The UK air quality legal framework is derived from a mixture of domestic and international legislation. The following legal frameworks are applicable both directly, and indirectly, to the UK aviation industry.
National Emission Ceilings Regulations (NECR)
Air pollution is transboundary in nature and given these potential transnational impacts, the European Commission set emission ceilings through the National Emission Ceilings Directive. This Directive was transposed into UK law in 2018 as the National Emission Ceilings Regulations (NECR).
The NECR sets national emission reduction commitments for nitrogen oxides (NOx), sulphur dioxide (SO2), non-methane volatile organic compounds (NMVOC), ammonia (NH3) and fine particulate matter (PM2.5). These national emission reduction commitments need to be met in two phases. This first phase is from 2020-2029 which is in-line with commitments set by the Gothenburg Protocol under the International Convention on Long-Range Transboundary Pollutants (CLRTAP), of which the UK is party. The second phase sets more stringent emission reduction commitments which need to be met from 2030 onwards. The 2030 targets are only set in the EU Directive and the NECR, and do not form part of CLRTAP.
Although air quality is a devolved matter in the UK, the NECR applies to the whole of the UK and therefore the UK Government and Devolved Administrations work together to meet the commitments set within the regulations. As part of this, Government produced a National Air Pollution Control Programme, setting out policies and measures required to meet the emissions reductions commitments of the NECR. The requirement on the UK Government to produce and update this document at least once every four years, which originally stemmed from EU law, was removed by provisions in the Retained EU Law (Revocation and Reform) Act 2023.
The reporting requirements for NECR are closely aligned with those of CLRTAP and emissions from the following aviation-related activities are reported under both:
- Domestic (civil) aviation Landing and Take-Off (LTO) cycle;
- International (civil) aviation LTO cycle; and
- Airport support machinery.
The emissions inventories reported as part of these obligations are published by the National Atmospheric Emissions Inventory.
Air Quality Standards Regulations (2010)
In the UK, concentrations of air pollutants in the ambient air are regulated through the Air Quality Standards Regulations 2010 and as air quality is a devolved matter this is enacted into domestic law for each devolved nation via the following regulations:
- The Air Quality Standards Regulations (2010) in England;
- The Air Quality Standards (Scotland) Regulations (2010);
- The Air Quality Standards (Wales) Regulations (2010); and
- The Air Quality Standards Regulations (Northern Ireland) (2010).
These regulations set limit values, target values and long-term objectives for ambient concentrations of the following pollutants: sulphur dioxide (SO2), nitrogen oxides (NOx), particulate matter (both PM10 and PM2.5), lead (Pb), benzene (C6H6), carbon monoxide (CO), ozone (O3), arsenic (As), cadmium (Cd), mercury (Hg), nickel (Ni) and polycyclic aromatic hydrocarbons.
In addition, concentrations of fine particulate matter (PM2.5) in England are regulated by more recent legislation, the Environmental Targets (Fine Particulate Matter) (England) Regulations (2023).
Environmental Targets (Fine Particulate Matter) (England) Regulation (2023)
The UK Environment Act (2021) established a duty for the UK Government to set a target in England to reduce PM2.5 concentrations, alongside at least one further long-term target on air quality. The long-term target is part of the wider framework for setting legally binding environmental targets, which also covers biodiversity, water, waste reduction and resource efficiency.
Within this framework, the Environmental Targets (Fine Particulate Matter) (England) Regulations (2023) set targets for:
- ambient concentrations of particulate matter measured as PM2.5; and
- the reduction of PM2.5 population exposure over the period between 2018 and 2040.
Local Air Quality Management Framework
Requirements for local air quality management are set out in Part IV of the Environment Act (1995) as amended by the Environment Act (2021), the Environment (Northern Ireland) Order (2002) and the Environment (Air Quality and Soundscapes) (Wales) Act 2024. Authorities are required to carry out regular reviews and assessments of air quality in their area and take action to improve air quality in those areas where objectives set out in regulation have been breached, or areas where it is thought there is a risk that they will be breached.
Local authorities in England, Scotland, Wales and Northern Ireland undertake a review and assessment against the respective air quality strategies’ objectives prescribed in the following regulations (as amended):
- Air Quality (England) Regulations (2000);
- Air Quality (Scotland) Regulations (2000);
- Air Quality (Wales) Regulations (2000); and
- Air Quality (Northern Ireland) Regulations (2003).
When the review and assessment process finds that an Air Quality Strategy objective has been exceeded, the local authority must declare an Air Quality Management Area and develop an Action Plan to tackle problems in the affected areas. Action Plans formally set out the measures the local authority proposes to take. As of 2022, local authorities in England (including London) must now state a date by which each measure will be carried out to secure achievement of air quality objectives.
See section 2.5.2 of Air Pollution in the UK 2024 for further information regarding the air quality strategies and objectives for each Devolved Administration.