ADVANCES
12 Scientific American, June 2019
SOURCE: “INEQUITY IN CONSUMPTION OF GOODS AND SERVICES ADDS TO RACIAL–ETHNIC DISPARITIES IN AIR POLLUTION EXPOSURE,”
BY CHRISTOPHER W. TESSUM ET AL., INPROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES USA,VOL.116, NO. 13; MARCH 26,2019Graphic by Melissa Thomas Baum, Buckyball Designwork, says this finding underscores the need
to craft policies that reduce such pollution in
the hardest-hit communities.
The researchers focused on fine partic-
ulate matter with a diameter of 2.5 microns
or less (PM2.5), generated by construction,
fires and the combustion of fossil fuels.
These particles can contain hundreds of
different chemicals and can penetrate deep
into the lungs, contributing to heart and
lung disease. As part of its study, the team
estimated that 102,000 people die prema-
turely every year from PM2.5 emissions
from human-made sources (as opposed to
wildfires or other natural sources). That
number is nearly double the amount of
people who die annually from car crashes
and murders combined, says study co-au-
thor Jason Hill, a biosystems engineer at
the University of Minnesota.
To trace exposure back to the root cause
of emissions, the investigators mined public-
ly available economic and PM2.5 data. They
linked emissions from various sources (such
as coal-fired power plants or diesel vehicles)
to economic activity that largely drives
these emissions (such as electricity use or
food purchases). Next they apportioned this
consumption among racial groups and
found stark disparities: on average, black
and Hispanic people are exposed to 56 and
63 percent more PM2.5, respectively, than
the amount generated by their consump-
tion, whereas white individuals are exposed
to 17 percent less ( graphic ). “It’s a pretty dra-
matic difference,” Hill says.
The analysis made clear that a wide
range of economic activity contributes to
PM2.5 exposure. It also showed that the
higher relative contribution from white peo-
ple was not the result of buying more from
highly polluting sectors but rather of higher
overall consumption. Household income
was a factor in the observed differences, but
it did not account for the entire mismatch.
Even though the total number of deaths
from PM2.5 exposure has declined in recent
years, most likely because of regulations, the
idea “that everyone is receiving the same
level of protection is blown away” by the
new findings, Bullard says. The results from
this study, he adds, emphasize the need to
undo the legacy of previous policies and de -
cisions that placed polluting infrastructure
disproportionately in low-income and minor -
ity communities. “How can we somehow
change this paradigm that it’s okay to keep
polluting communities of color and commu-
nities that have contributed least?” Bullard
asks. Hill says authorities cannot simply tar-
get any one category of emitter, such as
coal-powered plants or diesel vehicles; all
the involved industries must be addressed.
Scientists, legislators and communities
will need to jointly work out which policies
and regulations can tackle overall pollution
while reducing these inequities, Hill and oth-
ers say. This new framework for tracking
pollution exposure provides a tool to do
that, says Anjum Hajat, an epidemiologist at
the University of Washington School of Pub-
lic Health, who was not involved with the
research. It could, she says, be used to eval-
uate how regulations targeting certain airpollution sources actually reduce exposure
for various groups—and could also poten-
tially reveal any unintended consequences,
such as shifting pollution to other areas.
The work also underscores how impor-
tant existing air pollution regulations are at
a time when the Trump administration has
moved to roll back several of them, includ-
ing some governing pollution from coal-
fired power plants and fuel efficiency in
vehicles. When reached for comment, an
Environmental Protection Agency spokes-
person said the agency “will continue to
monitor and report on key environmental
indicators in low-income communities as
a part of our commitment to healthy air,
water and land for all Americans.”
Research shows that even low levels of
PM2.5 can be harmful to the most vulnera-
ble groups, such as children with asthma,
so officials should be ratcheting up efforts
instead of backing off, Hajat says. “We
have seen this decline in [overall] air pollu-
tion over time” even as consumption has
increased, she says, “so imagine what
could happen if we really did make an
effort as a society.” — Andrea Thompson0123456Passenger Gas Vehicles
Commercial Diesel Vehicles
Airplanes, Ships, Tractors and Trains
Road Dust
Construction
Industrial
Coal-Electric Utilities
Non-Coal-Electric Utilities
Residential (heating, cooking, etc.)
Commercial Cooking
Agriculture
Miscellaneous
White/
OtherWhite/ Black Hispanic
OtherBlackHispanicExposed CausedAverage for
entire U.S.
populationPMlevels (micrograms per cubic meter)2.Every year an
estimated 102,
people die from
human-caused
PM2.5 pollution.
Racial Groups’ Exposure vs. Contribution to Air Pollution
Black and Hispanic individuals in the U.S. are exposed to higher levels of fine particulate
matter (PM2.5), on average, than white individuals yet consume less of the goods
and services that cause such pollution. Black people, on average, experience the highest
absolute pollution levels of the groups studied, whereas Hispanic people are exposed
to the highest levels relative to their consumption.