Pollution
Gas & propane stoves increase nitrogen dioxide exposure to unsafe levels, finds US study
Homes with gas stoves expose residents to an estimated 4 parts per billion increase in NO2 on average over a year
By Nandita Banerji
Published: Thursday 09 May 2024
A recent study by Stanford University has raised concerns about the health risks associated with gas and propane stoves. The research revealed these appliances can significantly increase indoor air pollution levels of nitrogen dioxide (NO2), a pollutant linked to respiratory problems.
The study, published in journal Science Advances, found that homes with gas or propane stoves expose residents to an estimated 4 parts per billion (ppb) increase in NO2 on average over a year. This increase is concerning because it reaches 75 per cent of the World Health Organization’s (WHO) recommended safe limit for indoor and outdoor NO2 exposure.
Researchers placed sensors in over 100 homes to measure levels of NO2 before, during and after using gas stoves.
These homes varied in size, layout, and ventilation. The collected data was then fed into a software model that simulated airflow and the spread of contaminants in buildings. This helped the scientists estimate average NO2 exposures across the country, including short-term spikes, based on different scenarios and behaviours.
The researchers also verified their model results by comparing them with the actual readings from the homes they studied.
The new research confirmed that food emits little or no nitrogen dioxide as it cooks, however, and electric stoves produce no NO2.
The paper highlighted the pervasiveness of NO2 emissions from gas stoves, underlining that the pollution levels can remain elevated even in bedrooms far from the kitchen, posing a health risk to everyone in the household.
“I didn’t expect to see pollutant concentrations breach health benchmarks in bedrooms within an hour of gas stove use and stay there for hours after the stove is turned off,” said Stanford Doerr School of Sustainability Professor Rob Jackson, senior author of the study published May 3, 2024.
Read more: Clean(er) cooking in India: We need a transition to better solutions along with smarter policies
Pollution from gas and propane stoves isn’t just an issue for cooks or people in the kitchen, he said. “It’s the whole family’s problem,” he said in a statement on the university website.
Researchers believe this chronic exposure to NO2 could be responsible for a significant number of health problems, particularly for children. The study estimated that gas stove emissions might contribute to up to 200,000 current cases of childhood asthma in the United States, with NO2 playing a key role.
Long-term exposure to NO2 in American homes with gas stoves could lead to thousands of deaths annually, potentially up to 19,000, which is about 40 per cent of the yearly fatalities associated with secondhand smoke, the researchers said.
This estimate comes from recent research examining how much NO2 people inhale at home from gas stoves, using the most accurate data on mortality from long-term exposure to outdoor NO2, a pollutant regulated by the US Environmental Protection Agency.
The findings called for increased awareness of the health risks associated with gas stoves and potential changes in how we approach indoor air quality. The new research confirms that food emits little or no nitrogen dioxide as it cooks, however, and electric stoves produce no NO2.
Read more: India’s poor are being forced to return to unclean cooking fuels; here’s why
“We found that just how much gas you burn in your stove is by far the biggest factor affecting how much you’re exposed. And then, after that, do you have an effective range hood — and do you use it?” said lead study author Yannai Kashtan, a PhD student in Earth system science.
Some mitigation strategies include using range hoods that vent outdoors, ensuring proper ventilation while cooking, and considering alternative cooking appliances like electric stoves or induction cooktops.
While gas stoves offer certain advantages, like faster heating and precise temperature control, the potential health risks cannot be ignored. Further research is needed to fully understand the long-term health effects of chronic NO2 exposure from gas stoves, the researchers said.
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