Commercial kitchens, like restaurants, are physically demanding workplaces known for their challenging conditions. They are understudied exposure environments, though, with little research measuring the air pollution and heat that cooks, chefs, and other restaurant staff experience during a normal shift. 

A new peer-reviewed study by researchers from PSE Healthy Energy, the Stanford Doerr School of Sustainability, and New York University Grossman School of Medicine, in collaboration with Chef Christopher Galarza, published on October 6, 2026, in Environmental Research Letters, examined multiple air pollutants and air temperature in commercial kitchens across California, Pennsylvania, and New York. This is the first U.S. study to systematically compare air quality and heat exposures in gas, propane, and all-electric commercial kitchens as workers actually experience them, equipping decision-makers with actionable insights on the role that fuel choice and ventilation effectiveness play in shaping commercial kitchen conditions.

In roughly two-thirds of commercial kitchens with gas-fired appliances, pollutant concentrations exceeded health-based benchmarks in areas where employees work during restaurant service. During cooking hours, the hourly average nitrogen dioxide (NO₂) concentrations measured outside the ventilation hood systems exceeded the EPA’s outdoor standard of 100 parts per billion by volume (ppbv) in roughly 70% of the gas kitchens sampled. One kitchen in particular recorded a 15-minute average above 1,000 ppbv, exceeding the National Institute for Occupational Safety and Health’s (NIOSH) short-term occupational exposure limit for NO₂. 

Apart from NO₂, concentrations of the pollutants carbon monoxide (CO) and benzene, a known human carcinogen, exceeded California’s 1-hour exposure guidelines in three and five gas kitchens, respectively. Meanwhile, none of the electric kitchens exceeded any pollutant thresholds during cooking hours and consistently recorded some of the lowest pollutant concentrations across the entire study.

Commercial ventilation hoods reduced but did not eliminate pollutant exposure during cooking.

In approximately 68% of gas kitchens, temperatures exceeded both California’s indoor heat illness prevention regulations and the Occupational Safety and Health Administration’s (OSHA) proposed high heat trigger of 90°F (32ºC). Ten of those kitchens recorded maximum temperatures above 100°F (38ºC), and four exceeded 122°F (50°C).  Even on days when outdoor temperatures stayed below 75°F (24ºC), 10 of 13 gas kitchens still exceeded 90°F indoors, indicating that extreme heat is driven primarily by gas combustion in the kitchen rather than outdoor temperature. 

To capture the individual kitchen worker’s experience, the researchers monitored a chef’s personal heat exposure during a five-hour service. They found that the chef experienced an average temperature of 92°F (33°C) and a peak temperature of 106°F (41°C), both well above OSHA’s proposed heat regulations. All-electric kitchens were dramatically cooler; the two electric kitchens with temperature measurements recorded two of the three lowest in-service average temperatures across the entire study.

The study provides new evidence that cleaning crews, early-morning workers, and residents near commercial kitchens may be exposed to health-harming pollutants from pilot lights, which remain lit overnight. While many kitchens experienced high pollution and heat during service, over two-thirds recorded higher NO₂, CO, CO2, CH4, and benzene levels overnight when ventilation was off. Seven kitchens exceeded the 100ppbv NO₂ standard during off-work hours, raising concerns for cleaning crews and early-arriving staff. None of the electric kitchens exceeded any pollutant thresholds at any time of day or night.

The U.S. food service industry employs an estimated 15.7 million workers, and about five million of those spend their working hours in the kitchen. This study recorded air pollution and heat that exceeded health-based benchmarks in multiple sampling locations within commercial gas and propane kitchens, while all-electric kitchens consistently remained cooler and had lower pollutant concentrations that remained below the benchmarks. This study provides restaurant and building owners, chefs, other kitchen workers, and researchers with new information on how kitchen equipment and operating conditions, such as fuel choice and ventilation effectiveness, can shape the workplace environment. 

This work is part of PSE’s Methane + Health Initiative, a multi-year research initiative that aims to improve scientific and public understanding of the links between methane emissions, air pollution, and public health.