An air stagnation advisory issued today for much of the Inland Northwest has prompted Idaho authorities to impose an outdoor burning ban.
The burn ban was in effect for Boundary, Bonner, Kootenai, Shoshone and Benewah counties. Residents were also asked to voluntarily refrain from indoor burning until ventilation conditions improve.
The U.S. Environmental Protection Agency ordered outdoor burning bans on Indian reservations across the Pacific Northwest.
The Spokane Regional Clean Air Agency and Washington Department of Ecology had not yet imposed any burn bans, however the National Weather Service today said it expects pollution levels to rise to dangerous levels through the rest of the week and on Sunday.
Air quality in Kootenai and Spokane counties was in the good range today. However, air quality had deteriorated some from monitoring data taken on Monday.
A dense fog advisory was lifted, and the air stagnation advisory by the Weather Service was put in effect until 3 p.m. Sunday throughout the Inland Northwest as well as counties in central Washington and Columbia Basin.
The still air means pollution levels could increase to dangerous levels, according to the weather service. Those with respiratory illnesses could have some difficulty.
High pressure over the region is going to allow cooler air to pool along the ground and minimize the ability of the atmosphere to dilute pollutants through wind- and temperature-driven mixing. Fine particles of smoke were expected to be the main pollutant.
Temperatures for the area will remain seasonal, with a highs and lows both in the low- to mid-30s. The difference between day and nighttime temperatures often is only a couple of degrees when persistnent low clouds and fog settle over the region under a temperature inversion.
Air normally gets colder with elevation, but under an inversion, the air aloft can be markedly warmer than on the ground. Highs above the stratus layer could reach into the 40s, forecasters said.