Southbourne Allocation Development Plan Document Regulation 19 - Supporting Documents

We advise that the DPD wording should be amended to clarify that development may require
additional bespoke mitigation measures. We advise that the DPD wording should also include
additional information on the SANG design, as outlined in Annex 1. Provided that these
amendments are made, we would be satisfied that there will be no adverse effect on the integrity of
the Solent Habitats sites due to recreational pressure.

Southbourne Allocation Development Plan Document Regulation 19 consultation

Thank you for your consultation on the above dated 05 June 2026 which was received by Natural England on the same date.

Natural England is a non-departmental public body. Our statutory purpose is to ensure that the natural environment is conserved, enhanced and managed for the benefit of present and future generations, thereby contributing to sustainable development.

Natural England has reviewed the Southbourne Allocation Development Plan Document (DPD) together with the Habitats Regulations Assessment (HRA), Sustainability Appraisal (SA) and other relevant supporting evidence documents.

Summary of Natural England's advice

Natural England supports the principles of the avoidance and mitigation measures proposed to address impacts to designated sites from development at the allocation site. However, we suggest some further information is included in the DPD to ensure all impacts from development are fully mitigated and help ensure the DPD is sound.

Our detailed comments are provided in the following annexes:

Annex 1. Southbourne Allocation Development Plan Document (DPD) Annex 2. Habitats Regulations Assessment (HRA) Annex 3. Standard Advice for Air Quality Impacts for Local Plans

Please note that we have not provided comments on all aspects of the DPD but those which have the most influence on issues within our remit. It there are topics not covered in this response where your Authority would particularly value our advice, then please let us know. Other than referring to it when giving advice on the DPD, we do not have any general comments to make on the Sustainability Appraisal.

We remain committed to continuing to work closely with your Authority to help ensure that a sound plan is secured that enables growth in accordance with the principles of sustainable development. We would welcome the opportunity for further dialogue around matters raised here in more detail, although depending on the nature and scope of such discussion this may need to be on a cost- recovery basis.

Annex 1: Southbourne Allocation Development Plan Document (DPD)

Chapter 4. Vision and objectives

We welcome that the vision includes connecting residents with nature and support the objectives relating to the natural environment, including:

Objective 1 which highlights the important of nature for promoting health and wellbeing; Objective 4 which seeks to strengthen green and blue infrastructure and promote active travel; Objective 5 which seeks to preserve and enhance biodiversity and connect green spaces, parks and natural habitats; and Objective 6 related to impacts of development on Chichester Harbour National Landscape and South Downs National Park.

Chapter 5. The Allocation and Framework Masterplan

Development Policies / Principles

Policy SA1 - East of Southbourne

We recognise that the allocation masterplan incorporates an area of recreational open space intended to serve as a Suitable Alternative Natural Greenspace (SANG) to mitigate recreational disturbance on the Solent sites. We have provided further advice on the SANG provision throughout this letter. We advise that any changes made to the SANG design in light of this advice should be reflected in the framework masterplan (Figure 2).

Environment

Landscape strategy

We welcome the inclusion of adopting a multifunctional approach to open space including green and blue infrastructure and nature plus the use of planting and sustainable urban drainage systems for climate change adaptation and mitigation.

Landscape Impacts

We are pleased that views from the South Downs National Park and Chichester Harbour National Landscape and their settings have been considered in the preparation of the DPD and recognise that further consideration of this will be required at project level. We note that the Southbourne allocation site appears to be in the setting of both the South Downs National Park and Chichester Harbour National Landscape. Paragraph 189 of the NPPF states that development within the setting of National Parks and National Landscapes should be sensitively located and designed to avoid or minimise adverse impacts on the designated areas. Natural England considers the DPD to be sound in respect to impacts to protected landscapes. However, we advise that any proposed development at the allocation site should give consideration to the level of landscape sensitivity, risk of potential impacts on special qualities and views, and the scope for mitigation to ensure they are sensitively located and designed to avoid or minimise any adverse impacts.

Suitable Alternative Natural Green Space (SANG)

We recognise that the allocation masterplan incorporates an area of recreational open space intended to serve as a SANG to mitigate recreational disturbance on the Solent sites. We support that the open space should have a 2.5km walking route. However, we note that the walking route does not appear to utilise much of the open space (Figure 2 - Framework masterplan). We advise that the 2.5km walking route should be a circular route that utilises the open space as much as possible. We also note the area of open space to be provided is not yet determined. We would expect the area of open space to be identified in the DPD to ensure that it is of sufficient size to be able to provide an attractive semi-natural recreational area, incorporating natural features to provide an attractive and sufficiently long walking route. We advise that further information on the habitats and natural features that should be delivered should be included in the DPD to help ensure an attractive semi-natural open space is delivered. Your authority has measures in place to manage the potential impact of recreational pressure/disturbance on the Solent Habitats sites in the form of a strategic solution of Solent Recreation Mitigation Strategy (SRMS) payments. We advise that given the scale of the development and its proximity to coastal designated sites, standard financial contributions and on- site greenspace provision are unlikely to wholly mitigate the impact of increased recreational disturbance alone, and development may require additional bespoke mitigation measures in line with the Solent Recreation Mitigation Strategy (December 2017). We advise that this should be highlighted in the DPD to ensure it is clear that development proposals may be required to deliver additional bespoke mitigation. As outlined in Annex 2 of this letter, we advise that further bird surveys and a Habitats Regulations Assessment (HRA) should be conducted at development management stage to assess the strength of functional linkage of the allocation site and scope for mitigation. We advise that this should be added to the DPD wording to ensure it is clear that development proposals would be required to do this. Flooding We welcome the requirement for SuDS to be incorporated into the development's open space strategy, adopting a multi-functional approach to benefit people and nature.

Annex 2: Habitats Regulations Assessment (HRA)

Natural England has reviewed the Southbourne Site Allocation DPD Habitats Regulations Assessment (dated April 2026) and agree with the pathways for which significant effects cannot be ruled out. Natural England has provided standard advice on air quality impacts for Local Plans in Annex 3 of this letter. We provide the following advice on sites and pathways for which likely significant effects cannot be ruled out:

Solent Habitats sites - recreational pressure

We agree that the Solent Habitats sites should be taken forward to appropriate assessment on recreational pressure. However, we advise that there is currently insufficient information to conclude that there will be no adverse effect on the integrity of the Solent Habitats sites due to recreational pressure.

As noted in the HRA (paragraph 6.8), a SANG is unlikely to fully mitigate the impacts from increased recreational pressure due to the unique draw of the coast, and it is considered likely that additional development-specific mitigation measures will be needed to conclude no adverse effects on site integrity. Your authority has measures in place to manage the potential impact of recreational pressure/disturbance on the Solent Habitats sites in the form of a strategic solution of Solent Recreation Mitigation Strategy (SRMS) payments. We advise that given the scale of the development and its proximity to coastal designated sites, standard financial contributions and on- site greenspace provision are unlikely to wholly mitigate the impact of increased recreational disturbance alone, and development may require additional bespoke mitigation measures in line with the Solent Recreation Mitigation Strategy (December 2017).

