to atmospheric deposition, Up- persion model to estimate smoke emissions. Average per Frozen Lake, sampled once a year. Lake spring and fall broadcast- and pile-burned acres and
sampling protocols measure water chemistry, PM2.5 smoke emissions were tabulated by GYA unit plankton, macroinvertebrates, and several according to Society of American Foresters fuel code physical parameters. and vegetation type for 2002–2004. In addition, 10- • Bulk deposition: Two bulk deposition col- year (2005–2014) estimates of broadcast- and pile-
lectors that collect snow, rain, and dry depo- burned acres and PM2.5 smoke emissions by GYA sition, co-located with two of the long-term unit according to vegetation type and wildfire acres lakes (Black Joe and Hobbs). These sites are burned (2002–2004) were also modeled for smoke analyzed for chemical parameters. emissions (Table 2). The deposition monitoring data for the Wind The Caribou-Targhee, Bridger-Teton, and Sho- River Range NADP and bulk deposition sites indi- shone national forests had the largest numbers of cate that sulfates are decreasing while nitrates are in- acres of prescribed fires in 2002–2004, due mainly creasing. This is a common trend across the western to large number of sagebrush-treatment acres. Esti- U.S., which makes it complicated to try to relate the mated treatments for 2005–2014 include the Gallatin nitrate increases directly to accelerated energy devel- National Forest among the four largest prescribed- opment activities in southwest Wyoming. The Wind fire treatment programs in the GYA. All GYA units River Range lake chemistry data indicate a decreas- plan to increase prescribed fire treatment acreages ing trend of acid neutralizing capacity in some of the and prescribed fire smoke emissions during the next long-term lakes (i.e., lakes are becoming more acid- 10 years.
ic). Some long-term lakes are storing more nitrates, Estimated smoke emissions (PM2.5) are roughly which may lead to eutrophic conditions (Baron et al. proportional to prescribed burn acres (Figures 1 2001). A rigorous analysis of the lake data is needed and 2). Per-acre smoke emissions on the Bridger- to determine the significance of these trends. Teton National Forest were less for 2002–2004, and estimated to be less for 2005–2014 due to a high Prescribed-fire and wildfire smoke percentage of sagebrush in the prescribed fire treat- Wildfire smoke is the most dramatic air quality ment area, which produces fewer per-acre emissions impact, and prescribed fire is the predominant emis- than conifers (e.g., Douglas-fir, lodgepole pine, and sion-producing management activity practiced by spruce-fir). All GYA units would increase prescribed
the USFS and NPS in the GYA. Emissions from fire fire smoke emissions (PM2.5) during the next 10 (wildland and prescribed) are an important episodic years. The highest estimated emissions would be contributor to visibility-impairing aerosols, includ- for the Shoshone National Forest, where an aver- ing organic carbon, elemental carbon, and particu- age of 1,000 acres per year each of Douglas-fir and late matter. Wildfire impacts are increasingly difficult lodgepole pine are anticipated to be burned during to manage due to excessive fuel loads, history of fire the next decade. Over the entire GYA, yearly average exclusion, and climate change (drought and increas- prescribed fire emissions are anticipated to increase ing temperatures). Prescribed fire and fuel treat- by about 58% during the next 10 years. ment projects include broadcast burns (area burns The number of acres burned and the amount
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of smoke emissions (PM2.5) produced by wildfire age exceeded prescribed fire acreage by five times are much larger than the numbers of acres burned and wildfire smoke emissions (PM2.5) exceeded pre- and the amount of smoke emissions produced by scribed fire emissions by 24 times (Figure 3). prescribed fire in all GYA units. On a per-acre ba- As prescribed fire treatment programs increase sis, wildfire emissions produce more smoke than in the GYA, the differences between wildfire and pre- prescribed fire due to increased combustion from scribed fire smoke would be expected to decrease, more favorable burning conditions (fuel moisture but wildfire smoke will still be dominant in total and meteorology). During 2000–2004, wildfire acre- smoke emissions. Total smoke emissions will de-
Figure 1. Average and Estimated Figure 2. Average and Estimated PM2.5 Tons/Yr Broadcast- and Pile-burned Acres from Broadcast and Pile Burns 4,000 3,500 400 3,000 2,500 300
Acres 2,000
tons/yr 200 1,500 5 2. 1,000 100
500 PM 0 0 BDNF BTNF CTNF CNF GNF SNF GTNP YNP BDNF BTNF CTNF CNF GNF SNF GTNP YNP GYA unit GYA unit
Broadcast and pile burns, 2002–2004 Broadcast and pile burns, 2005–2014 Broadcast and pile burns, 2002–2004 Broadcast and pile burns, 2005–2014
Table 2. Prescribed burn and wildfire acres and smoke emissions (PM2.5) by GYA unit.
