Nanoparticles from gas stove could be deadlier than from car exhaust

Science and Health

More families are buying electric-induction cooktops rather than gas burners because they eliminate the danger of fires and harm to children, and are more convenient. Now there may be an additional reason to avoid gas-powered cooking surfaces. 

Cooking on a gas stove can emit more nano-sized particles into the air than those that run on gas, possibly increasing your risk of developing asthma or other respiratory illnesses, a new study at Purdue University in Indiana has found.

“Combustion remains a source of air pollution across the world, both indoors and outdoors. We found that cooking on your gas stove produces large amounts of small nanoparticles that get into your respiratory system,” said civil engineering Prof. Brandon Boor who led this research. Based on these findings, if not having an induction cooktop, the researchers encourage turning on a kitchen exhaust fan while cooking on a gas stove. 

The study, published in the journal PNAS Nexus under the title “Dynamics of nanocluster aerosol in the indoor atmosphere during gas cooking,” focused on tiny airborne nanoparticles that are only one to three nanometers in diameter – just the right size for reaching certain parts of the respiratory system and spreading to other organs. 

Recent studies have found that children who live in homes with gas stoves are more likely to develop asthma, but not much is known about how particles smaller than three nanometers, called nanocluster aerosol, grow and spread indoors because they’re very difficult to measure.

“These super tiny nanoparticles are so small that you’re not able to see them. They’re not like dust particles that you would see floating in the air,” Boor said. “After observing such high concentrations of nanocluster aerosol during gas cooking, we can’t ignore these nano-sized particles anymore.”

Using state-of-the-art air quality equipment, the researchers were able to measure these tiny particles down to a single nanometer while cooking on a gas stove in a “tiny house” lab that has all the features of a typical home but is equipped with sensors for closely monitoring the impact of everyday activities on a home’s air quality. The team collected extensive data on indoor nanocluster aerosol particles during realistic cooking experiments.

This magnitude of high-quality data enabled them to compare their findings with known outdoor air-pollution levels that are more regulated and understood than indoor air pollution. They found that as many as 10 quadrillion nanocluster aerosol particles could be emitted per kilogram of cooking fuel – matching or exceeding those produced from vehicles with internal combustion engines.

This would mean that adults and children could be breathing in 10 to 100 times more nanocluster aerosol from cooking on a gas stove indoors than they would from car exhaust while standing on a busy street. “You would not use a diesel engine exhaust pipe as an air supply to your kitchen,” said Prof. Nusrat Jung who designed the tiny house lab with her students and co-led this study.

The models showed that nanocluster aerosol particles are very persistent in their journey from the gas stove to the rest of the house. Trillions of these particles were emitted within just 20 minutes of boiling water or making grilled cheese sandwiches or buttermilk pancakes on a gas stove.

Even though many particles rapidly diffused to other surfaces, the models indicated that approximately 10 billion to one trillion particles could deposit into an adult’s head airways and tracheobronchial region of the lungs. These doses would be even higher for children, since the smaller the human, the more concentrated the dose.

The nanocluster aerosol coming from the gas combustion also could easily mix with larger particles entering the air from butter, oil or whatever else is cooking on the gas stove, resulting in new particles with their own unique behaviors. The team said that a gas stove’s exhaust fan would likely redirect these nanoparticles away from your respiratory system, but that remains to be tested.

“Since most people don’t turn on their exhaust fan while cooking, having kitchen hoods that activate automatically would be a logical solution,” Boor said. “Moving forward, we need to think about how to reduce our exposure to all types of indoor air pollutants.