The National Weather Service this morning enlarged an air stagnation advisory to include nearly all of Spokane County, which was followed by new burning restrictions by the Spokane Regional Clean Air Agency several hours later.
Spokane joined other areas east of the Cascades that are expected to see stagnant air this week. The air stagnation advisory began elsewhere on Monday, but has not included the Palouse region and North Idaho.
The advisory is in effect until 4 p.m. Friday.
As a result, wood burning is now limited to only those devices that are certified by the Environmental Protection Agency, which includes all burning devices sold since 1993.
Air agency officials are asking residents using certified appliances to burn as cleanly as possible by building a hot fire initially to get more efficient combustion and by using with only dry, seasoned wood.
The restrictions apply to Spokane’s smoke-control zone which includes urban and suburban areas in the county.
Fireplace burning without a certified insert is not allowed.
In addition, all outdoor burning is banned countywide.
In residential wood burning, flue and chimney smoke is limited to 20 percent opacity, which is the amount that the smoke obscures background objects. Brief start up and refueling periods can exceed opacity rules. That limit applies at all times.
North Idaho was not included in the advisory because of adequate ventilation from an east to southeast flow in that area.
Higher air pressure along the Pacific coast is causing cold air to become trapped near the ground, preventing it from mixing with milder air in the middle elevations. The classic wintertime inversion often leads to low clouds, fog and air pollution.
Air quality in Spokane today was in the moderately polluted category after being good on Monday. Forecasters are calling for a chance of freezing drizzle or snow flurries through tonight with a chance of snow flurries on Wednesday.
Highs are expected to reach the middle and upper 20s with lows in the teens. Snow flurries are possible tonight and Wednesday.
Late night and early morning fog are likely through the weekend. When the fog lifts, expect to see low clouds.
Forecasters said the conditions are likely to persist through at least Tuesday.