Explorebigsky.com Staff Writer
BOZEMAN – Looking south from
bozeman, Montana, sometimes
you can see the Gallatin Range and
sometimes you can’t. Storms aside,
this haze is caused by particles in the
atmosphere.
DISCOVER-AQ, a recent air-quality
study conducted by NASA, focused
on these particles and their impacts.
Forest fires, vehicles, woodburning stoves, campfires and
power plants all emit atmospheric
particles, as do trees and agriculture, according to Douglas Martins, Ph.D, a researcher with the
Pennsylvania State university
Department of Meteorology and
operator of a NASA ground site
in Porterville, California during
the study.
“If small enough, the particles can
enter our lungs and cause chronic
respiratory illnesses such as asthma,”
Martins said. Now EPA-regulated
pollutants, they are gaining attention
from NASA.
In January 2013, a group of 80 NASA
scientists and collaborators including Martins visited the southern San
Joaquin Valley, California, bringing
a fleet of sampling aircraft, ground
instrumentation and weather balloons
to study the particles. NASA chose
the region because 1 in 4 children
there have asthma, compared to the
national average of 1 in
10. Notably, the area’s
topography, agriculture
and forests are reminiscent of the Gallatin
Valley.
The scientists first measured ground-level pollution using a network
of spectrometry instrumentation similar to
that found on a satellite,
only measuring from the
ground up through the
atmosphere, rather than
vice versa. The team
then measured pollutants up to 3,000 feet
with tether balloons and
up to 100,000 feet with
free-flying balloons.
Finally, a b200 Super
King Air flew transects
at 28,000 feet, its instrumentation measuring
spatial variability of
pollution across the study
region, mimicking what
a satellite could do. A
second aircraft, a P3-b,
finished the test by conducting low-altitude transects over the
ground network, performing a vertical
profile over six of the ground sites.
“Ideally, all the measurements should
agree,” Martins said. “when they don’t,
[we] have to understand why, so we can
improve the algorithms used to process
the satellite data.”
Satellite measurements, he explained,
are prone to interferences including
clouds, particles and bright surfaces
such as those found in deserts. “Essentially, anything that impacts light
will impact how satellites measure
pollution.”
The EPA has designated a range of colors to convey to the public the amount
of particulates in the air: green, yellow, orange, red and purple, defining
anything orange or above as unhealthy.
Several times during the study particulate amounts reached this level;
in one instance, it was greater than 50 percent of the healthy standard – code
purple.
“As scientists improve our understanding of how these particles
are created, we can do our part to
mitigate humans’ impact on the
atmosphere,” Martins said.
