40 Scientific American, March 2020“This is inTeresTing. Not too thick,” said
Jim Crawford, an atmospheric chemist wearing
a motion-sickness patch behind his ear. It was
afternoon in late July 2019, and Crawford was
bearing down on a skein of wildfire smoke visi-
ble from the cockpit of a former commercial jet
that NASA had retrofitted into an airborne labo-
ratory. In the cabin, 35 scientists and engineers
were calibrating their instruments. The mood
was wired: Would their tools, most designed to
measure urban pollutants, work in air thick
with particulates? How would the 50-year-old
plane respond in a smoke column? The DC-8
shuddered and jumped as it entered a plume
lofted 12,000 feet high by a fire outside of Mis-
soula, Mont. “Forty-five seconds, then turn it
around,” Crawford directed the pilots. The tur-
bulence was surprisingly mild, and he wanted
to go back through it.This was only the third flight in the aerial segment of FIREX-
AQ, an ambitious three-year project led by the National Oceanic
and Atmospheric Administration and Nasa. It is attempting to
sniff out the precise chemical composition of smoke emitted
from biomass burns and determine, among other things, when,
and why, it is most dangerous for human health. For six weeks
last summer the DC-8 and a pair of Twin Otters similarly quilled
with atmospheric-sampling instruments flew through more than
100 different columns. They ranged from a bubble of smoke ris-
ing off a tiny agricultural burn in Kansas to a mushroom cloud
that shot up 31,000 feet from the Williams Flats Fire in Washing-
ton State, a burn one scientist compared to a volcanic eruption.
Never before has biomass smoke been studied in such detail and
range. Although fires contribute up to a third of all particles in
the atmosphere, “there are very few studies that examine the spe-cific role of the different components of smoke on disease and
the severity of the disease when people are exposed,” said a direc-
tor at the Environmental Protection Agency in 2018.
We know that chronic exposure to fine particulate matter,
which is in all smoke, can lead to heart and lung disease, irregular
heartbeats and aggravated asthma, among other issues. It was
estimated to cause 4.2 million premature deaths worldwide in- Likewise, long-term exposure to ozone, a gas that can form
via chemical reactions when smoke enters the atmosphere, is
blamed for at least one million premature deaths a year. What we
lack is a fundamental understanding of how and when these tox-
ic components and others form in different types of biomass
smoke. Currently air-quality regulators treat emissions from all
biomass burns as the same, even though that is not the case. By
learning about these processes, the FIREX-AQ team hopes to
Kyle Dickman is a freelance journalist and
a contributing editor at Outside magazine. He
is author of On the Burning Edge (Ballantine
Books, 2015). He spent five seasons fighting
wildfires in California.IN BRIEFThe acute and chronic effects of wildfire smoke
exposure in humans is poorly understood. As
wildfires intensify and occur in new places, they
are a growing public health threat.An unprecedented project led by NOAA and NASA
amassed more than 400 scientists to investigate
the precise chemical composition of smoke emitted
from biomass burns and how it changes over time.Data collected during the aerial campaign will help
determine what kinds of fires are most harmful. This
could inform how fire management, such as lighting
prescribed burns, is regulated and practiced.© 2020 Scientific American