Be prepared for several days of stagnate air in parts of the Magic Valley. The U.S. National Weather Service in Boise has issued an Air Stagnation Advisory for the western part of the Magic Valley up towards the Oregon state line until Sunday afternoon. The advisory says there could be times of air stagnation that could lead to the buildup of pollutants close to the ground.
Also:

If possible, reduce or eliminate activities that contribute to
air pollution, such as outdoor burning, and the use of
residential wood burning devices. Reduce vehicle trips and
vehicle idling as much as possible. Check with local agencies
for possible restrictions in your area.

It also recommends people with respiratory illness to check with their physician about dealing with air pollution and stagnant air.

U.S. National Weather Service Boise