Pictures of the Yellowstone Park Rangers wearing gas masks gained national attention to how much pollution snowmobiles were bringing into this world, national park areas and specifically Yellowstone National Park. In Yellowstone, where the cleanest air in the nation should be found, levels of pollution often exceed those of downtown Los Angelas (Measuring Concentrations of Selected Air Pollutants Inside California Vehicles Report). Studies were then quickly initiated and two stroke snowmobiles were banned from the park. Yet in many other places millions of riders still run these engines each winter to head into the snow covered play areas. There are no federal laws regulating snowmobile exhaust outside of Yellowstone. These machines are also not equipped with any devices that measure or control the pollution given off. Air pollution is well documented and can also be traced to many different health issues. This paper will review the snowmobiles history, the extent of snowmobile pollution and the impact on human health.
Snowmobiles first started gaining popularity in the 1960’s. At that time there were approximately a dozen different manufactures that sold their different versions of snowmobiles. Each snowmobile selling for a few hundred dollars a piece; each manufacturer selling 50-100 sleds each year. This is what started the sport, at that time nobody could imagine it would grow to what we have these days. This become more evident in the 1970’s with the “rapid technological advancements and more than 100 manufacturers that laid a major emphasis on racing and speed propelled snowmobiling as a sport” (American Snowmobiler: 30-31). During this time sales and promotional materials for snowmobiling showed happy eager riders bare handed and in stocking hats. Snowmobilers were having so much fun that the sales grew as fast as gas prices were raising. Most engines at that time cranked out approximately 20 to 35 horsepower. Snowmobile sales in 1971 rose to 495,000 worldwide, with more than two million sold between 1970 and 1973. By 1977 the list of manufacturers shrunk to about seven due to the lean snow years, an oil embargo and tough economic times that set in. By the end of the 70’s decade the annual sales settled at about 250,000 sleds.
Today’s snowmobiles have made drastic changes since the 60’s and 70’s era. There are now four different snowmobile manufacturers that build and sell snowmobiles. They are: Arctic Cat- headquarters in Thief River Falls, MN; Polaris- headquarters in Medina, MN; BRP (better known as Ski-Doo) – headquarters in Valcourt, Quebec and Yamaha Corporation- headquarters in Cypress, CA. Between the four manufacturers in 2008 there were about 163,753 sold worldwide; 79,552 were sold in the United States and 50,556 were sold in Canada. Snowmobiles now are lightweight, being built out of aluminum materials and powered by motors that have up to 225 horsepower, this being four times the horsepower of what some Harleys have. These machines can easily reach 120 mph and get a person to where they want to go and fast.
Among the many technological advances made by the manufacturer’s one of the biggest steps that has been and is being worked on is the cleaner four-stroke models. These new motors burn fuel the same way that a car engine does, which compared to a typical two-stroke motor it burns much cleaner and much more efficiently. But with efficiency and power also comes weight and clumsiness. These new sleds weight approximately 75-200 pounds more but also have 50% less emissions and create much less noise than the typical two-stroke snowmobile. Because of the weight differences and the inability for people to have the special add-ons, four-stroke snowmobiles have not made an enormous plunge quite yet in the world of snowmobiles. Therefore, the vast majority of snowmobilers still ride a two-stroke which are as polluting as their 1960’s era predecessors.
Two-stroke snowmobile engines discharge up to one-third of their fuel unburned into the environment and is one of the largest unchecked sources of hydrocarbon pollution worldwide. The major concern with the discharge is threefold: the effect of toxic emissions on our country’s air quality, the discharge of raw fuel and the effect of both on water quality.
