YSM Issue 97.1

Environmental Engineering
FOCUS
Oil production is estimated to be
responsible for around fifteen
percent of total global energy-
related emissions. From extraction to
refining to consumption, various stages of
oil production are heavily associated with air
pollution. But our ability to estimate organic
carbon emissions from these processes
may be threatened by the emergence of
more unconventional oil sources in recent
decades. Two of these sources, heavy oil and
bitumen deposits, are projected to account
for about forty percent of oil production by
the year 2040.
In a recent paper published in Science,
a team of researchers from Yale and
Environment and Climate Change Canada,
a department of the Canadian government,
examined the magnitude and impact of
traditionally unmonitored gases on total
organic carbon emissions.
Addressing Overlooked Air Pollutants
Organic carbon emissions, or gaseous
organic compounds, refer to substances
containing carbon and hydrogen that are
released into the atmosphere. Historically,
studies on carbon emissions have focused
on volatile organic compounds (VOCs),
a subset of organic carbon emissions that
have short- and long-term adverse effects on
human health and the environment. “These
compounds pose both environmental and
human health risks,” said Lexie Gardner
(YC ’23), a co-author of the study and
environmental engineer at CDM Smith.
Short-term health effects include respiratory
irritation, headaches, dizziness, and fatigue,
while more long-term effects include cancer,
organ damage, and neurological effects.
While certain subsets are typically the
focus of monitoring and industry reporting,
many types of emissions go unmonitored—
including emissions that still contribute
greatly to air pollution. These compounds
include intermediate-volatility organic
compounds (IVOCs) and semivolatile
organic compounds (SVOCs). Their
volatility, or tendency to evaporate at a given
temperature, influences their emissions
and abundance in the atmosphere, though
they all undergo chemical reactions in the
atmosphere that affect air quality. Up until
now, they have largely gone unmonitored
compared to VOCs. “There are opportunities
for improvement in emissions reporting,”
said Drew Gentner, an associate professor of
chemical and environmental engineering at
www.yalescientific.org
Yale and senior author of the study.
Studying unmonitored gases is
particularly important because the reported
concentration of emissions helps dictate
policy on environmental regulations. Air
pollution contributes to the worsening
effects of climate change, which has direct
ramifications on legislation. “Organic
carbon emissions encompass a wide range
of species with a diverse range of sizes and
functionalities,” said Megan He (YC '22),
the lead author of the study and a current
graduate student at Harvard University. “For
typical research and reporting purposes,
it is hard to measure all of these individual
species together,” He said.
Underreporting by Canadian Oil Sands
Operations
Oil sands are a critical contributor to
the majority of Canadian oil production,
particularly in the Athabasca oil sands
regions in northern Alberta, which make
up about two-thirds of Canadian oil
production. Oil sands provide a substantial
source of unconventional petroleum,
which refers to compounds of hydrogens
and carbons (hydrocarbons) extracted
from unconventional sources, such as tight
reservoirs and oil sands themselves. Special
extraction and processing techniques
are used to extract these compounds
from unconventional sources compared
to conventional ones. Oil sands, often
incorrectly known as tar sands, are composed
of bitumen—a heavier version of crude oil—
sand, and clay. The bitumen is separated
from the sand and the clay and is then refined
into various petroleum products. However,
the extraction and processing techniques
pose several environmental challenges, one
of which is their impact on air quality.
The researchers were interested in using
new measurements to quantify the total
carbon emissions and compare those values
to estimates reported by the industry on the
Athabasca oil sands. They performed both
airborne measurements and supplementary
laboratory experiments.
The first experiment they did was to
collect air samples and later analyze their
contents. The researchers used an aircraft
to measure the total carbon emissions in the
Athabasca oil sands. A total of thirty flights
were conducted flying both upwind and
downwind near five different facilities, some
of which were for surface mining and others
for in situ mining. Surface mining consists
of the removal of overlying rock or soil to
access the valuable minerals underneath
and is ideal when the minerals are located
close to the surface. In situ mining consists
of extracting minerals directly from their
location without the removal of overlying
rock or soil. The five facilities were Syncrude
Mildred Lake, Suncor, Canadian Natural
Resources, Imperial Kearl Lake, and MJP
Petroleum Corporation.
“The aircrafts were equipped with
instruments capable of analyzing gas-phase
organic pollutants and were supplemented
by samples taken in the field,” Gardner
said. After the samples were analyzed,
the researchers found that the total
reported annual carbon emissions were
underestimated by about 1,900 percent
to over 6,300 percent, depending on the
respective facility. The researchers focused
on the three facilities that had the highest
carbon emissions, which were Syncrude
Mildred Lake, Suncor, and Canadian Natural
Resources. Of the three facilities, Syncrude
Mildred Lake was found to have the highest
IMAGE COURTESY OF FLICKR
Various stages of oil production contribute to global emissions. Offshore oil rigs, constructed for the extraction,
storage, and processing of oil, release vast amounts of greenhouse gases into the atmosphere.
March 2024 Yale Scientific Magazine 17