The infernos raging in Southern California are raising concerns about the airborne risks they could leave behind.
Experts say that even if the fire is eventually extinguished, pollutants from the destroyed structures, some of which are potentially toxic, will remain in the air and pose an uncertain health threat. It warns that it may cause
Although it is not yet conclusive how many buildings were destroyed, estimates indicate that at least 15,000 buildings were destroyed in the blazes of the original Palisades and Eaton fires. And some people “would have suffered significant damage from the smoke and toxic ash buildup,” said Daniel Swain, a climate scientist at the University of California, Los Angeles. in a webinar earlier this week.
“This is a growing concern following this very urban fire that burned an entire building, including not only plants but also lead paint, asbestos, and various heavy metals found in batteries in cars and household systems. “There's backup and solar panels,” he said.
Swain described these losses as a “staggering toll” and warned of the indirect damage residents could suffer from exposure to smoke and toxic ash.
“The health risks, illnesses, and sometimes deaths caused by large-scale disasters and wildfires are not limited to those who cannot escape the fire area,” he added.
For the weekend that looks like it's going to rain, palisades fireThe city, which devastated the Pacific Palisades area, spans 23,448 acres and is 77 percent contained. eaton fire14,021 acres north of Pasadena were 95 percent contained. But new fuse fireThe operation, which began Wednesday near Castaic Lake, has grown to 10,396 acres but is only 56 percent contained.
Wildfire smoke contains a variety of pollutants, but the most well-studied component is fine particulate matter (PM 2.5). When inhaled, these small particles can enter the lungs and enter the bloodstream, said Tariq Benmania, a climate change epidemiologist at the University of San Diego's Scripps Institution of Oceanography. A recent commentator.
As well as worsening existing conditions such as asthma, repeated exposure to PM 2.5 is also linked to future lung cancer, cardiovascular disease and dementia, Benmania said. him and his A colleague recently demonstrated How repeated, multi-year exposure to PM 2.5 from wildfire smoke increases the risk of developing dementia and Alzheimer's disease.
To understand the reach of wildfire smoke, Scripps Oceanography researchers announced Tuesday that they had identified ash and debris as far as 100 miles offshore, raising concerns about its potential for fisheries and broader food webs. This is raising concerns about the negative impact.
“These fires are not only burning up vegetation, but also a lot of urban infrastructure,” said project leader Julie Dynaske. stated in a statement. “This introduces a new ‘urban ash’ component filled with highly toxic substances to wildfire sources.”
Among the substances she warned about were lead, arsenic, asbestos, microplastics and polycyclic aromatic hydrocarbons, organic compounds that occur naturally in fossil fuels.
“These fires pose a potentially serious threat to both humans and the ecosystem, as large amounts of toxic substances are introduced into the system,” Dynaske added.
Public health risks rife with uncertainty
Exactly how great the threat to public health from these wildfires will be, and when and who that threat will affect remains unclear.
Richard Castriotta, a pulmonologist at the Keck School of Medicine at the University of Southern California, said there is a “huge difference” between urban wildfires like those burning in Los Angeles and wildfires that only affect trees. pointed out.
Castriotta recognizes that the dangers associated with forest fire smoke are real, and that they pale in comparison to the potential pollutants released by burning buildings. -Told Hill.
He also said that high doses of toxic substances involved in exposure, such as chlorine, lead, asbestos, and nitrogen oxides, and mysterious substances produced as high-intensity flames “turn plastics and man-made materials into unknown substances.” He explained. ”
“The risk exists for everyone, but it's understandably more severe for people with lung disease, heart disease, diabetes, and weakened immune systems,” Castriotta said, adding that those who are pregnant or breastfeeding are at risk. He pointed out that people could also be at risk.
However, he stressed that children are particularly vulnerable and should not take part in cleaning up fire-damaged homes.
The short-term effects of smoke exposure tend to be felt in both the upper and lower respiratory tract, with the nose sifting out many large particles and then the lungs acting as “first responders” for some smaller particles. It works, Castriotta explained.
“This is our first immune response, so when these toxic particles enter in large numbers, it can overwhelm the immune response system,” he said. “Then, regardless of their prior health, that person becomes relatively immunocompromised and, like the firefighters themselves, unable to cope with the additional burden.”
In the coming days and weeks, a weakened immune system could make people more susceptible to respiratory illnesses such as pneumonia, influenza, COVID-19, and bronchitis, Castriotta said. added. For people who are already sick, he said exposure can worsen conditions such as asthma, chronic obstructive pulmonary disease, pulmonary fibrosis and heart disease.
However, Castriotta acknowledged that he does not know what the long-term effects of exposure to these fires will be, and that “we do not know if anyone will be affected.” He referenced the collapse of the Twin Towers on 9/11, noting how long it took to determine the health effects of first responders. And while he recognized the differences between these situations, he described similar uncertainties.
One potential problem in many of the burned down homes could be the presence of asbestos, which Castriotta described as “a durable fire-resistant fiber that lasts forever.” When these fibers enter the lungs, the “first responders” white blood cells “don't have the ability to digest and destroy them,” he explained.
“That's why the latency period from exposure to asbestos is long and the negative effects can last up to 30 years.”
At the same time, Castriotta pointed out that long-term effects depend on both the duration and extent of exposure, and that inhaling a single particle of asbestos will not lead to illness.
The situation could have been worse
Air pollution levels in these dense urban environments may be dire, but the situation could have been even worse had the fires occurred in the summer instead of the winter.
Alexei Kharizov, a professor of chemistry and environmental science at the New Jersey Institute of Technology, attributed the difference to the notoriously high ground-level ozone levels on Los Angeles summer days.
He explained that wildfires produce high concentrations of chemicals with a wide range of volatility, and that lower-volatile compounds quickly condense into soot particles as the smoke cools.
More volatile chemicals cannot condense as quickly and instead travel through the air with soot and interact with other pollutants, such as ozone, Harizov said. Only then, he noted, will the toxicity of these particles increase as they become less volatile and begin to condense on the soot.
Among the volatile compounds that most alarmed Khalizov was polyvinyl chloride (PVC), a common ingredient in plastics. He cited the 2023 train derailment in East Palestine, Ohio, after which authorities decided to burn a tanker of vinyl chloride (a carcinogenic chemical used in the production of PVC) to prevent an explosion. , controversial.
“Polyvinyl chloride is not that different from the chemicals used to make it,” he said.
In the urban wildfire scenario, Khalizov expressed concern about the combined effects of multiple pollutants, or what he described as “synergistic effects between pollutants.”
“Exposing smoke and ozone together can actually have an even worse effect,” he says.
Risks when returning home
As residents return to their burnt-out homes and begin cleaning up the wreckage, Castriotta recommends doing so wearing only N95 masks and goggles, while the air quality index does not take into account the toxic substances he mentioned. I warned you that there is no.
“People will look at the air quality index and say, 'Oh, it's moderate, or it's good, normal Los Angeles air,'” Castriotta said. “But it doesn't measure the specific toxins released from these specific fires.”
UCLA's Swain similarly cited countywide health advisories that say wind-borne ash could “fall from the sky” and urged residents to wear particulate masks and use HEPA filters indoors. encouraged the use of
Taking such measures could help minimize future impacts from such disasters, especially since smoke and ash can remain even after fires are mostly extinguished, he said. stated repeatedly.
“The health consequences, casualties and injuries in the days, weeks, months and even years that followed are indirect and even harder to count,” Swain added. “These kinds of large-scale disasters cause far more damage than what has actually been easily quantified in recent decades.”
