Chain saws and other two-cycle engine powered machinery have a reputation as being heavy polluters. We've all heard the stories. You could drive a car from Dallas, Texas, to Tallahassee, Fla., and send out a similar amount of pollution (in this casevolatile organic compounds) as using your chain saw for one hour. In 1991 the Environmental Protection Agency did a study on non-road equipment and discovered that these machines created almost as much pollution as all highway vehicles. Admittedly, thisincluded a broad range of machines - from backhoes to tractors to chain saws - but the agency also determined that non-road, spark-ignition engines under 25 hp (including everything from lawn mowers to string trimmers to chain saws) accounted for 16 percent of the hydrocarbon (HC) and 21 percent of the carbon monoxide (CO) emissions nationwide. In other words, small engines had become a problem. They were making a disproportionate amount of pollution for the size of the engine, and the EPA needed to create new guidelines to improve air quality.
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