Anyone who endured the October firestorms remembers the choking smoke followed by weeks of air that was acrid and irritating, while the surrounding world felt toxic after wildfires laid waste to 137 square miles of Sonoma County.
A research team from UC Davis now hopes to find out what, if any, potential health hazards may have resulted from the incineration of more than 5,100 homes and all they contained: cleaning products, paints, pesticides, electronics packed with rare earth elements, synthetic building materials, fuels.
The two-year investigation will focus on components in the smoke as the fires burned, as well as those left in the air and ash once the flames had roared through.
Researchers also plan to test the post-fire environment for any new chemicals that may have resulted from the transformation of existing materials under extremely high-temperature, low-oxygen conditions.
The project is aimed, in part, at understanding the array of substances residents may have been exposed to by breathing or sifting through the remains of neighborhoods afterward, as well as the potential health implications.
It also is intended to inform the environmental health response to future wildfires expected to proliferate in the urban-wildland interface as the climate shifts, researchers said.
In addition, online surveys and field interviews will be used to try to assess short- and long-term health impacts among residents exposed to smoke in Sonoma County and neighboring areas.
“We want to paint a picture of not only what happened in the moment, but also what’s happening now, with the cleanup and re-entry and the different phases as they unfold,” said Keith Bein, a scientist with the UC Davis Air Quality Research Center. “Because this is unprecedented. We don’t know what to expect.”
Led by Irva Hertz-Picciotto, an epidemiologist and director of the UC Davis Environmental Health Sciences Center, the multidisciplinary study is driven by recognition of how little is known about fires on the scale of those in the North Bay three months ago.
The contents of smoke from a wildland fire — where mainly organic matter burns — are better known, though there’s a push for more research there as well, given increased use of flame retardant and pesticides on forests and wild places, according to a separate UC Davis study.
But when a community burns, “there may be different kinds of health effects simply because the mix of chemicals is probably quite different,” Hertz-Picciotto said.
Among the involved researchers is doctoral student Gabby Black, a Sonoma native whose family still resides in the area and was evacuated during the first days of the inferno.
After watching helplessly from afar for several weeks, Black was back in Sonoma County around Halloween collecting samples of ash from inside the foundations of homes along the path of the Tubbs fire — Franz Valley Road, Larkfield/Wikiup, Coffey Park, Mark West and elsewhere — in each case scooping from areas that seemed to be the kitchen or garage.
She also took background samples of burned biomass from Robert Louis Stevenson State Park in Napa County for comparison.
The samples haven’t been analyzed yet, but the focus is on materials forged in the fire through synthesis, as well as those that survived the flames without breaking down into constituent substances, she said.
Bein already has stored samples of particulate matter filtered from the smoke that poured out of Sonoma during the fires.
He began collecting them the first night in his hometown of Oakland, as well as at Davis during the first days the North Bay burned.
He and his colleagues also plan continuous, 24-hour air sampling in Sonoma and Napa counties over the long term, capturing samples from places with a range of recovery and rebuilding activity.
His team is building a mobile air-monitoring unit for deployment once the wettest part of winter has passed that’s powered by the batteries in two all-electric vehicles so they can operate in areas without power.
Bein already surmises that tiny particles of ash will persist in the fire zone for years and potentially become airborne in dry conditions.
Particles small enough to get past human defense systems and penetrate deep into the lungs could spell trouble.
“That’s where the toxicity really happens,” he said.
Researchers also are hoping for the participation of thousands of residents from Sonoma County and neighboring areas exposed to smoke on an online survey that will go live as soon as it’s approved by a board that supervises studies on human subjects, Hertz-Picciotto said.