Air Quality Bandings
The Department of the Environment Food and Rural Affairs (DEFRA), Air Pollution Information Service has divided levels of air pollution into four bands that categorise their health impacts. The bands are: low, moderate, high and very high. Healthy people do not normally notice any effects from air pollution, except when air pollution is 'very high'.
| Low | Effects are unlikely to be noticed, even by people who know they are sensitive to air pollutants. |
| Moderate | Mild effects are unlikely to require action, but may be noticed by sensitive people. |
| High | Sensitive people may notice significant effects, and may have to take action to reduce or avoid them (for example, by reducing the time spent outdoors). Asthmatics will find that their reliever inhaler is likely to reverse the effects of pollution on their lungs. |
| Very High | The effects on sensitive people, described for 'high' levels of pollution, may worsen. |
| Pollutant | Pollutant Band |
| Low | Moderate | High | Very High |
| | | |
| Sulphur Dioxide | <110 | 100 - 199 | 200 - 399 | ≥ 400 |
| Parts per billion (ppb) 15 min averages |
| Ozone | <50 | 50 - 89 | 90 - 179 | ≥ 180 |
| ppb, hourly or 8 hour running average |
| Carbon Monoxide | <10 | 10 - 14 | 15 - 19 | ≥ 20 |
| ppm, 8 hour running average |
| Nitrogen Dioxide | <150 | 150 - 299 | 300 - 399 | ≥ 400 |
| ppb, hourly |
| PM10 Particulates | <50 | 50 - 74 | 75 - 99 | ≥ 100 |
| Micrograms per cubic metre, 24hr running |