In a two-stoke engine the oil is mixed with the fuel and 20% to 33% of the mixture is emitted unburned into the air and the snow pack (MDEQ 2004). Also, “the combustion process is relatively inefficient and results in high emissions of air pollutants” (NPS 2000). It is because of these two reasons the two stroke snowmobiles emit large amounts of carbon monoxide, smoke and unburned hydrocarbons. Other pollutants that are emitted include aldehydes, 3-butadiene, and benzene. “Tests have been done to prove that just one snowmobile creates the same amount of pollution that of 100 automobiles” (The New York Times, 2002). Every winter, snowmobiles dump more than 100,000 gallons of raw fuel and 2,500 gallons of raw two-cycle oil into just the National park ecosystems (J.T Turk).
Pollutants from the snowmobile emissions are locked within the snow pack. The toxic effects of the built up pollutants in the snow pack are magnified during the first few days of spring, when they are released during snowmelt, causing elevated acidity levels that are in the waterways. This results in higher death rates of aquatic insects and amphibians (J.T Turk). The impact or the spring pollutants may have consequences for the surrounding watersheds. Acidity fluctuations can disable a watershed’s ability to regulate its own pH level, which could trigger system-wide problems and result in a long-term alteration of an entire ecosystem (Yellowstone National Park Visitor Study.).
There has been a lot of research done on snowmobile pollution mainly in Yellowstone National Park, but as of today snowmobiles are permitted in 30 different park areas. Some of them include: Denali (AK), Grand Teton (WY), Voyageurs (MN), and Rocky Mountain (CO). Though many of the parks don’t allow snowmobiles to travel off the trail and also enforce speed limits, they still bring many people in for tourism and snowmobiling as a sport. As stated by John Little, “There are approximately 85,000 visitors each winter that generates over 30 million dollars throughout the surrounding states”. Those states include: Montana, Wyoming and Idaho. Along with the many visitors on snowmobiles, the money brought also come the pollution created by the sleds ridden throughout the parks.
The scale of pollution documented in Yellowstone National Park is amazing. Snowmobiles were responsible for 68% to 90% of hydrocarbons emissions and 35% to 68% of the carbon monoxide emissions each year (NPS 2000). On a peak day in Yellowstone National Park snowmobiles released approximately 20 tons of hydrocarbons and 54 tons of carbon monoxide into the air (NPS 2000). This compared to the 2.5 tons of hydrocarbons and the 17.9 tons of carbon monoxide emitted from cars on the average day in July (NPS 2000). Being that the snowmobile season in Yellowstone National Park generally only lasts three months from mid December to mid March their emissions equaled the total annual emissions for carbon monoxide and hydrocarbons form cars, buses and snowcoaches.
While four-stroke snowmobiles are the only snowmobiles allowed in Yellowstone National Park these days, it is said by Michael J. Yochim that “four-stroke snowmobiles may be quieter overall, but the noise-like that of many snowcoaches is a lower frequency that travels even farther than the high frequencies of two-stroke machines, particularly when the air is cold”(p.212).
Politically the sport of snowmobiling has also been affected. There have been many attempts to ban the use of snowmobiles in Yellowstone National Park and Grand Teton National Park. “Since 1996 the government has completed three major official assessments of snowmobiles’ impact on the parks in the winter” (New York Times, 2005). These studies helped to back the first attempt and gathering support to ban all snowmobile use in the National Parks in November 1999 by Congressman Bruce Vento (D-MN) and Chris Shays (R-CT). Then in April 2000, the ban was enforced in both parks only allowing the use of four-stroke snowmobiles and snowcoaches. This ban also enforced a limit as to how many (four-stroke) snowmobiles would be allowed into the park on a daily basis. This limit would be set at 540 per day. Since then there have been many attempts and suggestions to overturn the ban or alter it in different ways. None of which have been put through. In November of 2007, various officials in Washington compelled the Park managers to increase the number of snowmobiles allowed into the park on a daily basis. The limit was increased from 540 to 740 per day throughout the entire park.
The Government is now on the fourth three year study trying to get the facts that the public and Parks have been looking for. Being there are so many different view points on the subject and facts being slanted by peoples personal opinions. The facts are often hard to understand. While the most recent, “Winter Plan Use” has banned the use of two-stroke engines in Yellowstone National Park and Grand Teton National Park. Then replacing them with cleaner burning four-stroke machines and limiting the number allowed into the parks on a daily basis. The studies being done seem to be the best available science to measure the effects of snowmobiles around the world not just how they affect the park areas.
