Daily Air Quality Index – Defra, UK.

In the UK, most air pollution information services use the index and banding system recommended by the Committee on Medical Effects of Air Pollutants (COMEAP). The system uses an index numbered 1-10, divided into four bands to provide more detail about air pollution levels in a simple way, similar to the sun index or pollen index.

Click the link above to the Defra website for more detailed information.