atmos.today is an independent live air quality tracker covering 217 cities across 108 countries. We surface the US EPA Air Quality Index (AQI 0 to 500) plus raw pollutant readings: PM2.5, PM10, ground-level ozone, NO2, SO2 and CO, refreshed every 30 minutes and licensed CC-BY-4.0. Use the free public JSON API to embed live AQI in your own apps, or check the most polluted and cleanest cities right now. See methodology for how readings are calculated.
GLOBAL VIEW
Browse by country
FAQ
Frequently asked
What is atmos.today?
atmos.today is a free independent live air quality tracker covering 217 cities across 108 countries. It surfaces the US EPA Air Quality Index (AQI 0 to 500) and pollutant readings for PM2.5, PM10, ground-level ozone, NO2, SO2 and CO, refreshed every 30 minutes. Free, open, no signup, with a public JSON API licensed CC-BY-4.0.
How is the AQI calculated?
atmos.today uses the US EPA breakpoint formula on the dominant pollutant, usually PM2.5. The result maps to the standard AQI categories: Good (0-50), Moderate (51-100), Unhealthy for Sensitive Groups (101-150), Unhealthy (151-200), Very Unhealthy (201-300), and Hazardous (301+).
How often does the data update?
Air quality readings refresh every 30 minutes via incremental static regeneration. Most city pages will show data less than 60 minutes old at any time.
Can I use the API for free?
Yes. The JSON API at /api/aqi is free, requires no authentication, has CORS open, and is licensed CC-BY-4.0. Use it for apps, dashboards, smart-home automation, or AI assistants. See /api/docs for examples.
How do I get email alerts?
Sign up at atmos.today/alerts, pick a city and a threshold (for example AQI greater than 150). atmos.today emails you when the city crosses the threshold. Free, no account required.
Is atmos.today the same as Atmos Energy or Dolby Atmos?
No. atmos.today is an independent open-data air quality platform. It is unrelated to Atmos Energy (NYSE:ATO natural gas utility), Atmos Magazine (atmos.earth climate journalism), Atmos Rewards (Alaska Airlines loyalty program), Dolby Atmos (audio technology), or Atmos USA (online retailer). See /disambiguation for full detail.
EMAIL ALERTS
Get notified when air goes bad
Set a threshold for any city. We email when AQI crosses it. No account needed.