A familiar mucky gray haze blanketed Boise Monday afternoon — and real-time air monitors were indicating that wildfire smoke had diminished air quality to the “orange alert” level, or unhealthy for sensitive groups.

So far this summer, the Valley has seen 39 days with yellow, or moderate, levels of air pollution, and two days of orange alert-level pollution (both in August). Tuesday is expected to be another one of those orange days but hourly readings could show it’s better or worse (possibly in the red, or unhealthy for everyone, levels), according to an alert issued by IDEQ Monday afternoon.

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Children, the elderly and people with heart or lung conditions are advised to limit strenuous activities outdoors on Tuesday. All open outdoor burning is prohibited within Ada and Canyon counties, as well as all the cities within the counties.

What’s causing the air quality to get worse?

“The current low pressure system has helped to push/pull regional wildfire smoke into our area from Washington state and British Columbia,” said Michael Toole, regional airshed coordinator for Idaho Department of Environmental Quality’s Boise Regional Office. “There are also fires still in Idaho, northern California, Oregon, and other regional fires we have been impacted by.”

Monday was a windy day in the Valley but that only made things worse because the air coming out of the northwest was smoke-laden.

Winds picked up around 2 p.m. Monday, according to National Weather Service lead forecaster Les Colin. Sustained winds were about 25 mph, with gusts of 30 to 35 mph. The peak gust of the afternoon was 40 mph.

A small cluster of thunderstorms in northern Malheur County, Oregon, was moving toward the Treasure Valley at about 4:15 p.m. Monday afternoon. The Boise area could see outflow winds from the storms and possibly rain.

The red areas are under red flag warning Monday night. (National Weather Service)

A red flag warning, which means ideal conditions for new fire starts and rapid spread, was in effect until 8 p.m. Monday for most of southern Idaho, including the Treasure Valley. Projected wind speeds of 30 to 35 mph and humidity levels dropping to 10 to 15 percent were the main reasons for the warning, Colin said.

Air quality experts say these are things we can all do to help improve the Valley’s air quality:

Limit driving.

Car pool or take the bus.

Combine trips/errands.

Don’t idle cars.

Fuel cars later in the day.

Don’t use gasoline-powered equipment, or use them later in the day.

Don’t burn outdoors.

Katy Moeller: 208-377-6413