The Leader of the Pack

Motorcycles make up less than two per cent of registered motor vehicles and account for under 0.5 per cent of total emissions from on-road transportation sources in Canada. Overall, they are not significant contributors to air pollution in Canada. However, recent tests conducted at Environment Canada's Environmental Technology Centre (ETC) show that individually, motorcycles can emit considerably higher levels of air pollutants than cars and light-duty trucks.

The ETC tests were carried out last year on five motorcycles, two hybrid gasoline-electric automobiles, and 10 light-duty cars and trucks using special dynamometers to simulate urban and highway driving conditions. While the vehicles were in operation, their emissions were sent to a constant volume sampler that diluted the exhaust and routed it to various precision gas analyzers.

The motorcycles—three 4-cylinder and two 2-cylinder models with engines ranging in size from .8 to 1.5 litres—produced an average of ten times as much carbon monoxide as the other gasoline-powered vehicles, and more than 80 times as much as one of the gas-electric hybrids on a per-kilometre basis. For nitrogen oxides and hydrocarbons, the bikes emitted an average of three and 14 times as much pollution, respectively, as the other gas-powered vehicles. The one major area where the bikes outperformed some of the larger vehicles was in reduced emissions of the greenhouse gas carbon dioxide. Such emissions are directly related to fuel consumption, so more fuel-efficient vehicles, such as motorcycles, produce less carbon dioxide.

Beginning with model-year 1998, Canada aligned its motorcycle emission standards with those of the U.S. Environmental Protection Agency (EPA). However, emission-control technologies on motorcycles have not kept pace with the technologies found on today's cars. Few motorcycles are equipped with catalytic converters, and most have carburetors instead of fuel injection systems. As a result, they release more incompletely combusted compounds into the atmosphere.

Recognizing that many of the new technologies used to clean up car emissions could be adapted for use on motorcycles, Environment Canada has expressed its intent to work with the motorcycle industry to develop updated emissions standards for motorcycles in conjunction with the U.S. EPA. Revised standards are likely to be in place in the model-year 2005-08 time frame. This will result in per-kilometre emissions from new motorcycles being cut by at least 50 per cent.

In the meantime, the ETC is expanding its emissions research on a variety of vehicles to include the characterization of other air pollutants, such as fine particles as small as half a micron in diameter. These inhalable particles have been linked to respiratory problems in humans.

The Centre has also begun testing vehicles under more aggressive driving conditions—with fast starts and stops and higher cruising speeds—to see how they affect emission levels. Although results vary depending on specific test conditions, they show that such changes in driving patterns can cause a significant increase in pollution from all types of vehicles.

Increased public awareness about environmentally friendly technologies and driving practices can help to reduce emissions and, consequently, their impact on human health and the environment.

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