Is your gas stove a hidden health hazard? A new study reveals dangerous nitrogen dioxide (NO₂) levels from cooking, linking them to asthma. Learn how to protect your family.
Many people assume that staying indoors keeps them safe from harmful air, but a recent study challenges this assumption. Conducted by researchers at Stanford University and published in PNAS Nexus, the study reveals that gas and propane stoves emit significant amounts of nitrogen dioxide (NO₂), a harmful gas associated with asthma, lung diseases, preterm birth, diabetes, and cancer.
The study found that swapping gas stoves for electric ones can reduce NO₂ exposure by more than a quarter nationwide, and by about half for those who cook often. Although scientists have long been aware that gas stoves release NO₂, this is the first study to assess both indoor and outdoor exposure across the entire country.
Indoor Pollution Can Be Just as Dangerous
Indoor air pollution can be as dangerous as outdoor air pollution. In the US, outdoor air pollution causes hundreds of thousands of deaths annually, and globally, it leads to millions of new childhood asthma cases. While regulations like the US Clean Air Act have helped reduce outdoor pollution, indoor air quality remains largely unmonitored, despite its potential to be just as harmful.
This study is the first to evaluate nationwide exposure to NO₂ from both indoor and outdoor sources, including gas stoves, vehicles, and electricity production. Earlier research by the same team showed that NO₂ levels from gas stoves can reach unsafe levels that persist for hours after cooking ends. Other studies have also found that gas stoves emit benzene, a chemical connected to leukaemia and other blood disorders.
Mapping Pollution From Inside and Outside
To understand how people are exposed to nitrogen dioxide, researchers studied indoor air with outdoor pollution data, information on 133 million homes, and data on household behaviour. This approach helped identify pollution sources and their health impacts.
They also developed national maps showing long-term and short-term NO₂ exposure by zip code, both inside and outside homes. For most Americans, outdoor sources like traffic still contribute the most to NO₂ exposure. However, the maps revealed that 22 million people, particularly those in small homes or rural areas, experience NO₂ levels above safe limits solely from gas cooking. In rural areas, stoves contribute a larger share of overall exposure, while in big cities, the highest exposure happens because outdoor NO₂ is already high and smaller homes allow emissions to build up more quickly.
The study also found that the largest short-term spikes in NO₂ occur indoors, directly caused by gas stoves during cooking. These sharp increases are not from outside air but come from the concentrated pollution released while cooking.
Who Benefits Most From Cleaner Cooking
Switching to electric stoves or other clean cooking technologies could significantly reduce harmful indoor pollution. Policies such as rebates and tax incentives for electric stoves would be especially helpful for people in small homes and communities facing financial barriers to new technology.
Earlier research by the same team found that long-term NO₂ exposure is 60% higher in American Indian and Alaska Native households, and 20% higher in Black, Hispanic, or Latino households compared to the national average. Many of these communities also face high levels of outdoor NO₂ from traffic and industry. The study shows switching to electric stoves is a simple step towards cleaner cooking and better health for everyone.