Air Fryers Offer Least Polluting Cooking Method, Researchers Find

If you’re looking to keep your indoor air cleaner over the holidays, a new study has found that air fryers emit just a small portion of the indoor air pollutants produced by other cooking methods like pan and deep frying.

Most people spend most of their time — 80 percent — indoors, and cooking is a big contributor to indoor air pollution. The energy efficiency of air fryers has been amply studied, but less is known about their environmental benefits, a press release from England’s University of Birmingham said.

“As expected, oil-based cooking methods produced much more [particulate matter (PM)] and [volatile organic compounds (VOCs)] in the indoor environment than water-based methods,” the authors wrote in the study. “The air fryer generated the least PM emissions.”

Indoor pollutants are a significant health concern and can cause a range of symptoms and chronic conditions like respiratory, cardiovascular and neurodegenerative diseases.

As their test kitchen, the scientists used a well-controlled campus research kitchen as a compromise between experiments measuring pollution produced by various cooking methods conducted in a laboratory, and testing in the less regulated environment of a domestic kitchen.

For the experiments, the researchers used five different methods to prepare chicken breast: pan frying, deep-fat frying, stir-frying, boiling and air-frying. They then measured the levels of VOCs and PM emitted by each cooking method.

For PM, the research team used micrograms for each cubic meter of air to measure peak concentrations. The peak concentration for pan frying was 92.9, deep frying measured 7.7, stir-frying had a peak concentration of 26.7, boiling came in at 0.7 and air-frying 0.6.

The measurements for VOCs were “parts per billion,” or ppb. Pollution levels were relatively similar to the PM emissions across the variety of cooking methods. The team also identified and quantified certain VOCs emitted most during each activity.

“There are a number of factors that will affect the levels of pollution from cooking alongside the method used, including the amount of oil used, and the temperature of the stove. What we can say with certainty, however, is that improving the ventilation in kitchens by opening windows or using extractor fans, will help to disperse polluting particles and reduce personal exposure,” said lead author of the study Christian Pfrang, a professor of atmospheric science at University of Birmingham, in the press release.

The team kept measuring the pollution emitted for both VOCs and PM following the conclusion of the cooking process. They found that substantially higher pollution levels remained in the kitchen for more than an hour after cooking, even though the preparation only took about 10 minutes.

“It’s also really important to understand that particles will remain in the air for quite some time after you have finished cooking, so continuing to ventilate, or keeping extractor fans turned on for a period of time will really help to avoid the build-up of this indoor pollution and reduce the potential for the pollutants to be transported and distributed throughout the house with the associated higher personal exposures,” Pfrang added.

The study, “Impact of Cooking Methods on Indoor Air Quality: A Comparative Study of Particulate Matter (PM) and Volatile Organic Compound (VOC) Emissions,” was published in the journal Indoor Air.