The small
study — based on measurements from cooktops, ovens and broilers in 53 homes in
California — estimated that stoves emit between 0.8 percent-1.3 percent of the
natural gas they consume as unburned methane, a potent greenhouse gas. During
the course of a typical year, three-quarters of these emissions occur when the
devices are shut off, the study showed, which could suggest leaky fittings and
connections with gas service lines. Over a
20-year period, emissions from stoves across the United States could be having
the same effect in heating the planet as half a million gas-powered cars, the
study estimated. “People are
so attached to their stoves,” said Eric D Lebel, a senior scientist at the
nonprofit research institute PSE Healthy Energy and lead author of the study,
which was published Thursday in the journal Environmental Science &
Technology. “There’s something human about cooking on a gas stove, over an open
flame.” But more and
more evidence, he said, suggests that stoves are “damaging health and climate
all at once.” Growing
numbers of US cities, largely in Democratic-leaning states such as California
and Massachusetts, are shifting homes away from gas-powered cooking and
heating. New York City last month banned gas hookups in all new buildings. But
at least 20 mostly Republican-leaning states have barred cities from
restricting gas use, often with the support of natural gas companies and
utilities that see electrification as a threat to their bottom lines. There were
more than 40 million gas stoves in US households in 2015, the last year for
which there is detailed data from government surveys. In all, homes and
buildings are responsible for an estimated 13 percent of America’s greenhouse
gas emissions. Methane is
the main component of natural gas, and if it isn’t burned when released, it can
warm the Earth more than 80 times as much as the same amount of carbon dioxide
over a 20-year period. Methane also contributes to ground-level ozone
pollution, which can cause breathing problems and other health issues. Methane
leaks from oil and gas installations have attracted increasing attention in
recent years, and efforts are underway to plug thousands of inactive,
methane-spewing oil and gas wells across the country. But less research has
been done on emissions inside residences, said Rob Jackson, an earth scientist
at Stanford University who worked on the new study. Lebel,
Jackson and two co-authors used plastic sheets to seal off kitchens in private
homes, Airbnb rentals and properties for sale or rent. They found that on
average, igniting a burner on a gas stove emitted about the same amount of
methane as leaving it on and burning for 10 minutes. Gas ovens emitted methane
at a higher rate than cooktop burners, they found, because ovens periodically
ignite and extinguish their main burner to maintain the set temperature. The
researchers also measured emissions over five-to-10-minute periods when stoves
were off, though they did not try to pinpoint the sources of the leaks. “It’s almost
an inevitable byproduct of the natural gas supply chain,” Jackson said. “Every
coupling, every fitting, has the potential to leak, especially over time as the
stoves sit there for years.” None of the
gas leaks the researchers measured were of a concentration that might lead to
explosions, Lebel said. The
researchers found that when it came to methane emissions, older stoves did not
perform differently from newer ones, nor did pricier models outperform cheaper
ones. They
acknowledged, however, that they would have liked to conduct tests in more
homes owned by people who could not afford to replace or maintain old
appliances. This would help their results better capture the disproportionate
effects of gas emissions on low-income families, they said. Levels of
methane in the atmosphere have been skyrocketing in recent years, and
scientists do not fully understand why, said Kathryn McKain, a researcher with
the National Oceanic and Atmospheric Administration Earth System Research
Laboratory who did not work on the new study. More methane
seems to end up in the air than is accounted for by gas consumption on the
ground. Home appliances, McKain said, are “just one piece of the puzzle.”   © 2022 The
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