3. Healthy Cooking
When it comes to kitchen stoves, you have to pick your poison
It was my turn last night to cook dinner. I wasn’t feeling adventurous, and settled on pesto pasta - a family favorite. I’m happy to report that no one was injured.
A recent NPR story on indoor air quality was widely promoted this week on the health risks of gas stoves for domestic cooking. A reporter used air pollution monitoring equipment to measure concentration of gases in the home of an environmental epidemiologist. The main conclusion was that burning natural gas from your stove leads to degraded indoor air quality, particularly with increases of nitrogen dioxide, a harmful gas that causes inflamed airways, aggravates asthma, and probably leads to other important health effects.
All of this is true. But the story misses the mark in a few important areas.
Good Science from Good Measurements
Collecting measurements of pollutants, even with the best measurement equipment, needs to be very intentional. While it might seem appealing and convenient to rent an instrument, scientists are very careful where they choose to place equipment in a location, make informed decisions on what equipment is most useful to the question they are trying to address, and figure out if that equipment is working as intended.
It is difficult to gauge where the reporter in this piece took their measurements. But based on the photo in the story, if it was immediately adjacent to the stove, I’m surprised the concentrations were so low. Directly measuring a source is measuring only that source, and doesn’t allow us to understand whether that source posed a public health risk. Even in a perfectly ventilated home, a gas stove would still emit these pollutants if you were measuring only the source.
If there was a science do-over, I would choose to measure away from an immediate source like a stove, and in a location where people congregate. The kitchen table would probably be my first choice. And I would want to measure well before, during and well after stove use. This tells me a lot more about whether the room is ventilated than measuring just above a lit burner.
The selection of the right measurement equipment is also important. The device used in this piece appears to be an Aeroqual Series 200 sensor, configured for NO2 monitoring using a technology known as a electrochemical sensor. The manufacturer states that this version of instrument has a precision of +/- 20 ppb, meaning that the concentration the instrument is reporting might be higher or lower than what is reported on the screen by 20 ppb. Certainly not bad, but not great. But more worrisome is that even the vendor doesn’t recommend this device for use in indoor air quality applications. It’s just not sensitive enough for this type of short term use.
So do these limitations change the storyline that the use of natural gas for cooking leads to potentially hazardous conditions? No, it is still very much a risk. But it does provide enough holes for the gas industry to, once again, downplay its conclusions and sow more doubt and uncertainty.
The Risks are Real
Don’t get me wrong - I’m no advocate for the natural gas or stove industry. While I use a gas stove at home, I dislike the climate consequences of its use. I use a direct-vent, over-the-stove kitchen fan to remove the inevitable gases and particles that are formed when cooking. And I take seriously WHO indoor air quality standards for NO2, and lament that the US EPA doesn’t have similar guidelines.
And I agree that there is a health risk to using any combustion source indoors. Dr. Kephart, the subject of the NPR article, is exactly right when he notes of his concern for his children.
"It doesn't make any sense to me to add to the risk of them developing asthma or other respiratory diseases by having this source of pollution right inside our house”.
Social media response to this story was strong, with plenty of able people (read: wealthy) gloating about having previously switched to pricey induction stoves and, therefore, cooking with less risk to health or climate. But not everyone can be so fortunate.
So here’s the challenge: gas almost certainly increases risk to health and contributes to climate change, but there remains a huge economic barrier to making a switch. From the installation of new wiring to purchasing the stove itself, it remains impossible to make the switch for millions of homes. So many are stuck with stoves that continue to pose risk.
Surely government incentive programs would help, but is this how we should prioritize spending? That’s a political decision that is well outside of my lane. But count me in. There is no dispute that there are both health and climate impacts with the continued use of gas stoves and we have to work towards moving away from these fuels.
We must also realize that justifying these policy changes requires political will and sound and defensible science. And a recognition that this will be harder to do than expected because there are powerful industry-funded headwinds approaching. So we have to make sure we’ve done our homework correctly.
For today’s lunch, I brought leftover pesto. I think I’ll microwave it.