http://www.sciencenews.org | June 18, 2022 17OPPOSITE PAGE: JOSH EDELSON/AFP VIA GETTY IMAGES; THIS PAGE: JOSHUA STEVENS/NASA EARTH OBSERVATORY
A
fter a relaxing day at the Jersey Shore
last July, Jessica Reeder and her son
and daughter headed back home to
Philadelphia. As they crested a bridge
from New Jersey into Pennsylvania, they were
greeted with a hazy, yellow-gray sky. It reminded
Reeder of the smoky skies she saw growing up in
Southern California on days when fires burned in
the dry canyons.
Smelling smoke and worried about her asthma
and her kids, Reeder flipped the switch to recircu-
late the air inside the car instead of drawing from
the outside. At home, the family closed all the
windows and turned their air purifiers on high.
The smoke had traveled from fires raging on
the other side of the continent, in the western
United States and Canada. Although air quality in
Philadelphia didn’t come close to the record-bad air
quality that some western cities experienced, it was
bad enough to trigger air quality warnings — and not
just for people with asthma or heart problems.
Most large U.S. wildfires occur in the West. But
the smoke doesn’t stay there. It travels eastward,
affecting communities hundreds to
thousands of kilometers away from
the fires. In fact, the majority of
asthma-related deaths and emer-
gency room visits attributed to fire
smoke in the United States occur in
eastern cities, according to a study
in the September 2021 GeoHealth.
The big problem is fine par-
ticulate matter, tiny particles also
known as PM2.5. These bits of ash,
gases and other detritus sus-
pended in smoke are no more than
2.5 micrometers wide, small enough
to lodge in the lungs and cause permanent damage.
PM2.5 exacerbates respiratory and cardiovascular
problems and can lead to premature death. The
particles can also cause asthma and other chronic
conditions in other wise healthy adults and children.
Over the last few decades, U.S. clean air regu-
lations have cut down on particulate matter from
industrial pollution, so the air has been getting
cleaner, especially in the populous eastern cities.
But the regulations don’t address particulate matterfrom wildfire smoke, which recent studies show is
chemically different from industrial air pollution,
potentially more hazardous to humans and increas-
ing significantly.
So far, a lot of the research on how wildfire PM2.
can make people sick has been based
on people living or working near
fires in the West. Now, research-
ers are turning their attention to
how PM2.5 from smoke affects the
big population centers in the East,
far from the wildfires. One thing is
clear: With the intensity and fre-
quency of wildfires increasing due
to climate change (SN: 12/19/20 &
1/2/21, p. 32), people across North
America need to be concerned about
the health impacts, says Katelyn
O’Dell, an atmospheric scientist at
George Washington University in Washington, D.C.Bad air travels
Air pollution regulations limit PM2.5 from exhaust-
emitting cars and trucks and fossil fuel–burning
factories and power plants. These regulations have
done “a really good job” reducing anthropogenic
air pollution in the last couple of decades, says
Rosana Aguilera, an environmental scientist at the
Scripps Institution of Oceanography in La Jolla,Bad air in the East, from
fires in the West, sends
people to emergency
rooms By Megan SeverSmoke poured into the eastern United States and Canada from wildfires in the West
on July 21, 2021 (darker red is denser smoke). Residents of eastern cities received
code orange and code red warnings that air quality was unhealthy.With the intensity
and frequency
of wildfires
increasing due to
climate change,
people across
North America
need to be
concerned about
health impacts.