http://www.sciencenews.org | June 18, 2022 21MINNESOTA POLLUTION CONTROL AGENCY
near wildfires in the West may not represent the
full story of how smoke from distant fires affects
people in the East.
Liu, at Emory, hopes to see the U.S. government
revisit policies related to what PM2.5 levels are
dangerous, since they’re based on ambient and not
wildfire-related PM2.5. In March, an EPA advisory
panel recommended just that. In a letter to the
agency, the Clean Air Scientific Advisory Commit-
tee wrote: “Regarding the annual PM2.5 standard,
all CASAC members agree that the current level of
the annual standard is not sufficiently protective of
public health and should be lowered.” They added,
“There is substantial epidemiologic evidence from
both morbidity and mortality studies that the cur-
rent standard is not adequately protective.”
Local communities throughout the country need
to determine when to close schools or at least keep
kids inside, Liu says, as well as when to advise people
to close windows and turn on air purifiers. Good
masks — N95 and KN95 — can help too (yes, masks
that block viruses can also block particulate matter).
City, county and state governments also need
to prepare the health care system to respond to
increased asthma issues, Liu says. Some states
are starting to respond. In 2017, for example, the
Minnesota Pollution Control Agency increased its
air quality monitoring stations around the state
from two to 18. The agency is also working with the
National Weather Service, the Minnesota Depart-
ment of Health and the Minnesota Department of
Transportation to better communicate air quality
warnings.
In the meantime, much more research is needed
into the human health implications of increasing
wildfire smoke, Buchholz says, as well as the chemi-
cal interactions in the atmosphere, how climate is
changing fires, how fires change year after year,
and how they impact the atmosphere, not to men-
tion how different trees, buildings and other fuels
affect particulate matter.
“Wildfires are perhaps one of the most visible
ways that [climate change] is linked to health,”
Stowell says. And the reality is, she says, “we’re
going to see it remain as bad or worse for a while.” sExplore more
s Katelyn O’Dell et al. “Estimated mortality and
morbidity attributable to smoke plumes in the
United States: Not just a western US problem.”
GeoHealth. September 2021.Megan Sever is a freelance science editor and
writer based in Portland, Ore.Smoke gets on the brain
Health impact studies of air pollution, including
wildfire smoke, have mostly focused on the lungs.
But toxicologist Matthew Campen of the
University of New Mexico in Albuquerque is look-
ing at the brain.
In a study of the inflammatory effects of smoke
PM2.5 on the brains of mice, Campen and col-
leagues found that inflammation in the lungs was
modest compared with the “profound” inflam-
mation in the brain, Campen says. Given what’s
known about how damaging smoke can be in the
lungs, to find even greater effects on the brain is
troubling, he says.
The inflammatory effect on the mice’s brains
was almost immediate, within 24 hours of expo-
sure, the researchers reported in the March
Toxicological Sciences. The particulates enter
the body through the respiratory system, get
in the blood, and are small enough to cross the
blood-brain barrier and start affecting the brain.
Inflammation has been linked with dementia in
older people and neurodevelopmental issues in
younger people, plus mood disorders like anxiety
and depression, Campen says.
“I’m hoping that our study with mice spurs ...
epidemiologists to take a look,” he says. “The effects
we see are much stronger and more worrisome
than what we see in the lungs,” he says, but we don’t
know yet at what PM2.5 levels the danger begins.
“We need to explore this more rigorously.”
— Megan SeverMinnesota, after experiencing a rise in smoky summer days, has added
extra air quality monitoring stations to improve local forecasts.