DAVIS, Calif. — When wildfires rage in northern California, scenes of thick smoke often blanket the valley polluting the air for millions.
While scientists have studied and warned about the impact of wildfire smoke on the general population, a study closing soon out of UC Davis is aiming to shed a light on how some of California’s most vulnerable residents are directly impacted by the smoke: pregnant women and their babies.
“Even though it's one wildfire event, sometimes the smoke can linger for weeks, and even months lately,” said lead researcher, Dr. Rebecca Shmidt. “When we start seeing those kinds of exposures, you just kind of have to wonder whether it's doing harm, what type of harm and how to prevent that harm.”
In 2017, Dr. Shmidt, a molecular epidemiologist and mother met with researchers at UC Davis after seeing wildfires such as the Tubbs and Atlas fires raging in Sonoma County, producing unhealthy air quality for the valley.
“At the time, we had other pregnancy cohorts ongoing, and mothers were asking us, you know, 'what is the implication for all this wildfire smoke that I'm breathing while I'm pregnant, on my child?',” Dr. Schmidt said. “We kind of looked at the literature at the time, and at least in terms of wildfire smoke, there wasn't much out there really studying the impacts."
That lack of information did not sit well with Dr. Schmidt. The group began their study that year, recruiting pregnant women, asking them questions and collecting biospecimen samples such as nail, hair, blood and saliva.
“We collect lots of information on their wildfire experience so we get an idea of what their experience was,” Dr. Schmidt said.
Some of that information includes whether participants used air purifiers, masks outdoors, how often they went outdoors, how they are coping with the fires and if they were evacuated.
Later, after the child's birth, researchers return to collect more data and ask more questions.
"We follow it through first postnatal visits, so through the child's birth, and shortly after. Then, we get information on the health outcomes of the baby at birth and the pregnancy outcomes," Dr. Schmidt said. "Our hope is to bring them all back at some point and look at longer term health impacts, or potential impacts, on the children."
After collecting data for nearly five years, Dr. Schmidt says researchers are now getting a better idea of the impacts of wildfire smoke but are still analyzing their data.
"We're still at the phase where we're looking at data and some of the early things that we've seen," Dr. Schmidt said. "40% or so experienced respiratory symptoms, and that's in the mothers."
So far, Dr. Schmidt says the emotional and mental toll of wildfires has stuck out as having the most concrete impacts on pregnant women and their babies.
"Stress and anxiety about wildfires in general and potential health consequences or just, you know, the fact that their house could burn down at any point was a major concern for these families," Dr. Schmidt said. "The stress and anxiety and some sleep disturbances and things lasted much longer than some of those shorter term respiratory symptoms, so up to a year later."
With large and damaging grass fires already being reported across the state, Dr. Schmidt and her team are ready to continue their research into the next fire season.
Now, they find themselves in a familiar position, asking for volunteers to participate in the study for what is expected to be its last fire season.
“Anyone who is within a two-hour drive or so to Sacramento is eligible, and we hope that people participate if they were pregnant anytime during last year's 2021 fires, or shortly thereafter,” Dr. Schmidt said. “This is our last round of recruitment that's funded, we're hoping to get more funding to continue in the future.”
While more results from the study are forthcoming, Dr. Schmidt says it is best for all to stay safe during the fire season which can include low-cost or do-it-yourself solutions.
Most of the solutions require MERV 11 air filters, which Dr. Schmidt says can sometimes sell out during the fire season. She also recommends wearing N95 while outside on smoky days.
"Stay indoors, close your windows and have those filters help clean the air, run your house fan if you have them," Dr. Schmidt said. "A lower cost version is you can make your own box fan filter."
Those interested in participating in the study are asked to visit the project's website.