National Planning Framework 4 - improving air quality outcomes: research

Research findings on improving air quality outcomes that will help inform policy development for National Planning Framework 4.

2. Stage 1 - Outcomes


2.1 The initial focus of Stage 1 was to gain an overview of the differing approaches to air quality within LDPs and the overall representation of air quality. This included analysis of the direct representation of air quality within LDPs, and the creation of a scoring matrix for air quality specific policies. This was followed by an assessment of indirect air quality policies within LDPs.

2.2 To build upon the scoring matrix, the language of the air quality specific policies was examined to identify key themes and commonalities to inform the content and language of any air quality specific policies recommended for consideration as part of the development of NPF4.

Approaches to Air Quality

2.3 Different approaches to managing air quality are apparent across LDPs and LAQM. In LDPs for example, air quality may be directly represented by an air quality specific policy and may also be mentioned within other policies and topic areas. Contrastingly, an LDP may not have an air quality specific policy and there may be little mention of air quality or air pollution throughout an LDP.

2.4 The reasoning behind these apparent differences has been explored. For example, whether air quality was not always fairly represented in LDP because there is not clear guidance on how it should be represented, whether it’s because air quality issues are not apparent within the area of the Local Planning Authority responsible for the LDP (i.e. no AQMAs), or whether it’s because air quality is underrepresented within the planning framework, or whether it’s a combination of the above. These conclusions could inform NPF4 in the context of air quality and development plan policy to ensure that NPF4 can effectively set out and guide the best practice approach for implementation across Scotland.

Direct Air Quality Representation

2.5 The research project ‘Adoption of Scottish Planning Policy in Local Development Plans[7] has been reviewed to draw conclusions about the representation of air quality within LDPs in Scotland.

2.6 Firstly, the conclusions of the research project in regard to SPP, LDPs and air quality should be noted. As follows:

“It was noted that SPP should provide a clear policy framework for the consideration of air quality in delivering healthy places in both Development Plans and Development Management. It was noted that at the moment there is very little policy direction as to how Development Plans and Development Management can ensure development does not have a detrimental impact on local air quality.”

2.7 SPP states that development should “consider the implications […] for air […] quality” and in relation to mineral resources it states that proposals “need to address […] potential pollution of […] air […]”.

2.8 Whilst the issue of air quality is addressed within SPP, as the review concluded, there is little direction on the actions Local Planning Authorities should take to improve and preserve air quality, and the policy measures which would support this.

2.9 Following a review of the research project ‘Adoption of Scottish Planning Policy in Local Development Plans’ and of the policies within Scottish LDPs, it is clear that there are discrepancies in the approach to air quality within Scottish LDPs and that the topic is represented in varying degrees. This may be partially attributed to the lack of guidance provided within SPP on air quality.

2.10 Of the 34 Local Planning Authorities (including 32 Council areas and 2 National Park Authorities), 17 have a policy within their LDP which is specifically focused (in full or part) on air quality or air pollution. In addition to policies which directly relate to air quality, several of the Local Planning Authorities have policies which are not centred on air quality, but which make the link to air quality or air pollution. This is summarised in Table 2.11a below.

2.11 To provide a comparative example, Stirling Council does not have a specific air quality policy, or any directly linked policies, whereas East Lothian Council has a specific air quality policy and several other directly linked policies.

Table 2.11a: Summary of Air Quality Representation within LDP
Local Planning Authority Active AQMA present within LPA Area? Specific Air Quality Policy?
(Table 2.16a Ref No.)
Other Directly Linked Policies
Aberdeen City Council Yes

Yes – Policy T4: Air Quality

(Ref. 1)

Policy NC5: Out of Centre Proposals
Policy R8: Renewable and Low Carbon Energy Developments
Aberdeenshire Council No No Policy R3: Minerals and hill tracks
Angus Council No No Policy DS4: Amenity Policy
Policy PV17: Waste Management Facilities
Policy PV19: Minerals
Argyll and Bute Council No No Policy LDP STRAT 1: Sustainable Development
Clackmannanshire Council No No Policy SC11: Transport Networks
Policy SC13: Decentralised Energy
Policy EP10: Minerals – General Principles
Policy EA11: Environmental Quality
Policy EA16: Waste Management Facilities
Dumfries and Galloway Council No No Policy OP1: Development Considerations
Policy ED13: Minerals
Policy IN3: New Waste Management Infrastructure
Dundee City Council Yes

