SEATTLE — Air quality officials have banned all outdoor burning in the Puget Sound region because of diminished air quality affiliated with wildfire smoke.

The Puget Sound Clear Air Agency said as of Wednesday burning is prohibited in King, Kitsap, Pierce and Snohomish counties, until air quality improves.

The ban on burning includes: charcoal barbecues, fire pits, campfires, bonfires, fireplaces, uncertified wood stoves and agricultural fires.

Wildfire smoke from British Columbia has moved into the region making air pollution levels unhealthy for sensitive groups. Officials expect the smoke to last at least through Friday.

Officials say the purpose of the ban is to reduce any additional harm to sensitive populations from excess air pollution and is in addition to existing fire safety burn bans.