New maps reveal where wildfire smoke will darken skies across the U.S. on Thursday, with the heaviest concentrations expected in the Pacific Northwest and Northern Rockies. Air quality alerts have been issued for multiple states as particulate matter levels reach unhealthy thresholds.

Meteorologists track the smoke plume's movement using satellite data and atmospheric models. The smoke originates from active fires in Canada and the Western U.S., driven by prevailing winds. Residents in affected areas should limit outdoor activities and use air purifiers indoors.

Conditions may improve by Friday as a cold front pushes cleaner air into the region. However, fire season continues through September, meaning recurring smoke events are likely. Officials recommend monitoring local air quality indexes and following health advisories.