A new study suggests that gas stoves are not as safe for the environment as once believed. Even when a natural gas cooking stove isn’t on, it leaks methane gas, and the amount is significant.
A new Stanford-led study published in the journal Environmental Science and Technology, on January 27, concluded that U.S. gas stoves could emit as much greenhouse gas annually as a half-million cars, primarily in the form of methane, a gas that is more potent than carbon dioxide over a two-decade period.
Although carbon dioxide is more abundant in the atmosphere, methane’s global warming potential is about 86 times as great over a 20-year period
The Stanford scientists studied 53 California residences with 18 different types of gas stoves. The study found that nearly 75 percent of the methane measured by the researchers was leaked when the stoves weren’t being used.
“We found a slow bleed of methane that would happen while the stove was off,” said lead author Eric Lebel, a doctoral student at Stanford. Scientific American also reports that Lebel is also a senior scientist with PSE Healthy Energy, a public health nonprofit that is often critical of fossil fuels.
“Surprisingly, there are very few measurements of how much natural gas escapes into the air from inside homes and buildings through leaks and incomplete combustion from appliances,” said Lebel.
“It’s probably the part of natural-gas emissions we understand the least about, and it can have a big impact on both climate and indoor air quality,” he said, reports Market Watch.
Measuring methane leakage
A common cause of methane leakage from a turned-off stove is loose fittings between the stove and gas pipes, located in the kitchen itself. “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.org.
The researchers also measured the amount of methane that leaked when a stove burner was twisted on, as well as how much is released while cooking. They found that even new stoves leaked methane, and different brands did not seem to make any measurable difference.
More than one-third of American households – around 40 million homes – cook with gas. Gas stoves are usually found in active living spaces – like a kitchen – while gas space and water heaters are generally placed in areas away from living spaces.
Cooking appliances directly expose people to their emissions. And these emissions include formaldehyde, carbon monoxide, and nitrous oxides that can trigger asthma, coughing, wheezing, and difficulty in breathing.
Using a hood and ventilation can help reduce concentrations of nitrogen oxides and other co-produced pollutants in kitchen air, however, surveys show that home cooks on average use them only 25 to 40 percent of the time, according to the researchers. The highest emitters were cooktops that ignited using a pilot light instead of a built-in electronic sparked method.
Long-term effects are well-documented
Fossil-fuel combustion in buildings, which is mostly tied to heating, is responsible for about 13 percent of greenhouse-gas emissions in the U.S., according to 2019 figures from the EPA, the latest year for which there are complete data.
Research published last year by Harvard University found that the air pollution from burning gas to generate energy and heat homes and businesses caused more deaths than coal in the United States.
It is also well documented that communities of color are disproportionately impacted by exposure to air pollution caused by fossil fuels, which results in higher rates of asthma, hospital visits, and other adverse health impacts.
