Roughly 70% of workers in gas-fired commercial kitchens monitored in a new US study were exposed to air pollution levels exceeding World Health Organization guidelines — despite commercial-grade ventilation systems running during service.

The peer-reviewed research, published in Environmental Research Letters and conducted by researchers from PSE Healthy Energy and Stanford University, is the first of its kind. It monitored conditions in 27 kitchens across the United States: 24 cooking on gas or propane, three all-electric.

The findings have direct implications for Australia's hospitality workforce, where no equivalent study exists. Chefs in Australia work with comparable gas-fired appliances and mechanical extraction systems, and gas combustion produces the same pollutants regardless of geography. Concentrations can vary with equipment, kitchen design, ventilation and operating practices — but the baseline exposure conditions remain largely unmeasured for Australian commercial kitchen workers.

What did the monitoring find?

Researchers measured nitrogen dioxide (NO₂), carbon monoxide, carbon dioxide, methane and benzene at worker-relevant locations during service and overnight periods. The results split sharply along fuel type:

• 17 of the 24 gas and propane kitchens recorded hourly average NO₂ concentrations above the WHO one-hour guideline of 200 micrograms per cubic metre during service.
• "Combustion-generated" pollution escaped the ventilation hood and reached other occupied areas of the kitchen.
• All three electric kitchens recorded consistently low concentrations of combustion-related pollutants, with none exceeding WHO thresholds.
• More than two-thirds of gas and propane kitchens monitored overnight recorded higher median concentrations of several pollutants after ventilation was switched off, while gas pilot lights kept burning.

The last point matters for operators: pollution exposure does not end when service does, and pilot lights alone can sustain elevated pollutant levels in an unventilated kitchen.

How hot do gas kitchens get?

Heat exposure tracked the same fuel divide. The study found 52% of kitchens with gas appliances recorded maximum temperatures above 37°C in the area directly outside the ventilation lip, and four exceeded 50°C. Those peaks came on days when outdoor temperatures stayed below 23°C.

Electric kitchens ran at an average of 22°C throughout operation. Personal monitoring of one chef across roughly five hours of service recorded an average of 33°C at the chef's shoulder, peaking at 41°C.

What are researchers calling for?

Professor Lidia Morawska, an air quality expert at Queensland University of Technology, said the study shows the problem is global, not local to the US.

"It shows unequivocally that millions of U.S. workers face serious risk from heat and from pollution exceeding WHO health guidelines. Globally, the figure likely runs to hundreds of millions," Morawska said.

"More studies are needed in other countries, including here in Australia, but the conclusion is clear: we urgently need regulations to eliminate the source of pollution. That means replacing gas appliances with electric cooking equipment, which emits no polluting gases and generates less heat."

Morawska said the transition will not happen overnight and called for national transition strategies with defined implementation timelines.

What does switching cost operators?

Chef Luke Burgess, owner of Scholé in Hobart, has already made the move. After nearly 30 years in professional kitchens, he built an all-electric kitchen when he opened Scholé last year, accepting higher upfront costs to improve working conditions for his team.

"The difference in temperature is really noticeable, particularly during a busy service. The kitchen is cooler and more comfortable to work in and there's been no compromise when it comes to the food or how we cook," Burgess said.

He said many chefs and restaurant owners want to make the same switch, but the capital cost puts it out of reach for most. "Hospitality is already operating on incredibly tight margins, and there needs to be more support from governments to make electric kitchens accessible to businesses that want to transition," he said.

With no Australian data yet collected, researchers say further studies outside the US are needed to establish whether local kitchens carry the same exposure profile — and whether regulators will act on the findings before that evidence arrives.