URGENT: ANR proposes rule allowing ATVs on state land
Keep ATVs Off Vermont's Roads
Keep ATVs Off The Lamoille Valley River Trail
Economic Impact of Snowmobiling
ORV's and Air Quality
ATV Liability Issues
Peak Oil, Climate Change and ORVs
Gov. Douglas and The ATV Working Collaboration
Have an ORV story?
What Others Say About ORVs
Links & Resources
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Off-road Vehicles, Air Quality, and Human Health
Scenes of Yellowstone Park Rangers wearing gas masks brought national attention to snowmobile pollution. In Yellowstone, where the cleanest air in the nation should be found, levels of pollution often exceeded those of downtown Los Angeles. Studies were quickly initiated and two-stroke snowmobiles were banned from the Park. Elsewhere, millions of snowmobilers still rev up these engines each winter. No federal laws regulate snowmobile exhaust (outside Yellowstone) and accordingly they are not equipped with pollution control devices. Air pollution from snowmobiles is well documented and can result in a number of health problems.
Snowmobiles first gained popularity in the 1960s. At that time, the 6 horsepower machines reached speeds of 35 mph. Today's snowmobiles, powered by lightweight, high-power engines, boast up to 225 horsepower and can exceed 120 mph. While technological advances have also produced cleaner four-stroke engines, the vast majority of snowmobiles still use two-stroke engines, which are as polluting as their 1960s predecessors.
Two-stoke engines are highly polluting. The lubricating oil is mixed with the fuel, and 20 to 33 percent of this mixture is emitted unburned into the air and snowpack. Also, the combustion process itself is relatively inefficient. As a result, two-stroke snowmobiles emit very large amounts of carbon monoxide (CO), unburned hydrocarbons (HC) and particulates.
According to the EPA, ATVs emit more than 381,000 tons of hydrocarbons, 1,860,000 tons of carbon monoxide, and 11,000 tons of nitrogen oxide each year across the country. This represents a 42 percent increase over the past 20 years. The EPA also researched individual ATVs, and found that a two-stroke ATV could emit as much pollution as more than thirty automobiles operating in the same time frame. (As bad as ATVs are, 2-stroke snowmobiles are even worse, emitting as much as nearly 100 automobiles.)
The effects of ORV emissions on health
Emissions from ORVs have been found to contribute to serious health problems. Large numbers of ORVs in one area, cold stable weather conditions, and low wind speed all increase the accumulation of toxins and increase the risk of adverse health effects. Below are some of the potential health effects from inhaling HC, CO, and particulate matter (PM) emitted from ORVs.
Hydrocarbons are volatile organic compounds that include benzene, toluene, ethylbenzene, and xylenes. Studies have found high levels of exposure to benzene for various employees in Yellowstone National Park, who are frequently exposed to snowmobile emissions. While these compounds can cause dizziness, headaches, and loss of consciousness, the EPA has also identified benzene as a carcinogen, and those exposed to benzene have an increased incidence of leukemia.
Carbon Monoxide (CO)
Carbon monoxide binds to the hemoglobin in blood and inhibits the transportation of oxygen in the body. High levels of CO exposure have been shown to lead to visual impairment, reduced work capacity and mental dexterity, poor learning, nausea, headaches, dizziness, and even death.
Particulate Matter (PM)
Particulate matter, also found in ORV emissions, is detrimental in fine and coarse forms as it accumulates in the respiratory system and can lead to decreased lung function, respiratory disease and even death. Of the pollutants emitted by ORVs, particulates are of special concern because their small size makes them easily respirable and thus delivered directly into the lungs, causing any number of the aforementioned maladies.
The vast majority of snowmobiles in the U.S. use the out-dated two-stroke technology, as do many ATVs. Two-stoke engines are very polluting and the risk to human health has been well documented. If land managers are concerned about air pollution and its effects on human health, ORV use should be limited.
Adapted from Wildlands CPR RIPorter
Autumn Equinox 2007, Volume 12, #3, by Adam Switalski and Monica Wright
Spring Equinox 2006, Volume 11, #1m by Jason Brinistool