As thick layers of smoke from hundreds canada wildfire they landed in a big party America This week, millions of people were urged to stay indoors, use HEPA filters and only wear high-quality face protection when outdoors. Wildfire smoke, a seasonal hazard in some parts of the US, had become a problem for everyone almost overnight.
“It’s a threat to our health”says Christine Wiedenmayer, associate director of science at the University of Colorado Boulder’s Cooperative Institute for Research in Environmental Science. “That is all, from effects on the respiratory system, such as asthma, to cardiovascular, There is evidence that newborns of women exposed to wildfire smoke during pregnancy have a statistically lower birth rate.”
In many North American cities, some level of air pollution is routine, whether from fossil fuels, vehicle emissions, natural gas used for heating, or fumes from chemical production. But smoke from wildfires is particularly bad for humans.And it has to do with both the size of the particles involved and their composition.
Smoke is made up of “very small particles”
“Smoke from wildfires, especially long-haul smoke, is made up of very small particles”says Luke Montrose, an assistant professor and environmental toxicologist at Colorado State. “That’s what gives it the ability to be ephemeral.”
Because the particles in wildfire smoke are so small—much smaller than the tiniest grain of sand—they have little trouble passing through the barriers our bodies set up to keep pollutants out. Smoke particles can pass through the hairs of the nose and through the mucous membranes that line the upper respiratory tract.
smallest particles PM2.5 is known ascan also cross mucous membranes and reach the lower respiratory tract, The job of that airway is to “transfer oxygen across the blood barrier to the lungs,” Montrose said, making this type of contamination especially devastating for people who already have underlying lung conditions. asthma or COPD, Even people with healthy lungs effectively get less oxygen, and those effects are not always indicated by a visible symptom such as a cough.
“People who may not be sensitive often have other symptoms such as lethargy”Montrose said. “They may just feel bad, be giddy, or have no energy. And this can be attributed to the lack of oxygen in the body.”
This lack of oxygen This is why people who are exposed to poor air quality, especially outdoors, are discouraged from exercising. More activity means heavier, faster breathing, which brings more particles into the body and pushes them deeper into the lungs, ironically inhibiting the body’s ability to absorb oxygen when it is needed most. does. The effects can also be long lasting, A 2020 study looked at a community in Montana that was exposed to wildfire smoke for more than a month; One year later, the residents were still suffering from decreased lung function.
“Potentially toxic” compounds in wildfire smoke
Wildfire smoke also contains thousands of compounds, some of which potentially toxicsuch as volatile organic compounds, hydrocarbons and nitrogen oxides. A 2022 study published in The Lancet Planetary Health journal looked at the effects of wildfire smoke on Canadians, finding that those who lived within 30 miles of a wildfire had a 4.9% increased risk of cancer It was a risk. There was a 10% higher risk of lung cancer and brain. cancer compared to the unaffected population.
wildfire smoke hazard neither do they fade during the journey: Smoke released into the atmosphere becomes “old” and more toxic over time. A 2020 study found that smoke samples taken more than five hours after the fire was out Twice as toxic as when first released, After further aging in a lab, they were four times as toxic.
The smoke that traveled through, says Montrose, “had time to interact with chemicals in the air, had time to interact with the sun.”
This week’s fires are just the beginning of what could be a smoky summer in North America, and a new normal of sorts thanks to climate change. ,condition gets progressively worse, in terms of the severity of the fire, the length of the fire season, and the amount of smoke that’s been released into the air,” says Wiedenmire of the University of Colorado Boulder. “But there are ways to protect yourself. Stay inside, turn on your air conditioner when it’s smoky, wear a mask outside (and) avoid exercising so you don’t breathe these particles for a long time.”