Smoke driven by the wildfires in Canada lingered over the Northeast and Midwest on Friday. Conditions were expected to improve over the Fourth of July weekend.
Across the nation’s middle, unhealthy air from Canadian wildfires sent summer campers home and left residents coughing, and asking when this would end.
The smoke cast a pall over New York City and other parts of the East Coast on Tuesday, meteorologists said, and triggered air quality alerts from Massachusetts to Minnesota.