“Intense smoke blanketed the northeastern United States for a second day Wednesday, turning the air a yellowish gray and prompting warnings for people to stay inside and keep windows closed. The smoke was flowing from dozens of wildfires in several Canadian provinces.

Much of the air was in the ‘unhealthy or worse categories in areas from the mid-Atlantic through the Northeast and parts of the Upper Great Lakes,’ according to an advisory issued by the Environmental Protection Agency Wednesday night.”