Inversion leads to call for wood burning halt.
It's time to stop roasting chestnuts and put out that open fire.
Not only is Christmas over, but air quality is suffering from all the folks burning wood, whether they're doing it for roasting, toasting or bun warming. The problem is a typical one, an inversion that traps cold air at the surface and blocks off any breezes that other wise would carry wood smoke away.
That's why the Lane Regional Air Protection Agency is asking everyone in the Eugene-Springfield area to give their woodstoves and fireplaces a rest until an expected cold front pushes the inversion aside this weekend. Until then, continued burning would cause conditions to worsen as particulates build up.
The inversion, the first this winter, allows the very fine grit in wood smoke, called particulate, to build up and degrade air quality. Readings in the Eugene-Springfield area for the past two days have spiked in the yellow, or "moderate," range for air pollution, with the peaks rising each day.
The no-burn advisory is meant to avoid having conditions get worse, which could lead to an outright burning ban.
"Our concern is that when we put out a yellow advisory asking people not to burn in their woodstoves or fireplaces unless they need to, we're hoping to avoid a red advisory," said LRAPA spokeswoman Sally Markos. "If air pollution levels get to the point where we have to call a red advisory, no visible smoke is allowed from any chimney."
Both Eugene and Springfield have city ordinances that put teeth in the red advisory burn ban, and LRAPA would then patrol the area checking for smoke from chimneys or stovepipes. Violators could receive a warning or a fine.
The air protection agency figures that there are still about 8,000 old woodstoves in the Eugene-Springfield area that don't meet current certification requirements for particulate discharge. But Markos said almost none of those are the primary source of heat for the owners.
"So when we call a yellow advisory, if someone can use their other source of heat for a few days that would really help keep the air cleaner," she said. However, the advisory applies to all burning, including in new stoves.
For those few who need to burn, the agency asks people to burn cleanly by having only small, hot fires, leaving the damper open and allowing fires to burn out in the evening. Particulate levels typically hit their high point overnight and drop after sunrise.
The inversion layer has been topping out right around 1,000 feet, which means Oakridge is sitting above it and isn't experiencing the same problem. At 1,200 feet, Oakridge can get stuck in stagnant conditions that also limit stove use, but so far it hasn't been having problems from the current inversion episode.
Inversions form over the southern Willamette Valley several times each winter when high pressure forms over the region. That keeps winter storms away but traps air at the surface, leading to foggy nights that sometimes give way to sunny days but sometimes leave the area draped in fog all day long.
The National Weather Service has issued a stagnant-air advisory for the southern valley. A small front is expected to move through Wednesday night with a slight chance of rain, but forecasters don't expect it to be strong enough to clear the air.
The next chance for an inversion-clearing system is over the weekend, when a cold front is expected to wash through the region.