Transboundary air pollution (pollution that travels across geographical borders) is responsible for a significant amount of Ontario's smog. In fact, more than 50 per cent of our province's smog originates in the United States.
Specifically, elevated smog levels in Ontario have been linked to long-range transport and transboundary flow of pollutants from the highly industrialized and urbanized areas of the American Mid-West and Ohio Valley Regions.
Ontario, Canada and the United States have acted to address transboundary pollution through the implementation of emission control programs, cooperative efforts, and bi-national agreements.
Ontario has also participated in American initiatives in support of stricter control measures and standards that will have a positive impact on air quality in Ontario.
These efforts have led to many positive results. However, the transport of air pollution remains a complex issue which requires further study and assessment to understand how we can effectively manage it.