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Poor air quality is considered by the government to be “the largest environmental risk to public health in the UK”. As well as human health, air pollution also has implications for the natural environment and for the economy. Due to the transboundary nature of air pollution, action to manage and improve air quality in the UK has been driven by both international agreements and EU legislation, as well as national and devolved legislation.

This briefing gives an overview of the current outdoor air quality legal framework, the changing governance and enforcement mechanisms following the UK’s EU exit, forthcoming legislative changes and ongoing issues and concerns.

Information about road user charging schemes intended to reduce air pollution is set out in a separate Commons Library briefing, Clean Air Zones, Low Emission Zones and the London ULEZ.

For information about indoor air quality see Parliamentary Office of Science and Technology (POST) briefing, Indoor Air Quality.

Current law and policy

UK air quality legislation is a mesh of international commitments, retained EU law and domestic legislation.

At the international level, the Gothenburg Protocol and amendments to it set emissions ceiling levels for various pollutants.  Its aim is to control long-range transboundary pollution. Its main requirements have been implemented in the UK by the National Emission Ceilings Regulations 2018.

There is also legislation relating to ambient air quality (the air that more immediately surrounds us) at EU level through Directive 2008/50/EC (PDF) (the “Air Quality Directive”). Instead of setting a ceiling for pollutants, it sets “limit values” (parameters that must not be exceeded) for concentrations of different pollutants. These limit values remain part of UK law.

The UK Government has set two further targets for fine particulate matter (PM2.5 ) in England through The Environmental Targets (Fine Particulate Matter) (England) Regulations 2023 (SI 2023/96). The targets are:

  • An annual mean concentration target – a target of 10 micrograms per cubic metre (µg m3) to be met across England by 2040.
  • A population exposure reduction target – a 35% reduction in population exposure by 2040 (compared to a base year of 2018).

WHO guidelines

The World Health Organization (WHO) published updated Global Air Quality Guidelines in September 2021 covering Particulate matter (PM2.5 and PM10), ozone, nitrogen dioxide, sulphur dioxide and carbon monoxide. They provide guidance on thresholds and limits for key air pollutants that pose health risks. They are guidelines only and are not binding on any country unless that country chooses to adopt them into its own legislation. These guidelines are an update on the previous 2005 version,  Air quality guidelines for particulate matter, ozone, nitrogen dioxide and sulfur dioxide (PDF), which have frequently been referenced in debates about air quality targets.

UK air quality plans and policies

In the UK, air quality limit values are devolved to the administrations in Scotland, Wales, and Northern Ireland.  The Secretary of State for Environment, Food and Rural Affairs has responsibility for meeting the limit values in England and the Department for Environment, Food and Rural Affairs (Defra) co-ordinates assessment and air quality plans for the UK as a whole.

The UK Government and devolved executives published a Revised UK National Air Pollution Control Programme (NAPCP) in February 2023, to meet the national emissions ceilings legislation requirements, which must be met by the UK as a whole. The NAPCP sets out measures and analysis for meeting the emission reduction commitments. The requirement on the UK Government to produce and update this document, which originally stemmed from EU law, is set to be removed by provisions in the EU Law Revocation and Reform Act 2023.

At a national level, the UK Government and the devolved executives are required to produce a national air quality strategy. In 2007 the Air Quality Strategy for England, Scotland, Wales and Northern Ireland was published. In April 2023 the UK Government published a document, Air quality strategy: framework for local authority delivery, which supersedes the 2007 Strategy in respect of England only.

Each government within the UK can also choose to publish its own air quality strategy. See in particular:

EU infringement proceedings

Enforcement mechanisms for failure to meet air quality limit values were previously carried out by EU institutions.

In February 2014 the European Commission began infringement proceedings against the UK (as well as other countries) for its failure to meet air quality targets for nitrogen dioxide set by the EU Air Quality Directive in certain parts of the UK.

On 4 March 2021, the found that the UK had failed to fulfil its obligations under the provisions of EU Directive 2008/50/EC and that it had failed to ensure that the period of exceedance of limit values was kept as short as possible. Media reports on the case suggested that there was some uncertainty about what would happen if the UK still failed to comply within a “reasonable” period, questioning whether the UK could be forced to pay a fine.

Judicial review and air quality plan compatibility with EU legislation

Separate to the Commission proceedings, but arising from the same EU Air Quality Directive, private judicial reviews have also been brought against the UK Government stemming from the admitted and continuing failure of the United Kingdom, since 2010, to comply (in certain zones), with the limits for nitrogen dioxide levels.  These proceedings have resulted in the government being required by the courts to produce a number of different air quality plans aimed at reducing roadside nitrogen dioxide levels.

Governance and enforcement bodies

As a result of leaving the EU, environmental law and policy (including on air quality), which was derived from the EU, is no longer subject to the oversight of EU institutions, including the Court of Justice of the European Union (CJEU). As environmental matters are generally devolved, each government/executive within the UK has now put the following in place:

Future EU air quality changes

In November 2019, the European Commission published a Fitness Check of the Ambient Air Quality Directives. It concluded that these Directives have been partially effective in improving air quality, but not fully effective, and not all objectives have been met. The European Commission therefore intends to revise the Ambient Air Quality Directive, to align air quality standards more closely with the recommendations of the World Health Organization, subject to future consultation. A Proposal for revision of the Ambient Air Quality Directives was published in October 2022. Further information is available on the European Commission webpage, Revision of the Ambient Air Quality Directives.

Health concerns

Air quality has long been a high-profile issue, with specific concerns around human health. This was recently highlighted in the Chief Medical Officer’s annual report 2022: air pollution, published in December 2022. Academic research has found big differences in air pollution across communities, with deprived areas often the worst affected. Children, the elderly and individuals with pre-existing cardiovascular and respiratory conditions are particularly vulnerable to the effects of poor air quality. In 2020 a coroner found that air pollution was a significant contributory factor to the death of 9-year-old child.

The Covid-19 pandemic has raised questions about whether there is a link between poor air quality and Covid-19 outcomes (PDF). Researchers are also beginning to examine the effect of lockdown measures on air quality and work out what any findings mean for future policy.

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