Yes – Policy 40: Air Quality

(Ref. 2)

Policy 39: Environmental Protection
East Ayrshire Council No

Yes – Policy ENV12: Water, air and light and noise pollution

(Ref. 3)

East Dunbartonshire Council Yes No Policy 4: Sustainable Transport
Policy 15: Renewable Energy and Low-Carbon Technology
East Lothian Council Yes

Yes – Policy NH12: Air Quality

(Ref. 4)

Policy T19: Transport Improvements at Musselburgh Town Centre
Policy T26: Transport Improvements at Tranent Town Centre
Policy MIN8: Mineral Extraction Criteria
East Renfrewshire Council No

Yes – Policy E3: Protecting Air Quality

(Ref. 5)

Policy D1: Placemaking and Design
Policy E12: Minerals
Edinburgh City Council Yes

Yes – Policy Env 22: Pollution and Air, Water and Soil Quality

(Ref. 6)

Falkirk Council Yes

Yes – PE26: Air Quality

(Ref. 7)

Policy PE01: Placemaking
Policy IR05: Transport Assessment
Policy IR12: Energy Generation Development
Policy IR16: Assessment of Mineral Proposals
Fife Council Yes No Policy 10: Amenity
Glasgow City Council Yes No The Placemaking Principle
Resource Management
Highland Council Yes

Yes – Policy 73: Air Quality

(Ref. 8)

Policy 28: Sustainable Design
Policy 72: Pollution
Inverclyde Council No

Yes – Policy 12: Air Quality

(Ref. 9)

Policy 4: Supplying Energy
Midlothian Council No

Yes – Policy ENV 17: Air Quality

(Ref. 10)

Moray Council No No DP1: Development Principles
EP14: Pollution, Contamination and Hazards
DP9: Renewable Energy
North Ayrshire Council No No Policy 27: Sustainable Transport and Active Travel
Policy 33: Responsible Extraction of Mineral Resources
North Lanarkshire Council Yes No Policy EDQ 3: Quality of Development
Orkney Islands Council No No No
Perth and Kinross Council Yes

Yes – Policy 57: Air Quality

(Ref. 11)

Policy 33A: New Proposals for Renewable and Low-Carbon Energy
Policy 36B: New Waste Management Infrastructure
Renfrewshire Council Yes

Yes – Policy ENV5: Air Quality

(Ref. 12)

Policy I4: Renewable and Low Carbon Energy Developments
Scottish Borders Council No

Yes – Policy EP16: Air Quality

(Ref. 13)

Policy PMD1: Sustainability
Policy IS10: Waste Management Facilities
Shetland Islands Council No No No
South Ayrshire Council No

Yes – LDP Policy: Air, Noise and Light Pollution

(Ref. 14)

Strategic Policy 1: Sustainable Development
LDP Policy: Waste Management
LDP Policy: Minerals, Aggregates and Coal
South Lanarkshire Council Yes

Yes – Policy DM17: Air Quality

(Ref. 15)

Policy 2: Climate Change
Policy 13: Green Network and Greenspace Green Network
Policy 15: Travel and Transport
Policy 17: Waste
Policy MIN5: Controlling Impacts from Extraction Sites
Stirling Council No No No
West Dunbartonshire Council No

Yes – Policy ENV8: Air, Light and Noise Pollution

(Ref. 16)

Western Isles (Comhairle nan Eilean Siar) Council No No Policy ED5: Minerals
West Lothian Council Yes

Yes – Policy EMG 4: Air Quality

(Ref. 17)

Policy DES 1: Design Principles
Policy MRW 8: Waste Management Facilities
Cairngorm National Park Authority No No Policy 7: Renewable Energy
Loch Lomond National Park Authority No No Overarching Policy 1
Overarching Policy 2
Renewable Energy Policy 1

Air Quality Policy - Scoring Matrix

2.12 The initial review of the LDPs found that air quality regularly features as a standalone policy and is also integrated into other policies. Integrated policy approaches are largely recognised as an essential part of sustainable development and in achieving alignment and cooperation across government bodies and departments[8]. Integrated policies, which consider more than one topic area, recognise the interconnections between policy areas of the LDP. They are thought to be more wide-reaching in terms of their impact, as they influence other policy areas as well as their own.

