It kills more people each year than car crashes, war or drugs do. This invisible killer is the air pollution from sources like cars and trucks or factory smokestacks.
But as wildfires intensify and grow more frequent in a warming world, the smoke from these fires is emerging as a new and deadly pollution source, health experts say. By some estimates, wildfire smoke — which contains a mixture of hazardous air pollutants like particulate matter, nitrogen dioxide, ozone and lead — already causes as many as 6,75,000 premature deaths a year worldwide, as well as a range of respiratory, heart and other diseases.
Research shows that wildfire smoke is starting to erode the world’s progress in cleaning up pollution from tailpipes and smokestacks, as climate change supercharges fires.
“It’s heartbreaking, it really is,” said Dr. Afif El-Hasan, a paediatrician who specialises in asthma care at Kaiser Permanente in Southern California and a board director of
the American Lung Association. Wildfires “are putting our homes in danger, but they’re also putting our
health in danger,” Dr. El-Hasan said, “and it’s only going to get worse”.
Those health concerns were coming to the fore this week as wildfires ravaged the Los Angeles area. Residents began to return to their neighbourhoods, many strewed with smouldering ash and rubble, to survey the damage. Air pollution levels remained high in many parts of the city, including in northwest coastal Los Angeles, where the air quality index climbed to “dangerous” levels.
Los Angeles, in particular, has seen air pollution at levels that could be raising daily mortality by between 5 to 15 per cent, said Carlos F. Gould, an expert in the health effects of air pollution at the University of California, San Diego.
That means current death counts, “while tragic, are likely large underestimates”, he said. People with underlying health issues, as well as older people and children, are particularly vulnerable.
The rapid spread of this week’s fires into dense neighbourhoods, where they burned homes, furniture, cars, electronics and materials like paint and plastic, made the smoke more dangerous, said Dr Lisa Patel, a paediatrician in the San Francisco Bay Area and the executive director of the Medical Society Consortium on Climate and Health.
A recent study found that even for homes that are spared destruction, smoke and ash blown inside could adhere to rugs, sofas and drywall, creating health hazards that can linger for months. “We’re breathing in this toxic brew of volatile organic compounds and polycyclic aromatic hydrocarbons and hexavalent chromium,” Dr. Patel said. “All of it is noxious.”
Intensifying and more frequent fires, meanwhile, are upending experts’ understanding of smoke’s health effects. “Wildfire season is no longer a season,” said Colleen Reid, who researches the effects of air pollution from wildfires on health at the University of Colorado Boulder. “We have fires all year round that affect the same population repeatedly.”
“The health impacts are not the same as if you were exposed once, and then not again for 10 years,” she said. “The effects of that is something that we still don’t really know.”
A United Nations report from 2022 concluded that the risk of devastating wildfires around the world would surge in the coming decades. Heating and drying caused by climate change, along with development in places vulnerable to fire, was expected to intensify a “global wildfire crisis”, the report said. Both the frequency and intensity of extreme wildfires have more than doubled in the past two decades. In the US, the average acreage burned a year has surged since the 1990s.
Now, pollution from wildfires is reversing what had been a decades-long improvement in air quality brought about by cleaner cars and power generation. Since at least 2016, in nearly three-quarters of states in the US mainland, wildfire smoke has eroded about 25 per cent of progress in reducing concentrations of a type of particulate matter called PM 2.5, a Nature study in 2023 found.
New York Times News Service
