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Working Together for Cleaner Air

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Multiple environmental and health problems (including acid rain, impaired visibility, damaged ecosystems, and respiratory illness) are caused or worsened by air pollution from mobile and stationary emission sources in Canada and the United States. Both nations have an interest in reducing transboundary air pollution.

aved the way for cooperation on a variety of air quality issues. While the initial focus of the Agreement was on acid rain, the two nations recently expanded cooperative efforts to control transboundary ground-level ozone and to conduct joint analyses on transboundary particulate matter (PM).

After more than a decade of scientific research and discussions, Canada and the United States signed a historic Air Quality Agreement in Ottawa, Canada, on March 13, 1991. The Agreement established a formal and flexible method of addressing transboundary air pollution and p

Canada/U.S. Percentage of Key Emissions by Sector (1999)

Canada/U.S. Percentage of  Key Emissions by Sector (1999)The main body of the Agreement lays out overall air quality objectives and specific requirements for both countries, including regular communication, exchange of information, and consultation and settlement of issues of concern.

A bilateral Air Quality Committee is responsible for coordinating the overall implementation of the Agreement. Two subcommittees—Program Monitoring and Reporting, and Scientific Cooperation—meet annually with the Air Quality Committee and carry out yearly activities. The two nations prepare a joint progress report every two years and conduct a regular five-year review and assessment of the Agreement.

Shared Benefits
of the Agreement

The Air Quality Agreement was signed in 1991 and included two annexes. Annex 1, the Acid Rain Annex, focuses on the commitments of both nations to reduce sulfur dioxide (SO2) and nitrogen oxides (NOx) emissions, the primary precursors of acid rain. Under Annex 1, both Canada and the United States have committed to monitoring utility emissions. Continuous emission monitors (CEMs) are widely utilized in the United States; Canada uses CEMs along with other alternative methods. Under Annex 2, the Scientific and Technical Activities and Economic Research Annex, Canada and the United States agree to coordinate their air pollution monitoring networks; use compatible formats and methods for monitoring and reporting; and cooperate and exchange information about the causes and effects of air pollution and the use of market-based programs, such as the U.S. Acid Rain Program, to address air pollution issues.

In December 2000, Canada and the United States added Annex 3, the Ozone Annex, to the Agreement. This Annex commits the two nations to reducing emissions of NOx and volatile organic compounds (VOCs)—the precursor pollutants to ground-level ozone, which is the major component of smog.


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