Average
PM2.5 tons/ Estimated
Average Estimated yr from PM2.5 tons/ Average Average broadcast- broadcast- broadcast yr from wildfire wildfire
and pile- and pile- and pile broadcast and acres PM2.5 tons/ burned acres, burned acres, burns, 2002– pile burns, burned, yr, 2002– Unit 2002–2004 2005–2014 2004 2005–2014 2002–2004 2004 Beaverhead- Deerlodge NF (Madison 184 830 54 215 183 88 Ranger District) Bridger-Teton 2,380 3,670 129 279 11,945 5,782 NF Caribou- 2,416 2,503 287 260 2,672 1,293 Targhee NF Custer NF (Beartooth 364 514 9.4 20 2,091 1,012 Ranger District) Gallatin NF 1,546 3,000 153 374 11,359 5,498 Shoshone NF 2,093 2,040 294 351 9,383 4,541 Grand Teton 1,294 530 103 81 2,471 1,196 NP Yellowstone 27 161 2.6 53 11,397 5,516 NP Total GYA 10,304 13,248 1,032 1,633 51,501 24,926
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public health. Figure 3. Wildfire and Prescribed The Montana/Idaho State Airshed Group’s Fire PM2.5 for 2000–2004 Smoke Monitoring Unit (SMU) consists of the USFS, tons 5 2. 7,000 the states of Montana and Idaho, the BLM, the NPS, 6,000 5,000 and private burners. The purpose of the group is to 4,000 manage and limit the impacts of smoke generated 3,000 2,000 from prescribed burning. Accumulation of smoke 1,000 from controlled burning is managed through moni- 0 Average yearly PM BDNF BTNF CTNF CNF GNF SNF GTNP YNP toring of weather conditions and formal coordina- GYA unit tion. Members submit a list of planned burns to the
Wildfire PM2.5 Prescribed fire PM2.5 SMU in Missoula, Montana. For each planned burn, information is provided describing the type of burn to be conducted, the number of acres, and the loca- pend largely on wildfire acreage, which is managed tion and elevation at each site. Burns are reported by primarily through fire suppression. Wildfire smoke is airshed—geographical areas with similar topography considered to be a temporary natural source by the and weather patterns. The program coordinator and EPA and the DEQs of Montana, Idaho, and Wyo- a meteorologist provide timely restriction messages ming, and is therefore not directly regulated. Pre- for airsheds with planned burning. The Missoula scribed fire smoke, however, is subject to NAAQS, SMU issues daily decisions that can restrict burning and is managed to minimize smoke encroachment when atmospheric conditions are not conducive to on sensitive areas (e.g., communities, Class I areas, good smoke dispersion. Restrictions may be direct- high-use recreation areas, and scenic vistas) during ed by airshed, elevation, or by special impact zones sensitive periods. In the GYA, smoke dispersion is around populated areas. The SMU announces burn- generally quite robust, with strong ridgetop winds ing restrictions via 17 airshed coordinators located generally blowing west or southwest. The most sen- throughout Idaho and Montana. The operations sitive areas are communities in valley locations such of the Montana/Idaho State Airshed Group are of- as Lander, Dubois, and Jackson, Wyoming, and Red ficially recognized as BACT by the Montana DEQ. Lodge, Big Sky, and West Yellowstone, Montana, The Montana/Idaho State Airshed Group Operating which are downwind of forested areas subject to Guide can be found at
can concentrate and elevate PM2.5 levels to nui- Regulations and developed a new Section 4, “Smoke sance concentrations, but generally not in excess Management Requirements.” The new Section 4 3 of the 24-hour PM2.5 standard of 65 µeq/M . All of regulates large-scale vegetative burning—specifi-
