Daily Air Quality Index (DAQI)

The Daily Air Quality Index (DAQI) is used to describe and communicate the current and/or forecast levels of air pollution in the UK. It has been approved by the Committee on Medical Effects of Air Pollution (COMEAP).

The air pollutant indices range from 1 to 10 and are calculated for each pollutant based on its concentration over a specific period of time. The air pollutants used to calculate the DAQI are nitrogen dioxide (NO₂), sulphur dioxide (SO₂), ozone (O₃), particles <10 um (PM10) and particles <2.5 um (PM_2.5). The pollutant that has the highest air quality index is reported as the DAQI for the site or region.

The table below shows the air pollution categories associated to the reported DAQI alongside the accompanying health messages for the general population.

How to use the Daily Air Quality Index

Step 1

Determine whether you (or your children) are likely to be at risk from air pollution. Information on groups who may be affected is provided in the Health Advice section. Your doctor may also be able to give you advice.

Step 2

If you are at-risk, and are planning strenuous activity outdoors, check the air pollution regional forecast on the Home page.

Step 3

Use the health messages corresponding to the highest forecast level of pollution as a guide.

Air Pollution Banding	Value	Accompanying health messages for at-risk individuals*	Accompanying health messages for the general population
Low	1-3	Enjoy	Enjoy
Moderate	4-6	Adults and children with lung problems, and adults with heart problems, who experience symptoms, should consider reducing strenuous physical activity, particularly outdoors.	Enjoy your usual outdoor activities.
High	7-9	Adults and children with lung problems, and adults with heart problems, should reduce strenuous physical exertion, particularly outdoors, and particularly if they experience symptoms. People with asthma may find they need to use their reliever inhaler more often. Older people should also reduce physical exertion.	Anyone experiencing discomfort such as sore eyes, cough or sore throat should consider reducing activity, particularly outdoors.
Very High	10	Adults and children with lung problems, adults with heart problems, and older people, should avoid strenuous physical activity. People with asthma may find they need to use their reliever inhaler more often.	Reduce physical exertion, particularly outdoors, especially if you experience symptoms such as cough or sore throat.

* It is important to note children and adults with pre-existing health conditions are at greater risk of health symptoms caused by air pollution. It is possible that very sensitive individuals may experience health effects even on Low air pollution days.

The air pollution categories and indices by air pollutant