Air quality compliance data
Under the Air Quality Standards Regulations 2010, the UK undertakes an air quality assessment and reports the findings on an annual basis. The assessment is based on a range of high-quality evidence including measurements from established monitoring networks and supplementary assessment in the form of air quality modelling. In 2020, Defra established the non-automatic UK Urban NO2 Network (UUNN) to complement the existing evidence base. The evidence is compared against Objective thresholds set for different pollutant/metric combinations associated for example with health effects and vegetation and ecosystem damage (see table below).
This page provides links to the following data resources, each associated with the compliance status and underlying evidence:
- Compliance map – a streamlined viewer facilitating summaries of compliance status across different geographies for different pollutant metrics based on modelled background data, modelled roadside data and measurements. A guidebook provides further instructional use.
- Compliance data hub – a comprehensive data catalogue and extraction tool for underlying data that serves the compliance app. This allows users to acquire the data behind the compliance status either for a specific zone/agglomeration or Local Authority or for the whole of the UK in one process. A guidebook provides further instructional use.
- XML file library – a catalogue of download links for the machine-readable XML formats of the compliance data. The library is available below. For previous submissions, please see the European Environment Agency website.
- Air Pollution in the UK annual report.
Pollutants, metrics and legislative thresholds
The table below summarises the pollutant metrics in the UK’s Air Quality Standards Regulations (2010). These are the thresholds used to determine compliance and are referred to across the compliance app, compliance data hub, XML file library and in Air Pollution in the UK report.
| Pollutant | Averaging Period | Objective | Objective Type |
|---|---|---|---|
|
NO2 |
Annual mean | 40 µg m-3 | Limit Value |
| NO2 | Hourly mean | 200 µg m-3, 18 permitted exceedances each year | Limit Value |
| NOX | Annual mean | 30 µg m-3 | Critical Level |
| SO2 | Hourly mean | 350 µg m-3, with 24 permitted exceedances each year | Limit Value |
| SO2 |
24-hour mean |
125 µg m-3, with 3 permitted exceedances each year |
Limit Value |
|
SO2 |
Annual mean |
20 µg m-3 |
Critical Level |
|
SO2 |
Winter mean |
20 µg m-3 |
Critical Level |
|
PM10 |
Annual mean |
40 µg m-3 |
Limit Value |
| PM10 | 24-hour mean | 50 µg m-3, with 35 permitted exceedances each year | Limit Value |
| PM2.5 | Annual mean | 20 µg m-3 | Limit Value (stage 2 – came into force 01/01/2020) |
| Benzene | Annual mean | 5 µg m-3 | Limit Value |
|
CO |
maximum daily 8-hour mean |
10 mg m-3 |
Limit Value |
| O3 |
maximum daily 8-hour mean |
120 µg m-3, not to be exceeded on more than 25 days per calendar year averaged over three years |
Target Value |
| O3 |
maximum daily 8-hour mean |
120 µg m-3 |
Long Term Objective |
|
O3 |
AOT40 (calculated from 1-hour values, May to July averaged over five years) |
18000 μg m-3.h |
Target Value |
|
O3 |
AOT40 (calculated from 1-hour values, May to July) |
6000 μg m-3.h |
Long Term Objective |
|
As |
Annual mean |
6 ng m-3 |
Target Value |
|
Cd |
Annual mean |
5 ng m-3 |
Target Value |
|
Ni |
Annual mean |
20 ng m-3 |
Target Value |
|
Pb |
Annual mean |
0.5 µg m-3 |
Limit Value |
|
benzo(a)pyrene (B(a)P) |
Annual mean |
1 ng m-3 |
Target Value |