the highest smoke concentrations in the GYA in the cally, vegetative burns in excess of 0.25 tons of PM10 last two decades have been due to wildfires—many emissions per day—for the management of air qual- from regional fires west of the GYA. The southern ity emissions and smoke impacts on public health part of the GYA, particularly the Bridger-Teton and and visibility. Section 4 succinctly lists the specific Caribou-Targhee national forests and Grand Teton requirements of burners under a range of circum- National Park (GRTE), is subject to smoke from ag- stances. The requirements of Section 4 are effective ricultural burning in the Snake River valley. These for planned burn projects and unplanned fire events impacts are cumulative with smoke emissions in the occurring on or after January 1, 2005. GYA. NEPA analysis for prescribed burning projects In support of Chapter 10, Section 4, the Wyo- considers the sensitivity of smoke impacts, and when ming DEQ’s Air Quality Division (WDEQ-AQD) appropriate, the use of mitigation measures such as developed the Wyoming Smoke Management Pro- per-day burn acreage limitations, burning during gram Guidance Document to assist burners with periods of good wind dispersion, and non-burning implementation of the regulations. The guidance alternatives to minimize conflicts. A key factor in document contains a review and explanation of prescribed fire implementation is coordination with the regulation’s requirements, and is structured the DEQs in Montana, Idaho, and Wyoming, which to include comprehensive resource material into have regulatory authority over smoke emissions and two major sections: Wyoming Smoke Management
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Program and Forms and Instructions. prevented sampling of the snow-packed roadway at A copy of Chapter 10 is posted in the Standards the West Entrance during the drier years of 2000 and and Regulations portion of the WDEQ-AQD web- 2001, so alternate locations were chosen at a low- site. The entire document, along with a quick ref- and at a high-traffic site: the South Entrance and the erence version, is posted in the Open Burning and West Parking Lot at Old Faithful, respectively. In all Smoke Management portion of the WDEQ-AQD cases observed from 1996 to 2002, concentrations website, at
166 Greater Yellowstone Public Lands Proceedings 167 Story et al.
butadiene, formaldehyde, and acetaldehyde. In addi- YNP is using ethanol-blend fuels and low-emission tion, 20–33% of the snowmobiles’ fuel was emitted lubricating oils to further reduce emissions. Ethanol- as unburned aerosols. blend and biodegradable low-emission lubricating Monitoring by the Montana DEQ document- oils in two-stroke engines reduce CO emissions by ed that the air quality at the West Entrance was, at 7–11%, PM by 25–70%, and HC by 16–38% (Mon- times, very close to being in violation of the eight- tana DEQ 2005). Use of 10%-ethanol blend requires hour NAAQS for CO, usually on calm winter days no engine modifications or adjustments; it is now the when there was little air dispersion. only unleaded “regular” fuel sold at the YNP gas sta- The controversy about snowmobile emissions tions. Snowmobile and snowcoach rental operators and access to U.S. national parks and other public in and around YNP have taken similar steps to pro- lands has prompted studies, rulings, lawsuits, and tect air and water quality, using 10%-ethanol-blend technological innovations aimed at producing clean- fuel and synthetic lubricating oils in their machines. er, quieter snowmobiles. One of the most significant Winter season gasoline sales in the park dropped technological changes has been the development of 82% from 2001 to 2005 (Guengerich 2005). Typi- commercially available four-stroke snowmobiles, cal four-cycle engine snowmobiles get significantly especially those that meet the NPS’s BACT require- better mileage (25–30 mpg) than typical two-cycle ments. Laboratory testing of snowmobile emissions snowmobiles, at 9–13 mpg (H. Haines, pers. comm.). concluded that commercially available BACT four- Thus, snowmobilers can now complete their trips in stroke snowmobiles are significantly cleaner than one tank of gas and typically no longer have to refuel two-stroke snowmobiles. Compared to previously in YNP. tested two-strokes, these four-stroke snowmobiles Air quality monitoring began at YNP’s West emit 95–98% fewer HC, 90–96% less PM, 85% less Entrance in the winter of 1998–1999, and at the Old CO, and 90% fewer toxic HC such as 1,3-butadiene, Faithful development area in the winter of 2002– benzene, formadehyde, and acetaldehyde than two- 2003. A significant decrease in air pollutant concen-
