The health effects of air pollution

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.
• Step 3: Use the health messages corresponding to the highest forecast level of pollution as a guide.

The Air Pollution Bandings and Index Points

Air Pollution Banding	Value	Accompanying health messages for at-risk groups and the general population
		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 Additional information on the short-term effects of air pollution provided on the Defra UK-AIR website.

Boundaries Between Index Points for Each Pollutant

The table below shows the boundaries between each index points for common pollutants measured. For more further details about this information, please visit the standards information on the on the Defra UK-AIR website (opens in new window).

Band	Index	Nitrogen dioxide (NO2)	Ozone (O3)	PM10 Particulate matter (PM10)	PM2.5 Particulate matter (PM25)	Sulphur dioxide (SO2)
		Hourly mean	8 hourly or hourly mean	Running 24 hour mean		15 minute mean
		µg/m3	µg/m3	µg/m3 (TEOM FDMS)	µg/m3	µg/m3
Low	1	0 - 66	0 - 33	0 - 16	0 - 11	0 - 88
Low	2	67 - 133	34 - 65	17 - 33	12 - 23	89 - 176
Low	3	134 - 199	66 - 99	34 - 49	24 - 34	177 - 265
Moderate	4	200 - 267	100 - 120	50 - 58	35 - 41	266 - 354
Moderate	5	268 - 334	121 - 140	59 - 66	42 - 46	355 - 442
Moderate	6	335 - 399	141 - 159	67 - 74	47 - 52	443 - 531
High	7	400 - 467	160 - 187	75 - 83	53 - 58	532 - 708
High	8	468 - 534	188 - 213	84 - 91	59 - 64	709 - 886
High	9	535 - 599	214 - 239	92 - 99	65 - 69	887 - 1063
Very High	10	600 or higher	240 or higher	100 or higher	70 or higher	1064 or higher

Monitoring Site Environments

The table below shows the typical types of environmental that air pollution monitoring stations are located. A brief description for each one is provided.

Location Type	Description
Rural	An open countryside location, in an area of low population density distanced as far as possible from roads, populated and industrial areas.
Kerbside	A site sampling within 1m of the kerb of a busy road.
Remote	A site in open country, located in an isolated rural area, experiencing regional background pollutant concentrations for much of the time.
Roadside	A site sampling between 1m of the kerbside of a busy road and the back of the pavement. Typically this will be within 5m of the road, but could be up to 15m.
Suburban	A location type situated in a residential area on the outskirts of a town or city.
Urban Background	An urban location distanced from sources and therefore broadly representative of city-wide background conditions e.g. urban residential areas.
Urban Centre	An urban location representative of typical population exposure in towns or city centres e.g. pedestrian precincts and shopping areas.
Urban Industrial	An area where industrial sources make an important contribution to the total pollution burden. Intermediate. 20-30m from the kerb of a busy road.
Intermediate	20-30m from the kerb of a busy road
Airport	Monitoring within the boundary of an airport perimeter.
Other	Any special source-orientated or location category covering monitoring undertaken in relation to specific emission sources such as power stations, car parks or tunnels.