How is AQI calculated?

We use an extrapolation model that converts densely populated individual sensor readings into 'geospatial raster data' (a picture of data displayed in pixels, like a digital photograph). A hyper-local resolution map that refreshes every five minutes.

As the pollution changes, so does the map. The following chart explains how we visualise the AQI levels according to its individual pollutant concentrations.

In real time, the dominant pollutant determines the relative value of the AQI. For historical levels, the AQI is weighted towards the prolonged existence of all four pollutants in that time period.