Air pollutant emission factors from new and in-use motorcycles

The emissions of carbon monoxide (CO), nitrogen oxides (NO,) and total hydr ocarbon (THC) from 7 new and 12 in-use motorcycles with or without the cata lyst were evaluated by testing these vehicles on a dynamometer. Also the co ncentrations of volatile organic compounds (VOCs) in five driving patterns, including idle, acceleration, 30 km h(-1) cruise, 50 km h(-1) cruise, and deceleration, were monitored. Experimental results indicate that the emissi ons of CO and THC from in-use motorcycles are significantly higher than new ones, but not for NO,, and the emissions of THC from 2-stroke motorcycles are much higher than 4-stroke ones. The emissions of VOCs from in-use motor cycles are higher than new motorcycles for all five driving patterns, and t hose from 2-stroke engines are higher than 4-stroke motorcycles. Emission o f VOCs in the modes of deceleration and idle accounts for the most mass emi tted during the test driving cycle. (C) 2000 Elsevier Science Ltd. All righ ts reserved.