2.13 The 17 specific air quality policies were analysed further to make a judgement on how well they were integrated with other policy areas. A scoring matrix based on the complexity of the policy and the degree in which it integrates with other LDP policies was created.

2.14 The qualitative scoring matrix is defined in Table 2.15a. Firstly, it should be noted that the presence of any air quality specific policy, whether ‘simple’ or ‘integrated’ is considered better than having no air quality policy at all. As the matrix moves from ‘simple’ to ‘basic’ to ‘advanced’ it increasingly incorporates the factors considered necessary within an air quality policy. The policies classified as ‘integrated’ contain linkages to other topic areas; namely ‘sustainable transport’, ‘behavioural change’ and ‘placemaking’.

2.15 A policy incorporating all of the matrix scoring criteria is integrated with other topic areas and contains the factors considered appropriate and proportionate for an air quality policy. This type of policy would be viewed as more effective than a ‘simple’ only policy, for example.

Table 2.15a: Air Quality Policies Scoring Matrix

(Score and Code)

Simple: the policy contains a simple statement regarding air quality, development and adverse effects. - S

Basic: the policy recommends that an air quality assessment be undertaken. - B

Advanced: the policy states that mitigation measures to prevent air quality impacts must be considered. - A

Integrated with sustainable transport: the policy is integrated with sustainable transport initiatives. Sustainable transport actions would include those relating to public transport, low emission vehicles and active travel. - I-ST

Integrated with behavioural change: the policy is integrated with behavioural change initiatives. Behavioural change with regards to air quality would aim to encourage actions that bring about its improvements, including modal shift. - I-BC

Integrated with placemaking: the policy is integrated with placemaking and comments in relation to this and air quality. Placemaking here refers to correct placement and design of development i.e. not introducing receptors to areas of poor air quality and ensure there is no land-use conflict. - I-P

2.16 The 17 specific air quality policies were scored in line with the matrix above, and the results are presented in Table 2.16a below. The reference numbers of the air quality policies correlate to the authorities in Table 2.11a and the full-length policies are presented in Annex B.

Table 2.16a: Scoring Results of Air Quality Policies
Policies Ref.
Score 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17

Note: Boxes marked ‘X’ or ‘O’ show how policies have been scored, ‘O’ indicates a weaker score, where a linkage is only implied. Scoring is explained in table 2.15a and paragraphs 2.12-2.16.  The formatting of this table has been adjusted for HTML use, the table appears differently in the PDF version.

2.17 It is noted, that some of the air quality policies incorporate more of the matrix than others. For example, Policy Ref No. 17 scores within all areas and makes links between air quality, sustainable transport, behavioural change and placemaking. Comparatively, Policy Ref No. 14 only scores within the ‘simple’ area and constitutes a basic statement surrounding air quality and adverse effects. As an air quality policy, it doesn’t maximise it’s potential by including more of the factors considered appropriate for an air quality specific policy.

2.18 The scoring results suggest the need for standardised text, specifically surrounding placemaking, sustainable transport and behavioural change, to be recommended for inclusion within air quality specific policies; as, at present, these topic areas are underrepresented.

2.19 This would constitute positive action towards the recommendations of the ‘Cleaner Air for Scotland strategy: Independent Review’, notably, ‘T8: Spatial planning and transport planning need to work together to be effective in ensuring local decision-making does not undermine national objectives for air quality’ and ‘LG1: Realising effective Placemaking in practice’. For local decision-making to ensure it does not conflict with air quality, the linkages between the two must resonate throughout LDPs and inclusion of an integrated air quality policy would help achieve this.

