Yellowstone’s snowmobiles are, in a manner of speaking, on the wild frontier of government regulation. By placing the Yellowstone snowmobile experience in the broader context of environmental problem-solving, we gain some perspective about the future of environmental management.
Wintertime motorized access to most of Yellowstone National Park is limited to snowmobiles and enclosed multi-passenger snowcoaches. Despite its remote location, however, winter visitation and snowmobile use have soared over the years.
In their efforts to balance wilderness protection with year-round public access, the Park Service has considered policies that range from allowing some snowmobile access to phasing out snowmobiles completely.
The current interim policy limits Yellowstone snowmobile entries to 720 per day; in December 2007 the National Park Service finalized a more restrictive rule allowing 540 entries per day that will apply starting in Winter 200-8/2009.
While there haven’t been violations of health-based air quality standards since monitoring began in 1998, there is some evidence that air quality has declined along snowmobile corridors and Park employees have been adversely affected by exposure to snowmobile emissions.
Consequently, in addition to snowmobile entry limits which protect wildlife and park aesthetics, snowmobiles that enter the park must now meet emissions standards that are more stringent than nationwide requirements.
Unregulated snowmobiles are comparable to unregulated automobiles manufactured through 1965. Automotive emissions technologies in 1965 were akin to the frontier old West, but think “tailpipe smoke” instead of “gun smoke.”
Cars used to emit enormous amounts of pollution. Picture a pair of Ford Mustangs, one from 1965 and the other from 2005. Compared to its older sibling, the 2005 vehicle is a remarkably clean car.
Per mile emission rates for three of the main combustion pollutants, hydrocarbons (HCs), carbon monoxide (CO) and oxides of nitrogen (NOx), have all been reduced by 90% or more from their 1965 values. These reductions have dramatically improved air quality in our largest urban areas despite huge increases in the miles we collectively drive.
Today, most operating snowmobiles are powered by uncontrolled two-stroke engines. They emit over seven times more HC per mile than a 1965 automobile, and more than 50 times what modern cars emit.
Cleaner snowmobiles, which are just now penetrating the market place, typically use a four-stroke engine with unsophisticated engine controls relative to a modern automobile.
These cleaner snowmobiles use “oxidation catalysts” roughly similar in concept to the equipment on a late 1970’s automobile. Catalysts are the heart of a car’s pollution control system; they help convert pollutants to carbon dioxide and water.
Four-stroke snowmobiles emit 60% less CO and over 95% less HC than an uncontrolled two-stroke snowmobile. The one drawback is that they actually emit about 10 times more NOx than older snowmobiles.
In the 1980’s, car manufacturers introduced three-way catalysts to simultaneously control three pollutants: CO, HC, and NOx. Snowmobile controls are still in the early stages of the pollution control lifecycle, as demonstrated by the increased NOx emitted by recent four-stroke snowmobiles.
Over time, emission durability requirements have created cleaner, longer-lasting cars and have prompted the use of emission control techniques (think gasoline-electric hybrids) that would have been considered exotic 40 years ago.
If history is our guide, snowmobiles have just entered the emissions control era, and it will be possible to cut snowmobile emissions of CO, HC, and NOx by an additional 90% or more.
Snowmobile regulations mark a recent broadening of emission controls to include off-road equipment, covering everything from bulldozers to lawn mowers.
Today, there are still hundreds of areas in the United States that fail to meet air quality standards set by the U.S. Environmental Protection Agency (EPA). The old pollution abatement strategies – focus emissions controls on cars and other obvious pollution sources – no longer apply. Further controls on today’s relatively clean cars, while helpful, are not sufficient to achieve clean air.
Off-road equipment, long on the frontier edge of emissions control, has begun moving towards the center of regulatory focus. Given the history of automotive emissions controls, we can expect dramatic advances as regulators ratchet down emissions from snowmobiles and other off-road equipment.
Although the history of automotive controls provides a roadmap for where snowmobile and off-road equipment emissions may be headed, the Yellowstone snowmobile program may set the stage for a new paradigm in environmental management.
Given its mandate to protect the Yellowstone ecosystem, the NPS has considered a spectrum of snowmobile effects, from air quality and economic impacts to visitation quality and wildlife stress.
At the federal level, we tend to treat urban environmental problems, such as air and water pollution and ecosystem protection, as independent goals bearing little relationship to one another.
Although urban areas differ from the unique beauty of Yellowstone, it may be time for our growing urban areas to approach clean air, water, and park preservation plans in the broader context of improved urban design and ecosystem preservation.
Dana Rowan is a research assistant with the University of California-Davis Caltrans Air Quality Project. Douglas Eisinger is the program manager of the U.C. Davis-Caltrans Air Quality Project and director of transportation planning at Sonoma Technology, Inc. Deb Niemeier is principal investigator for the U.C. Davis-Caltrans Air Quality Project, director of the U.C. Davis John Muir Institute on the Environment, and professor of civil and environmental engineering at U.C. Davis.