We advise that the DPD wording should be amended to clarify that development may require additional bespoke mitigation measures. We advise that the DPD wording should also include additional information on the SANG design, as outlined in Annex 1. Provided that these amendments are made, we would be satisfied that there will be no adverse effect on the integrity of the Solent Habitats sites due to recreational pressure.

Solent Habitat sites - water quality

We agree that the Solent Habitat sites should be taken forward to appropriate assessment on water quality. Natural England supports the preparation of a nutrient budget to cover the planned dwellings. We agree with the HRA conclusion of no adverse effect on the integrity of the Solent Habitats sites based on the nutrient budget calculations taken place, which show that no additional mitigation is required. As stated in the HRA (paragraph 6.21), we advise that an updated nitrogen budget will be required with any planning application at the allocation site to determine if any mitigation measures are required.

Chichester and Langstone Harbours SPA and Ramsar site - loss of functionally linked habitat

We agree that Chichester and Langstone Harbours SPA and Ramsar site should be taken forward to appropriate assessment on loss of functionally linked habitat. It is understood that the Council's preferred option for the Southbourne Allocation has been in part chosen because it avoids the development of a Secondary Support Area for brent geese (p.23 of SA). We recognise that the Southbourne Allocation area in the DPD is not identified as a key functionally linked habitat parcel in the Solent Waders & Brent Goose Strategy. However, we advise that areas that have not been identified within the Solent Wader & Brent Goose Strategy still have the potential to provide functional linkage to the Chichester and Langstone Harbour SPA and Ramsar site.

We note that winter bird surveys conducted in 2022/2023 found lapwing and snipe utilising the site. The HRA considers these to be in sufficiently low numbers that the SPA bird features will not be materially affected by the allocation, and therefore that adverse effects on the integrity of the SPA and Ramsar can be ruled out. We have not seen the detailed survey methods and results of the winter bird surveys but, from the information provided in the HRA, we advise that there is currently insufficient certainty to conclude that there will be no adverse effect on integrity due to loss of functionally linked habitat. It is our understanding that one survey per month from October to February were carried out. We recommend that more detailed winter bird surveys should be carried out at the development management stage to determine the strength of functional linkage and if any mitigation measures are required for the loss of functionally linked land. Any changes in habitat suitability on the allocation site should also be assessed. We advise that the DPD policy wording should be amended to include a requirement for detailed bird surveys and a HRA to be conducted at development management stage. Provided that this is added to the DPD wording, we would agree that the DPD would have no adverse effect on the integrity of the sites due to loss of functionally linked land.

Annex 3: Standard Advice for Air Quality Impacts for Local Plans

Local Plans are likely to generate increased emissions of nitrogen oxides (NOx) and ammonia, and additional nitrogen deposition as a result of increased traffic generation associated with new development. As impacts from individual development management proposals would be difficult to quantify without an overarching assessment of the cumulative impacts from Local Plan development, it is necessary for this to be considered strategically at plan level. Natural England would expect the environmental assessment of the plan including the Sustainability Appraisal (SA) and the Habitats Regulations Assessment (HRA) to consider any detrimental impacts on the natural environment from these emissions. It should also suggest appropriate avoidance or mitigation measures where applicable. Technical guidance about the ecological impacts from road transport can also be found in the Natural England research report The ecological effects of air pollution from road transport: an updated review' (NECR199).

Protected sites are 'sites of special scientific interest' (SSSIs) and 'habitats sites' (also called 'European sites'). For the purposes of this advice, Habitats Sites are Special Areas of Conservation (SACs), possible SACs, Special Protection Areas (SPAs), Potential SPAs, Ramsar sites, and sites identified, or required, as compensatory measures for adverse effects on Habitats Sites.

Although their regulatory frameworks differ, the general principles and approach for air pollution assessment outlined for Habitats Sites are also relevant for SSSIs. Where the following advice applies to both, we use the term protected sites. Where the advice or approach differs, the individual terms are used.

Habitats Sites and SSSIs at risk from local impacts are those within 200m of a road with increased traffic, which feature habitats that are vulnerable to nitrogen deposition and/or acidification.

Natural England provides the following standard advice on air pollution. This advice relates to the protection of protected sites under the Conservation of Habitats and Species Regulations 2017 (the Habitats Regulations) and the Wildlife and Countryside Act 1981 and should also be taken as Natural England's formal representation under the Town & Country Planning (Local Planning) Regulations 2012. This standard advice is applicable to all stages of the Local Plan process. This includes advice on information that is required to assess air quality and how to interpret the results of air quality modelling for your LPA to conclude whether air quality impacts would have an adverse effect on the integrity of a Habitat site or a SSSI. Detailed guidance on how to undertake a Habitats Regulations Assessment for air pollution impacts generated from traffic can be found here Natural England's approach to advising competent authorities on the assessment of road traffic emissions under the Habitats Regulations (NEA001).

You should also consider any relevant caselaw that could affect how you carry out any air quality assessments.

Air pollutants

This advice covers the following air pollutants:

ammonia (NH3)
nitrogen oxides (NO, NO2 or NOx)
nitrogen deposition
acid deposition
sulphur dioxide (SO2)
Standing advice on air pollution and development is also available here: https://www.gov.uk/guidance/air-pollution-and-development-advice-for-local-authorities

Whilst the standing advice does not cover Local Plans, it does include additional technical advice which may prove useful. However, in summary, Table 1 provides the steps that we advise should be taken by local planning authorities.

Table 1: Sequential approach to air quality assessments
(See attachment)

Additional advice

For many protected sites, the current background pollution may already be exceeding the relevant critical load/level from a different source type to the project being assessed (e.g. the main source of background exceedance is due to agriculture, but the proposal is a road scheme). Proposals must consider their own impacts against the relevant environmental thresholds. There are many reasons why background levels are high, but the conservation objective is to 'maintain or restore' air pollutants to within these benchmarks. The objective would be undermined by proposals that add further emissions, including if it compromises any strategic initiatives to reduce air pollution levels.

Where an air quality report concludes that only a very small area of the site will be impacted, the assessment of effects on integrity or damage to the site, should take into account the interest features of the site, their distribution and how they will be impacted by proposals rather than on specific percentages of site. Dependent on features being present in the area to be impacted, this could have a disproportionate impact on the site if an area of a rare habitat type were lost rather than a judgement just on the percentages of habitat.

Improvements in vehicle technology and a move to further electrification of the vehicle fleet will, over time, result in lower background levels of nitrogen deposition and Nitrogen Oxide pollution near to roads. As most sites are currently over the relevant thresholds and have a "restore" objective, this should be noted as a "retardation" of the restore objective and expressed in months and years. Retardation of less than one year is acceptable as air quality is considered against an annual average. Please note that ammonia impacts cannot be assessed in this manner as there is no certainty of a declining trend.

Common Standards Monitoring is used to define the ecological condition of a protected site. It is undertaken on a broader level and does not currently consider air quality impacts. The relevant benchmark for assessing impacts is the critical thresholds. Therefore, the existing status of a designated site should not be the sole reason for judgement on potential impact.

