Air pollution from large trucks and buses

Trucks and buses are types of heavy-duty vehicles used in Canada. From a regulatory perspective, any on-road vehicle that has a Gross Vehicle Weight Rating (GVWR) of more than 3,856 kg (8, 500 pounds), a curb weight of more then 2,722 kg (6,000 pounds) or a basic vehicle frontal area in excess of 4.2m2 (45 square feet) is classified as a heavy-duty vehicle. Most heavy-duty vehicles are powered by diesel engines.

These vehicles play an integral role in driving the Canadian economy and it is important to ensure that their environmental impact continues to be addressed. On January 1, 2004, the new On Road Vehicle and Engine Emission Regulations (full regulation) came into effect under the Canadian Environmental Protection Act, 1999. For heavy-duty diesel vehicles, the regulations will phase-in more stringent standards for smog forming emissions between 2004 and 2010. These regulations will result in a reduction of nitrogen oxides and particulate matter emissions from new vehicles by 95 per cent and 90 per cent respectively, relative to previous requirements.

Low levels of sulphur in diesel fuels are necessary to ensure the effective operation of advanced emission control technologies. These heavy-duty vehicle technologies will be used to meet the more stringent emission standards prescribed by the Regulations. The Sulphur in Diesel Fuel Regulations (full regulations) require that the sulphur level in Canadian on-road diesel fuel be reduced to a maximum of 15 parts per million (ppm) in June 2006.

While these new standards go a long way in addressing emissions from new vehicles there is still much work to be done to reduce the environmental impacts of heavy-duty vehicles currently on Canadian roads. Toward this end, Environment Canada and the Canadian Urban Transit Association (CUTA) have partnered to achieve real and quantifiable benefits toward clean air by retrofitting urban transit buses with diesel oxidation catalysts.