The Daily Air Quality Index (DAQI) tells you about levels of air pollution and provides recommended actions and health advice. 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, similar to the sun index or pollen index.

Index and Bands
Health Advice
How to use the Daily Air Quality Index
Boundaries Between Index Points for Each Pollutant

Index and Bands

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

1-3 (Low)
4-6 (Moderate)
7-9 (High)
10 (Very High)

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

Nitrogen Dioxide
Sulphur Dioxide
Ozone
Particles PM_2.5
Particles < 10µm (PM₁₀)

For more information about the boundaries between index points for each pollutant, visit the Defra UK-AIR Daily Air Quality Index page.

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Health Advice

Latest studies report that:

When air pollution is LOW (1-3) effects are unlikely to be noticed even by those who are sensitive to air pollution.
When air pollution is MODERATE (4-6) sensitive people may notice mild effects but these are unlikely to need action.
When air pollution is HIGH (7-9) sensitive people may notice significant effects and may need to take action.
When air pollution is VERY HIGH (10) effects on sensitive people, described for HIGH pollution, may worsen.

Air pollution can cause short-term health effects to sensitive individuals (people who suffer from heart disease or lung diseases, including asthma). Effects on sensitive people can be reduced by spending less time outdoors. 'Reliever' inhalers should lessen effects on asthma sufferers.

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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 on the Additional information on the short-term effects of air pollution page on the Defra UK-AIR website. Your doctor may also be able to give you advice.

Step 2: If you may be at-risk, and are planning strenuous activity outdoors, check the air pollution forecast 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 groups and the general population
Air Pollution Banding	Value	At-risk individuals*	General population
Low	1-3	Enjoy your usual outdoor activities.	Enjoy your usual outdoor activities.
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.

* Adults and children with heart or lung problems are at greater risk of symptoms. Follow your doctor's usual advice about exercising and managing your condition. It is possible that very sensitive individuals may experience health effects even on Low air pollution days. Anyone experiencing symptoms should follow the guidance provided on the Defra UK-AIR website.

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Boundaries Between Index Points for Each Pollutant

Band	Index	Ozone Running 8 hourly mean	Nitrogen Dioxide Hourly Mean	Sulphur Dioxide 15 Minute Mean	PM_2.5 Particles 24 Hour Running Mean	PM₁₀ Particles 24 Hour Running Mean
Band	Index			µgm^-3	µgm^-3	µgm^-3	µgm^-3	µgm^-3
Low
	1	0-33	0-67	0-88	0-11	0-16
	2	34-66	68-134	89-177	12-23	17-33
	3	67-100	135-200	178-266	24-35	34-50
Moderate
	4	101-120	201-267	267-354	36-41	51-58
	5	121-140	268-334	355-443	42-47	59-66
	6	141-160	335-400	444-532	48-53	67-75
High
	7	161-187	401-467	533-710	54-58	76-83
	8	188-213	468-534	711-887	59-64	84-91
	9	214-240	535-600	888-1064	65-70	92-100
Very High
	10	241 or more	601 or more	1065 or more	71 or more	101 or more

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Probability