Defra Emissions Factor Toolkit

The Defra Emission Factor Toolkit (EFT) allows for gradual introduction of electric vehicles into the fleet (cars and LGVs) up to 2050. These are the emission factors we advise that Local Plans should be using (which we advise should also consider ammonia emissions as well as NOx - using one of three sets of emission factors available). However, the User Guide to the EFT highlights that calculation tools only support assessment years 2018 up to 2030, reflecting that predictions and assumptions beyond then become less certain. Where EFT calculated emissions are to be used after 2030 to inform air quality assessments, the EFT indicates that appropriate caveats around the limitations of the analysis must be included to accompany the assessment.

We therefore advise that emission factors no later than 2030 are used for HRAs- which would mean percentages of EVs are at predicted 2030 levels. A key concern is that, although EVs themselves have no tailpipe emissions, and the percentage of them will increase, the remaining combustion engine vehicles on the road may become more polluting as they age as selective catalytic reduction technology may create 'ammonia slip' over time. Ammonia slip is the unreacted ammonia (NH₃) that escapes from a selective catalytic reduction (SCR) or selective non-catalytic reduction (SNCR) system used to reduce NOx in exhaust gases. Motorways within the affected road network There is potentially an added complexity to the need for in-combination assessments when considering traffic on motorways, as including these roads can mean that the assessment takes account of traffic growth related to strategic factors or long range (external) trips that are independent of the specific plan or project and neighbouring plans or projects. These roads are strategically important and tend to have high volumes of traffic as well as being well represented in traffic models. The air quality assessment should therefore include traffic flows on these roads, but the external trips can be excluded from the initial screening assessment. A justification and explanation of which journeys are included and excluded in the traffic model should be provided. The conclusions reached on the air pollution impacts of the HRA must be incorporated into the wider HRA conclusions for other impact pathways identified for the local plan. How to Use this Advice in Decision Making Provided you have followed the above advice and have been able to conclude there would be no adverse effects on any protected sites we would be able to agree with the conclusions of your HRA in relation to air quality impacts and that the Local Plan is sound in this regard.

Southbourne Allocation Development Plan Document Regulation 19 consultation

Thank you for your consultation on the above dated 05 June 2026 which was received by Natural England on the same date.

Natural England is a non-departmental public body. Our statutory purpose is to ensure that the natural environment is conserved, enhanced and managed for the benefit of present and future generations, thereby contributing to sustainable development.

Natural England has reviewed the Southbourne Allocation Development Plan Document (DPD) together with the Habitats Regulations Assessment (HRA), Sustainability Appraisal (SA) and other relevant supporting evidence documents.

Summary of Natural England's advice

Natural England supports the principles of the avoidance and mitigation measures proposed to address impacts to designated sites from development at the allocation site. However, we suggest some further information is included in the DPD to ensure all impacts from development are fully mitigated and help ensure the DPD is sound.

Our detailed comments are provided in the following annexes:

Annex 1. Southbourne Allocation Development Plan Document (DPD) Annex 2. Habitats Regulations Assessment (HRA) Annex 3. Standard Advice for Air Quality Impacts for Local Plans

Please note that we have not provided comments on all aspects of the DPD but those which have the most influence on issues within our remit. It there are topics not covered in this response where your Authority would particularly value our advice, then please let us know. Other than referring to it when giving advice on the DPD, we do not have any general comments to make on the Sustainability Appraisal.

We remain committed to continuing to work closely with your Authority to help ensure that a sound plan is secured that enables growth in accordance with the principles of sustainable development. We would welcome the opportunity for further dialogue around matters raised here in more detail, although depending on the nature and scope of such discussion this may need to be on a cost- recovery basis.

Annex 1: Southbourne Allocation Development Plan Document (DPD)

Chapter 4. Vision and objectives

We welcome that the vision includes connecting residents with nature and support the objectives relating to the natural environment, including:

Objective 1 which highlights the important of nature for promoting health and wellbeing; Objective 4 which seeks to strengthen green and blue infrastructure and promote active travel; Objective 5 which seeks to preserve and enhance biodiversity and connect green spaces, parks and natural habitats; and Objective 6 related to impacts of development on Chichester Harbour National Landscape and South Downs National Park.

Chapter 5. The Allocation and Framework Masterplan

Development Policies / Principles

Policy SA1 - East of Southbourne

We recognise that the allocation masterplan incorporates an area of recreational open space intended to serve as a Suitable Alternative Natural Greenspace (SANG) to mitigate recreational disturbance on the Solent sites. We have provided further advice on the SANG provision throughout this letter. We advise that any changes made to the SANG design in light of this advice should be reflected in the framework masterplan (Figure 2).

Environment

Landscape strategy

We welcome the inclusion of adopting a multifunctional approach to open space including green and blue infrastructure and nature plus the use of planting and sustainable urban drainage systems for climate change adaptation and mitigation.

Landscape Impacts

We are pleased that views from the South Downs National Park and Chichester Harbour National Landscape and their settings have been considered in the preparation of the DPD and recognise that further consideration of this will be required at project level. We note that the Southbourne allocation site appears to be in the setting of both the South Downs National Park and Chichester Harbour National Landscape. Paragraph 189 of the NPPF states that development within the setting of National Parks and National Landscapes should be sensitively located and designed to avoid or minimise adverse impacts on the designated areas. Natural England considers the DPD to be sound in respect to impacts to protected landscapes. However, we advise that any proposed development at the allocation site should give consideration to the level of landscape sensitivity, risk of potential impacts on special qualities and views, and the scope for mitigation to ensure they are sensitively located and designed to avoid or minimise any adverse impacts.

Suitable Alternative Natural Green Space (SANG)

We recognise that the allocation masterplan incorporates an area of recreational open space intended to serve as a SANG to mitigate recreational disturbance on the Solent sites. We support that the open space should have a 2.5km walking route. However, we note that the walking route does not appear to utilise much of the open space (Figure 2 - Framework masterplan). We advise that the 2.5km walking route should be a circular route that utilises the open space as much as possible. We also note the area of open space to be provided is not yet determined. We would expect the area of open space to be identified in the DPD to ensure that it is of sufficient size to be able to provide an attractive semi-natural recreational area, incorporating natural features to provide an attractive and sufficiently long walking route. We advise that further information on the habitats and natural features that should be delivered should be included in the DPD to help ensure an attractive semi-natural open space is delivered. Your authority has measures in place to manage the potential impact of recreational pressure/disturbance on the Solent Habitats sites in the form of a strategic solution of Solent Recreation Mitigation Strategy (SRMS) payments. We advise that given the scale of the development and its proximity to coastal designated sites, standard financial contributions and on- site greenspace provision are unlikely to wholly mitigate the impact of increased recreational disturbance alone, and development may require additional bespoke mitigation measures in line with the Solent Recreation Mitigation Strategy (December 2017). We advise that this should be highlighted in the DPD to ensure it is clear that development proposals may be required to deliver additional bespoke mitigation. As outlined in Annex 2 of this letter, we advise that further bird surveys and a Habitats Regulations Assessment (HRA) should be conducted at development management stage to assess the strength of functional linkage of the allocation site and scope for mitigation. We advise that this should be added to the DPD wording to ensure it is clear that development proposals would be required to do this. Flooding We welcome the requirement for SuDS to be incorporated into the development's open space strategy, adopting a multi-functional approach to benefit people and nature.

