As Canada grapples with one of its worst wildfire seasons on record, smoke from the blazes have prompted air quality alerts across the U.S.

A thin veil of smoke from wildfires burning in Canada is worsening air quality and putting a lid on temperatures in the D.C. area. The smoke, which has resulted in some of the world’s worst air quality in the Upper Midwest and Northeast, is only wafting through the Mid-Atlantic in limited quantities, but it’s enough to have a small impact.

Flights at Logan airport were operating on a delay of 52 minutes due to low visibility on Monday afternoon, according to an advisory from the Federal Aviation Administration. Earlier on Monday, there was a brief ground stop at the airport "due to smoke and haze impacting operations," according to the FAA.