When fires ripped through suburban subdivisions in Santa Rosa last October, they may have done more than reduce homes to ashes.
By incinerating all kinds of materials — insulation, electronics, furniture, cleaning products, pesticides — at very high temperatures, they could have created unknown or previously unrecognized health hazards in the smoke and ash.
Now, researchers from UC Davis, are trying to figure out just what is in that ash and air.
The fires in Northern California’s wine country destroyed an estimated 7,500 structures over 210,217 acres and caused $1.045 billion in damages. But those same fires — in addition to devastating the landscape — also caused serious pollution.
“What we’re interested in looking for are transformation products of household products that have burned in the fires,” said Gabby Black, a fourth-year graduate student in agricultural and environmental chemistry at UCD.
According to Tom Young, professor in the Department of Civil and Environmental Engineering and Black’s faculty adviser, the health hazards these compounds pose are not yet known.
“Conventional assessments rely on things that we already know are pollutants, such as industrial chemicals,” Young said. “But we don’t know what new chemicals might have been created from combustion.”
The fires — both those in Northern and Southern California — have already caused unhealthy air and the sudden release in carbon dioxide that drives climate change.
According to Julie Cart of the news service CalMatters, the extensive efforts of industry and regulators to protect the environment can be partly undone in one firestorm. In particular, as raging blazes pump more carbon into the atmosphere, state officials are grappling with the potential effect on California’s ability to adequately reduce greenhouse gas emissions.
The state’s environmental regulations are known to be stringent, but they have limits: They apply only to human-caused emissions. Carbon and other pollution generated by wildfires is outside the grasp of state law.
“The kinds of fires we’re seeing now generate millions of tons of GHG emissions. This is significant,” said Dave Clegern, a spokesman for the state Air Resources Board, a regulatory body.
In less than one week, for example, October’s wine country fires discharged harmful emissions equal to that of every car, truck and big rig on the state’s roads in a year. The calculations from the subsequent fires in Southern California are not yet available, but given the duration and scope of the multiple blazes, the more recent complex of fires could well exceed that level.
The greenhouse gases released when forests burn not only do immediate harm, discharging carbon dioxide and other planet-warming gases, but also continue to inflict damage long after the fires are put out. In a state where emissions from nearly every industry are tightly regulated, if wildfires were treated like other carbon emitters, Mother Nature would be castigated, fined and shut down.
The air board estimates that between 2001 and 2010, wildfires generated approximately 120 million tons of carbon. But Clegern said a direct comparison with regulated emissions is difficult, in part because of limited monitoring data.
At UC Davis, the Northern California Fire and Health Impacts project, also known as “Wildfires and Health: Assessing the Toll in NOrthWest California” (WHAT NOW-California) is being led by Irva Hertz-Picciotto, professor of public health sciences and director of the UCD Environmental Health Sciences Center.
In addition to sampling ash and air, researchers from the center plan to survey residents of Napa, Sonoma and other Northern California counties affected by the fires or the smoke. The survey asks about how the fires have affected them and other household members, including their experiences as well as their health before, during and after the fires.
Black, who was born and raised in Sonoma, has collected ash samples from a series of sites burned by the Tubbs Fire in October, from wildland in Robert Louis Stevenson State Park into the city of Santa Rosa.
In addition, researcher Keith Bein and colleagues from the UCD Air Quality Research Center plan to regularly collect air samples from these sites as the area recovers from the fires. While the fires were still burning, Bein’s team collected samples of smoky air in the Bay Area and Davis. But for years to come, they expect, dust in the burned area will contain particles of fire ash. The researchers will look specifically at airborne particles less than 2.5 microns in size that can penetrate deep into the lungs.
Air and ash samples will be analyzed by the latest techniques that can generate high-resolution profiles of hundreds or thousands of molecules in a sample. The researchers will compare the samples to existing databases and also look for new compounds.
“This was a very unique type of fire, an urban wildfire,” Bein said. “We know what wildfire smoke is composed of, but we have no idea what will be in this — we expect it to be very different.”
The air quality team has set up a mobile air sampling unit powered by an electric vehicle. The system can carry out 24 hours of continuous sampling in a remote area with no accessible power. They plan to begin monthly sampling in the Sonoma and Napa areas this spring. In future, Bein hopes that the mobile unit can be deployed quickly into an affected area.
The project has received initial funding from the UCD Environmental Health Science Center, sponsored by the National Institute for Environmental Health Sciences. Black is supported by an NSF graduate student fellowship.
