When Kate Gammon and her family fled their Santa Monica, California, home during the recent wildfires, she wasn't sure what they would find when they returned.
Although they were not under an evacuation order, Gammon, who has asthma, told CBC News that the air quality was getting worse and the fires were volatile, so they left on January 8, when the fires were about six kilometers away. Four days later, she returned to find that the house had been saved from the flames, but she was horrified when she saw a layer of ash covering everything in her garden.
“It just rains on us at night,” she said. “They kind of look like big, white pieces of ash.”
Researchers now say that because of the size of these wildfires and the type of structures that are burning, people may be returning home when the initial fire danger is over. still health concerns from airborne compounds in the ash and smoke.
State firefighters are still working to put out the two largest fires in Altadena and Pacific Palisades, which have killed at least 27 people and destroyed more than 12,000 structures including homes, schools and banks. Thursday, the Los Angeles County Health Officer Prohibit cleanup or removal of fire debris until hazardous materials inspections are completed.
Asbestos can be found in ash and dirt in debris from residential and structural fires, heavy metals and other hazardous substancessaid the health official, noting that people can be exposed to toxic substances by ingesting ash or particles of fire dust, or through contact with the skin or a contaminated drinking water supply.
As an environmental journalist, Gammon has been there before reported the health hazards of ash, not only from brush, but also from thousands of burned structures. That's why she says she avoids touching the ashes and wears a mask outside.
Earlier this week, scientists they published their findings about how wildfires that burn in both wildland and urban areas affect indoor air. They studied the 2021 Marshall Fire in Boulder, Colo., where about 1,000 structures burned in eight hours, potentially shedding light on urban fires like those in L.A.
Headache after fire, itchy eyes
Colleen Reid, a professor at the University of Colorado, studied the health effects among people who returned to unburnt homes after that fire. She and her colleagues surveyed residents who lived near burned structures.
Over about five weeks, they also measured levels of volatile organic compounds (VOCs) at one home that survived the fires, but was heavily affected by the smoke.
They found that higher than normal levels of VOCs persisted for nearly a month inside the home before returning to normal indoor levels.
“People who said their home smelled different after the firewere more likely six months after the fireto have headaches, dry coughs, itching, watery eyes , a strange taste in the mouth and sneezing,” said Reid, an environmental epidemiologist.
As evacuees in Los Angeles begin to consider returning home, research shows that the toxic side effects of urban wildfires can linger for months in structures that survive the flames.
Reid and her team also surveyed people six months after the fire (642 respondents) and again a year later (413 respondents). Results included:
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65 percent of respondents reported ashes in their homes after the fire.
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Most of the respondents were less confident about the air quality both in the home and in the neighborhood six months after the fire. Most regained confidence within a year.
Cleanup tips after wildfires
Delphine Farmer, a Canadian scientist with Colorado State University, studies indoor air as part of test at the US National Institute of Standards and Technology in Gaithersburg, Md., where she and her team analyzed the composition of particles inside a home laboratory after they were exposed to fire smoke to introduce wild.
A farmer found that smoke buries itself into a painted surfacethen slowly begins to return to the air, which means that residents are exposed to indoor pollution for a long time after a fire.
WATCH | The science of indoor air after wildfires:
To guide people who need to clean up after a fire, the scientists are also studying how different air cleaners work and how surface cleaning affects air quality.
Based on her findings, Farmer's cleaning recommendations include:
- Opening windows as soon as smoke pollution clears. The sooner you clear the smoke, the better.
- Wash clothing such as bed sheets, clothing and curtains that may have retained smoke.
- Empty floor. Use an N95 mask while doing this because it can smoke soot or debris.
- Mop floors with soap and water and wipe down every surface you reasonably can, including walls if your area has experienced a lot of smoke. Wash ceiling fans and other surfaces that are not cleaned frequently. Change the water as it becomes dirty.
- Clean the 'hidden places' of your home such as attics, basements, closets and garages.
- If your HVAC system is leaking, consider having it professionally cleaned. Change the filters on your home HVAC system or air cleaners and run the fans regularly.
- Vacuum and wash the furniture as soon as possible. If you still smell smoke, consider deep cleaning or replacing.
