Weekend Reads | Gas Cooktops and Childhood Asthma

by Kevin Schofield

This week, a new front opened up in America's culture wars: gas cooktops in homes. An official with the Consumer Product Safety Commission (CPSC) called the pollutants emitted by gas stoves a "hidden hazard," and claimed that all options were on the table for addressing it — including banning gas stoves. This led critics of the Biden administration (and lobbyists for the appliance and natural gas industries) to create an uproar with complaints of government overreach. The CPSC and White House quickly backed off any notion that gas stoves would be banned.

Our "weekend read" is the research paper that led the CPSC official to make his statement in the first place. Published just last month, it looks at whether there is a connection between gas stoves and childhood asthma.

The researchers used national data from the American Housing Survey for the U.S. and state-level data (which was only available for nine states) to see if childhood asthma is more prevalent in households with gas stoves. Nationally, about 8% of American children show symptoms of asthma, and the researchers found that 12.7% (roughly one-eighth) of those childhood asthma cases could be attributed to gas stoves. So together, that means about 2% of American kids have asthma as a result of exposure to gas stoves.

However, there are many complicating factors in interpreting this result and deciding what we should do about it. For starters, the percentage of homes with gas stoves is not consistent across the United States, so the public health impact of gas stove pollutants is higher in places where there are more gas stoves. Nationwide, about 36% of homes have gas stoves, but in Illinois, 69% have them, and in Florida, only 6% do. So the contribution of gas stoves to childhood asthma is much higher in Illinois than in Florida. Also, in some homes, the gas stove is used for heating as well as cooking: That can dramatically increase exposure to harmful pollutants.

And an equally important factor is the existence and use of ventilation hoods over gas stovetops. A separate study showed that running a ventilation fan to exhaust fumes outside can dramatically decrease the level of exposure to pollutants — but it depends on the quality of the ventilation system, which can vary from 98% efficiency all the way down to 15%. I wrote a lengthier review of this study, discussing its strengths and weaknesses, a few years ago for my previous publication, SCC Insight.

None of this is really new information, though. Studies on the pollutant emissions from burning natural gas in furnaces and stoves has been ongoing for decades. By 2001, there was recognition that "residential exposures" to pollutants in homes, including those from gas stoves, were contributors to a rise in childhood asthma cases. Since then, multiple studies have confirmed and reconfirmed these findings as related specifically to nitrogen dioxide emissions from gas stoves, expanded them to other childhood respiratory illnesses, and identified other harmful effects from the carbon monoxide and formaldehyde produced by gas combustion in furnaces and stoves. In retrospect, it's stunning that so little has been said publicly about this hazard since it's so well understood.

That said, it's also true that cooking on electric appliances can generate some harmful emissions — but well below the level of gas stoves.

Defenders of gas stovetops point out that they have some advantages for cooking over electric cooktops; the two main ones are that you can instantly change the heating level, and you can very precisely control the amount of heat generated. That's very true with traditional electric burners that take a while to heat up and cool down and can be difficult to control precisely, but the newer generations of electric "induction" cooktops move a long way toward evening the playing field. Of course, many households can't afford to replace their stove, and even if they could, their kitchen may not be wired for an electric stovetop.

It's also worth mentioning that methane, which makes up a significant portion of the natural gas piped to our homes, is a "greenhouse gas" that is a much more potent contributor to global warming than carbon dioxide. While it's fairly "clean burning" in most stovetops and furnaces, the pipeline infrastructure that distributes it is well known to be leaky, and those leaks are exacerbating climate change. There are already separate efforts underway to transition us away from natural gas as a fuel as "green" electricity sources, such as wind, solar, and hydroelectric, become available in quantities that can replace it — but that is a topic for another day.

So where does this leave us? The CPSC official who spoke out recently has the science on his side: Gas cooktops emit dangerous levels of pollutants, and they contribute to childhood asthma cases (as well as other childhood illnesses). Ideally, we should significantly reduce our own and our families' exposure to these pollutants by switching to electric cooktops (and from gas furnaces to electric heat pumps). But in many places, and for many households, that is not yet a feasible option, so even setting aside the culture wars over a potential government ban on new gas cooktops, they aren't going away anytime soon. But at a bare minimum, one should never, ever use a gas cooktop without turning on the ventilation hood to exhaust as much of the emissions outside as possible.

Population Attributable Fraction of Gas Stoves and Childhood Asthma in the United States

Featured image by Mircea Moira/Shutterstock.com.