stroke engines. The four-stroke engines, however, trations for CO and PM2.5 has been measured at both emit 7–12 times more NOx (Lela and White 2002). sites. A 60% decrease in CO and a 40% decrease in
To address historical concerns of snowmobile PM2.5 were recorded at the West Entrance in 2003– use and types, including air quality, the NPS has ad- 2004, compared with the previous winter. A 23% de-
opted a multifaceted approach for Yellowstone and crease of CO and a 60% decrease in PM2.5 were re- Grand Teton national parks that includes limiting corded at Old Faithful for the same time period. This snowmobile numbers, requiring that snowmobilers closely tracks with a 56% decrease in the number of use commercial guides, and requiring that snowmo- snowmobiles entering the West Entrance and a 53% biles be BACT, which are the cleanest and quietest decrease in the snowmobiles counted at Old Faithful four-stroke snowmobiles available. The commercial (Ray 2005). Carbon monoxide has been decreasing guide requirement helps ensure that the snowmo- at the West Entrance since 1998. Mean monthly CO biles meet the BACT requirements, comply with levels at the West Entrance show an annual cycle, speed limits, and stay on designated roads. Reduc- with the highest concentrations in winter and sum- tion in overall snowmobile numbers also has result- mer and lowest in spring and fall. Winter CO levels ed in fewer emissions and better compliance with are now similar to those of July and August. This rep- winter air quality objectives. resents a substantial change from 1998–2002, when In November 2004, the NPS approved tempo- winter CO levels were much higher than summer rary winter use plans for Yellowstone and Grand levels. Teton national parks and the John D. Rockefeller, Monitoring in winter 2004–2005 (Bishop et al. Jr., Memorial Parkway (JODR). This decision allows 2005) revealed a substantial finding: snowcoaches 720 commercially guided recreational snowmobiles have higher emissions than individual snowmo- per day in YNP. In GRTE and JODR, 140 snowmo- biles, and the increase in snowcoach use is offsetting biles per day are allowed. With minor exceptions, some of the snowmobile emission reductions. On a all snowmobiles are required to meet NPS BACT per-passenger basis, snowcoach emissions nearly requirements. The plan will be in effect for three equal four-stroke snowmobile emissions. Bishop (et winters, allowing snowmobile and snowcoach use al. 2005) measured emission rates and reported that through the winter of 2006–2007. older snowcoaches, such as the fuel-controlled car- In addition to switching to BACT snowmobiles, buretor Bombardier and fuel-injected, gasoline-van
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Xanterra snowcoaches, had high CO and HC emis- laboration from the NPS, USFS, and BLM for major sions. Newer snowcoaches, such as the fuel-injected sources such as PSD. The largest cities around the MPI Bombardier used by Yellowstone AlpenGuides, GYA, such as Billings/Laurel and Bozeman, Mon- and the NPS diesel van, had CO and HC emissions tana; Cody, Lander, and Jackson, Wyoming; and Ida- that were only 1–2% of that of older snowcoaches. ho Falls, Idaho, are substantial sources of multiple Bishop (2005) discouraged the use of vintage, fuel- emissions. controlled carburetor engines in snowcoaches. This Currently, the largest air quality concerns in the could substantially reduce overall snowcoach emis- GYA come from gas field development in southwest sions. Wyoming and emissions from energy-related indus- tries. The southwest Wyoming gas fields, primar- Summary of management implications and ily on BLM lands, are