My co-founder Jennifer has asthma, and the two of us have lived through years of wildfire seasons in Sonoma County, seasons that put real pressure on our family. The question we kept coming back to was simple: is the air outside safe right now, or not.
The tools that were supposed to answer that question didn't. AirNow gave us the county's official number, a day behind and averaged over 24 hours. PurpleAir gave us a live reading from a sensor down the block, with no context attached, so figuring out what to do was left to us. I wrote about that exact gap in an earlier post: the government number and the neighborhood number can both be correct and still leave you standing in the driveway, unsure.
Canairy is the app we built to close that gap. It's live now, free, on iOS and Android.
What Canairy shows you
Canairy pulls from PurpleAir's sensor network, government monitors, and the Google Air Quality API, then folds all three into one plain-English verdict for each place you care about — home, or a kid's school. You can watch the trend for each location over the day and set push alerts before the air turns.
Building it meant deciding that a raw number isn't useful on its own, then building the translation layer that turns parts-per-million and 24-hour averages into something closer to "it's fine, go outside" or "keep the windows shut this afternoon."
Canairy also shows a pollen forecast for your location, read at a glance instead of buried in a weather app you have to dig through.
The trend view matters as much as the current reading. A single AQI number tells you nothing about direction. Canairy shows whether a location is clearing up or getting worse over the day, which is usually the more useful question when you're deciding whether to reschedule a kid's soccer practice or just wait an hour.
Why we built it this way
Jennifer spent 12 years in regulated industries before Canairy. I'd spent the years before that working with wineries, where the same problem shows up constantly: good data that nobody translates for the person who has to act on it under pressure. Canairy is that lesson applied to something more personal than a spreadsheet.
Jennifer led product and design. I built the engineering underneath it, including the systems that turn raw sensor readings into the plain-English verdict you see on the screen. Neither of those jobs works without the other — a well-designed screen showing a number nobody can interpret is just a prettier version of the same problem we started with.
We wanted something a parent could glance at from the kitchen counter and act on. Canairy answers one question — is the air where you are, or where your kid is, okay right now — and gets out of the way once it has.
Free, on both platforms
Canairy is free to download on Google Play and the App Store, with one location tracked at no cost. Paid Plus and Pro tiers add more locations and SMS alerts, plus faster refresh, for households that want them, but the core app costs nothing to start.
The sensor network runs everywhere PurpleAir and government monitors report, so Canairy works outside California too. If you're somewhere with a real wildfire season, it's worth putting on your phone before the next smoke event shows up.
Alongside the app, we built a library of plain-language guides on pollutants, protection steps, and what the research says, for anyone who wants more than a single verdict on a given day. You can read those, and more about the app itself, at canairy-aq.com.