Of Course Your House Is Killing You

There’s nothing as bad for you as living well.

Here’s a nice memory: My wife and I are in Aspen, sitting by a fire that is a little bigger than it really needs to be, drinking a nice Margaux; the dachshund is tuckered out from hiking up the mountain earlier in the day and is fast asleep with her belly turned toward the fire. Dinner is simmering in the kitchen. 

Horrors, all, of course: There’s getting there, to begin with, and the dose of radiation you get every time you fly (“aircrew have the largest average annual effective dose of all US radiation-exposed workers”) added to the extra radiation you get just from being in the mountains (“calculations based on data from NCRP reports show that the average level of natural background radiation (NBR) in Rocky Mountain states is 3.2 times that in Gulf Coast states”), the magnificent fireplace (“Wood-burning fireplaces: Not such a hot idea”) that makes the emissions from the gas range look like the purest oxygen in one of those weird Japanese oxygen bars by comparison, the Margaux (“Even a Little Alcohol Can Harm Your Health,” the New York Times warned last week), the sweet little puppy (“pet dander can potentially be harmful to your respiratory system”), the bacteria-laden spice rack in the kitchen, the steak …

And there is nowhere to go to cleanse yourself from all that contagion: “Your bath mat is disgusting,” reports the New York Times. And don’t even ask about taking a long, hot shower or a warm bath on a cold winter night. 

You thought this was just about your gas range? Oh, no, Sunshine—your gas cooktop probably isn’t even the top gas-burning appliance in your house—if you have gas heat, a gas clothes-dryer, or a gas oven, the range is probably pretty far down the list. Your electric stuff probably runs on gas in no small part, too. Natural gas is the most common fuel source for generating electricity in the United States, but that’s another subject.

Do you have an attached garage on your house? If you do, then all the stuff that’s in your garage air—from car exhaust to fumes from all those cleaners and solvents and paint and stuff you have in the garage—is probably in the air in your bedroom, kitchen, nursery, etc. Are you worried about radon and mold? Because you have radon and mold—you may not have enough to set off the alarm bells, but you have those and other pollutants in your house. The question is not whether you have this stuff in your indoor air—the question is, How much? 

Richard Trumka of the Consumer Product Safety Commission (who has kept the family tradition of wearing a Stalin mustache but has severed the coal-mining roots) caused a major public kerfuffle earlier this month when he floated a trial balloon for banning gas stoves in homes. New York City has banned gas connections for new buildings (the governor would like the state to follow suit), a move that, like the campaign against gas stoves, is mainly about climate change and the categorical push against fossil fuels, with the indoor-air stuff appended for the benefit of easily terrified suburban mothers, a critical progressive political constituency. The conversation unfolded in the usual, predictably stupid culture-war way, which probably was not entirely unwelcome for the Biden administration, which would rather talk about almost anything other than special counsels and the Corvette That Knew Too Much. A nice little skirmish that gives progressives a chance to shriek “Republicans don’t believe in The Science and they hate children!” was just the thing for the Democrats’ political moment. 

So, how big a deal is this, really? I don’t mean from the political/legal/constitutional point of view—do these CPSC clowns really just get to ban gas ranges?—but from an actual indoor-air-quality point of view. 

The most important question to ask in these situations is, of course: “Compared to what?” 

Gas ranges produce a couple of categories of things that are worth worrying about: the first category is potentially harmful or dangerous gases, mostly nitrogen oxides of different kinds (particularly nitrogen dioxide) but also carbon monoxide; the second category is small particles, particularly the ones known as “PM2.5”—meaning “particulate matter less than 2.5 microns in width,” a micron being one-millionth of a meter—which are small enough to sneak around the nose-hairs and other bodily-filtration barriers and wedge in the lungs. The most famous PM2.5 you’ve heard of is asbestos, which isn’t actually dangerous until it is suspended in the air in the form of those tiny particles. Fry bacon on your induction cooktop and you’ll produce itty-bitty particles, too, including potentially dangerous ones. 

Gas ranges produce problem gasses and PM2.5 in two ways: One is simply through the combustion of natural gas, and the second is through the process of cooking itself. Because electric cooking doesn’t involve natural-gas combustion, nitrogen dioxide isn’t an issue, but most cooking, irrespective of the heat source, produces particulate matter, including PM2.5. Gas cooking produces it, electric cooking produces it, electric toasters produce it, ovens of all kinds, outdoor barbecues, etc. Microwaving popcorn produces a good deal of PM2.5—but even microwaving water produces a little bit. Gas ranges typically produce more PM2.5 than electric ranges do—about twice as much, some studies find—but whether this is a real problem depends on a number of factors, a critical one being ventilation. But there are lots of variables, including ones you’d never think of: Cooking with olive oil produces more PM2.5 than does cooking with peanut oil. 

In the poorer parts of the world, particularly in colder poor places, people often cook indoors with wood or coal or animal dung and do so in places that often are poorly ventilated. There is a big difference between somebody who cooks with fire three times a day in a mud house with no real ventilation and someone who sits next to a wood-burning fireplace a few nights in the winter in a house with a proper chimney and a properly designed overall ventilation system. 

