Last week, some folks in the Bay Area spent a few days nursing sore throats and achy heads, lugging out the air purifiers they’d just put away a few weeks earlier and hoping their symptoms weren’t actually COVID-19.
The poor air quality that briefly choked the Bay Area is actually typical this time of year, according to Kristine Roselius, a spokesperson for the Bay Area Air Quality Management District (BAAQMD), the agency regulating air pollution in the region. She said we’re simply more attuned to it now because of our recent experiences with wildfire smoke.
Last week’s haze was caused by a “temperature inversion,” which occurs on cool, calm days, when a layer of warm air acts as a lid trapping and concentrating air pollution close to the ground. In the Bay Area in the winter, the largest source of the unhealthy “fine particulate” pollution is wood smoke — from fireplaces, mainly — though vehicle emissions, and in this case pollution from the San Joaquin Valley, also contribute. Particulate matter contains tiny, inhalable particles and droplets that can get into your lungs and bloodstream and threaten your health.
Many people are already aware of the dangers of wood burning, but confusion abounds about exactly what is and isn’t allowed or recommended locally. Read on for answers to some of the most common questions.
Am I allowed to use my fireplace?
Wood burning is generally permitted, but it’s illegal whenever BAAQMD puts out a Spare the Air Alert. You can sign up to receive those alerts by phone or email, or find out online if it’s a Spare the Air day, which is declared when unhealthy conditions are forecasted and the AQI is expected to exceed 100. In the past, the air district could only ban wood burning during Spare the Air days between November and February, but in 2019 a rule change gave the district the authority to instate a ban anytime an alert is issued, such as during a wildfire in August or September. The ban applies to indoor and outdoor wood burning, including fireplaces, fire pits, and wood stoves.
So it’s OK to use the fireplace or fire pit on other days, if the air is clear?
It’s not illegal, but Roselius from the air district still cautions against it. “Wood burning is really not the most efficient way to heat a home — 80-90% of the heat goes up the chimney,” she said. Even one fireplace blaze can negatively impact conditions around it. “It has significant pollution impacts not only in the neighborhood where the fire is, but fine particulate matter moves around. I think the public is beginning to understand this, with wildfires,” Roselius said. Cooking fires — think barbecues — are always permitted, but the air district recommends using propane or gas devices over wood or charcoal if you can.
What if wood burning is my only source of heat?
You’re allowed to use a wood-burning device any day of the year if it’s your only option for heat. But in that case, you must use an EPA-approved device that you register with the air district. Newly constructed buildings in the Bay Area no longer permit wood-burning devices at all. Alternatives like gas and electric fireplaces are still allowed.
Just how bad is wood burning?
According to the air district, wood burning typically contributes about 40% of fine particulate pollution in the winter. No other source comes close. That fine particulate pollution can cause “significant and immediate health impacts for many people,” Roselius said. “It can exacerbate respiratory conditions and cause an asthma attack” in people with medical vulnerabilities, “but it impacts all of us. We might experience a scratchy throat or watery eyes.” In the warmer months, ozone, or smog, is the primary pollutant, not fine particulate matter, and it often comes from vehicle emissions. “The best way to improve air quality on a daily basis is to drive less,” says the air district. Some areas in the region consistently experience worse air quality than others, including from toxic emissions from industrial businesses.
But fireplaces are cozy!
True. Roselius says the shift away from wood burning is one that society must and will eventually accept. “Back when cigarette smoking on airplanes was banned, people were really upset initially, but now it’s just not done,” she said. “It takes time for people to make that connection from what they thought of as a cozy winter tradition to something that’s harmful.” Of course, many people living in apartments and elsewhere don’t have access to a fireplace in the first place. Those residents and anyone else trying to cut down on burning wood can always turn to the virtual option. The Yule Log traditionally broadcasts on Christmas, but thanks to the internet, you can stream a slowly burning log on any Spare the Air day.