UK Air Quality Policy Context

In the UK, concentrations of key pollutants in outdoor air are regulated by the Air Quality Standards Regulations 2010,  the Air Quality Standards (Wales) Regulations 2010, the Air Quality Standards (Northern Ireland) 2010 and the Air Quality Standards (Scotland) Regulations 2010.

These Regulations seek to control human exposure to pollutants in outdoor air to protect human health and the environment by requiring concentrations to be within specified limit values. In the event of exceedances, the Regulations require the publication of Air Quality Plans setting out “appropriate measures” that will ensure that the exceedance period is kept “as short as possible”.

These Regulations set:

  • Legally binding limits for concentrations in outdoor air of major air pollutants that impact public health: sulphur dioxide, nitrogen oxides, particulate matter (as PM10 and PM2.5), lead, benzene, carbon monoxide and ozone.
  • Targets for levels in outdoor air for four elements; cadmium, arsenic, nickel and mercury, together with polycyclic aromatic hydrocarbons (PAH).

These Air Quality Standards Regulations set ‘limit values’, ‘target values’ and ‘long-term objectives’ for ambient concentrations of the pollutants listed above. More information on these values and how they differ can be found on the UK Air Quality Limits page.

Separate legislation exists for emissions of air pollutants. The National Emissions Ceiling Regulations 2018 sets national (UK wide) emission limits or ‘ceilings’ for sulphur dioxide, oxides of nitrogen, ammonia non-methane volatile organic compounds in 2010, 2020 and 2030 and for PM2.5 in 2020 and 2030.

The ceilings in 2010 and 2020 closely reflect those agreed under the UNECE Gothenburg Protocol which sets national emission limits (ceilings) for SO2, NOX, NH3 and non-methane volatile organic compounds for countries to meet from 2010 onwards, with the addition of PM2.5 from 2020 onwards.

UK Level: National and Local Authorities

In the UK, responsibility for meeting air quality limit values is devolved to the national 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.

In England there are additional regulations relating to the air pollutant of most harm to health - fine particulate matter (PM2.5). The Environmental Targets (fine particulate matter) (England) Regulations 2023 set two PM2.5 targets to be met by 2040, these require that:

  • The annual mean concentration is 10 µg m-3 or lower
  • That the population exposure is reduced by 35% compared to 2018 levels

The meaning of “targets” is different in these regulations to that in the Air Quality Standards Regulations wherein a “target value” has a specific meaning. These targets are legally binding.

More information on the England PM2.5 targets can be found here.

The Environment Act 1995 requires the Government to produce a national Air Quality Strategy (AQS) for the UK setting out air quality standards, targets, objectives, and measures for improving ambient air quality. The last comprehensive review of the Strategy was published in 2007, with a review yielding some minor changes published in 2011. The strategy sets out the UK’s air quality objectives and recognises that action at national, regional, and local level may be needed, depending on the scale and nature of the air quality problem. Under the Environment Act 2021, the Secretary of State must review the Strategy for England at least every five years, with a commitment for an initial review within 12 months of the measures coming into force. The first review will be published in 2023.

Part IV of the Environment Act 1995 and Part II of the Environment (Northern Ireland) Order 2002 requires local authorities in the UK to review air quality in their area and designate air quality management areas if improvements are necessary. Where an air quality management area is designated, local authorities are also required to work towards the Strategy’s objectives prescribed in regulations for that purpose. An air quality action plan describing the pollution reduction measures must then be put in place. These plans contribute to the achievement of air quality limit values at local level.