Are electric stoves better for our health than gas stoves? Which are better for the environment?
Gas stoves are often the gold standard for serious home cooks, including bakers, who want a more professional, high-end kitchen. But some studies, including a recent one published in Environmental Science & Technology, note that natural gas stoves, cooktops and ovens tend to leak gases — even when not in use — that can build up in the home and possibly cause health problems. Further, gas stoves release into the outdoor environment some levels of gases, such as carbon dioxide and methane, that are associated with climate change.
How much harm could they cause, compared with electric stovetops and ovens? We asked Michael Bisesi, PhD, CIH, a scientist who’s studied the effects of environmental and job-related effects on our health for more than 40 years. Bisesi also serves as vice dean for Academic Affairs and Academic Administration, and professor and interim chair of Environmental Health Sciences in The Ohio State University College of Public Health.
- Question What do we know about how gas stoves/ovens can negatively affect air quality in the home, when compared with electric?
With gas cooking, as compared with electric cooking, more chemical combustion products are being released into your home. This is because of the way heat is generated with gas — there’s ignition and a visible flame, which represents the combustion (burning) of the organic fuel (gas) right there in the home. With electric cooking, the combustion happens far away, at a power plant or some other offsite energy source, to create the energy that generates heat.
When combustion occurs in your home, more products of that combustion — ultrafine particulate matter and gases such as methane, harmful nitrogen oxides or even deadly carbon monoxide — are released into the indoor air if the gas appliance isn’t ventilated properly.
The leakage that’s been detected in some gas stoves/ovens can happen wherever there’s a natural gas utility connection in the home, sometimes at the stovetop or oven itself. Older appliances that aren’t as well-maintained may have undetected or slow gas leakage, and gas combustion when cooking or baking may be less efficient. Without proper local exhaust ventilation, such as a kitchen exhaust fan, or sufficient overall general ventilation, ultrafine particulate matter and harmful gases may accumulate.
- Question What can we do to prevent the buildup of these gases or combustion products? Should we go all-electric in our cooking?
The best way to prevent harmful gases or contaminants from accumulating in the air you breathe at home is to make sure your home is well-ventilated. Many kitchens these days have just a microwave and fan over the stovetop, and that doesn’t necessarily do a good job of taking contaminants outside. What’s best is a local exhaust fan, such as an over-the-range hood that, when operating, ventilates contaminated air out of the room and exhausts it outdoors. A local exhaust fan in kitchens, combined with the optimization of a home’s general ventilation, will contribute substantially to keeping gas stove/oven combustion products from accumulating to potentially harmful concentrations indoors.
Well-maintained equipment also can contribute to a safer home cooking environment. Maintenance to ensure these appliances have as few leaks as possible is often done by the manufacturer, but there are also services than can make sure your stove/oven is adjusted optimally to have the most efficient output. One quick check, if your stove/oven has a visible flame, is to check the flame’s color. If it’s more yellow, that means it’s less efficient and may produce higher levels of combustion products. The bluer the flame, the hotter and more efficient it will be while cooking.
But it’s not just gas versus electric cooking that influences how much particulate matter and gaseous contaminants are generated and accumulate in air. It’s also what you’re cooking and how frequently you’re cooking. If you’re boiling eggs every morning, that’s going to produce fewer products in the air than frying bacon every day. This is because food, which is composed of organic matter, changes during cooking as the temperature increases and results in release of similar combustion products in the form of airborne gases and particulate matter.
So, are there more contaminants generated from a gas stove than an electric one? Yes. Does that increase the potential for hazard? Yes. But are there things we can do to reduce those hazards, other than replacing our gas stoves? Yes.
While not everyone can afford to replace their cooking appliances right away or retrofit their kitchens, we can all take reasonable, practical steps to protect our health and the environment.
- Question What do these airborne particulate and gas products potentially do to our health?
In general, certain particulate and gaseous contaminants released into the air can contribute to increased exposure when inhaled at higher concentrations and/or for prolonged periods over time. For some people, inhalation of these contaminants can aggravate symptoms of allergies; chronic lung diseases, such as asthma and cystic fibrosis; and chronic obstructive pulmonary disease (COPD), which includes emphysema and chronic bronchitis. Excessive exposure to the contaminants can also help initiate other health conditions.
Nitrogen oxide gases — like those detected leaking from gas stoves in some studies — also can irritate the respiratory system in high concentrations, further aggravating lung conditions. These gases also affect the environment by contributing to acid rain and other atmospheric pollution.
Methane gas from gas stoves doesn’t directly expose the user and is not associated with any specific health concerns. However, it’s a contributor to climate change. Methane is more than 25 times as potent as the carbon dioxide emissions that come from our cars, even though it’s more short-lived than carbon dioxide. That’s why the EPA and other environmental organizations have prioritized reductions in methane emissions — concentrations of methane over the years have swiftly multiplied, but because it’s so potent and simultaneously short-lived, reducing methane could have a big effect on reducing global warming. The recent study of gases leaking from gas-fueled stoves noted the release of methane even when the stoves aren’t being used.
Carbon monoxide gas, similar to the creation of smoke and particulate matter, results from incomplete or inefficient gas fuel combustion. When generated through the burning of natural gas, carbon monoxide, like other contaminants mentioned, may accumulate in rooms with inadequate ventilation. Unlike the other contaminants, excessive accumulation and concentrations of the odorless carbon monoxide can contribute to carbon monoxide poisoning and even become deadly within hours.
Particulate matter from combustion consists mainly of various carbon-based products and may contribute to short-term irritation of the respiratory system and a range of other potential inflammatory impacts. The main contributor to the generation of particulate matter during cooking/baking is smoke. Toxicity hazard is influenced by both the chemistry of the particulate matter and the size of the particles, which are measured in microns. (One micron is about 1/25,000th of an inch.) Particulate matter less than 10 microns in diameter is more able to be breathed into the lungs. Even smaller sizes (for example, less than 2.5 microns) can travel even deeper into the respiratory system. Ultrafine particulate matter (smaller than 1.0 micron) can potentially move from the lungs into the general circulation.
- Question Are electric stoves/ovens better overall for the environment, contributing less to climate change?
This is tough to say, because so many factors could be involved. Separate from the emissions from cooking or baking, gas stoves contribute to more overall combustion products and leaking emissions. This includes release of some methane and carbon dioxide into the air, which may contribute to outdoor environmental levels associated with causing climate change. But if you have an electric oven, where is the energy source coming from to create that electricity, and what type of power was used to make the electric appliance in the first place? In many cases, the sources of electrical energy for electric stoves are coal-fueled power plants. Processes used at these plants generate the same potentially harmful emissions. So, if your electric power is being generated from a coal power plant, for example, it’s hard to say exactly how much the environment will benefit if you replace a gas stove/oven with an electric one.
We do know that, overall, electric stoves directly generate lower levels of airborne contaminants. This reduces a potential exposure hazard and associated health risk. If you’re replacing your stove/oven anyway, electric is likely a better choice both for better indoor air quality and the general environment. But we do have tools, such as adequate local and general indoor ventilation, to help reduce the hazardous emissions from gas stoves/ovens, so this isn’t all doom-and-gloom for owners of these appliances.