Real-Time Air Quality Index
Pollutant concentrations come from Open-Meteo in µg/m³, and the index is calculated from them rather than the other way round. Where a station network reading is the only thing available, WAQI fills the gap.
PM2.5
Fine particles under 2.5µm, small enough to reach deep into the lungs
PM10
Coarse particles under 10µm: dust, pollen and mould
O₃
Ground-level ozone, formed when sunlight meets other pollutants
NO₂
Nitrogen dioxide, mostly from traffic and combustion
SO₂
Sulphur dioxide, mostly from industry and power plants
CO
Carbon monoxide, from incomplete combustion
AQI Scale (US EPA)
Weather Data
Weather comes from Open-Meteo, which aggregates national meteorological models and gives temperature, humidity, wind, pressure and conditions for any coordinate in the world.
UV index is cloud-adjusted rather than a clear-sky figure, and visibility is taken from the same hourly series. Weather and air quality are fetched in parallel on every page load.
Data Sources
Open-Meteo
Weather, UV and visibility, plus pollutant concentrations in µg/m³ and the US AQI derived from them
CAMS
Per-species pollen forecasts for Europe, through Open-Meteo's air quality API
WAQI
Ground-station index, used as a fallback when modelled data is unavailable
OpenWeather
Secondary fallback for pollutant concentrations
Geoapify
Turning coordinates into a street and city name
Supabase
Accounts and saved reading history
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