Air quality policy begins at the international level. The Gothenburg Protocol is the key international directive. The protocol was first adopted in 1999 and sets the limits of air pollution.
International regulations are implemented at the EU and national level through several methods. The UK has air quality laws originating from EU legislation in domestic legislation.
The Air Quality Strategy
The National Air Quality Strategy, sets out air quality objectives and policy options to further improve air quality in the UK, in the short and the long term. The strategy outlines the UK Air Quality Standards and Objectives, which have been set to measure the improvement of air quality.
Clean Air Strategy
The Department for Environment, Food and Rural Affairs published the UK Clean Air Strategy in 2019:
- Protect the nation’s health
- Protect the environment
- Secure clean growth and innovation
- Reduce emissions from transport, homes, farming and industry
- Monitor progress
UK Air Quality Limits
The Air Quality Standards Regulations 2010 sets binding limits for concentrations of outdoor air pollutants that are known to have a significant impact on human health.
The following table shows the national air quality objectives for nitrogen dioxide (NO2), ozone (O3), PM10 and PM2.5.
The PM2.5 targets are set out in The Environment Act 2021 which supersede those set out in the Air Quality Standards Regulation 2010. The Environment Act 2021 established a legally binding duty on the government to bring forward at least two new air quality targets. This duty sits within the environmental targets framework outlined in the Environment Act (Part 1).
| Pollutant | Objective | Concentration measured as | Date to be achieved by (and maintained thereafter) |
|---|---|---|---|
| Particles (PM10) |
50µg/m3 not to be exceeded more than 35 times a year
|
24 hour mean | 31st December 2004 |
|
40µg/m3
|
Annual mean | 31st December 2004 | |
| Particles (PM2.5) |
35% reduction in population exposure by 2040 (compared to a base year of 2018)
|
Annual mean | 2040 |
|
10µg/m3
|
Annual mean | 2040 | |
| Nitrogen dioxide (NO2) |
200µg/m3 not to be exceeded more than 18 times a year
|
1 hour mean | 31st December 2005 |
|
40µg/m3
|
Annual Mean | 31st December 2005 | |
| Ozone (O3) |
100µg/m3 not to be exceeded more than 10 times a year | Annual mean | 31st December 2005 |
WHO Air Quality Guidelines
World Health Organization (WHO) updated it's Air Quality Guidelines in 2021. This new document provides clear evidence of the damage air pollution inflicts on human health at much lower concentrations than the existing legal limit values for air pollutants.
| WHO Air Quality guidelines |
|---|
| Pollutant | Averaging time | 2005 air quality guideline | 2021 Air Quality Guidelines level |
|---|---|---|---|
| Particles (PM10) |
Annual |
20µg/m3 | 15µg/m3 |
|
24-hour* |
50µg/m3 |
45µg/m3 |
|
| Particles (PM2.5) |
Annual |
10µg/m3 | 5µg/m3 |
|
24-hour* |
25µg/m3 |
15µg/m3 |
|
| Nitrogen dioxide (NO2) |
Annual | 40µg/m3 |
10µg/m3 |
|
24-hour* |
25µg/m3 | ||
| Ozone (O3) |
Peak season** | 100µg/m3 | 60µg/m3 |
| 8-hour* | 100µg/m3 |
*99th percentile (3 to 4 exceedance days per year).
**Average of daily maximum 8-hour mean O3 concentration in the 6 consecutive months with the highest 6-month running-average O3 concentration.