The pollution-laden haze, which prompted delays at the busy airport here and degraded air quality across the region, was pushed down from extensive wildfires that have spread across western Canada and have forced more than 10,000 Canadians from their homes. Environmental problems linked to the fires have been felt from Washington State to Colorado, where the unhealthy fog has disrupted everyday life for many people. Families have been keeping their youngest and oldest members indoors, asthmatics are keeping their inhalers close at hand, and more than a few lovers of the outdoors have grumbled about canceled climbing excursions and camping trips.