There may be many reasons why you might want to ride a motorcycle or scooter, but clearer air should not be among them.
Despite their reputation as being more earth-friendly than other motorized forms of transport, two-wheelers are actually some of the biggest polluters on the road.
"The cleanest motorcycle engine is far dirtier than the dirtiest car," says Warren Milner, Honda Canada's senior motorcycle manager.
In fact, two-wheelers appear to be so dirty that Wheels was unable to convince a local dealer to run a Drive Clean test on them because the emissions could seriously damage the testing machines.
This might be news to advocates of two-wheelers as a more earth-friendly means of commuting in congested urban areas like the GTA.
The confusion seems to arise because motorcycles and scooters burn far less fuel than even the most fuel-efficient car or truck. Carbon dioxide emissions are directly proportional to the amount of gas you burn, meaning two-wheelers contribute fewer greenhouse gas emissions per kilometre than their four-wheeled cousins.
But that's only one part of the air quality equation. When it comes to emissions of nitrogen oxide and hydrocarbons – so-called smog-forming pollutants – motorcycles and scooters emit many times more per kilometre than cars and trucks.
In the lead up to tougher emissions rules in 2005 – the first in 27 years – the U.S. Environmental Protection Agency found the standards for motorcycles and scooters to be 90 times dirtier than those for cars. One of its comparisons was a Yamaha YZR R6, which emitted 4.19 grams/mile of hydrocarbons compared to a Dodge Durango with 4WD, which emitted .073 gm/mile.
A widely cited Swiss study from 2005 of eight different types of scooters and motorcycles found that despite the proportionately smaller number of two-wheelers on the road, they accounted for about one-fifth of nitrous oxide emissions of the cars.