Annex 2: Habitats Regulations Assessment (HRA)

Natural England has reviewed the Southbourne Site Allocation DPD Habitats Regulations Assessment (dated April 2026) and agree with the pathways for which significant effects cannot be ruled out. Natural England has provided standard advice on air quality impacts for Local Plans in Annex 3 of this letter. We provide the following advice on sites and pathways for which likely significant effects cannot be ruled out:

Solent Habitats sites - recreational pressure

We agree that the Solent Habitats sites should be taken forward to appropriate assessment on recreational pressure. However, we advise that there is currently insufficient information to conclude that there will be no adverse effect on the integrity of the Solent Habitats sites due to recreational pressure.

As noted in the HRA (paragraph 6.8), a SANG is unlikely to fully mitigate the impacts from increased recreational pressure due to the unique draw of the coast, and it is considered likely that additional development-specific mitigation measures will be needed to conclude no adverse effects on site integrity. Your authority has measures in place to manage the potential impact of recreational pressure/disturbance on the Solent Habitats sites in the form of a strategic solution of Solent Recreation Mitigation Strategy (SRMS) payments. We advise that given the scale of the development and its proximity to coastal designated sites, standard financial contributions and on- site greenspace provision are unlikely to wholly mitigate the impact of increased recreational disturbance alone, and development may require additional bespoke mitigation measures in line with the Solent Recreation Mitigation Strategy (December 2017).

We advise that the DPD wording should be amended to clarify that development may require additional bespoke mitigation measures. We advise that the DPD wording should also include additional information on the SANG design, as outlined in Annex 1. Provided that these amendments are made, we would be satisfied that there will be no adverse effect on the integrity of the Solent Habitats sites due to recreational pressure.

Solent Habitat sites - water quality

We agree that the Solent Habitat sites should be taken forward to appropriate assessment on water quality. Natural England supports the preparation of a nutrient budget to cover the planned dwellings. We agree with the HRA conclusion of no adverse effect on the integrity of the Solent Habitats sites based on the nutrient budget calculations taken place, which show that no additional mitigation is required. As stated in the HRA (paragraph 6.21), we advise that an updated nitrogen budget will be required with any planning application at the allocation site to determine if any mitigation measures are required.

Chichester and Langstone Harbours SPA and Ramsar site - loss of functionally linked habitat

We agree that Chichester and Langstone Harbours SPA and Ramsar site should be taken forward to appropriate assessment on loss of functionally linked habitat. It is understood that the Council's preferred option for the Southbourne Allocation has been in part chosen because it avoids the development of a Secondary Support Area for brent geese (p.23 of SA). We recognise that the Southbourne Allocation area in the DPD is not identified as a key functionally linked habitat parcel in the Solent Waders & Brent Goose Strategy. However, we advise that areas that have not been identified within the Solent Wader & Brent Goose Strategy still have the potential to provide functional linkage to the Chichester and Langstone Harbour SPA and Ramsar site.

We note that winter bird surveys conducted in 2022/2023 found lapwing and snipe utilising the site. The HRA considers these to be in sufficiently low numbers that the SPA bird features will not be materially affected by the allocation, and therefore that adverse effects on the integrity of the SPA and Ramsar can be ruled out. We have not seen the detailed survey methods and results of the winter bird surveys but, from the information provided in the HRA, we advise that there is currently insufficient certainty to conclude that there will be no adverse effect on integrity due to loss of functionally linked habitat. It is our understanding that one survey per month from October to February were carried out. We recommend that more detailed winter bird surveys should be carried out at the development management stage to determine the strength of functional linkage and if any mitigation measures are required for the loss of functionally linked land. Any changes in habitat suitability on the allocation site should also be assessed. We advise that the DPD policy wording should be amended to include a requirement for detailed bird surveys and a HRA to be conducted at development management stage. Provided that this is added to the DPD wording, we would agree that the DPD would have no adverse effect on the integrity of the sites due to loss of functionally linked land.

Annex 3: Standard Advice for Air Quality Impacts for Local Plans

Local Plans are likely to generate increased emissions of nitrogen oxides (NOx) and ammonia, and additional nitrogen deposition as a result of increased traffic generation associated with new development. As impacts from individual development management proposals would be difficult to quantify without an overarching assessment of the cumulative impacts from Local Plan development, it is necessary for this to be considered strategically at plan level. Natural England would expect the environmental assessment of the plan including the Sustainability Appraisal (SA) and the Habitats Regulations Assessment (HRA) to consider any detrimental impacts on the natural environment from these emissions. It should also suggest appropriate avoidance or mitigation measures where applicable. Technical guidance about the ecological impacts from road transport can also be found in the Natural England research report The ecological effects of air pollution from road transport: an updated review' (NECR199).

Protected sites are 'sites of special scientific interest' (SSSIs) and 'habitats sites' (also called 'European sites'). For the purposes of this advice, Habitats Sites are Special Areas of Conservation (SACs), possible SACs, Special Protection Areas (SPAs), Potential SPAs, Ramsar sites, and sites identified, or required, as compensatory measures for adverse effects on Habitats Sites.

Although their regulatory frameworks differ, the general principles and approach for air pollution assessment outlined for Habitats Sites are also relevant for SSSIs. Where the following advice applies to both, we use the term protected sites. Where the advice or approach differs, the individual terms are used.

Habitats Sites and SSSIs at risk from local impacts are those within 200m of a road with increased traffic, which feature habitats that are vulnerable to nitrogen deposition and/or acidification.

Natural England provides the following standard advice on air pollution. This advice relates to the protection of protected sites under the Conservation of Habitats and Species Regulations 2017 (the Habitats Regulations) and the Wildlife and Countryside Act 1981 and should also be taken as Natural England's formal representation under the Town & Country Planning (Local Planning) Regulations 2012. This standard advice is applicable to all stages of the Local Plan process. This includes advice on information that is required to assess air quality and how to interpret the results of air quality modelling for your LPA to conclude whether air quality impacts would have an adverse effect on the integrity of a Habitat site or a SSSI. Detailed guidance on how to undertake a Habitats Regulations Assessment for air pollution impacts generated from traffic can be found here Natural England's approach to advising competent authorities on the assessment of road traffic emissions under the Habitats Regulations (NEA001).

You should also consider any relevant caselaw that could affect how you carry out any air quality assessments.

Air pollutants

This advice covers the following air pollutants:

ammonia (NH3)
nitrogen oxides (NO, NO2 or NOx)
nitrogen deposition
acid deposition
sulphur dioxide (SO2)
Standing advice on air pollution and development is also available here: https://www.gov.uk/guidance/air-pollution-and-development-advice-for-local-authorities

Whilst the standing advice does not cover Local Plans, it does include additional technical advice which may prove useful. However, in summary, Table 1 provides the steps that we advise should be taken by local planning authorities.