expanding at a very high rate recommendations because this area provides a significant contribution Air quality in the GYA remains generally ex- to the U.S. energy supply. The Clean Air Act requires cellent, as the GYA is largely undeveloped and has the NPS and USFS to identify, monitor, and pro- limited emissions sources and predominantly robust tect AQRVs in adjacent Class I areas. Visibility, lake dispersion. Emission sources on NPS and USFS chemistry, and biota in the Bridger-Teton Wilder- lands in the GYA primarily consist of prescribed fire ness Area are being subjected to increasing levels of smoke, transportation and recreational sources, and air pollution impacts from the gas field development. management activity sources such as mining, road The Fitzpatrick and Popo Agie wilderness areas are construction, and ski areas. These sources are indi- also affected. Grand Teton National Park person- rectly managed by the NPS and USFS, and are usual- nel would like to establish NADP/NTN (National ly not significant air quality issues, except for snow- Atmospheric Deposition Program/National Trends mobile emissions at concentrated winter use areas Nework), CASTNet (Clean Air Standards and such as the West Entrance. The NPS has greatly re- Trends Network), and IMPROVE monitoring sites duced winter emissions related to park management in Grand Teton National Park for at least five years, with the use of “green” fuels and products, and by to compare with the network sites in Yellowstone requiring four-stroke snowmobile engines in YNP National Park and determine if it is appropriate to and GRTE. augment the YNP air quality monitoring sites with Wildfire emissions are the most significant emis- more specific monitoring information from GRTE. sions within and around the GYA, but are not con- Compliance with NAAQS and protection of trollable by management except indirectly, by fire AQRVs will require continued close coordination suppression. During the last three years, prescribed between the NPS, USFS, BLM, and the DEQs in Wy- fire emissions in the GYA have increased due to the oming, Montana, and Idaho. The GYACAP has been Healthy Forests Initiative legislation; they are antici- a useful forum to facilitate coordination between the pated to continue to increase by about 58% over the GYA air quality management agencies. next 10 years. Overall smoke emissions (wildfire and prescribed) are expected to remain about the same, Recommendations but with the major variable of weather conditions. 1. Comply with NAAQS, PSD increments, and Because much of the GYA, like most of the American AQRV thresholds. West, has an accumulation of fuels resulting from 2. Cooperate with the Wyoming DEQ, BLM, wildfire suppression, wildfire levels are expected to and energy companies to manage southwest be high during dry summer periods for the next sev- Wyoming oil and gas energy impacts. eral decades. 3. Continue the system of air quality monitor- The greatest threat to air quality in the GYA is ing throughout the GYA. Air-quality-related- from anthropogenic sources upwind and adjacent value monitoring of lakes, deposition, and to national park and national forest boundaries. Ur- visibility in the Wind River Range is critical. ban and industrial air pollution, although moderate 4. Continue to encourage cleaner snowmobiles compared to that in much of the U.S., has a persis- and snowcoaches, and to manage their win- tent impact, because many of these emissions occur ter use impacts. year-round, including during winter inversion pe- 5. Aggressively pursue fuel reduction projects riods. These sources are managed primarily by the and disclose smoke impacts and NAAQS DEQs in Montana, Wyoming, and Idaho, with col- compliance in NEPA documents.
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6. Continue GYACAP annual meetings, coordi- west Research Institute, report number SwRI 08.05486.
168 Greater Yellowstone Public Lands Proceedings 169