Study compares pollution from gas stoves to second-hand cigarette smoke
The news
Using a single gas stove burner may increase indoor benzene concentrations, which are linked to cancer risk, beyond what is found in secondhand tobacco smoke and even to levels that have prompted local scrutiny when detected outdoors, according to a new study .
For the peer-reviewed study, researchers at Stanford’s Doerr School of Sustainability measured benzene emissions from stoves in 87 homes in California and Colorado and found that natural gas and propane stoves emitted benzene that often reached concentrations indoors that exceeded health benchmarks set by the World Health Organisation. and other government agencies.
In about one-third of homes, a single gas burner on high or an oven set to 350 degrees Fahrenheit for 45 minutes raised benzene levels above the upper range of indoor concentrations seen in secondhand tobacco smoke, the researchers found. They noted that similar concentrations, when identified in 2020, near schools in Greater Los Angeles And the Front Range of Coloradoled to investigations by the authorities there.
“I found it surprising,” says Yannai Kashtan, the study’s lead author, “that concentrations that were enough to cause a public outcry when detected outside are concentrations that we’ve repeatedly found indoors, just from heaters in people’s houses.”
Why it matters: Studies demonstrating the dangers are piling up.
An increasing number of studies have documented significant indoor air pollution and negative health effects from gas stoves. Gas stoves emit other harmful pollutants, such as nitrogen dioxide, carbon monoxide and formaldehyde, and can also leak methane, a powerful greenhouse gas, even when they’re turned off. That’s what a study published in December estimated 12.7 percent of childhood asthma in the United States it was linked to gas heaters.
But the latest study published this week in the journal Environmental Science and Technologywas the first to focus on quantifying the benzene released from a stove’s flame during the combustion process.
The United Nations International Agency for Research on Cancer and the United States Environmental Protection Agency define benzene as a human carcinogen. Inhaling the chemical can increase the risk of leukemia and lymphoma, among other serious health effects. Doctors say no level of exposure is safe.
The Stanford team measured emissions from the food itself, frying some fish and bacon, and found negligible emissions of benzene. Home emissions from electric and induction cooktops are also negligible, according to research from Stanford and other studies.
Background: Stoves have become a matter of “culture war.”
Concerns about the health effects of gas stoves have already prompted some cities and states to phase out gas hookups in residential buildings. The federal government wants to tighten efficiency standards for gas stoves.
Yet the issue has become politicized. On Wednesday, House Republicans approved a bill that would prevent federal funds from being used to regulate gas stoves as a dangerous product. The measure was not expected to pass the Senate, but underlined the issue’s division among the country’s politicians, despite the science.
Mr. Kashtan, a Ph.D. candidate who is the lead Stanford researcher noted that the study focused on single-family homes in California and Colorado, which tend to be larger than apartments in major cities like New York. More recent tests by the Stanford team found higher concentrations of some contaminants from gas stoves in small New York kitchens and found that those contaminants traveled quickly throughout the home and lingered, sometimes for hours.
Dr. Janice L. Kirsch, an oncologist and former investigator of a large-scale childhood leukemia study who was not involved in the Stanford study, said the levels of benzene the researchers found emanating from gas stoves in people’s homes were alarming.
“We knew that if you burn methane, you get benzene. But to actually make the measurements is groundbreaking and the levels are higher than expected. It’s much more dangerous,” said Dr. Kirsch. “Benzene is the stuff nightmares are made of.”
What worried her most was that increasing research showed how people were exposed to harmful chemicals, both outdoors, from things like traffic, factories or wildfire smoke, and indoors.
But inside, at least people have a little more control over their exposure. “That gives us a way forward,” said Dr. Kirsch. People can buy relatively cheap induction cookers, she said, or use toasters and kettles where possible. “And ventilate,” she said. “You need to vent.”