A growing body of international research suggests that smoke pollution from wildfires can produce cognitive deficits, post-traumatic stress and even increase the risk of dementia, Alzheimer’s and Parkinson’s disease.
Until recently, the effects of forest fires have been studied on the lungs, heart and blood of patients. But several researchers have begun to study how fine particles from wildfire smoke can enter the body and travel to the brain.
Kent Pinkerton, professor of pediatrics at the University of California, Davis, explains that the nose is generally a good filter and retains a number of inhaled particles out of the lungs. But there are concerns that during wildfires, tiny soot particles and other chemicals in the smoke have the ability to enter the cells and nerves of the nose. Scientists have demonstrated that these two elements have a direct link with the brain.
Cells and nerves connecting the nose-brain passageway, Pinkerton says, can be inflamed and damaged by smoke from wildfires.
“It has been shown that certain particles from forest fire smoke are able to cross the blood-brain barrier and cause inflammation in the brain,” he said in an interview.
This year has been one of the worst wildfire seasons in Canada, with nearly 137,000 square kilometers of forest burned. Currently, wildfires are raging out of control in the Northwest Territories and British Columbia, forcing thousands of people from their homes.
Smoke from wildfires is not only made up of vegetation from burned trees and other plants, but also everyday products caught in the flames, including metals from vehicles and homes, plastics and clothes.
Ray Dorsey, professor of neurology at the University of Rochester in New York, says some of the particles from wildfire smoke are small enough to travel to the brain’s olfactory centers.
“Toxic pieces of metals are carried on these tiny particles: lead from leaded gasoline, iron from brake pads and platinum from catalytic converters,” he says.
The brains of people with Parkinson’s disease and Alzheimer’s disease have higher concentrations of heavy metals, Professor Dorsey points out. Damage to the brain’s olfactory centers is seen almost universally in patients with both diseases, he adds.
A study from July 2018 published in the journal Environmental Research reports that a group of international researchers discovered that people exposed to air pollution in Mexico City showed signatures of Alzheimer’s and Parkinson’s in their brains.
“Exposure to air pollutants plays a major role in the development and/or acceleration of Alzheimer’s disease,” says the study, titled “Characteristics of Alzheimer’s disease are relentlessly changing in infants, children and young adults of the Mexico City metropolis”.
Mr Dorsey says he has seen recent reports suggesting that air pollution caused by wildfires has a denser or higher concentration of particles than air pollution caused by automobile traffic.
“In short, whether you’re a newborn or an elderly person with Alzheimer’s disease, air pollution is likely harmful to your brain,” he says.
A study published in January in the journal PLOS Climate found that people exposed to smoke from the Camp Fire — the deadliest and most destructive wildfire in California history — in 2018 had ‘significantly’ more chronic symptoms of the disorder post-traumatic stress, anxiety and depression than those who were not exposed to fire.
“The study of cognitive abilities is important because they are essential to the functioning of daily life and can be essential to understanding individual needs when rebuilding and rehabilitating disaster-affected communities,” the study says. .
Exposure to wildfires also led to a decrease in cognitive performance, i.e. the ability to suppress distractions and concentrate on the task at hand, mentions Jyoti Mishra, lead author of the study on the California wildfires and associate professor of psychiatry at the University of California, San Diego.
The study began six months after the forest fire and the smoke disappeared. The particles may have entered the lungs during the height of the wildfires and chronically affected the brain, she said.
“We don’t know the exact link as to how the particles can affect brain systems over the long term, but what we found in a series of studies is that there was indeed a prevalence climatic trauma,” she says.
There are “a lot of complex interactions” when someone suffers a loss of property, family or injury, she adds. Wildfires can trigger emotional reactions commonly associated with post-traumatic stress disorder. Particles from smoke from forest fires cause the body to react in the same way as in an ignition.
“We see the end result, we see there are cognitive deficits, brain changes, psychiatric symptoms, but how do you get from wildfire smoke to that kind of endpoint? M asksme Mishra. These intermediate complexities and mechanisms are not well understood. »