Exhaust Emissions from Four-Stroke Lawn Mower Engines

Abstract

Emissions were characterized from 10 four-stroke lawn mower engines. The ages of the engines ranged from new to 15 years, and each was tested using two gasoline fuels:a 1990 national average blend and a reformulated gasoline. Reformulated gasoline usage resulted in lower organic and carbon monoxide emissions that contributed to lower reactivity-weighted emission rates. Aggregate toxic emissions were also reduced because benzene emissions were lower. On the other hand, increases in nitrogen oxide emission rates were observed with the reformulated gasoline. Compared to the newer engines, older engines had dramatically higher organic and carbon monoxide and lower nitrogen oxide emissions.