How Bands Are Calculated
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
- Carbon Monoxide
- Particles < 10µm (PM10) [Please note only TEOM data can be used for particulate bandings]
Air Pollution Forecasts
Air Quality Forecasts are issued on a regional basis for three different area types:
- In towns and cities near busy roads
- Elsewhere in towns and cities
- In rural areas
Forecasts are based on the prediction of air pollution index for the worst-case of the five pollutants listed above, for each region.
Table Summary
The table below provides an explanation to the bands and colours used to represent the air quality and air pollution levels.
| Band | Index | Ozone | Nitrogen Dioxide | Sulphur Dioxide | Carbon Monoxide | PM10 Particles | |||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Running 8 hourly or hourly mean* | hourly mean | 15 minute mean | Running 8 hourly mean | Running 24 hour mean | |||||||
| µgm-3 | ppb | µgm-3 | ppb | µgm-3 | ppb | mgm-3 | ppm | µgm-3 (Grav. Equiv.) |
µgm-3 (TEOM) |
||
| Low | |||||||||||
| 1 | 0-33 | 0-16 | 0-95 | 0-49 | 0-88 | 0-32 | 0-3.8 | 0.0-3.2 | 0-21 | 0-16 | |
| 2 | 34-65 | 17-32 | 96-190 | 50-99 | 89-176 | 33-66 | 3.9-7.6 | 3.3-6.6 | 22-42 | 17-32 | |
| 3 | 66-99 | 33-49 | 191-286 | 100-149 | 177-265 | 67-99 | 7.7-11.5 | 6.7-9.9 | 43-64 | 33-49 | |
| Moderate | |||||||||||
| 4 | 100-125 | 50-62 | 287-381 | 150-199 | 266-354 | 100-132 | 11.6-13.4 | 10.0-11.5 | 65-74 | 50-57 | |
| 5 | 126-153 | 63-76 | 382-477 | 200-249 | 355-442 | 133-166 | 13.5-15.4 | 11.6-13.2 | 75-86 | 58-66 | |
| 6 | 154-179 | 77-89 | 478-572 | 250-299 | 443-531 | 167-199 | 15.5-17.3 | 13.3-14.9 | 87-96 | 67-74 | |
| High | |||||||||||
| 7 | 180-239 | 90-119 | 573-635 | 300-332 | 532-708 | 200-266 | 17.4-19.2 | 15.0-16.5 | 97-107 | 75-82 | |
| 8 | 240-299 | 120-149 | 636-700 | 333-366 | 709-886 | 267-332 | 19.3-21.2 | 16.6-18.2 | 108-118 | 83-91 | |
| 9 | 300-359 | 150-179 | 701-763 | 367-399 | 887-1063 | 333-399 | 21.3-23.1 | 18.3-19.9 | 119-129 | 92-99 | |
| Very High | |||||||||||
| 10 | 360 or more |
180 or more |
764 or more |
400 or more |
1064 or more |
400 or more |
23.2 or more |
20 or more |
130 or more |
100 or more |
|
* For ozone, the maximum of the 8 hourly and hourly mean is used to calculate the index value.
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