Air quality standards
Air quality is measured by comparing against a range of health-effects based standards. This page gives information about what this means.
Standards for air pollution are created by setting an acceptable level for concentrations of pollutants in the air over a given time period. They are based on what is known about the effects of each pollutant on health and on the environment. They can also be used as a benchmark to see if air pollution is getting better or worse. Pollution levels exceed a standard when the concentration is higher than that set down by the standard. In order to make useful comparisons between pollutants we often report the number of days that the standard has been exceeded.
A target is set for the maximum number of times a standard can be exceeded over a specific time period.
The objectives adopted in the UK are based on the Air Quality Regulations 2000 and (Amendment) Regulations 2002 for the purpose of Local Air Quality Management. These air quality regulations have adopted the limit values required by EU Daughter Directives on Air Quality into UK law.
A summary of the current UK Air Quality Objectives is provided here.
Summary of objectives of the National Air Quality Strategy
| Pollutant | Objective | Measured as | To be achieved by |
|---|---|---|---|
| BenzeneAll Authorities | 16.25 µgm3 | Running Annual Mean | 31 December 2003 |
| Benzene Authorities in England and Wales only | 5 µgm3 | Annual Mean | 31 December 2010 |
| BenzeneAuthorities in Scotland and Northern Ireland onlya | 3.25 µgm3 | Running Annual Mean | 31 December 2010 |
| 1,3-Butadiene | 2.25 µgm3 | Running Annual Mean | 31 December 2003 |
| Carbon monoxideAuthorities in England, Wales and Northern Ireland onlya | 10.0 mg/m3 | Maximum daily running 8 Hour Mean | 31 December 2003 |
| Carbon monoxide Authorities in Scotland only | 10.0 mg/m3 | Running 8 Hour Meanb | 31 December 2003 |
| Lead | 0.5 µgm3 | Annual Mean | 31 December 2004 |
| 0.25 µgm3 | Annual Mean | 31 December 2008 | |
| Nitrogen dioxidec | 200 µgm3Not to be exceeded more than 18 times per year | 1 Hour Mean | 31 December 2005 |
| 40 µgm3 | Annual Mean | 31 December 2005 | |
| Nitrogen Oxides** | (V) 30 µgm3 | Annual Mean | 31 December 2000 |
| Ozone* | 100 µgm3Not to be exceeded more than 10 times a year | 8 hourly running or hourly mean | 31 December 2005 |
| Particles (PM10)(gravimetric)dAll authorities | 50 µgm3Not to be exceeded more than 35 times per year | Daily Mean | 31 December 2004 |
| 40 µgm3 | Annual Mean | 31 December 2004 | |
| Particles (PM10)Authorities in Scotland onlye | 50 µgm3Not to be exceeded more than 7 times per year | Daily Mean | 31 December 2004 |
| 18 µgm3 | Annual Mean | 31 December 2004 | |
| Sulphur dioxide | 266 µgm3Not to be exceeded more than 35 times per year | 15 Minute Mean | 31 December 2005 |
| 350 µgm3Not to be exceeded more than 24 times per year | 1 Hour Mean | 31 December 2004 | |
| 125 µgm3Not to be exceeded more than 3 times per year | 24 Hour Mean | 31 December 2004 | |
| (V) 20 µgm3 | Annual Mean | 31 December 2000 | |
| (V) 20 µgm3 | Winter Mean (01 October - 31 March) | 31 December 2000 |
Notes:
- In Northern Ireland none of the objectives are currently in regulation. Air Quality (Northern Ireland) Regulations are scheduled for consultation early in 2003.
- b. The objectives for nitrogen dioxide are provisional.
- c. Measured using the European gravimetric transfer sampler or equivalent.
- d. These 2010 Air Quality Objectives for PM 10 apply in Scotland only, as set out in the Air Quality (Scotland)Amendment Regulations 2002.
- e. These 2010 Air Quality Objectives for PM 10 apply in Scotland only, as set out in the Air Quality (Scotland) Amendment Regulations 2002.
- µgm3 - micrograms per cubic metre
- mg/m3 - milligrams per cubic metre
- *Ozone is not included in the Regulations
- ** Assuming NOx is taken as NO2
- (V) These standards are adopted for the protection of vegetation and ecosystems. All of the remainder are for the protection of human health.
New particle objectives for England, Wales, Northern Ireland and Greater London not included in Regulations
| Region | Objective | Measured as | To be achieved by |
|---|---|---|---|
| Greater London | 50 µgm3 not to be exceeded more than 10 times per year | 24-hour Mean | 31 December 2010 |
| Greater London | 23 µgm3 | Annual Mean | 31 December 2010 |
| Greater London | 20 µgm3 | Annual Mean | 31 December 2015 |
| Rest of England, Wales and Northern Ireland | 50 µgm3 not to be exceeded more than 7 times per year | 24-hour Mean | 31 December 2010 |
| Rest of England, Wales and Northern Ireland | 20 µgm3 | Annual Mean | 31 December 2010 |