After brief respite, wildfire smoke again engulfs Boise. How long will it last?

After two days of clearer skies, wildfire smoke again rolled into the Treasure Valley on Sunday, obscuring the Boise Foothills and casting an orange haze over the city by Monday morning.

Michael Toole, airshed coordinator for the Idaho Department of Environmental Quality, told the Statesman in a phone interview that air quality improved beyond expectations on Friday and Saturday, even dropping into the “good” rating on Friday — the best possible air quality category.

By Monday morning, the air quality index showed Boise just below 100 — at the top of the moderate, or yellow, category and inching toward the orange category, which denotes air that is unsafe for children and the elderly. Toole said the Treasure Valley will remain in that range for days to come thanks to unrelenting pollution from wildfires, mainly burning in Oregon and Northern California. Numerous fires in North and Central Idaho are also contributing to the smog.

Toole said Boise might not see relief from the smoke for 7-10 days.

There also is little relief from the heat. The National Weather Service’s Boise office tweeted Monday that the area had broken yet another heat record — this time for the longest streak of days with a low temperature of 60 degrees or warmer. Monday was the 38th day in a row in which temperatures did not fall below 60 degrees.

Highs this week will be at or near 100 until the weekend, when temperatures could fall into the upper 80s on Saturday and Sunday. Lows will continue to be in the 60s and 70s.