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The health effects of air pollution

The Air Pollution Bandings and Index Points describe how air pollution may affect the health of sensitive people. For more information read the free leaflet Air Pollution - What it means for your health, which is available on the Defra website.

The Air Pollution Bandings and Index Points

Banding	Index	Health Effects
Low	1	Effects are unlikely to be noticed even by individuals who know they are sensitive to air pollutants
	2
	3
Moderate	4	Mild effects, unlikely to require action, may be noticed amongst sensitive individuals.
	5
	6
High	7	Significant effects may be noticed by sensitive individuals and action to avoid or reduce these effects may be needed (e.g. reducing exposure by spending less time in polluted areas outdoors). Asthmatics will find that their 'reliever' inhaler is likely to reverse the effects on the lung.
	8
	9
Very High	10	The effects on sensitive individuals described for 'High' levels of pollution may worsen.

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 UK Air Quality Archive website (opens in new window).

Band	Index	Carbon monoxide (CO)	Nitrogen dioxide (NO2)	Ozone (O3)	PM10 Particulate matter (Grav Eq) (PM10)	Sulphur dioxide (SO2)
		8 hourly mean	Hourly mean	8 hourly or hourly mean*	Running 24 hour mean	15 minute mean
		mg/m3	µg/m3	µg/m3	µg/m3 (TEOM FDMS)	µg/m3
Low	1	0 - 3.8	0 - 95	0 - 33	0 - 19	0 - 88
Low	2	3.9 - 7.6	96 - 190	34 - 65	22 - 42	89 - 176
Low	3	7.7 - 11.5	191 - 286	66 - 99	41 - 62	177 - 265
Moderate	4	11.6 - 13.4	287 - 381	100 - 125	65 - 74	266 - 354
Moderate	5	13.5 - 15.4	382 - 477	126 - 153	75 - 86	355 - 442
Moderate	6	15.5 - 17.3	478 - 572	154 - 179	85 - 94	443 - 531
High	7	17.4 - 19.2	573 - 635	180 - 239	97 - 107	532 - 708
High	8	19.3 - 21.2	636 - 700	240 - 299	108 - 118	709 - 886
High	9	21.3 - 23.1	701 - 763	300 - 359	119 - 129	887 - 1063
Very High	10	23.2 or higher	764 or higher	360 or higher	130 or higher	1064 or higher

* For ozone, the maximum of the 8 hourly and hourly mean is used to calculate the index value.

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.