Air quality index for the UK’s largest cities.
About the air quality index
European Air Quality Index (EAQI)
The Daily Air Quality Index (DAQI), used by Defra and UK health agencies, is based on four pollutants: particulates PM2.5 and PM10, nitrogen dioxide (NO₂) and ozone (O₃). The scale runs 1–10: Low (1-3), Moderate (4-6), High (7-9) and Very high (10), with health advice for at-risk groups from the Moderate band upwards.