Los Angeles is already known for its poor air quality. But the fires now burning in the area are sending up clouds of black smoke that pose a greater threat to human health than normal wildfires.
Fire smoke can to linger for weeks and travel across the continent.
But what sets the LA fires apart, researchers say, is the toxic mix of substances in the smoke from burning buildings, vehicles, electronics, plastics and other components of the urban environment, in addition to the trees and other vegetation that typically burn in wildlands. Here what is known about health risks of such smoke in the short and long term:
The lungs receive the first blow
In the short term, fire smoke, like any other smoke, inflames the lungs, says Dr. Chris Carlsten, professor of medicine and director of the Air Pollution Exposure Laboratory at the University of British Columbia.
But fire smoke has its own effects on the blood, which are thought to increase the risk outside the lungs when the blood circulates to the heart.
Los Angeles Mayor Karen Bass said fire crews and water tankers were being deployed in strategic locations as officials prepared for what forecasters warned would be strong, dangerous winds.
Wildfire smoke contains fine particles that can travel deep into the lungs when inhaled. When the lungs become inflamed, scientists suspect they send inflammatory cells into the bloodstream that affect other organs, including brain.
The smoke can also irritate the eyes and throat, leading to itching, coughing and sneezing, Carlsten says.
Acute symptoms may also include chest tightness and wheezing, a fast or irregular heartbeat, and excessive fatigue. These symptoms typically ease after the smoke clears, according to the University of California, Davis.
Smoke questions
Urban fires combined with wildfire smoke, like what’s happening in LA, don’t happen often, and scientists are just beginning to study the effects.
dr. John Balmes, professor emeritus at the University of California, San Francisco, says such urban wildfires release a cocktail of chemicals from paint, metal, plastic and other synthetic materials beyond what comes from burning vegetation.
Smoke from standard wildfires is “bad enough,” Barnes said. “When synthetic materials burn, they release even more toxic materials.”
For example, Balmes says that such fires are liberating benzenea known cause of cancer, which researchers found in plastic pipes in the previous urban fire in California in 2018.
The health effects of seasonal wildfire smoke exposure are also a new topic for scientists.
Who is the most sensitive?
When people with asthma and chronic obstructive pulmonary disease (COPD) inhaling fire smoke are at greater risk of worsening conditions, which can result in, for example, an asthma attack. People with lung disease are encouraged to update their medications when wildfire smoke is in the air, says Colleen Reid, an associate professor of geography at the University of Colorado Boulder who studies the health effects of exposure. air pollution from forest fires.
Because we lose the ability to tolerate or cope with the short-term damage of smoke as we age, older adults are also more vulnerable to the ill effects, Carlsten says.
But children are also at greater risk from poor air quality during wildfires because their lungs are still growing, according to Balmes.
For those who are pregnant, pollutants from wildfire smoke can also have an effect fetus.
Lasting effects
What is known about the chronic health effects of wildfire smoke comes from wildland firefighters, who often work without the breathing apparatus of urban firefighters.
Long-term effects on them have not been studied, but Balmes is a co-author of the study who extrapolated chronic health effects based on known worker exposure to fine particles.
“We found a likely increased risk of mortality from heart or cardiovascular disease and lung cancer,” he said.
Another study by researchers at McGill University in Montreal also suggests the lungs and brain risk of cancer associated with long-term exposure to fire smoke.
