Since the Camp wildfire tore through more than 150,000 acres in Northern California, the air quality in cities from Chico to Bakersfield has reached unhealthy and even hazardous levels. In Sacramento, some schools and businesses remain closed. And across the state, health officials are warning people to stay indoors and avoid outdoor physical activity.
But will exposure to the smoke have long-term impacts on our health?
Dr. Gina Solomon, a professor of occupational and environmental medicine at UC San Francisco, says scientists don’t have a conclusive answer.
“We know a lot about what short term exposure does to people, we know a lot about what lifetime exposure does to people,” she said. But she added that, as the wildfire seasons grow longer and smoke becomes an “annual event” in California, “we’re going to be entering into some uncertain territory."
Wildfire smoke contains particles that are so small, they can slip through the lungs and into the bloodstream. Some of them are carcinogenic. They exacerbate pre-existing conditions such as asthma, heart disease and chronic obstructive pulmonary disease, and can make it hard for seniors with respiratory problems to breathe.
Even healthy, young people may experience coughing, eye irritation, fatigue, chest pain and other symptoms. But experts said most of these will go away when the smoke dissipates.
“The mild irritation that most of us experience will be gone, and we will be fine,” said Dr. John Balmes, a member of the California Air Resources Board.
But people up in Butte County who had respiratory or cardiovascular problems before the fire could see a permanent worsening of those conditions, according to Balmes.
He also noted that limited exposure, for a week or two, doesn’t come close to the long-term population-level impacts experienced by people who live in highly polluted countries year-round.
An analysis out of UC Berkeley shows that spending a day in 22 micrograms of air pollution is comparable to smoking one cigarette. This week, the air quality in Sacramento lingered around 170 micrograms — roughly equivalent to eight cigarettes. Balmes said it takes thousands of cigarettes over a period of years to increase cancer risk.
Children are more vulnerable, however, as they breathe more quickly, and have smaller airways. Solomon with UCSF said she’s concerned that continued severe and lengthy wildfire seasons will take a toll, as kids can be primed to asthma.
Particles that inflame airways also can interact with common allergens and make people develop new allergies. And there are studies indicating that kids who were exposed to high levels of particulate in Southern California in the ’90s grew up with more lung problems than children who lived in the same places decades later, after Los Angeles took air quality improvement measures.
“Their lungs never fully grow and develop to the complete size and normal function that a child growing up in clean air develops,” Solomon said. “You develop slightly stunted lung function.”
Other research on chronic air pollution has shown low birth weights for babies whose mothers were exposed, and high asthma rates among those who must breathe it in daily. But there just isn’t enough evidence to show whether wildfire smoke a few times a year is causing similar problems.
UC Davis researchers are analyzing the blood, hair and breast milk of women who were pregnant during last year's wildfires — plus placenta, umbilical cord and other samples from their babies — to explore whether wildfire causes problems for infants.
Other teams there are looking at what happens when farm lands sprayed with pesticides burn up, and whether chemicals from insulation, electronics and other products make the air more toxic.
In the meantime, health officials are advising people to stay indoors to avoid short-term symptoms. Physicians at Sutter Health and UC Davis Health say they aren’t seeing a huge spike in people coming to emergency rooms with respiratory problems, because people seem to be following those warnings.
Those who must work outside or stay outside for extended period are advised to wear a properly fitted N95 mask. There are also indoor air filters, and devices that can measure air quality in a home or office.