Table 1: Sequential approach to air quality assessments
(See attachment)

Additional advice

For many protected sites, the current background pollution may already be exceeding the relevant critical load/level from a different source type to the project being assessed (e.g. the main source of background exceedance is due to agriculture, but the proposal is a road scheme). Proposals must consider their own impacts against the relevant environmental thresholds. There are many reasons why background levels are high, but the conservation objective is to 'maintain or restore' air pollutants to within these benchmarks. The objective would be undermined by proposals that add further emissions, including if it compromises any strategic initiatives to reduce air pollution levels.

Where an air quality report concludes that only a very small area of the site will be impacted, the assessment of effects on integrity or damage to the site, should take into account the interest features of the site, their distribution and how they will be impacted by proposals rather than on specific percentages of site. Dependent on features being present in the area to be impacted, this could have a disproportionate impact on the site if an area of a rare habitat type were lost rather than a judgement just on the percentages of habitat.

Improvements in vehicle technology and a move to further electrification of the vehicle fleet will, over time, result in lower background levels of nitrogen deposition and Nitrogen Oxide pollution near to roads. As most sites are currently over the relevant thresholds and have a "restore" objective, this should be noted as a "retardation" of the restore objective and expressed in months and years. Retardation of less than one year is acceptable as air quality is considered against an annual average. Please note that ammonia impacts cannot be assessed in this manner as there is no certainty of a declining trend.

Common Standards Monitoring is used to define the ecological condition of a protected site. It is undertaken on a broader level and does not currently consider air quality impacts. The relevant benchmark for assessing impacts is the critical thresholds. Therefore, the existing status of a designated site should not be the sole reason for judgement on potential impact.

Defra Emissions Factor Toolkit

The Defra Emission Factor Toolkit (EFT) allows for gradual introduction of electric vehicles into the fleet (cars and LGVs) up to 2050. These are the emission factors we advise that Local Plans should be using (which we advise should also consider ammonia emissions as well as NOx - using one of three sets of emission factors available). However, the User Guide to the EFT highlights that calculation tools only support assessment years 2018 up to 2030, reflecting that predictions and assumptions beyond then become less certain. Where EFT calculated emissions are to be used after 2030 to inform air quality assessments, the EFT indicates that appropriate caveats around the limitations of the analysis must be included to accompany the assessment.

We therefore advise that emission factors no later than 2030 are used for HRAs- which would mean percentages of EVs are at predicted 2030 levels. A key concern is that, although EVs themselves have no tailpipe emissions, and the percentage of them will increase, the remaining combustion engine vehicles on the road may become more polluting as they age as selective catalytic reduction technology may create 'ammonia slip' over time. Ammonia slip is the unreacted ammonia (NH₃) that escapes from a selective catalytic reduction (SCR) or selective non-catalytic reduction (SNCR) system used to reduce NOx in exhaust gases. Motorways within the affected road network There is potentially an added complexity to the need for in-combination assessments when considering traffic on motorways, as including these roads can mean that the assessment takes account of traffic growth related to strategic factors or long range (external) trips that are independent of the specific plan or project and neighbouring plans or projects. These roads are strategically important and tend to have high volumes of traffic as well as being well represented in traffic models. The air quality assessment should therefore include traffic flows on these roads, but the external trips can be excluded from the initial screening assessment. A justification and explanation of which journeys are included and excluded in the traffic model should be provided. The conclusions reached on the air pollution impacts of the HRA must be incorporated into the wider HRA conclusions for other impact pathways identified for the local plan. How to Use this Advice in Decision Making Provided you have followed the above advice and have been able to conclude there would be no adverse effects on any protected sites we would be able to agree with the conclusions of your HRA in relation to air quality impacts and that the Local Plan is sound in this regard.

We advise that the DPD policy wording should be amended to include a requirement for detailed
bird surveys and a HRA to be conducted at development management stage. Provided that this is
added to the DPD wording, we would agree that the DPD would have no adverse effect on the
integrity of the sites due to loss of functionally linked land.

Southbourne Allocation Development Plan Document Regulation 19 consultation

Thank you for your consultation on the above dated 05 June 2026 which was received by Natural England on the same date.

Natural England is a non-departmental public body. Our statutory purpose is to ensure that the natural environment is conserved, enhanced and managed for the benefit of present and future generations, thereby contributing to sustainable development.

Natural England has reviewed the Southbourne Allocation Development Plan Document (DPD) together with the Habitats Regulations Assessment (HRA), Sustainability Appraisal (SA) and other relevant supporting evidence documents.

Summary of Natural England's advice

Natural England supports the principles of the avoidance and mitigation measures proposed to address impacts to designated sites from development at the allocation site. However, we suggest some further information is included in the DPD to ensure all impacts from development are fully mitigated and help ensure the DPD is sound.

Our detailed comments are provided in the following annexes:

Annex 1. Southbourne Allocation Development Plan Document (DPD) Annex 2. Habitats Regulations Assessment (HRA) Annex 3. Standard Advice for Air Quality Impacts for Local Plans

Please note that we have not provided comments on all aspects of the DPD but those which have the most influence on issues within our remit. It there are topics not covered in this response where your Authority would particularly value our advice, then please let us know. Other than referring to it when giving advice on the DPD, we do not have any general comments to make on the Sustainability Appraisal.

We remain committed to continuing to work closely with your Authority to help ensure that a sound plan is secured that enables growth in accordance with the principles of sustainable development. We would welcome the opportunity for further dialogue around matters raised here in more detail, although depending on the nature and scope of such discussion this may need to be on a cost- recovery basis.

Annex 1: Southbourne Allocation Development Plan Document (DPD)

Chapter 4. Vision and objectives

We welcome that the vision includes connecting residents with nature and support the objectives relating to the natural environment, including:

Objective 1 which highlights the important of nature for promoting health and wellbeing; Objective 4 which seeks to strengthen green and blue infrastructure and promote active travel; Objective 5 which seeks to preserve and enhance biodiversity and connect green spaces, parks and natural habitats; and Objective 6 related to impacts of development on Chichester Harbour National Landscape and South Downs National Park.

Chapter 5. The Allocation and Framework Masterplan

Development Policies / Principles

Policy SA1 - East of Southbourne

We recognise that the allocation masterplan incorporates an area of recreational open space intended to serve as a Suitable Alternative Natural Greenspace (SANG) to mitigate recreational disturbance on the Solent sites. We have provided further advice on the SANG provision throughout this letter. We advise that any changes made to the SANG design in light of this advice should be reflected in the framework masterplan (Figure 2).

Environment

Landscape strategy

We welcome the inclusion of adopting a multifunctional approach to open space including green and blue infrastructure and nature plus the use of planting and sustainable urban drainage systems for climate change adaptation and mitigation.

Landscape Impacts

We are pleased that views from the South Downs National Park and Chichester Harbour National Landscape and their settings have been considered in the preparation of the DPD and recognise that further consideration of this will be required at project level. We note that the Southbourne allocation site appears to be in the setting of both the South Downs National Park and Chichester Harbour National Landscape. Paragraph 189 of the NPPF states that development within the setting of National Parks and National Landscapes should be sensitively located and designed to avoid or minimise adverse impacts on the designated areas. Natural England considers the DPD to be sound in respect to impacts to protected landscapes. However, we advise that any proposed development at the allocation site should give consideration to the level of landscape sensitivity, risk of potential impacts on special qualities and views, and the scope for mitigation to ensure they are sensitively located and designed to avoid or minimise any adverse impacts.

