Inversion settling in; burn restrictions in place

SALT LAKE CITY — With the new year and the onset of January also comes the unwelcome temperature inversion brought on by snow cover and stagnant weather conditions.

For the Wasatch Front and Cache Valley, the strengthening inversion means air quality will continue to deteriorate and on Monday, the Utah Division of Air Quality issued a mandatory ban on wood burning and asked people to limit their driving.

Although the levels of fine particulate matter, or PM2.5, remain below the federal threshold of 35 micrograms per cubic meter in the non-attainment counties and Cache Valley on Monday, the division called for mandatory action to try to lessen the inversion's impacts.

As an example, values in Weber County were 27 at 1 p.m. Monday, but had dropped to just shy of 12 by an hour later. Salt Lake County recorded 15.6 at 1 p.m., but had also dropped to a "good" classification of 11.1.

Regulators, however, were keeping the pressure on to stop or limit pollution-causing activities, with an eye to potentially worsening conditions.

"The Department of Environmental Quality is trying to be proactive," said Donna Kemp Spangler, agency spokeswoman. "We are calling for mandatory restrictions to not burn wood because we are in an inversion. It doesn't make sense to wait until we reach the federal health standard when we know there's no significant storms in sight and the air quality will continue to deteriorate."

Under these restrictions, households in the non-attainment areas are to refrain from the burning of any solid fuel, including wood, coal or pellets, and motorists are asked to limit driving as much as possible by taking mass transit, carpooling, telecommuting or trip-chaining.

Those mandatory restrictions will likely remain in effect through the week as the Wasatch Front settles into a monotonous weather pattern unlikely to change, warned Monica Traphagan, a meteorologist with the National Weather Service in Salt Lake City.

"Unfortunately our fears are being realized. As we are heading into those January doldrums, it is bringing forth the strengthening inversion and diminishing air quality, and everything that goes with it," she said.

High temperatures along the Wasatch Front will remain in the high 30s or low 40s throughout the week and no significant storms are poised to bring much relief, Traphagan added.

"There are some indications there may be a weak storm that may come in Saturday or Sunday. The chances are not good; there is a twinkle of slight hope."

Both Traphagan and Bo Call, the division's air monitoring section manager, said residents can take comfort in that this inversion didn't come at a time when temperatures are dreadfully low.

Call added that as the days pass this week and more snow on the ground melts, it will temper what is already a weak inversion.

"We will have to see how clean it gets or how cold it gets before we get our next storm," he said.

Public hearings

The division is about to launch a series of public hearings to gauge residential interest and willingness to have an inversion-season wood smoke ban in non-attainment counties for PM2.5,or fine particulate pollution. The proposal would have to be adopted by the Utah Air Quality Board and may include exemptions for residences above 6,000 feet — above the inversion level.

Households that would be under the ban would be Utah, Salt Lake and Davis counties, portions of Weber, Box Elder and Tooele counties, and Cache Valley.

Clean air advocates have been on a push the last few years for an outright ban on wood or solid fuel burning, and Utah Gov. Gary Herbert has said tighter restrictions may be necessary in the areas that struggle with air quality.

Advocates say burning wood in a fireplace is the equivalent of 90,000 natural gas powered furnaces running, or driving a car 1,150 miles.

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