Potential Environmental Impacts Related to Proposed Runway Expansion at Toronto's International Airport

Abstract

Major emissions from aircraft jet engines include CO, C0₂, NO_x, N₂0, SO_x, and NMHC. Although all internal combustion engines produce these emissions, jet engines cycle large amounts of air under high temperature and pressure and hence produce significant quantities of the oxides of nitrogen. These emissions affect the environment at local, regional, and global levels. Lester B. Pearson International Airport (LBPIA), situated in the northwest portion of metropolitan Toronto, is the busiest in Canada, acting as a hub with at least one-third of alt scheduled air carrier operations in Canada itinerant through LBPIA. In order to relieve the congestion and delay in air traffic passing through LBPIA, Transport Canada has proposed the construction of three more runways. An alternative to runway expansion is to cap the existing facilities and shift the short-haul traffic to alternate modes (train or automobile). Comparison of the three modes on a short-haul trip (Toronto-Montreal) shows that, on a grams per passenger kilometer basis, the LRC train produces the least amounts of CO, NMHC, N₂0, and C0₂, and the 1988 automobile the least amount of NO_x. Travel by DC 10-30 aircraft always produces the highest quantity of each gas emitted. Of the emissions from combustion processes in aircraft, none contribute more than 3% of the total emissions of that gas per year in Canada. Thus, any reductions achieved through modal substitution will be less than 1% of the totals for each gas generated annually in Canada, which is not a significant reduction in absolute terms. These reductions, however, represent a step toward the goals of emission reduction and, moreover, would cause an improvement in the distribution of these gases in the environment.