8. Assessment of Air Quality

Figure 2 - Staged Approach

In order to ensure air quality is adequately and proportionately assessed in terms of the planning regime, a staged approach should be taken using relevant guidance and accepted methodologies:

Staged Approach

Section 1 - Development Design

8.1 New Forest District is characterised by generally high environmental quality with towns and villages set within attractive countryside with significant visual, recreational, heritage and ecological value. The qualities of the area and the sensitivities of its landscapes and habitats demand commensurate care and attention to quality in new development.

8.2 Developers should seek ways in which the places and spaces that are created can be sustainable. As Policy ENV3 of the Local Plan sets out, the Council expects development to offer a high-quality living environment for current and future residents.

8.3 Whilst it is acknowledged the design of a proposed development has to consider a number of parameters such as landscaping, property design and layout, the design stage should also consider how emissions could be reduced. This could include the following mitigation measures:

• Minimising the number of vehicles on site
• Removing street canyons by design
• Minimising public exposure to pollutants, for example by siting outside space away from busy roads / industrial sites
• Installation of electric vehicle charging points or a production of an electric vehicle charging scheme
• Energy efficient properties, reducing the need for heating
• Easy connections to public transport, walking and cycling networks to encourage the use of alternatives to cars
• Green Infrastructure, landscaping and planting

Section 2 - Requirement for an Air Quality Statement or Assessment

Air Quality Statement OR Assessment?

8.4 New Forest District Council use air quality planning guidance (Land-Use Planning & Development Control: Planning for Air Quality. January 2017. Environmental Protection UK, Institute of Air Quality Management) to determine whether a detailed air quality assessment is needed as part of the planning application. An air quality assessment is a detailed assessment to predict the impact of a proposed development on local air quality.

8.5 If there is no requirement to provide an air quality assessment, then an air quality statement will be needed. An air quality statement will include a commitment to implement measures to reduce emissions from the proposed development.

8.6 Table 1 summarises the development criteria for an air quality statement or assessment in a stepped process.

As an example, if the proposed development is greater than 10 residential units there may be a requirement for an air quality assessment, however, if the proposed development does not generate more than 500 light duty vehicle movements a day and no other criteria are met, then an air quality statement rather than an air quality assessment will be required.

The criteria presented in Table 1 are provided as guidance, there may be circumstances where an air quality assessment is needed due to local sensitivities outside the criteria.

Table 1 - Air Quality Statement or Assessment

Notes:* 'adjacent to' can also include a location where the majority of traffic from a proposed development is travelling through an AQMA even if the development is not physically adjacent to the AQMA. The determination of 'adjacent to' will be at the discretion of the Local Planning Authority.

Section 3 - Air Quality Statement

Content of an Air Quality Statement

8.7 An air quality statement should include the following:

• why an air quality statement rather than an assessment is being submitted, with reference to relevant guidance
• statement confirming 3 mitigation measures to be implemented as part of the development from the list detailed in Appendix 1.

8.8 An Air Quality Statement will be submitted as part of the application.

Section 4 - Prior to submission of an Air Quality Assessment

8.9  It is strongly recommended that the applicant agrees the following points with the Local Planning Authority prior to submission of a planning application to reduce the need to request further information during the application process:

• The requirement to undertake an air quality assessment - if there is uncertainty of the potential impact of the proposed development
• Details of assessment model.  This includes: 

1. relevant air quality model. This depends on what is being modelled for example road or industrial / point emissions.
2. emission data. If roads are being modelled the most up to date vehicle emission factor should be used
3. transport data(need to be agreement with HCC/LPA)
4. meteorological data
5. pollutants being assessed
6. baseline pollutant concentrations
7. background pollutant concentrations
8. choice of baseline year
9. use of local monitoring data
10. verification of air quality model

• Agreement of extent of assessment - whether the assessment includes the development alone, other locations and / or other local developments (cumulative impacts). It should be noted that a route / location of interest may be some distance from the development but is still considered relevant to the proposed development.
• Cumulative Impact the NPPF(paragraph 181) recognises that a number of individual developments proposals within close proximity of each other require planning policies and decisions to consider the cumulative impact of them. Difficulties arise when developments are permitted sequentially, with each individually having only a relatively low polluting potential, but which cumulatively result in a significant worsening of air quality. This will occur where:

1. A single large site is divided into a series of units, such as an industrial estates
2. A major development is broken down into a series of smaller planning applications for administrative ease; and
3. There are cumulative air quality impacts from a series of unrelated developments in the same area

In criteria (i) and (ii) the cumulative impact will be addressed by the likelihood that a single developer will bring forward an outline application for the whole site which should include an air quality assessment as part of an Environmental Assessment. For major developments that are broken down into a series of smaller planning applications, the use of a Master or Parameter Plan that includes an air quality assessment will address the cumulative impact.

• Agreement of the traffic figures, fleet composition and routes. This will require agreement from the highway authority. If these traffic figures change, the air quality assessment may be inaccurate and may require to be re-assessed.

The traffic figures must be agreed with the relevant highway authority, in consultation with the LPA prior to submission of an air quality assessment.

Section 5 - Air Quality Assessment

Expectations

8.10 An air quality assessment is a detailed assessment which predicts the potential impact of the proposed development on local air quality. An air quality assessment will;

• follow current air quality / planning guidance;
• utilise current air quality assessment methodologies, which have ideally been agreed with the Local Planning Authority in advance of an application being submitted;
• effectively assess the significance of the potential impact of the proposed development on local air quality;
• use professional judgement; and,
• commit the applicant to implementing proportionate mitigation measures to minimise air quality emissions from the proposed development. The types of mitigation measures will be dependent on the outcome of the agreed air quality assessment.