Indirect Air Quality Representation

2.20 In addition to direct linkages with air quality, the LDP policies were examined further for potential missed opportunities where air quality could have been linked to the policy but was not.

2.21 Air pollution is known to adversely affect human health, the environment (ecosystems) and amenity. Consequently, air quality can be influenced by many factors. Actions and measures that are often designed and adopted to influence these factors can therefore impact on air quality.

2.22 Figure 2.22a below depicts some of the linkages between air quality and other topics which regularly feature within LDP and LAQM. The topic of active travel (i.e. walking and cycling) is often connected to air quality; as an increase in the number of people walking or cycling rather than driving a vehicle, results in less vehicle trips, reduced emissions from road vehicles and therefore reduced ground level concentrations of air pollutants, thus resulting in improved air quality. Whilst this oversimplifies the relationship between air quality and active travel, the general principle here applies; that positive actions in certain topic areas can positively impact air quality.

Figure 2.22a Linkages to Air Quality
Image Description below

Image Description

This image links a range of topics to air quality: transport, climate change, mineral sites, green infrastructure, traffic management, emissions, active travel, amenity (dust), electric vehicles, health, schools e.g. cleaner routes, public transport, industry, and ports and shipping.

2.23 All of the LDPs reviewed had some policy that focused on or mentioned active travel, however only a few specifically made the connection with air quality. These may be considered as ‘missed opportunities’ to represent air quality within the LDP.

2.24 Some topics which link to air quality were underrepresented in the LDPs. For example, the uptake of Electric Vehicles (EVs) and Ultra Low Emission Vehicles (ULEVs) and measures to install charging points. Measures relating to EVs are regularly utilised within LAQM and AQAPs. Of the LDPs reviewed, 14 of the 34 Local Planning Authorities have policies which detail EVs/ULEVs and charging points. 

2.25 In view of the Climate Emergency declared by the Scottish Government in April 2019 and the Climate Change (Emissions Reduction Targets) (Scotland) Act 2019[9] which received Royal Assent on 31 October 2019, opportunities to implement policy within LDPs that result in carbon emission reductions, such as those relating to EVs/ULEVs, should be taken.

2.26 The NPF4 will incorporate SPP and will have development plan status. The development of the NPF4 therefore presents an opportunity in terms of air quality. The current SPP and NPF3 provides little direction for the management of potential air quality issues. As noted in the previous sections, air quality is not consistently represented in LDPs and this could, in part, be attributed to the current representation of air quality within SPP and NPF3. 

2.27 The development of NPF4 therefore presents an opportunity to provide a consistent approach to air quality in national planning policy and also direction for the representation of air quality within LDPs if further, additional representation of air quality is required at the local level; to account for specific air quality issues or conditions within the Local Planning Authority. NPF4 policy that generates consistent approaches would set out the topic of air quality and state the negative impacts of poor air quality on human health and ecosystems. It would also link air quality to other relevant policy areas, to ensure integration where possible.

Language Analysis

2.28 In addition to the scoring of air quality specific policies, the 17 policies were analysed further in relation to the language used. Common themes, phrases and words are noted throughout the policies; which overall, seem to exhibit a similar message although with a varying degree of complexity.

2.29 The key words or phrases picked out and their respective counts are displayed below in Table 2.29a.

Table 2.29a: Language Analysis of Air Quality Policies
Word or Phrase Count
Development 17
Mitigation (mitigation measures, mitigate) 15
Air Quality Assessment (assessment) 13
Significant (significance) 10
Adverse 8
Cumulative 6
Receptor / Exposure 6
Air Quality Management Area (AQMA) 5
Detrimental 5
Sensitive 5
National Air Quality Standards / Objectives 4
Exacerbate 4
Environment 4
Health 4
Link to other policy area (i.e. transport) 3
Human 3
Air Quality Action Plan (AQAP) 2

2.30 As shown by the count of 17, all of the air quality policies made the link between air quality impacts and development proposals. 15 of the 17 policies then stated that air quality impacts would need to be mitigated and mitigation measures implemented. A further 13 then detailed the potential need for an air quality assessment to be undertaken.