Suitable Alternative Natural Green Space (SANG)

We recognise that the allocation masterplan incorporates an area of recreational open space intended to serve as a SANG to mitigate recreational disturbance on the Solent sites. We support that the open space should have a 2.5km walking route. However, we note that the walking route does not appear to utilise much of the open space (Figure 2 - Framework masterplan). We advise that the 2.5km walking route should be a circular route that utilises the open space as much as possible. We also note the area of open space to be provided is not yet determined. We would expect the area of open space to be identified in the DPD to ensure that it is of sufficient size to be able to provide an attractive semi-natural recreational area, incorporating natural features to provide an attractive and sufficiently long walking route. We advise that further information on the habitats and natural features that should be delivered should be included in the DPD to help ensure an attractive semi-natural open space is delivered. Your authority has measures in place to manage the potential impact of recreational pressure/disturbance on the Solent Habitats sites in the form of a strategic solution of Solent Recreation Mitigation Strategy (SRMS) payments. We advise that given the scale of the development and its proximity to coastal designated sites, standard financial contributions and on- site greenspace provision are unlikely to wholly mitigate the impact of increased recreational disturbance alone, and development may require additional bespoke mitigation measures in line with the Solent Recreation Mitigation Strategy (December 2017). We advise that this should be highlighted in the DPD to ensure it is clear that development proposals may be required to deliver additional bespoke mitigation. As outlined in Annex 2 of this letter, we advise that further bird surveys and a Habitats Regulations Assessment (HRA) should be conducted at development management stage to assess the strength of functional linkage of the allocation site and scope for mitigation. We advise that this should be added to the DPD wording to ensure it is clear that development proposals would be required to do this. Flooding We welcome the requirement for SuDS to be incorporated into the development's open space strategy, adopting a multi-functional approach to benefit people and nature.

Annex 2: Habitats Regulations Assessment (HRA)

Natural England has reviewed the Southbourne Site Allocation DPD Habitats Regulations Assessment (dated April 2026) and agree with the pathways for which significant effects cannot be ruled out. Natural England has provided standard advice on air quality impacts for Local Plans in Annex 3 of this letter. We provide the following advice on sites and pathways for which likely significant effects cannot be ruled out:

Solent Habitats sites - recreational pressure

We agree that the Solent Habitats sites should be taken forward to appropriate assessment on recreational pressure. However, we advise that there is currently insufficient information to conclude that there will be no adverse effect on the integrity of the Solent Habitats sites due to recreational pressure.

As noted in the HRA (paragraph 6.8), a SANG is unlikely to fully mitigate the impacts from increased recreational pressure due to the unique draw of the coast, and it is considered likely that additional development-specific mitigation measures will be needed to conclude no adverse effects on site integrity. Your authority has measures in place to manage the potential impact of recreational pressure/disturbance on the Solent Habitats sites in the form of a strategic solution of Solent Recreation Mitigation Strategy (SRMS) payments. We advise that given the scale of the development and its proximity to coastal designated sites, standard financial contributions and on- site greenspace provision are unlikely to wholly mitigate the impact of increased recreational disturbance alone, and development may require additional bespoke mitigation measures in line with the Solent Recreation Mitigation Strategy (December 2017).

We advise that the DPD wording should be amended to clarify that development may require additional bespoke mitigation measures. We advise that the DPD wording should also include additional information on the SANG design, as outlined in Annex 1. Provided that these amendments are made, we would be satisfied that there will be no adverse effect on the integrity of the Solent Habitats sites due to recreational pressure.

Solent Habitat sites - water quality

We agree that the Solent Habitat sites should be taken forward to appropriate assessment on water quality. Natural England supports the preparation of a nutrient budget to cover the planned dwellings. We agree with the HRA conclusion of no adverse effect on the integrity of the Solent Habitats sites based on the nutrient budget calculations taken place, which show that no additional mitigation is required. As stated in the HRA (paragraph 6.21), we advise that an updated nitrogen budget will be required with any planning application at the allocation site to determine if any mitigation measures are required.

Chichester and Langstone Harbours SPA and Ramsar site - loss of functionally linked habitat

We agree that Chichester and Langstone Harbours SPA and Ramsar site should be taken forward to appropriate assessment on loss of functionally linked habitat. It is understood that the Council's preferred option for the Southbourne Allocation has been in part chosen because it avoids the development of a Secondary Support Area for brent geese (p.23 of SA). We recognise that the Southbourne Allocation area in the DPD is not identified as a key functionally linked habitat parcel in the Solent Waders & Brent Goose Strategy. However, we advise that areas that have not been identified within the Solent Wader & Brent Goose Strategy still have the potential to provide functional linkage to the Chichester and Langstone Harbour SPA and Ramsar site.

We note that winter bird surveys conducted in 2022/2023 found lapwing and snipe utilising the site. The HRA considers these to be in sufficiently low numbers that the SPA bird features will not be materially affected by the allocation, and therefore that adverse effects on the integrity of the SPA and Ramsar can be ruled out. We have not seen the detailed survey methods and results of the winter bird surveys but, from the information provided in the HRA, we advise that there is currently insufficient certainty to conclude that there will be no adverse effect on integrity due to loss of functionally linked habitat. It is our understanding that one survey per month from October to February were carried out. We recommend that more detailed winter bird surveys should be carried out at the development management stage to determine the strength of functional linkage and if any mitigation measures are required for the loss of functionally linked land. Any changes in habitat suitability on the allocation site should also be assessed. We advise that the DPD policy wording should be amended to include a requirement for detailed bird surveys and a HRA to be conducted at development management stage. Provided that this is added to the DPD wording, we would agree that the DPD would have no adverse effect on the integrity of the sites due to loss of functionally linked land.

Annex 3: Standard Advice for Air Quality Impacts for Local Plans

Local Plans are likely to generate increased emissions of nitrogen oxides (NOx) and ammonia, and additional nitrogen deposition as a result of increased traffic generation associated with new development. As impacts from individual development management proposals would be difficult to quantify without an overarching assessment of the cumulative impacts from Local Plan development, it is necessary for this to be considered strategically at plan level. Natural England would expect the environmental assessment of the plan including the Sustainability Appraisal (SA) and the Habitats Regulations Assessment (HRA) to consider any detrimental impacts on the natural environment from these emissions. It should also suggest appropriate avoidance or mitigation measures where applicable. Technical guidance about the ecological impacts from road transport can also be found in the Natural England research report The ecological effects of air pollution from road transport: an updated review' (NECR199).

Protected sites are 'sites of special scientific interest' (SSSIs) and 'habitats sites' (also called 'European sites'). For the purposes of this advice, Habitats Sites are Special Areas of Conservation (SACs), possible SACs, Special Protection Areas (SPAs), Potential SPAs, Ramsar sites, and sites identified, or required, as compensatory measures for adverse effects on Habitats Sites.