Which is to say, the question in isolation of whether you have an electric range or a gas range is, in most cases, going to be a pretty minor variable in terms of your overall life situation. One of the things that correlates very strongly with the particulate-matter levels in your house is—this will not surprise you—the particulate-matter levels outside in the air around where you live. If you live near a coal-fired power plant or a freeway or a busy street with lots of diesel exhaust—and a lot of tires rubbing on a lot of asphalt—a gas range probably isn’t your top air-quality worry. 

A compounding factor is that the people who do live near power plants and industrial facilities and such tend to be poor, meaning that they often live in older, leakier houses with ventilation and filtration systems that are not very effective—and these communities also tend to have higher levels of childhood asthma and other health problems exacerbated by poor air quality. As so often is the case, the question relevant to rich, college-educated people—Should I replace my gas range with an electric-induction cooktop?—rises to the top of the conversation, while the gnarlier and more complex problems of the poor are left to fester. 

John Balmes is a moderate gas-cooking hawk. He is a professor of medicine at UC-San Francisco and a professor of environmental science at UC-Berkeley. If you have a sneaking suspicion that this gas-stove business is mostly about climate activists who want to get rid of fossil-fuel use entirely looking for a health issue to open a second front in their war on gas, Professor Balmes will be happy to tell you that this is, in fact, the case—not that he thinks that’s a bad thing. 

He is working on a project trying to get households in which there are children with asthma to replace gas cooking appliances with electric to document health benefits. “The greater motivation is for climate-change mitigation purposes,” he says. “That’s the reason California Energy is funding our research project, to see if we can show health benefits. We don’t have definitive evidence yet.” Even if the health evidence is less than definitive, he argues, there’s a good case for relatively robust government action. “I don’t think the problem is so bad that we have to rip gas stoves out of everybody’s homes,” he says, “but in the future the policy that we have here in Berkeley, to move away from gas appliances for climate change, probably also has health benefits. Those benefits are not as well-documented as they could be—that’s why they’re funding this project we have.”

Balmes puts gas stoves fairly high on his list of indoor-air menaces: “Candles, incense, smoking indoors—smoking anything, not just tobacco—those are all problems as well. Smoking tobacco in the home is probably the worst for a kid with asthma, and smoking marijuana second, but only because there’s less smoke generated, because people smoke fewer joints than cigarettes. And then I’d probably put gas cooking next.” 

His wife has asthma, and he is, as you might imagine, something of an enthusiast when it comes to air quality: He not only has an electric-induction cooktop, but he also has a MERV-13 filter for his HVAC system (meaning that the air filter is hospital-grade) and portable HEPA filters in the rooms where he and his wife spend the most time. (Do you have a medical-grade MERV-13 filter? No? Well, it takes all kinds.) Balmes advised the Biden administration on including subsidies for portable HEPA filters (the systems cost a few hundred bucks) for people who are dealing with smoke from wildfires, but that didn’t make the final infrastructure bill. That kind of smoke can be a real problem—whether the fire is accidental or ornamental. 

“A fireplace can be a problem, no question about it,” he says. “It depends on how well-vented the fireplace is. I live in Berkeley, where they ban wood-burning fireplaces in new homes, and there are days when you can’t burn due to the Bay Area Air Quality Management District’s concern about particulate levels.” He admits to having a fireplace but says he doesn’t use it. “Outdoor barbecues can be pretty nasty, too, if you’re using charcoal or wood. Propane is less polluting in terms of fine particulate—there is NO₂ generated, but it’s outside, so it’s diluted.” He doesn’t worry much about electric toasters—“unless you’re burning the shit out of the toast.” 

But any kind of smoky cooking is producing more particulate than non-smoky cooking—particulate matter is what smoke is. Broiling a steak indoors can raise the particulate level in your home—and so can using a feather duster. So can simply inviting people into your home. 

For cooking with gas, a good range hood can make a big difference, not only for the cooktop but also for the oven if it is underneath the range and doesn’t have its own ventilation to the outside. 

Speaking of which: A lot of this is a game of relative air pressures. If you live in an older house, even a nice one, it’s probably less airtight than a new house would be, owing to changes in the way we build. We create negative-pressure zones in our houses because we expel all sorts of air—range exhaust, bathroom fan, anything venting to the outside—but don’t always match that outgoing air with “dedicated makeup air,” to use the term of art in the trade. That’s how you end up sucking the fumes out of your attached garage into your living room or pulling outside air in through walls and roofs with all their chemicals and paints and solvents and sealants and insulation and such. Your problem probably isn’t a gas stove—it may be that your house is, essentially, a vacuum-cleaner of filth, which you don’t want it to be.

Unless you do. Seriously—there’s science involved in designing and building houses, but it is mainly an aesthetic exercise. Marble countertops sell a lot more houses than well-insulated attics do. If you have a family member with asthma or another breathing complaint, then your calculations will be different. And, sure, get a good range hood and make sure it ventilates to the outside rather than spewing that stuff back into your house. (Seems obvious, but you’d be surprised.) Maybe MERV up your filters, if that’s an option for you. Get the radon test. 

And then maybe have a drink next to a big, satisfying fire—it may not be good for the lungs, but it is great for the soul.