The Georgia Basin Puget Sound (GBPS) airshed spans the border between British Columbia in Canada and Washington State in the United States.

The GBPS airshed encompasses approximately 10 million hectares of land, and contains diverse landscapes and environments such as mountainous wilderness, densely developed urban areas, and open marine waters.

Over 6 million people live, work, and recreate in the GBPS airshed, and these human activities contribute to air quality throughout the region.

Air quality in the GBPS airshed is generally quite good in relation to other developed areas in North America. However, given forecasts of increases in both population growth and urban development, important research on the effects of air pollution on human health is required.