Local air quality management: policy guidance

10: Relationships between Local Air Quality Management and EU air quality legislation and policy

Local Air Quality Management and the EU Directives on Ambient Air Quality

10.1 The Scottish Government has made clear its commitment to maintain or exceed EU standards, following the UK's departure from the European Union (EU). The Scottish Government is committed to ensuring that EU environmental principles continue to sit at the heart of environmental policy and law in Scotland.

10.2 The UK Withdrawal from the European Union (Continuity) (Scotland) Act 2021^[10] brings the guiding European principles on the environment into force in Scots law, including the precautionary principle, polluter pays principle, prevention principle, rectification at source principle and the integration principle. In relation to current regulation, retained EU law will continue to apply, as will domestic regulations made to transpose EU Directives.

Local Air Quality Management and Directive 2008/50/EC – Key differences

10.3 Although LAQM and Directive 2008/50/EC^[11] on ambient air quality have the shared aim of improving human and environmental health through reducing air pollution, the rationale and approach employed in each system have some quite important differences.

Definitions

10.4 Under LAQM the standards are defined as objectives, whereas in the Directive they are limit or target values. This different wording reflects the differing legal status of the standards, as outlined in the following paragraph.

Legal responsibility

10.5 As explained in section 1 of this guidance, under the Environment Act 1995 and associated regulations, local authorities are required to review and assess air quality in their areas against objectives for several air pollutants of particular concern for human health. Authorities are not legally obliged to achieve the objectives by the required dates, but to demonstrate they are doing all that is reasonably possible to work towards them. This is because some pollution sources are outwith direct local authority control, for example Transport Scotland controlled trunk roads and SEPA regulated processes. However, authorities are expected to liaise with these and other relevant organisations when developing action plan measures.

10.6 In contrast, the Scottish Government is responsible for securing compliance with the Directive limit values. Local authorities have no legal responsibility in relation to the Directive, even though the work undertaken by authorities through LAQM makes an important contribution to actions being implemented by central government.

Attainment dates

10.7 In most cases, the attainment dates are identical for LAQM objectives and Directive limit values. There are some differences, most notably for the Scottish PM objectives, however as these attainment dates are now passed the differences are largely academic.

Scope of assessment

10.8 Under LAQM, assessment is required in locations where members of the public are regularly present and there is exposure to the pollutant in question over the timescale for which the objective is defined. The Directive requirements are slightly different and assessment is undertaken anywhere the public has access, irrespective of whether this is regular access. The exceptions are workplaces which are covered by health and safety legislation, locations with no fixed habitation, and road carriageways and central reservations (unless there is public access to the central reservation).

Assessment methodology

10.9 Monitoring requirements are defined more precisely in the Directive than for the purposes of LAQM. The Directive requires Scotland to be divided into zones and agglomerations based on population (an agglomeration is defined as a zone if it is a conurbation of greater than 250,000 inhabitants). Within each zone/agglomeration there is a minimum number of sampling points for each pollutant and also a provision for reducing these by up to 50% if modelling can be shown to provide equivalent data of a sufficient quality. In addition, there are detailed criteria for sampling locations, including that traffic related sites should be representative of air quality for a street segment no less than 100m in length. Finally, there is a requirement to use reference monitoring equipment as specified in the Directive, or alternatively equipment that can be shown to be equivalent to the reference methods.

10.10 For LAQM monitoring, although detailed requirements are set out in the technical guidance LAQM. TG (22), there is more flexibility as to where monitoring sites can be located and greater scope for tailoring monitoring to specific local circumstances. Also, there is no legally defined requirement to use reference or equivalence methods although this is strongly encouraged and is the Scottish Government's preferred approach.

10.11 These differences in assessment methodology are why it is difficult to directly compare LAQM review and assessment with work undertaken by central government to assess compliance with the Directive. It is also the reason why it is not always possible to incorporate local authority monitoring sites into the Automatic Urban and Rural Network (AURN). The two systems are set up for different purposes, with LAQM by definition focusing much more on the local situation. The apparent anomaly between the number of AQMAs which remain in Scotland and the conclusion that we are almost fully compliant with the Directive requirements is simply a reflection of these differences. Using LAQM data to supplement UK Government submissions to the European Commission (EC) also requires careful consideration due to the very specific requirements of the Directive and explains why, historically, this has only been done in a very limited way.