2.31 The policies are also heavily centred around the impacts of air quality; suggested through use of words such as ‘adverse’, ‘detrimental’ and ‘exacerbate’. They are concerned with establishing the likelihood of impacts occurring and how impacts can be lessened and mitigated to an acceptable level through potential modification of approach.

2.32 In addition, three of the policies are noted to link to other key policy areas, such as transport and active travel. This is similar to how other policies were found to often link to air quality (see Paragraph 2.22), and also reflects on how the majority of policies did not score within the ‘integrated’ section of the scoring matrix. For the determination of air quality impacts the word ‘significant’ or ‘significance’ appears in 10 of the policies. However, no definition is given and therefore the method by which each Local Planning Authority would determine significance is not stated or known.

2.33 Policies score better than others within the scoring matrix largely due to varying complexities and integration with other LDP policy areas. Those policies which scored well could be used to determine future suggestions relating to the wording and language contained within air quality policies; for national planning policy and LDP, if required due to specific local air quality issues or conditions.

Summary of Stage 1

2.34 The policy links between air quality and other disciplines including transport, climate change and sustainability are well documented. Therefore, the direction and application of any policy from these disciplines can affect air quality. The review of LDP policies across Scotland indicated a varying approach in linking air quality with other relevant policy areas. Standalone air quality policies were well represented in the policy database, from simple statements to more prescriptive policies referencing approach to assessments and assigning significance to potential air quality impacts. There were, to a lesser extent, examples of policies linking air quality with transport, placemaking and behaviour change. However, there were also LDPs where air quality was not mentioned, either directly or indirectly.  There are opportunities to link air quality in NPF4 with other policy areas, as this approach is likely to provide the greatest air quality improvements that are sustainable. NPF4 therefore presents an opportunity to ensure air quality is consistently represented across Scotland even when it is absent from LDPs.

2.35 The varying degrees of inclusion of air quality is partially attributed to the lack of direction within the SPP. This was recognised within the Scottish Government 2019 research project[10] where feedback from consultees stated that the SPP was often unclear and not prescriptive in providing direction for the implementation of SPP within LDPs. The above, coupled with the fact that Scotland does not have widespread air quality issues and therefore it is not a priority issue for a number of Local Planning Authorities, may explain the differing approaches to air quality within Scottish LDPs.

2.36 The 17 specific air quality policies found across the LDPs were analysed in detail, to assess their content and the language used. Some of the policies scored better than others, within the developed scoring matrix, in terms of their complexity and degree of integration with other policy areas. There are however some commonalities that exist between the air quality policies, with some more developed than others. This presents an opportunity to consider within NPF4 a sufficiently prescriptive air quality specific policy, referencing the need to assess air quality and the need for mitigation, allowing it to be widely applied, removing the need for Local Planning Authorities to develop, within their respective LDPs, detailed air quality specific policies unless necessary due to local factors. 

2.37 In respect to the integrated policies that relate to air quality that were extracted from the LDP review, there is scope to utilise the high scoring policies from the matrix to formulate standardised statements to be incorporated within air quality specific policies of the NPF4. Also, air quality can be referenced in NPF4 policies relating to transport, placemaking and behavioural change therefore promoting best practice identified as part of this research project. This would ensure that air quality has both a specific policy as well as being integrated with other policy areas allowing them to be more wide-reaching.  

2.38 Conclusions from Stage 1 include the following:

  • Linkages between air quality and other related topic areas should be made within NPF4, where possible, to promote integration of topic areas at the national level and also the local, LDP level; and
  • NPF4 has the opportunity to provide a sufficiently prescriptive air quality specific policy, removing the need for Local Planning Authorities to develop, within their respective LDPs, detailed air quality specific policies unless necessary due to local factors. 

2.39 Stage 2 develops on the research and findings of Stage 1 to set Scotland-specific case studies within a UK-wide and Europe-wide context. Comparisons of policy and practice have then been utilised to inform recommendations of best practice.



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