Pollution Alert tracks air quality in over 190 countries and territories and about a thousand of the world’s largest cities — free, in 10 languages, updated every day.
Every city and country page presents the current fine-dust concentrations PM2.5 and PM10, nitrogen dioxide (NO₂), ozone (O₃), sulphur dioxide (SO₂) and carbon monoxide (CO), with a history of recent days. On top of that you will find the UV index, pollen levels, sea temperature, a 16-day weather forecast, official weather warnings, nearby-city comparisons and daily rankings of the most and least polluted cities.
Air-quality values come from the Open-Meteo air-quality API based on the CAMS model (Copernicus Atmosphere Monitoring Service). They are model estimates for each city's coordinates — not readings from individual street stations — which lets us show fresh values for every city, every day. Weather, UV, pollen and sea temperature also come from Open-Meteo; official warnings from Meteoalarm (Europe) and the WMO (worldwide).
PM2.5 means fine particles below 2.5 microns that penetrate deep into the lungs. As a rule of thumb: up to 15 µg/m³ is good (the WHO 24-hour guideline), 15–40 is moderate, and above 40 sensitive groups should limit outdoor exertion.
The data is updated every day, early in the morning (Central European Time).
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