Every other Friday, the Outside/In team answers one listener question about the natural world.
This week's question comes from Ingrid in Newmarket, N.H., after she got a curious weather alert during a January snowstorm.
"I looked at my phone’s weather app to see when there might be a break to see when I might time my shoveling. Out popped an air quality alert of 'dangerous carbon monoxide levels.' Was it because it was so cold that morning that everyone’s furnace was blowing more carbon monoxide in the outside air?"
Producer Marina Henke looked into it.
This has been lightly edited for clarity.
Marina Henke: A few weeks ago, I sent off an email to the New Hampshire Department of Environmental Services, asking for help.
Kathleen Simmons: My name is Kathleen Simmons. I work with the New Hampshire Department of Environmental Services.
Marina Henke: Kathleen Simmons was all in. Think of her as a weather forecaster, but for air quality. Kathleen pulled up the carbon monoxide levels from January 26th, the day of Ingrid’s worrisome alert. This data came from the Londonderry monitoring station, about 25 miles away, but the closest sensor to where Ingrid lives in Newmarket.
Kathleen Simmons: And the data didn't really show anything substantial. The highest it got for an hourly reading was 0.4 ppm.
Marina Henke: For context, that’s way lower than what the EPA would consider a dangerous level of hourly outdoor carbon monoxide: which is anything over 35 ppm. So why was Ingrid’s weather app saying the levels were dangerous? Carbon monoxide can accumulate outdoors, but it happens in pretty specific areas…
Kathleen Simmons: Like say you're right next to the tailpipe of a car or you're near a power plant or something.
Marina Henke: For that reason, Kathleen wasn’t so sure about Ingrid’s furnace hypothesis. Even with a ton of people heating their homes, exhaust dissipates quickly once it hits the outdoors. Undeterred, she looked at the rest of the day’s weather report. Maybe Ingrid had been confusing carbon monoxide with another air quality metric, like particulate matter, which can rise in the winter due to wood stoves.
Kathleen Simmons: But overall, I'd say it seems pretty typical for winter time.
Marina Henke: Once she’d seen this, Kathleen formed a hypothesis. Ingrid’s weather app was just plain wrong.
Kathleen Simmons: Sometimes we see those discrepancies because these apps and phones are just pulling from everything.
Marina Henke: This includes the state’s data, but they can also pull from low cost sensors that anyone can install outside their homes.
Kathleen Simmons: For the most part, a lot of this data, when someone's buying a sensor is publicly available.
Marina Henke: Weather app companies take advantage of this data, and it opens them up to a lot of user error. People might set up their sensors next to a vent, too close to the ground… all kinds of things.
Kathleen Simmons: Whereas we have an entire team going out to our very robust, very expensive monitoring equipment.
Marina Henke: And even when the apps use data gathered by this fancy equipment, mistakes can still happen.
Kathleen Simmons: One time someone reached out to me and they had something on their phone. They showed just apocalyptic values of carbon monoxide.
Marina Henke: But, there was no apocalypse. That morning the state’s carbon monoxide monitor in Peterborough had malfunctioned. Kathleen’s team had already flagged the mistake and removed any incorrect data.
Kathleen Simmons: But some of these apps or companies, they don't see that and it shows a completely different story to the people in that area.
Marina Henke: So we can’t be sure, but it seems likely that on January 26th a low-cost sensor snuck in some bad data to a weather app or incorrect state data slid in before Kathleen’s team corrected it. With this unpredictability in mind, Kathleen has some simple advice for weather-app checkers.
Kathleen Simmons: So I would just advise to check the regulatory network before getting worried or concerned. We have a web page that has all of our live hourly readings on it. But of course, we're always happy to check on things for people and, and look into it further.
Marina Henke: To check out that webpage you can go to www.airnow.gov.
If you’d like to submit a question to the Outside/In team, you can record it as a voice memo on your smartphone and send it to outsidein@nhpr.org. You can also leave a message on our hotline, 1-844-GO-OTTER.
