SEATTLE (AP) — Air quality conditions are improving in the Seattle region after days of unhealthy smoke and haze but officials warn it's not over yet.

The National Weather Service has had an air quality alert since Sunday and it remains in effect until noon Thursday.

The Puget Sound Clean Air Agency reports the smoke has begun clearing but there's still moderate to unhealthy amounts of pollution remaining this morning.

Even healthy adults in Snohomish County north of the city should remain indoors.

In Seattle, the air is still unhealthy for those with sensitive health considerations, including children, pregnant women, the elderly and those with heart and lung problems.

Outside of the metro area, an industrial fire in Shelton caused toxic smoke to release into the air late Wednesday night into Thursday morning.