With temperatures hitting record-breaking lows, wood-burning homes are preparing to light the season's first fires.

But Multnomah County officials are asking residents to take a step before reaching for the kindling: Check the air quality.

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The county’s seasonal wood smoke restrictions take effect Tuesday, barring homes and businesses from burning wood on the worst air quality days of the year for the next six months.

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All fall and winter, wood stoves and fireplaces spew tiny toxic particles. On days where air pollution levels are already high, wood smoke pollutants can significantly worsen air quality, aggravating the lungs of children, seniors and those with breathing conditions.

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In the hopes of sparing sensitive residents – and complying with national air quality standards – Multnomah County passed an ordinance in February 2018, banning the use of wood stoves, fireplaces, outdoor fire pits and free-standing chimeneas on poor air quality days.

The rule makes exceptions for low-income families and households who rely solely on wood as their heating method. Homes and restaurants that use wood to cook are also exempt.

Everyone else risks a fine for routinely generating wood smoke on highly polluted days. But Nadège Dubuisson, an air quality specialist with Multnomah County, said the county plans to stick to warnings for first and second-time offenders.

Last year, the county had only two no-burn days. Seven households received warning letters, but none were fined.

“We’re hoping people will mainly voluntarily comply with the rules and think about those who are really sensitive to wood smoke before they burn on those bad air quality days,” Dubuisson said. “Enforcement is mainly complaint driven, so we don’t go out inspecting folks.”

The restrictions will stay in place through February. Until then, the county is directing residents to its website for information on the day's air quality. Notifications also go out on the county's social media channels or residents can sign up for emailed alerts.

On days where forecasters predict the air quality could become dangerous, a 24-hour ban will be announced by 11 a.m. to go into effect at noon.