Smoke from wildfires burning in three Canadian provinces covered about a third of the U.S. on Wednesday, forecasters said, but had little effect on air quality except in New England and parts of New York state and the Midwest.

More than 25,000 residents in three provinces have been evacuated as dozens of wildfires remained active Sunday and

Smoke from the Canadian wildfires continues to bring potentially dangerous air quality to parts of the northern U.S., with hazy skies possible.