Transportation is a major source of greenhouse gas (GHG) emissions and air contaminants. While considerable progress has been made in reducing transportation’s contribution to air contaminants, GHG emissions remain a problem. Transportation is a major emitter of three air contaminants: nearly three-quarters of the carbon monoxide (CO), more than one-half of the nitrogen oxides (NOx) and more than one-quarter of the volatile organic compounds (VOC) in 2004. The good news is that, over time, transportation’s output of these air contaminants which contribute to smog, acid rain and human health issues, has declined. For example, NOx emissions from transportation were 19% lower in 2004 than in 1990. In the same period, CO and VOC emissions each dropped 37%, according to data published by Statistics Canada in its report Human Activity and the Environment: Annual Statistics.

In 2004, transportation accounted for 26% of total GHG emissions in Canada. Greenhouse gases emitted by transportation include carbon dioxide, methane and nitrous oxide. From 1990 to 2004, GHG emissions from transportation rose 30%, or almost 45 megatonnes. Eighty-six per cent of the increase in transportation’s emissions came from road vehicles, in particular light trucks and heavy-duty vehicles. The share of freight moved by road relative to other types of transportation is also affecting GHG emissions. From 1990 to 2003, the amount of freight carried by the for-hire trucking industry (not including small and local for-hire carriers) grew nearly three times faster than all other modes combined. Just-in-time delivery may have helped reduce inventories – but it also means trucks are making more trips. The number of tractor trailers registered was 32% larger in 2005 than in 2000; the number of straight trucks was up 12%, according to Statistics Canada records.