A Stanford University–led study published December 2 in PNAS Nexus finds that gas and propane stoves expose millions of Americans to substantial indoor nitrogen dioxide levels, in many cases matching or exceeding outdoor pollution. According to the research, replacing gas with electric stoves could cut average nitrogen dioxide exposure nationwide by more than one quarter, with particularly large benefits for people in smaller homes, renters, and rural households.
Gas and propane stoves in U.S. homes emit significant amounts of nitrogen dioxide (NO₂), a pollutant associated with asthma, obstructive pulmonary disease, preterm birth, diabetes, and lung cancer, according to the Stanford-led study.
The research team produced what they describe as the first nationwide assessment that integrates both indoor and outdoor NO₂ exposure from gas and propane stoves and other sources. To do so, they combined indoor air measurements with outdoor pollution data, information on 133 million residential dwellings, and statistical samples of household behavior to develop exposure maps by ZIP code.
Senior author Rob Jackson, the Michelle and Kevin Douglas Provostial Professor in Earth System Science at the Stanford Doerr School of Sustainability, said, "We know that outdoor air pollution harms our health, but we assume our indoor air is safe. Our research shows that if you use a gas stove, you're often breathing as much nitrogen dioxide pollution indoors from your stove as you are from all outdoor sources combined."
The analysis found that for most Americans, outdoor sources such as cars and trucks and electricity generation still account for the majority of NO₂ exposure. However, cooking with gas and propane drives indoor levels high enough that about 22 million people — especially residents of smaller homes and those in rural areas — experience long-term NO₂ exposure above recommended limits when indoor and outdoor sources are combined, even though outdoor exposure alone would not exceed those thresholds.
Short-term NO₂ spikes during cooking were found to occur almost entirely indoors and to be directly tied to stove use, rather than to outdoor pollution drifting inside. A separate 2024 study by many of the same Stanford researchers reported that gas and propane stoves can emit NO₂ at levels that exceed health benchmarks for hours after burners and ovens are turned off. Other Stanford-led work has identified gas stoves as a source of benzene, a carcinogen linked to leukemia and other blood cancers.
Lead author Yannai Kashtan, an air quality scientist at PSE Healthy Energy who conducted the work while a graduate student in Jackson’s lab, said, "It's time to redirect our focus to what's happening inside our homes, especially as families spend more time indoors."
According to the new PNAS Nexus study and related Stanford summaries, switching from gas to electric stoves would reduce NO₂ exposure by more than 25% on average across the United States and by about 50% for the heaviest stove users. The largest relative benefits are projected for people in smaller homes, renters who often cannot choose their appliances, and lower-income communities that may face barriers to adopting electric alternatives.
Previous Stanford-led research has also found that long-term NO₂ exposure is about 60% higher for American Indian and Alaska Native households and about 20% higher for Black and Hispanic or Latino households than the U.S. average, reflecting combined indoor and outdoor burdens.
"As we strive for cleaner air and healthier living, we should prioritize indoor air quality," Jackson said. "Switching to electric stoves is a positive step towards cleaner cooking and better health."
Co-authors of the new study include Chenghao Wang of the University of Oklahoma and Kari Nadeau of the Harvard T.H. Chan School of Public Health. The research was funded by the Stanford Doerr School of Sustainability and its Department of Earth System Science, as well as Stanford’s Knight-Hennessy Scholars Program.
