Daily Air Quality Index - DAQI

The Daily Air Quality Index - DAQI tells you about levels of air pollution. It also provides health advice in the form of recommended actions you may wish to take, according to the level of air pollution. The index is numbered 1-10 and divided into four bands, low (1) to very high (10), to provide detail about air pollution levels in a simple way. This system was recommended by the Committee on Medical Effects of Air Pollutants (COMEAP).

You should follow the 3 step method to use the index.

Defra applies the DAQI to its air quality forecasts to tell you what pollution levels are predicted to be the next day. The forecasts are provided to allow you to plan ahead and where relevant, take the recommended action to reduce the effects of air pollution. In addition, Defra's latest air pollution monitoring data are displayed using the same index and this tells you what pollution has been like.


Index Bands







Very High

The overall air pollution index for a site or region is determined by the highest concentration of five pollutants:

Nitrogen Dioxide
Sulphur Dioxide
Particles < 2.5µm (PM2.5)
Particles < 10µm (PM10)

How does the Air Quality Index link with Health Advice?