The United States and Canada formally signed an agreement last week to sharply reduce smog-causing pollution emitted mainly by power plants.
The treaty was signed with the aim of bringing healthier air to millions of people living in both countries by 2010.
Officials said the deal, which was finalized in October, would reduce both nitrogen oxide and volatile organic compounds caused by power plants and commercial and consumer products.
"Canada and the United States broke new ground with the acid rain agreement of the 1980s and this agreement takes us further in protecting our citizens from the health effects of dirty air," said David Anderson, Canada''s minister for the environment, who represented Ottawa at the signing ceremony.
Air pollution currently accounts for about 5,000 premature deaths in Canada and about 60,000 in the United States annually.
The agreement specifically takes aim at lung-damaging ground-level ozone in the eastern half of North America, the industrial heartlands of both industries.
The cross-border agreement will require power plants and other industrial sources to cut their nitrogen oxide emissions by 50 percent to 75 percent by 2004.
The United States will reduce nitrogen oxide emissions by 35 percent by 2007, which implies a 70 percent reduction from power plants and major industrial sources.
The aim is to reduce U.S. annual emissions by 43 percent by 2010.
Both countries also pledged to cut production of volatile organic compounds (VOCs). When combined with nitrogen oxide in sunlight, VOCs create ground-level ozone.
Canada also plans to tighten its vehicle emission standards and bring them into line with those in the United States.
by Virginia Sutcliffe