Tens of thousands of childhood asthma cases have been linked to gas and propane heaters, a study suggests.
Researchers in California and Boston measured nitrogen dioxide levels in more than a hundred American kitchens while the stoves were on, and then measured how the chemical spread to other rooms after the appliances were turned off.
The team combined the data with figures from the US Energy Information Administration on how often people use their heaters, giving them an estimate of the exposure people face each year.
They found that stoves using gas and propane together produced an annual nitrogen dioxide exposure of 4 parts per billion, which they estimated was responsible for about 50,000 cases of asthma in children.
The study comes at a time when officials have considered banning the device over fears of asthma and climate damage, but many scientists have questioned the validity of the research methods involved in the studies.
Researchers found that stoves using gas and propane together produced an annual nitrogen dioxide exposure of 4 parts per billion, which they estimated was responsible for about 50,000 cases of asthma in children.
“Short-term exposure to NO2 from normal gas stove use often exceeds benchmarks set by both the World Health Organization and the U.S. Environmental Protection Agency,” the researchers wrote.
This is because people living in spaces smaller than 800 square meters were exposed to up to 7.5 parts per billion, well above the World Health Organization’s annual limit of 5.3 parts per billion for both indoor and outdoor exposure.
Nitrogen dioxide is a pollutant composed of oxygen and nitrogen that is created when fossil fuels such as coal, oil and methane gas are heated at high temperatures.
According to the American Lung Association, nitrogen dioxide has been shown to cause increased inflammation in the airways, coughing, wheezing, decreased lung function and asthma attacks.
Data was collected from homes in the following cities: San Francisco, California; Los Angeles, California; Bakersfield, California; Denver, Colo.; Houston, Texas; New York, New York; and Washington DC.
The team took into account scenarios such as windows being open or closed, burners on low or high and extractor hoods on or off.
In addition to nitrogen dioxide exposure levels, the team found that people living in homes less than 800 square feet had four times the nitrogen dioxide exposure than people living in homes larger than 3,000 square feet.
And the team also pointed out racial disparities. American Indian and Alaska Native households had 60 percent more long-term exposure than the study average, and black and Hispanic households had 20 percent more exposure.
Poorer people were also at increased risk.
Dr. Rob Jackson, co-author of the study and professor of earth sciences at Stanford University, said: ‘We found that poor people breathe dirtier air outdoors and – if they have a gas stove – also indoors.’
“People in public housing and poorer neighborhoods who often rent cannot trade their appliances because they don’t own them or they can’t afford to do so.”
However, caveats to the study included its reliance on self-reported behavioral data, such as asking people how high they turn up their stove, and did not take into account individual health concerns.
Previous studies have also shown an increased risk of asthma in children due to exposure to gas and propane heaters. a Report 2022For example, research showed that these devices increased the risk of asthma in children by 13 percent.
Additionally, scientists from Purdue University and Indiana University found that cooking on a gas stove resulted in greater exposure to harmful nanoparticles than breathing in car exhaust.
Last year, New York became the first state to call for a ban on gas appliances.
However, research linking these devices to asthma has been criticized by other researchers and health authorities for flawed methodology and lack of concrete evidence.
The American Gas Association, which represents energy companies that supply natural gas, questioned past research cited by the study authors.
It pointed to one February study which showed that although cooking with gas slightly increased the risk of asthma in children, the result was not statistically significant. This led the agency to call the findings “misleading and unsupported.”
The research was published in the journal on Friday Scientific progress.