With the negative impacts of snowmobiles there are several strategies for minimizing pollution that will be identified. These include using oxygenated fuels like ethanol-based fuel and direct injection two-stroke engines. However, only four-stroke engines have been found to significantly reduce emissions. Electric prototype snowmobiles that produce no emissions have been developed, but not yet available to the public.
According to an article in Snowest magazine, “The University of Denver tested the benefits of using oxygenated fuels in snowmobiles in Yellowstone” (Fuel the Fire”). Oxygenated fuels allow for more efficient combustion and reduced pollution. Although they found 3% to 11% reduction of carbon monoxide, there was no reduction in hydrocarbon emissions. Direct-injection two-stroke engines have been shown to decrease hydrocarbon emissions from snowmobiles by 70 to 75% when compared with conventional two-stroke engines, but still had similar emissions for other pollutants (NPS 2000). However, either oxygenated, bio fuels or direct-injection two-stroke engines were shown to significantly reduce emissions and also have their performance drawbacks.
Biofuels, including oxygenated fuels are becoming a bigger part of everybody’s lives whether we like it or not. Some negative aspects of using biofuels in two-stroke engines tend to cause issues. The blend does not burn as hot or as high as the octane fuel which requires the motors to be set up differently than if a high octane fuel is being used. Engines are designed for maximum power output and biofuels tend to also dry out the rubber-based o-rings, seals, gaskets and diaphragms in the fuel pumps of older sleds. Biofuels have been known to go stale faster, which also can cause problems in the fuel delivery systems in the older two-stroke engine.
Several studies have also recommended replacing two-stroke engines with four-stroke engines to significantly reduce emissions and noise (NPS 2000). Banning two-stroke engines in Yellowstone National Park has resulted in a 60% reduction in carbon monoxide and a 96% reduction in Hydrocarbon emissions (Bishop et al. 2006). Additional, Bishop et al (2006) found improved fuel efficiency, reduction in visible exhaust clouds, odor and noise.
In conclusion, throughout the many years snowmobiling as a sport has evolved into a major activity for many people throughout the world. With the technology evolvement that has happened from the 60’s to the current years, the rules and regulations have also evolved at the same time. The facts of pollution have made it clear that emissions are an issue that needs to be dealt with and handled. While Yellowstone National Park has banned two-stroke engines and the vast majority of snowmobilers in the United States use the out-dated two-stroke technology. Two-stroke engines are very polluting and the risk to the environment has been well documented. If land managers are concerned about air pollution and its effect on our environment, snowmobile use needs to be improved upon.
Bishop, G.A. 2006. Winter motor-vehicle Emissions in Yellowstone National Park. Environmental Science and Technology 40(8): 2505-2510
Janes, Steve. “Fuel the Fire”. Snowest’s Mod-Stock 2008: 68-71.
Little John, M. Yellowstone National Park visitor Study. University of Idaho, Cooperative Park Studies Unit. Report 75 1996
Montana Department of Environmental Quality (MDEQ). 2004. Solutions- Oxygenated Fuels. http://www.deq.state.mt.us/cleansnowmobile/solutions/fuels/Oxygenated
National Park Service (NPS). 2000. Air Quality Concerns Related to Snowmobile Usage in National Parks. Washington, D.C.: Feb.2000.
The New York Times Sept 17, 2002, P. A30(N)
Savage, Mark. “Those 70’s Sleds!”. American Snowmobiler 2008: 30-31.
Rodes, C., 1998. Measuring Concentrations of Selected Air Pollutants Inside California Vehicles, Final Report under Contract No 95-339. California Air Resources Board.
Yochim, Micheal. Yellowstone and the Snowmobile: Locking Horns Over National Park Use. University Press of Kansas, 2009.