Although their regulatory frameworks differ, the general principles and approach for air pollution assessment outlined for Habitats Sites are also relevant for SSSIs. Where the following advice applies to both, we use the term protected sites. Where the advice or approach differs, the individual terms are used.

Habitats Sites and SSSIs at risk from local impacts are those within 200m of a road with increased traffic, which feature habitats that are vulnerable to nitrogen deposition and/or acidification.

Natural England provides the following standard advice on air pollution. This advice relates to the protection of protected sites under the Conservation of Habitats and Species Regulations 2017 (the Habitats Regulations) and the Wildlife and Countryside Act 1981 and should also be taken as Natural England's formal representation under the Town & Country Planning (Local Planning) Regulations 2012. This standard advice is applicable to all stages of the Local Plan process. This includes advice on information that is required to assess air quality and how to interpret the results of air quality modelling for your LPA to conclude whether air quality impacts would have an adverse effect on the integrity of a Habitat site or a SSSI. Detailed guidance on how to undertake a Habitats Regulations Assessment for air pollution impacts generated from traffic can be found here Natural England's approach to advising competent authorities on the assessment of road traffic emissions under the Habitats Regulations (NEA001).

You should also consider any relevant caselaw that could affect how you carry out any air quality assessments.

Air pollutants

This advice covers the following air pollutants:

ammonia (NH3)
nitrogen oxides (NO, NO2 or NOx)
nitrogen deposition
acid deposition
sulphur dioxide (SO2)
Standing advice on air pollution and development is also available here: https://www.gov.uk/guidance/air-pollution-and-development-advice-for-local-authorities

Whilst the standing advice does not cover Local Plans, it does include additional technical advice which may prove useful. However, in summary, Table 1 provides the steps that we advise should be taken by local planning authorities.

Table 1: Sequential approach to air quality assessments
(See attachment)

Additional advice

For many protected sites, the current background pollution may already be exceeding the relevant critical load/level from a different source type to the project being assessed (e.g. the main source of background exceedance is due to agriculture, but the proposal is a road scheme). Proposals must consider their own impacts against the relevant environmental thresholds. There are many reasons why background levels are high, but the conservation objective is to 'maintain or restore' air pollutants to within these benchmarks. The objective would be undermined by proposals that add further emissions, including if it compromises any strategic initiatives to reduce air pollution levels.

Where an air quality report concludes that only a very small area of the site will be impacted, the assessment of effects on integrity or damage to the site, should take into account the interest features of the site, their distribution and how they will be impacted by proposals rather than on specific percentages of site. Dependent on features being present in the area to be impacted, this could have a disproportionate impact on the site if an area of a rare habitat type were lost rather than a judgement just on the percentages of habitat.

Improvements in vehicle technology and a move to further electrification of the vehicle fleet will, over time, result in lower background levels of nitrogen deposition and Nitrogen Oxide pollution near to roads. As most sites are currently over the relevant thresholds and have a "restore" objective, this should be noted as a "retardation" of the restore objective and expressed in months and years. Retardation of less than one year is acceptable as air quality is considered against an annual average. Please note that ammonia impacts cannot be assessed in this manner as there is no certainty of a declining trend.

Common Standards Monitoring is used to define the ecological condition of a protected site. It is undertaken on a broader level and does not currently consider air quality impacts. The relevant benchmark for assessing impacts is the critical thresholds. Therefore, the existing status of a designated site should not be the sole reason for judgement on potential impact.

Defra Emissions Factor Toolkit

The Defra Emission Factor Toolkit (EFT) allows for gradual introduction of electric vehicles into the fleet (cars and LGVs) up to 2050. These are the emission factors we advise that Local Plans should be using (which we advise should also consider ammonia emissions as well as NOx - using one of three sets of emission factors available). However, the User Guide to the EFT highlights that calculation tools only support assessment years 2018 up to 2030, reflecting that predictions and assumptions beyond then become less certain. Where EFT calculated emissions are to be used after 2030 to inform air quality assessments, the EFT indicates that appropriate caveats around the limitations of the analysis must be included to accompany the assessment.

We therefore advise that emission factors no later than 2030 are used for HRAs- which would mean percentages of EVs are at predicted 2030 levels. A key concern is that, although EVs themselves have no tailpipe emissions, and the percentage of them will increase, the remaining combustion engine vehicles on the road may become more polluting as they age as selective catalytic reduction technology may create 'ammonia slip' over time. Ammonia slip is the unreacted ammonia (NH₃) that escapes from a selective catalytic reduction (SCR) or selective non-catalytic reduction (SNCR) system used to reduce NOx in exhaust gases. Motorways within the affected road network There is potentially an added complexity to the need for in-combination assessments when considering traffic on motorways, as including these roads can mean that the assessment takes account of traffic growth related to strategic factors or long range (external) trips that are independent of the specific plan or project and neighbouring plans or projects. These roads are strategically important and tend to have high volumes of traffic as well as being well represented in traffic models. The air quality assessment should therefore include traffic flows on these roads, but the external trips can be excluded from the initial screening assessment. A justification and explanation of which journeys are included and excluded in the traffic model should be provided. The conclusions reached on the air pollution impacts of the HRA must be incorporated into the wider HRA conclusions for other impact pathways identified for the local plan. How to Use this Advice in Decision Making Provided you have followed the above advice and have been able to conclude there would be no adverse effects on any protected sites we would be able to agree with the conclusions of your HRA in relation to air quality impacts and that the Local Plan is sound in this regard.

Southbourne Allocation Development Plan Document Regulation 19 consultation

Thank you for your consultation on the above dated 05 June 2026 which was received by Natural England on the same date.

Natural England is a non-departmental public body. Our statutory purpose is to ensure that the natural environment is conserved, enhanced and managed for the benefit of present and future generations, thereby contributing to sustainable development.

Natural England has reviewed the Southbourne Allocation Development Plan Document (DPD) together with the Habitats Regulations Assessment (HRA), Sustainability Appraisal (SA) and other relevant supporting evidence documents.

Summary of Natural England's advice

Natural England supports the principles of the avoidance and mitigation measures proposed to address impacts to designated sites from development at the allocation site. However, we suggest some further information is included in the DPD to ensure all impacts from development are fully mitigated and help ensure the DPD is sound.

Our detailed comments are provided in the following annexes:

Annex 1. Southbourne Allocation Development Plan Document (DPD) Annex 2. Habitats Regulations Assessment (HRA) Annex 3. Standard Advice for Air Quality Impacts for Local Plans

Please note that we have not provided comments on all aspects of the DPD but those which have the most influence on issues within our remit. It there are topics not covered in this response where your Authority would particularly value our advice, then please let us know. Other than referring to it when giving advice on the DPD, we do not have any general comments to make on the Sustainability Appraisal.

We remain committed to continuing to work closely with your Authority to help ensure that a sound plan is secured that enables growth in accordance with the principles of sustainable development. We would welcome the opportunity for further dialogue around matters raised here in more detail, although depending on the nature and scope of such discussion this may need to be on a cost- recovery basis.

