A new study suggests that gas stoves are not as safe for the environment as once believed, Scientific American reports. Even when a natural gas cooking stove isn’t on, it leaks methane gas, and the amount is significant in the aggregate, per NPR. In fact, about 80% of the methane released from gas stoves happens when the stove is turned off, according to a Stanford University study of 53 California residences with 18 different types of gas stoves. Methane is a greenhouse gas, and it's actually a stronger one than carbon dioxide, though it does not remain in the atmosphere as long.
Common causes of methane leakage from a turned-off stove are loose fittings between the stove and gas pipes. "Simply owning a natural gas stove and having natural gas pipes and fittings in your home leads to more emissions over 24 hours than the amount emitted while the burners are on," one of the study’s authors, Rob Jackson, tells NPR. Scientists also measured how much of the gas is emitted when a person twists the knob and how much is released while cooking. Even new stoves leaked methane, and the brand also did not seem to make any measurable difference.
Jackson, a Stanford earth sciences professor, says there are around 40 million gas stoves in the US, and, as a whole, they have the same effect on the environment as half a million gas-fueled motor vehicles, per NPR. The study’s main author, Eric Lebel, led the research while a graduate student at Stanford, and the findings were published this week in the peer-reviewed Environmental Science & Technology. In all, about 1.3% of the gas used for an individual stove is believed to leak away, per NPR.
Researchers say that if switching to electric isn't an option, those with gas stoves should at least check and tighten their stove's fittings if needed. The long-term respiratory effects of living in homes with gas stoves also must be considered, according to another NPR report. It cites a study suggesting that children have a 20% higher risk of respiratory illnesses if they live in homes with gas stoves. Environmental concerns with gas stoves are not new—the most common pollutants are actually nitrogen dioxide, carbon monoxide, and formaldehyde—and the National Sierra Club has a YouTube campaign urging people to shift to electric. (Read more climate change stories.)