Gas stoves, commonly found in over 40 million U.S. homes, may be contributing to the development of pediatric asthma, according to a new research study. The study, conducted by researchers at Stanford University and published in the journal Science Advances, suggests that around 50,000 current cases of pediatric asthma in the United States are associated with long-term exposure to nitrogen dioxide emitted from gas and propane stoves.

Nitrogen dioxide is produced during the combustion of natural gas at high temperatures, and it is known to irritate airways and worsen respiratory problems. Previous studies have also reported a connection between long-term exposure to gas stoves and an increased risk of asthma and chronic lung disease.

The research team measured nitrogen dioxide levels inside more than 100 U.S. kitchens while stoves were in operation, and then monitored its spread to other rooms after the stoves were turned off. They took into account various factors such as open or closed windows, burner settings, and the use of range hoods. By combining this data with information from a U.S. Energy Information Administration survey on stove usage and indoor ventilation, the researchers estimated the annual exposure to nitrogen dioxide in U.S. homes. They then used this estimate to calculate the approximate number of new asthma cases that could be expected based on previous studies.

The study revealed that the average yearly exposure to nitrogen dioxide from gas and propane stoves in U.S. homes approaches the limit set by the World Health Organization. On average, gas or propane stoves contribute to a yearly exposure of around 4 parts per billion, while the WHO's annual limit for indoor and outdoor air combined is approximately 5.3 parts per billion.

Notably, smaller homes, those where cooking is frequent, and homes without range hoods had higher levels of long-term nitrogen dioxide exposure. For example, homes under 800 square feet were found to have four times the amount of exposure compared to homes larger than 3,000 square feet, surpassing the WHO's safe limit.

The study also highlighted racial disparities, as American Indian and Alaska Native households had 60% more long-term exposure to nitrogen dioxide compared to the national average, while Black and Hispanic households had 20% more exposure. Lower-income families also faced an increased risk.

The American Gas Association (AGA), a trade group representing energy companies that supply natural gas, questioned some of the previous research on which the new study is based. AGA President and CEO Karen Harbert called the study's conclusions "misleading and unsupported."

To reduce exposure to nitrogen dioxide, opening windows or installing range hoods that vent outdoors may help, although it may not completely eliminate the problem. The researchers suggested that families with gas stoves consider using a portable induction cooktop as an alternative. Additionally, implementing policies that prohibit the installation of gas stoves in new buildings could be a potential solution.

While New York state and Berkeley, California, have taken steps to restrict gas stove use in new buildings, at least two dozen states have passed laws preventing local governments from imposing such restrictions. Some House Republicans have also introduced bills to limit regulations on gas stoves, with a vote on the Hands Off Our Home Appliances Act expected next week.

The study emphasizes the importance of addressing indoor sources of air pollution, particularly gas stoves, as they may have significant implications for respiratory health. It is crucial to prioritize interventions and find viable alternatives to gas stoves to improve air quality and reduce the risk of pediatric asthma.