Since 1991, the United States and Canada have made considerable progress in reducing emissions of acid rain precursors and smog-forming compounds, in particular in areas near the border where transboundary transport is a particular concern. For example, the United States reduced sulfur dioxide emissions from covered sources by 52 percent from 1990 levels, and reduced nitrogen oxide emissions by 55 percent from their 1990 levels. Canada has made similar progress in reducing emissions of these substances and is meeting its agreed caps under the Agreement. These reductions demonstrate remarkable progress in less than two decades from identifying a serious cross-border problem to taking meaningful action to address it.
The Air Quality Agreement continues to be a dynamic instrument protecting human health and the environment on both sides of the shared border. We look forward to continuing our cooperation with the Government of Canada to sustain the progress we have made in maintaining air quality in the border region.