A ban on any type of wood burning in the Puget Sound area likely will remain in effect at least until Sunday.

Stagnant air and elevated pollution levels have prompted officials with the Puget Sound Clean Air Agency to continue the ban put in place earlier in the week.

No burning is allowed in any wood-burning fireplaces, wood stoves, fireplace inserts or pellet stoves unless it is the household’s only adequate source of heat, said Amy Warren, a spokeswoman for the agency. Burn ban violations are subject to a $1,000 penalty.

A temperature inversion, in which warm air holds colder air close to the ground, is still in place in the area, according to the agency’s meteorology staff. The warmer air acts as a lid, holding down pollutants along with the colder air.

Wood burning has continued despite the ban, increasing pollution to the point where the air is unhealthy for the very young, elderly and people with heart and lung ailments, Warren said.

The state Department of Health advises people in high-risk groups to check conditions before spending much time outdoors or engaging in any strenuous activity. Often pollution can’t be seen or smelled, so it’s difficult to judge air pollution levels, according to the health department.

People with stoves are asked to rely instead on their home’s other, cleaner source of heat, such as a furnace or electric baseboard heater for a few days until the ban is canceled.

Even if a household fireplace, pellet stove or wood stove is the only adequate source of heat, no visible smoke is allowed, Warren said.

Outdoor fires also are prohibited, including bonfires, campfires and the use of fire pits and chimineas.

It is OK to use natural gas and propane stoves or inserts during the burn ban.

The agency will monitor conditions and could lift the ban on Sunday if conditions change, Warren said.