I know my stove is killing me. The Post has covered the harmful effects of nitrogen dioxide, NO2, the toxic by-product of burning gas. My old place’s 1950s Wedgewood stove, with a pilot light strong enough to lift a hot-air balloon, contributed to a data analysis on the subject. And yet on New Year’s Eve, I reverse-seared a prime rib for six hours in our cramped apartment with our two kids and my wife — a public health professional — present.
For home cooks, the love of cooking with gas is real. In the face of what we know about gas and health, it defies logic. Stanford University researchers recently made the most comprehensive model of indoor air pollution attributable to gas stoves. The results are — well, let’s look for ourselves.
Longer term exposure above the WHO limit increases rates of lung cancer, heart diseases, diabetes, preterm birth and rates of childhood asthma, according to researchers. A meta-analysis on NO2 exposures and health found death rates rose by 6 percent with every 10 ppb increase in levels of exposure. Another study of older adults found no amount of NO2 that is safe.
Air quality scientist Yannai Kashtan, the lead author of the new study, said his team used the WHO’s threshold of 5.2 ppb, because it is based on the best scientific evidence for improving public health. Some countries, though, have set looser limits as they balance health concerns with other factors. The United States has a threshold that’s more than 10 times higher, at 53 ppb, which the Environmental Protection Agency has not changed since 1971.
The American Gas Association declined to respond to multiple requests for comment. A statement from their website argues that the principal source of indoor NO2 comes from outdoor sources. Kashtan’s study demonstrates that gas stoves alone can account for a quarter to a half of a person’s exposure to nitrogen dioxide.
Julian Marshall, professor of environmental engineering at the University of Washington, says that “the health effects of emissions from gas stoves, especially NO2 air pollution … have been known for a long time.”
Go ahead and fiddle with the inputs and see if you fare any better than I did with my kitchen. If you own an electric stove, you can input your friends’ or in-laws’ info, if you like. For our Alaska, Hawaii and Puerto Rico residents, researchers were only able to model the contiguous U.S. because of data availability.
You might notice that no matter what you do, short of using an electric stove, your total NO2 exposure still puts you at a high rate of exposure. For instance, if you live along the Interstate 95 corridor, your outdoor NO2 levels probably put you at higher risk. This is because the combination of traffic, industry and dense urban living means poorer air quality overall. On the whole, though, outdoor concentrations of nitrogen dioxide have dipped to the lowest level since the EPA began measuring them in 1988. As that air quality improves, understanding how stoves harm human health matters more.
When we look across the contiguous U.S. in half the counties modeled, how your stove is powered matters. In these places the outdoor air quality is low enough that the use of a gas stove might be the tipping point. In other words, using an electric range can make all the difference for 22 million people, researchers found.
In modeling NO2 across the country, researchers considered common home types and population density as well as outdoor factors such as wind, temperature and air quality to get a detailed picture of indoor and outdoor attributable rates of NO2. Where you live matters. If details about my home here in New York were applied to Missoula, Montana, me and my family’s exposure would drop from 17.05 to 2.95 ppb outdoors.
David Holt, president of the Consumer Energy Alliance, an industry advocacy group, says that the Stanford University study is yet one more data point for consumers evaluating their risks, but that the risks must be weighed against financial costs of switching off gas. “We’re all environmentalists, right?” Holt says. “We want a cleaner environment for our children … but it’s got to be that balance: environmental performance, affordability, and reliability.”
When I weigh the risks, I — like many of our readers — have to think about the costs. Replacing your stove is expensive. And if you are a renter like me, it might be unfeasible. Studies suggest, though, that air purifiers with HEPA and carbon filters can lower indoor NO2 levels.
Marshall says my experience is a common story. Replacing a gas stove and sometimes rewiring your own home (if you own) can be costly, he says. Marshall cites a study that looked at three interventions: replacing a gas stove, improving your range hood exhaust and using an air purifier. Of the interventions, the purifier and electric stove decreased levels the most.
Magali Blanco, assistant professor in the department of environmental and occupational health sciences at the University of Washington, says that it’s true that environmental risks are higher for lower income individuals. “But I don’t think it necessarily means that if you don’t have a ton of resources that you can’t keep yourself safe.” Blanco points to using more electrical appliances at home such as a kettle, microwave or pressure cooker to lower NO2 gases.
Kashtan hopes the new research powers long-term health studies and influences future policymaking. In the paper, the scientists write that providing a more complete picture of who is most exposed to this pollution “may help decision-makers prioritize locations for building electrification and ventilation retrofits.”
Gas stove acolytes, I hear you. I am still processing the health risks. Costs tie my hands a bit on switching to an induction stove, but maybe I can charm my landlord.