8.11 An air quality assessment is expected to include:

• Details of the proposed development.
• Policy context for the assessment. This should include local and national policies
• Description of relevant air quality standards and objectives.
• Details of assessment methodologies - as advised in Section 4.
• Identify relevant receptors. This is dependent on the emissions of concern and relevant air quality objectives.
• Description of baseline conditions
• Use appropriate mathematical verification of the model in accordance with guidance
• Provide results of the model outputs for all pollutants of concern at all relevant receptors locations. All modelled results should be presented as;

1. baseline pollutant concentrations (current air quality concentrations)
2. pollutant concentrations without development (at development completion year)
3. pollutant concentrations with development (at development completion year) and if appropriate;
4. pollutant concentrations with development plus identified cumulative impacts
5. appropriate sensitivity test

• Provide robust determination of the significance of the likely impact of the proposed development at all relevant receptor locations. This should follow relevant guidance and use professional judgement when required.
• Provide details on mitigation measures based on the determination of significance with regards to the impact on local air quality
• Summary of the Air Quality Assessment

8.12 The methodology to be used for the determination of pollution concentration change should meet the requirement of the Department for the Environment, Food and Rural Affairs (DEFRA) Technical Guidance Note LAQM TG (16) or any subsequent relevant guidance.

Appropriate Mitigation

8.13 For proposed developments requiring an Air Quality Statement there will be a requirement to include a minimum of 3 mitigation measures. A list of suggested mitigation measures is available in Appendix 1, other appropriate mitigation measures can be proposed by the developer

8.14 For proposed developments requiring an Air Quality Assessment, the level of required mitigation is dependent on the outcome of the assessment:

A. Proposed developments determined to have a significant impact on local air quality - the applicant will be required to put in place mitigation measures which can demonstrate compliance with current air quality objectives. This may include an agreed reduction in emissions from the development site that is retained and maintained, and the installation of real time monitoring of pollutants to assess the impact on local air quality.

B. Proposed developments determined to not have a significant impact will be required to include as a minimum 3 mitigation measures. A list of suggested mitigation measures is available in Appendix 1, other appropriate mitigation measures can be proposed by the developer.

Section 6 - Dust Impact Assessment

8.15 An air quality statement or assessment must also assess the potential impact from dust from the construction phase of the development on local relevant receptors.

Requirement for a Dust Impact Assessment

8.16 A dust impact assessment is required where there is a human receptor within:

• 350m of the site boundary, or 
• 50m of the route(s) used by construction vehicles on the public highway, up to500m from the site entrance(s)

8.17  The assessment of dust from construction sites (dust impact assessment) can be undertaken within the air quality statement or assessment, or as a separate assessment, but in either case should follow current relevant guidance (Guidance on the assessment of dust from demolition and construction. Institute of Air Quality Management. February 2014).

8.18  The significance of the impact of construction dust is determined as a human health and dust soiling (nuisance) impact, and should be assessed for the following construction phases:

• Demolition
• Earthworks
• Construction
• Track out

8.19 The dust impact assessment will identify the potential impact at each phase of construction work against each type of impact (human health and / or dust soiling). The outcome of which may recommend mitigation measures to reduce the predicted impact to an acceptable level.

8.20 The Council advise that only a dust impact assessment is submitted as part of the application process. A Dust Management Plan (see Section 7), if required, will be agreed as part of a Construction Environmental Management Plan (CEMP) planning condition.

Section 7 - Dust Management Plan

8.19  Should the Dust Impact Assessment identify the likelihood of a dust impact either to human health and/or from dust soiling at relevant receptors the applicant will be required to submit an appropriate Dust Management Plan.

Expectations

8.20 A Dust Management Plan will:

• follow current air quality/planning guidance;
• include the Dust Impact Assessment which will identify the locations of potential impact and specific works requiring mitigation;
• be site specific, taking into account site layout, machinery and equipment to be used on site, vehicle emissions and any occupiers of the site as development continues; and,
• commit the applicant by a planning condition to implement appropriate mitigation measures to minimise dust and particulate emissions from the development site. Appropriate mitigation measures are provided in the guidance and should be adopted where appropriate. This may include the need to monitor the dust from the construction site.

Submission of Dust Management Plan

8.21 Should the Dust Impact Assessment identify the likelihood of a dust impact either to human health and/or from dust soiling at relevant receptors the applicant will be required to submit an appropriate Dust Management Plan.

Operational Phase

8.22 A Dust Management Plan will:

• follow current air quality/planning guidance;
• include the Dust Impact Assessment which identifies the locations of potential impact and specific works requiring mitigation;
• be site specific, taking into account site layout, machinery and equipment to be used on site, vehicle emissions and any occupiers of the site as development continues; and,
• commit the applicant by a planning condition to implement appropriate mitigation measures to minimise dust and particulate emissions from the development site. Appropriate mitigation measures are provided in the guidance and should be adopted where appropriate. This may include the need to monitor the dust from the construction site.

Submission of Dust Management Plan

8.23 You may be required to submit of a Dust Management Plan as part of a CEMP condition should planning permission be granted. If you submit a Dust Management Plan as part of the application the Plan will not be reviewed or commented on.