Ecocentricity Blog: Cooking With Gas, and Why We Probably Shouldn't Be

When it comes to food, we all have our opinions and preferences. But those opinions also extend to how we prepare our food. For some, the oven is their go-to. For others, food always tastes better when it’s hot off the grill. Air fryers seem to be the trendy thing right now, and they can make a surprisingly wide range of food types. Still others are happy with the instant convenience offered by the humble microwave. Nothing has quite the same place in the American kitchen, however, as the trusty stove. And from what I can tell, most people consider gas stoves to reign supreme.

Why Americans Love Their Gas Stoves

I have seen estimates that about 35-40% of Americans cook on gas stoves at home, and I’ll admit that you have to count me in that number (so in this respect, I am absolutely a slug calling a sloth slow). When we bought our home, that’s what it had in it, and we have grown quite accustomed to its benefits. It brings water to boil quickly, it burns at a consistent temperature, that temperature can be modified precisely, it cooks evenly, and that steady blue flame really has a nice hue to it. If the power goes out, you can still cook with a gas stove (and a match to ignite it).

But as you might have guessed, this is not a pro-gas blog. I’ve long known about the climate change concerns associated with gas stoves, and I’ll write more about those below. I’ve also known that burning natural gas presents some risk of carbon monoxide accumulation in homes. But I didn’t realize how far some of the climate and health concerns about residential natural gas extend.

The Byproducts of Burning Natural Gas

First, the science of natural gas (bear with me here!). There isn’t a precise chemical formula for natural gas, because it’s actually a mixture of several things. Mostly though, it consists of methane (CH4), a combustible hydrocarbon gas. Natural gas is colorless and odorless, which presents a problem since it lights on fire and we use it in our homes. That’s why natural gas providers tend to add a “rotten egg” smell to it, helping people detect when the gas is leaking.

Thanks to the handy-dandy first law of thermodynamics, we know that energy is conserved in a system. That means when we burn natural gas, the molecules in it don’t disappear. The chemical bonds are instead broken, releasing energy in the form of heat (duh) and resulting in the formation of other residual chemicals. Much like how wood logs leave ash behind after they burn, so too does natural gas leave other stuff behind. Also, the heat from the fire can cause chemical reactions to occur in the ambient air, generating additional byproducts. So what is the stuff that natural gas leaves behind?

The main thing is carbon dioxide (CO2). Burning natural gas definitely produces less of the stuff per unit of energy than burning oil and coal, but it’s still a major source of the primary greenhouse gas driving global warming. I’ve already mentioned that carbon monoxide (CO) is a byproduct, and if you end up with high levels of this gas, it is extremely dangerous to humans. Tiny bits of particulate matter and sulfur dioxide (SO2) can also result from burning gas. But the one I hadn’t heard much about until recently was nitrogen dioxide (NO2).

The Problem with Nitrogen Dioxide and Gas Stoves

I recently found this NPR article from last October to be very illuminating. In it, the journalist interviewed an environmental epidemiologist who conducted an experiment in his own home. He rented a NO2 monitor and measured the baseline concentration of the gas in the kitchen air (about 24 parts per billion, or ppb). Then he started baking some muffins and boiling water, to simulate a standard use of the natural gas stove and oven. After 12 minutes, NO2 measured in at 168 ppb. After 30 minutes, it measured 207 ppb.

So what’s the big deal with these numbers? I went looking for what the EPA says about nitrogen dioxide. The recommended standard not to be exceeded for one-hour of exposure to nitrogen dioxide is 100 ppb, which was definitely exceeded in the experiment. The EPA also states, “There continues to be strong scientific evidence indicating that short-term exposures to NO2 can worsen asthma symptoms in people with the disease. Some new evidence also supports an association between long-term NO2 exposures in children and the development of asthma.”

Hmmmmmm. I have young children. I also had asthma as a kid. Where’s the “dislike” button on this thing?

To be fair, the experiment from this NPR article is a single data point. Moreover, the epidemiologist’s home did not have a hood vent that could suck all of the byproducts from burning natural gas out of the home. There are safety mechanisms built into many gas stoves that can help mitigate this problem. If nothing else though, this shows the importance of properly venting your kitchen when cooking on a gas stove.

Methane Leaks Constantly: Quite the Escape Artist

The problems don’t stop there, however. I found another NPR article from a month ago, which profiled a new study out of Stanford on leaky natural gas appliances. On average, they found that appliances produce more emissions during the time they are off than the time they are on, mainly as a result of leaks from loose couplings and fittings. They estimated that 1.3% of natural gas piped into stoves is leaked into the atmosphere.

That’s exactly where we don’t want it. Since methane is the primary component of natural gas, and since methane is an extremely potent greenhouse gas, these leaks add up. The researchers extrapolated their findings to estimate that leaks from gas stoves in America add up to the global warming equivalent of the carbon dioxide from 500,000 gasoline-powered cars.

This leaking problem extends upstream as well. It turns out that methane doesn’t just want to escape the pipes in our homes and offices - it wants to escape everywhere, along the entire extraction/production/transportation supply chain. Especially at fracked natural gas wellheads, we can be sure that the extraction companies are not capturing all of the natural gas contained underground. A name has coalesced for such leaks - “fugitive gas emissions.” They are extremely hard to measure, but estimates seem to range from a leakage rate of 0.6% of total production on the low end to 9% on the high end.

Induction Cooktops: A Great Alternative to Gas Stoves

For my part, I’m committing to doing more cooking on an induction cooktop. Typical electric stoves take forever to heat up and don’t always cook food evenly, but magnetic induction solves those problems while still being entirely electric. If you are interested in learning more, here’s an informative Consumer Reports article about the pros and cons of induction cooking. Consider joining me. “Now we’re cooking with an electromagnetic field” has a nice ring to it, doesn’t it? Way better than, “Now we’re cooking with gas,” if you ask me.

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