Get an alert when your city turns
We’re collecting signups, not sending yet
US law (CAN-SPAM) requires a physical mailing address in every commercial email, and this project doesn’t have one to publish yet. Rather than send you something non-compliant, or pretend the list is live, we hold your signup until it is. You’ll get one email when alerts start — and nothing before that.
Your city crosses your number at some point this year. The only question: do you hear about it before you smell it, or after?
Alerts are not being sent yet. Signups are open and held; the first email goes out when sending starts, and nothing before it. Everything below describes the alert that list is waiting for.
Pick your number, not the site’s
Pick the profile closest to you at signup: asthma sits near 60, parent near 100, runner near 110. Or skip the presets and set your own number. An asthmatic and a runner respond to identical air about 80% apart — that gap is the two community-reported cutoffs below, 60 against 110, not a clinical finding.
Several runners and asthmatics who track their own numbers also drop that cutoff by roughly one EPA band. That happens once the cause is smoke, not ordinary pollution.
What will the alert say?
It will name the cause behind the number, not just the number — the dominant pollutant is already in every hourly reading this site takes. Denver crossing AQI 100 usually means wildfire smoke and ground-level ozone stacking together — a “double whammy,” per one widely-upvoted r/Denver post. Seattle crossing the same 100 usually means smoke alone. The bare number can’t tell the two apart; the message is meant to.
Denver’s “double whammy” is wildfire PM2.5 drifting in combined with ground-level ozone cooked out of traffic and industry, the city sitting in a bowl of both at once. Seattle’s number usually means smoke, and on the days the sky looks worse than the number, it’s smoke still sitting aloft, above the monitor.
How is an alert different from checking the map?
The map answers when you look at it; an alert answers when it matters. The live map shows every metro’s current reading the moment you open it, but only then. An alert speaks once, the moment a chosen threshold in a chosen city is crossed, so nobody has to keep checking. Readings come from EPA AirNow through this project’s own hourly pipeline.
This site does not forecast. It reports the reading now and keeps a record of the readings before it; for the days ahead, AirNow’s own forecast is the agency source, and wildfire smoke covers how far out a smoke forecast can honestly be trusted.
What will trigger an alert?
Once sending starts, an alert fires when a tracked city crosses the number set for it. Nothing runs on a fixed schedule. Nothing arrives because a day was quiet. Track more than one city — work, family, travel, whatever crosses more than one place. Each city keeps its own threshold. No promised delivery window, no subscriber count to advertise — just a trigger tied to the number someone picked.
Why this matters more than it sounds
An alert closes the gap between buying mid-emergency and buying ahead. One r/AirPurifiers shopper, November 2024, bought an air purifier with the air already stinging and the store’s selection picked over. A r/Portland poster, months ahead in March 2023, urged buying “now instead of waiting until July and panicking because they’re all sold out.”
An alert is the gap between those two people. One bought at the worst possible moment. The other already knew.
Signup checklist
- Threshold crossings for the cities picked, at the number set. Nothing else.
- No address gets sold or rented to anyone.
- One click to unsubscribe. No account, no phone call, no form.
Data-handling detail lives on the privacy page, not repeated here. Find a city on the state-grouped index, or check what each AQI band means on the scale decoder first.