Studies find burning from gas stoves can increase levels of chemicals in a room

Chemicals linked to a higher risk of leukemia and other blood cell cancers creep into millions of homes every time residents turn on their gas stoves. A new Stanford-led analysis found that a single high-temperature gas burner or gas oven set to 350 degrees Fahrenheit can increase indoor levels of the carcinogen benzene over secondhand tobacco smoke. Benzene also drifts throughout the house and lingers in the air for hours, according to a paper published June 22 in Environmental Science & Technology.

Benzene is formed in fires and other high-temperature environments, such as flares found in oil fields and refineries. We now know that benzene also forms in the flames of gas stoves in our homes,” said study senior author Rob Jackson, Michelle and Kevin Douglas Provostial Professor and professor of Earth system science at Stanford Doerr School of Sustainability. “Good ventilation helps reduce pollutant concentrations, but we found that exhaust fans were often ineffective at eliminating benzene exposure.”

Worse than cigarette smoke

Overall, the researchers found that indoor benzene concentrations formed in gas stove flames can be worse than average concentrations from cigarette smoke, that benzene can migrate to other rooms far from the kitchen, and that concentrations measured in bedrooms can be beyond national and international levels. health benchmark. They also found residential hoods were not always effective at reducing concentrations of benzene and other pollutants, even when hoods were ventilated outdoors.

This new paper is the first to analyze benzene emissions when a stove or oven is in use. Previous studies have focused on leakage from stoves when they are turned off, and have not directly measured the concentration of benzene produced. Researchers found gas and propane burners and ovens emit 10 to 50 times more benzene than electric stoves. Induction cooktops emit no detectable benzene at all. The levels of benzene emitted during combustion are hundreds of times higher than the levels of benzene emissions identified in other recent studies from unburned gas leaks into homes.

The researchers also tested whether cooked food released benzene and found zero benzene emissions from fried salmon or bacon. All of the benzene emissions the researchers measured came from the fuel used rather than the food being cooked.

A Stanford-led study previously showed that gas-fired stoves in US homes emit methane with a climate impact comparable to the carbon dioxide emissions of about 500,000 gasoline-powered cars. They also expose users to pollutants, such as nitrogen dioxide, which can trigger respiratory ailments. A 2013 meta-analysis concluded that children living in homes with gas stoves had a 42% greater risk of developing asthma than children living in homes without gas stoves, and a 2022 analysis calculated that 12.7% had childhood asthma. -children in the US are caused by gas. stove.

“I rented an apartment that happened to have an electric stove,” said study lead Yannai Kashtan, a graduate student in Earth system science. “Before starting this research, I never thought twice, but the more we learn about pollution from gas stoves, the more relieved I am to live without gas stoves.”

Jackson is also a senior fellow at the Stanford Woods Institute for the Environment and the Precourt Institute for Energy. Study co-authors also include Metta Nicholson and Colin Finnegan, environmental science research professionals in Stanford’s Department of Earth System Science; Zutao Ouyang, research fellow in physics at Stanford’s Department of Earth System Science; and researchers at PSE Healthy Energy, University of California, Berkeley, and Lawrence Berkeley National Lab.

This study was funded by the High Tide Foundation.

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How to reduce exposure to pollutants from gas stoves

In addition to ensuring good ventilation with a hood or window open, relatively inexpensive approaches to reducing pollutant exposure from gas stoves include:

• Use a portable induction hob, which can be found for less than $50 new.
• Use electric kitchen appliances, such as tea kettles, toaster ovens and slow cookers.
• When available, take advantage of state and local rebates and low- or no-interest loans (such as these programs for California and the San Francisco Bay Area) to offset the cost of replacing gas equipment.
• A federal tax credit is available now, and federal rebates will be available later this year or sometime in 2024 to help offset the cost of replacing gas equipment.

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