Gas stoves emissions worse than secondhand cigarette smoke

(Our Science Desk)

Millions of homes are at risk of elevated benzene exposure every time their gas stoves are ignited, warns a recent Stanford-led study.

Benzene is a chemical associated with an increased risk of leukemia and other blood cell cancers. It appears to become an unwelcome guest when residents prepare meals on their gas stoves.

According to the research, the activation of a single gas cooktop burner or setting a gas oven to 350 degrees Fahrenheit can elevate indoor benzene levels. Shockingly, these levels often exceed those found in second hand tobacco smoke.

Benzene from gas stoves is a menace to homes: To add to the concerns, benzene, it turns out, doesn’t confine itself to the kitchen. The harmful carcinogen spreads throughout the house. It will linger for hours in the air, as outlined in the paper published on June 22 in Environmenal Sciences and Technology.

Rob Jackson, the study’s senior author, explains: “Benzene forms in flames and other high-temperature environments, such as the flares found in oil fields and refineries. We now know that benzene also forms in the flames of gas stoves in our homes.”

Jackson is the Michelle and Kevin Douglas Provostial Professor and professor of Earth system science at the Stanford Doerr School of Sustainability.  He adds a rather alarming note on the efficacy of exhaust fans: “Good ventilation helps reduce pollutant concentrations, but we found that exhaust fans were often ineffective at eliminating benzene exposure.”

What the researchers learned about gas stoves?

The research reveals that the indoor benzene concentrations resulting from gas stoves can sometimes be worse than average levels from secondhand smoke.

It also shows that benzene doesn’t respect boundaries; it can migrate into rooms far removed from the kitchen. This means that bedrooms can harbor benzene levels exceeding national and international health benchmarks.

Another disturbing find is that even range hoods designed to reduce pollutant concentrations are not always successful. This is especially true when it comes to benzene, and this remains true even when the hoods vent outdoors.

Benzene does the most damage when gas stoves are turned on: Previous studies have mainly investigated benzene emissions from stoves when they are turned off and leaking. This study, however, is the first to focus on emissions when a stove or oven is in active use.

The findings indicate that gas and propane burners and ovens discharge 10 to 50 times more benzene than their electric counterparts. Induction cooktops,, on the other hand, emit no detectable benzene at all.

The rate of benzene emitted during combustion far outstrips the emission rates of benzene from unburned gas leaks identified in recent studies.

What about food that is exposed to benzene?

The researchers went even further to scrutinize whether the foods being cooked emit benzene. They found zero benzene emissions when pan-frying salmon or bacon. It’s clear from their findings that all benzene emissions measured emanated from the fuel used rather than the food cooked.

Earlier studies led by Stanford have shed light on how gas-burning stoves inside U.S. homes leak methane with a climate impact equivalent to the carbon dioxide emissions from about 500,000 gasoline-powered cars.

They also expose users to pollutants such as nitrogen dioxide, which can trigger respiratory diseases. Indeed, a 2013 meta-analysis concluded that children living in homes with gas stoves faced a 42% greater risk of asthma compared to those living in homes without gas stoves. Additionally, a 2022 analysis attributed 12.7% of childhood asthama  in the U.S. to gas stoves.

Reflecting on his personal circumstances, study lead Yannai Kashtan, a graduate student in Earth system science, says, “I’m renting an apartment that happens to have an electric stove. Before starting this research, I never thought about it twice, but the more we learn about pollution from gas stoves, the more relieved I am to be living without a gas stove.”

How to reduce gas stove pollutants: The researchers suggest several ways to reduce exposure to pollutants from gas stoves.

Adequate ventilation, such as using a range hood or keeping a window open, is recommended.

In addition, cost-effective measures can be adopted. One such idea is utilizing portable induction cooktops, which are often available for less than $50.