At least twelve states have issued air quality alerts and advisories due to the ongoing Canadian wildfires sending smoke down to the Great Lakes region and the northeastern United States, the National Weather Service reported on Tuesday.

Red flag warnings remain in place for parts of Nevada, Utah, Colorado and Wyoming due to very dry conditions, low humidity and gusty winds.

Air quality has taken a serious hit across the United States as a two-fold blow of wildfires in the West and in Canada have sent smoke pouring across large sections of the country — a problem that’s set to linger for days.