Gas Stoves: Like a Cigarette Smoker in Your Kitchen?

The researchers collected 185 unburned gas samples from 159 houses of varying types throughout California, and then modeled concentrations of a number of hazardous air pollutants (HAPs), including the carcinogen benzene, in indoor air under a variety of conditions.

Most of the simulations did not result in benzene concentrations above California’s reference exposure levels (RELs), which are benchmarks for how much of a given pollutant is considered acceptable for human health. But there were notable exceptions.

In some places, benzene concentrations in the gas supply were simply higher. In two regions of California, the Los Angeles area and the North San Fernando/Santa Clarita valleys, “REL exceedances” were significant, “irrespective of ventilation or building type or other indoor sources of benzene,” the researchers wrote. The authors attribute this variability in benzene concentrations to the complex gas supply chain in the state. “These exceedances” in the North San Fernando/Santa Clarita valleys “produce indoor concentrations of benzene similar to concentrations to environmental tobacco smoke (i.e., secondhand smoke),” they said.

Benzene concentration of the fossil gas was the dominant factor in ambient benzene concentrations, with ventilation rates secondary. Does this mean people whose gas source has lower benzene concentrations are in the clear? Not necessarily, the researchers say.

“This modeling approach almost certainly underestimates the true quantity of behind-the-meter [natural gas] emissions, which also may include leaks from other gas appliances and emissions of natural gas when the stove/oven is on,” the authors note. Also, the methodology set a conservative background benzene concentration, for outdoor air, even though VOC concentrations tend to be higher in indoor air. Not mentioned by the researchers? Lower ventilation rates than assumed by the study could also lead to higher benzene concentrations.

Advising caution and calling for further research, the authors conclude, “Weatherization and building efficiency measures should be coupled with residential and other building electrification measures to support multiple health, air quality, and climate co-benefits by mitigating HAPs and methane emissions while appliances are both off and on.”

The study also modeled outdoor benzene emissions from gas distribution networks, calculating that “the current emissions inventory underestimates benzene emissions for the residential sector by approximately 44%.”

More on gas appliances

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Energy Star Removes Gas Appliances from “Most Efficient” List

Gas Is Going Out of Style

For more information:

Environmental Science & Technology
pubs.acs.org