Research continues to show that gas stoves worsen indoor air quality and can have negative health effects, especially for children. Research, debate, and legislative efforts around gas appliances have focused mainly on those at home.
But what about restaurants?
A first-of-its-kind project is seeking to understand the effect that commercial-grade gas appliances have on indoor air quality and worker safety. Preliminary results showed that most commercial kitchens with gas appliances had significantly higher concentrations of air pollutants than kitchens with exclusively electric appliances, and ambient levels of pollutants far exceeded health-related benchmarks even with proper ventilation hoods.
Turning Up the Heat and Pollution
Most home cooks with gas stoves use one to four burners at a time for short intervals. Gas actively flows at ignition and during cooking and stops when the burner is turned off. But even when functioning properly, home gas stoves tend to leak methane, nitrogen oxides, and benzene. These and other pollutants released by gas stoves, like hexane, toluene, and heptane, can cause asthma and cancer and, in the case of methane, even contribute to climate change.
Commercial-grade gas stoves work differently, explained Seth Shonkoff, an environmental health scientist and executive director of PSE Healthy Energy, which is running the commercial kitchen study. Those stoves tend to still have pilot lights, which burn gas even when the appliance is idle. They’re used differently, too: Restaurant cooks tend to have more gas burners fired up simultaneously for many hours at a time and often at higher intensities than in home cooking. These stoves are used across the country in restaurant kitchens, university dining halls, assisted living facilities, and other commercial-grade kitchens.
“Common sense dictates that people who work in commercial kitchens may face substantially greater exposure to gas stove pollution.”
“We’ve seen that cooking a few meals per day at home produces high levels of indoor air pollution that can harm health,” said Josiah Kephart, an environmental epidemiologist at Drexel University in Philadelphia who was not involved with the research. “Common sense dictates that people who work in commercial kitchens may face substantially greater exposure to gas stove pollution, where multiple stoves may be burning at high volumes for long stretches of the day.”
The researchers sought volunteer restaurants willing to let them temporarily install monitoring equipment in their kitchens. In the first batch of a dozen or so participants, ranging from upscale restaurants to casual cafés, the researchers set up air quality sensors near stoves at cooks’ breathing level, inside and outside ventilation hoods, and at other strategic areas throughout the kitchen. Some kitchens exclusively used gas appliances, and others were fully electric.
They measured carbon dioxide, methane, benzene, toluene, ethylbenzene, xylene, carbon monoxide, nitrogen oxides, particulate matter, and hexane. They collected data for 24–48 hours in each location, aiming to capture both ambient levels (typically overnight) and levels during active business hours.
“We aim to be as discreet as possible,” Shonkoff said. “We don’t want to impact the business function or the cooking patterns, or what people are doing and where people are in the kitchen.”
Occupational Safety
The team found, as expected, that kitchens with gas-powered appliances had worse air quality than exclusively electric-powered kitchens. Pollutant levels often exceeded health-related standards.
“When they are high quality and working properly, active ventilation hoods do a pretty good job of removing pollutants,” Shonkoff said, but the team still measured kitchen-wide spikes of nitrogen dioxide, carbon monoxide, and benzene when vent hoods were running.
In one restaurant, the team measured nitrogen dioxide levels of about 240 parts per billion by volume overnight, more than 4 times the annual mean standard set by the Clean Air Act. In another restaurant, overnight methane levels were 25 parts per million, about 13 times higher than ambient atmospheric levels.
The team suspected that pilot lights might be partly to blame.
“When you turn your ventilation off when you leave the building or the kitchen, and you leave the pilots on, preliminarily that has shown spikes in air pollutants over the course of an evening.”
“In a commercial setting, there can be 20 or 30 pilot lights if you add together the stove, the fryers, and the other appliances,” Shonkoff said. “When you turn your ventilation off when you leave the building or the kitchen, and you leave the pilots on, preliminarily that has shown spikes in air pollutants over the course of an evening.”
These results will be presented on 12 December at AGU’s Annual Meeting 2024 in Washington, D.C.
Kephart called this work “very important” and added, “This study of gas stove pollution in commercial kitchens produces important evidence about an understudied occupational hazard. This is a serious worker safety concern that deserves more attention.”
Shonkoff said the team shares results with the restaurants so they can make informed decisions about their operations and worker safety. The group is looking for more restaurants to participate in the study so they can do a more comprehensive analysis of the impacts of commercial gas stoves.
The researchers also hope their work might lead to more buy-in from the restaurant industry in the effort to regulate and transition away from gas stoves and improve kitchen working conditions.
—Kimberly M. S. Cartier (@AstroKimCartier), Staff Writer
Citation: Cartier, K. M. S. (2024), Cooking with gas creates unhealthy work environments, Eos, 105, https://doi.org/10.1029/2024EO240561. Published on 12 December 2024.
Text © 2024. The authors. CC BY-NC-ND 3.0
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