Annex 1: Southbourne Allocation Development Plan Document (DPD)

Chapter 4. Vision and objectives

We welcome that the vision includes connecting residents with nature and support the objectives relating to the natural environment, including:

Objective 1 which highlights the important of nature for promoting health and wellbeing; Objective 4 which seeks to strengthen green and blue infrastructure and promote active travel; Objective 5 which seeks to preserve and enhance biodiversity and connect green spaces, parks and natural habitats; and Objective 6 related to impacts of development on Chichester Harbour National Landscape and South Downs National Park.

Chapter 5. The Allocation and Framework Masterplan

Development Policies / Principles

Policy SA1 - East of Southbourne

We recognise that the allocation masterplan incorporates an area of recreational open space intended to serve as a Suitable Alternative Natural Greenspace (SANG) to mitigate recreational disturbance on the Solent sites. We have provided further advice on the SANG provision throughout this letter. We advise that any changes made to the SANG design in light of this advice should be reflected in the framework masterplan (Figure 2).

Environment

Landscape strategy

We welcome the inclusion of adopting a multifunctional approach to open space including green and blue infrastructure and nature plus the use of planting and sustainable urban drainage systems for climate change adaptation and mitigation.

Landscape Impacts

We are pleased that views from the South Downs National Park and Chichester Harbour National Landscape and their settings have been considered in the preparation of the DPD and recognise that further consideration of this will be required at project level. We note that the Southbourne allocation site appears to be in the setting of both the South Downs National Park and Chichester Harbour National Landscape. Paragraph 189 of the NPPF states that development within the setting of National Parks and National Landscapes should be sensitively located and designed to avoid or minimise adverse impacts on the designated areas. Natural England considers the DPD to be sound in respect to impacts to protected landscapes. However, we advise that any proposed development at the allocation site should give consideration to the level of landscape sensitivity, risk of potential impacts on special qualities and views, and the scope for mitigation to ensure they are sensitively located and designed to avoid or minimise any adverse impacts.

Suitable Alternative Natural Green Space (SANG)

We recognise that the allocation masterplan incorporates an area of recreational open space intended to serve as a SANG to mitigate recreational disturbance on the Solent sites. We support that the open space should have a 2.5km walking route. However, we note that the walking route does not appear to utilise much of the open space (Figure 2 - Framework masterplan). We advise that the 2.5km walking route should be a circular route that utilises the open space as much as possible. We also note the area of open space to be provided is not yet determined. We would expect the area of open space to be identified in the DPD to ensure that it is of sufficient size to be able to provide an attractive semi-natural recreational area, incorporating natural features to provide an attractive and sufficiently long walking route. We advise that further information on the habitats and natural features that should be delivered should be included in the DPD to help ensure an attractive semi-natural open space is delivered. Your authority has measures in place to manage the potential impact of recreational pressure/disturbance on the Solent Habitats sites in the form of a strategic solution of Solent Recreation Mitigation Strategy (SRMS) payments. We advise that given the scale of the development and its proximity to coastal designated sites, standard financial contributions and on- site greenspace provision are unlikely to wholly mitigate the impact of increased recreational disturbance alone, and development may require additional bespoke mitigation measures in line with the Solent Recreation Mitigation Strategy (December 2017). We advise that this should be highlighted in the DPD to ensure it is clear that development proposals may be required to deliver additional bespoke mitigation. As outlined in Annex 2 of this letter, we advise that further bird surveys and a Habitats Regulations Assessment (HRA) should be conducted at development management stage to assess the strength of functional linkage of the allocation site and scope for mitigation. We advise that this should be added to the DPD wording to ensure it is clear that development proposals would be required to do this. Flooding We welcome the requirement for SuDS to be incorporated into the development's open space strategy, adopting a multi-functional approach to benefit people and nature.

Annex 2: Habitats Regulations Assessment (HRA)

Natural England has reviewed the Southbourne Site Allocation DPD Habitats Regulations Assessment (dated April 2026) and agree with the pathways for which significant effects cannot be ruled out. Natural England has provided standard advice on air quality impacts for Local Plans in Annex 3 of this letter. We provide the following advice on sites and pathways for which likely significant effects cannot be ruled out:

Solent Habitats sites - recreational pressure

We agree that the Solent Habitats sites should be taken forward to appropriate assessment on recreational pressure. However, we advise that there is currently insufficient information to conclude that there will be no adverse effect on the integrity of the Solent Habitats sites due to recreational pressure.

As noted in the HRA (paragraph 6.8), a SANG is unlikely to fully mitigate the impacts from increased recreational pressure due to the unique draw of the coast, and it is considered likely that additional development-specific mitigation measures will be needed to conclude no adverse effects on site integrity. Your authority has measures in place to manage the potential impact of recreational pressure/disturbance on the Solent Habitats sites in the form of a strategic solution of Solent Recreation Mitigation Strategy (SRMS) payments. We advise that given the scale of the development and its proximity to coastal designated sites, standard financial contributions and on- site greenspace provision are unlikely to wholly mitigate the impact of increased recreational disturbance alone, and development may require additional bespoke mitigation measures in line with the Solent Recreation Mitigation Strategy (December 2017).

We advise that the DPD wording should be amended to clarify that development may require additional bespoke mitigation measures. We advise that the DPD wording should also include additional information on the SANG design, as outlined in Annex 1. Provided that these amendments are made, we would be satisfied that there will be no adverse effect on the integrity of the Solent Habitats sites due to recreational pressure.

Solent Habitat sites - water quality

We agree that the Solent Habitat sites should be taken forward to appropriate assessment on water quality. Natural England supports the preparation of a nutrient budget to cover the planned dwellings. We agree with the HRA conclusion of no adverse effect on the integrity of the Solent Habitats sites based on the nutrient budget calculations taken place, which show that no additional mitigation is required. As stated in the HRA (paragraph 6.21), we advise that an updated nitrogen budget will be required with any planning application at the allocation site to determine if any mitigation measures are required.

Chichester and Langstone Harbours SPA and Ramsar site - loss of functionally linked habitat

We agree that Chichester and Langstone Harbours SPA and Ramsar site should be taken forward to appropriate assessment on loss of functionally linked habitat. It is understood that the Council's preferred option for the Southbourne Allocation has been in part chosen because it avoids the development of a Secondary Support Area for brent geese (p.23 of SA). We recognise that the Southbourne Allocation area in the DPD is not identified as a key functionally linked habitat parcel in the Solent Waders & Brent Goose Strategy. However, we advise that areas that have not been identified within the Solent Wader & Brent Goose Strategy still have the potential to provide functional linkage to the Chichester and Langstone Harbour SPA and Ramsar site.

We note that winter bird surveys conducted in 2022/2023 found lapwing and snipe utilising the site. The HRA considers these to be in sufficiently low numbers that the SPA bird features will not be materially affected by the allocation, and therefore that adverse effects on the integrity of the SPA and Ramsar can be ruled out. We have not seen the detailed survey methods and results of the winter bird surveys but, from the information provided in the HRA, we advise that there is currently insufficient certainty to conclude that there will be no adverse effect on integrity due to loss of functionally linked habitat. It is our understanding that one survey per month from October to February were carried out. We recommend that more detailed winter bird surveys should be carried out at the development management stage to determine the strength of functional linkage and if any mitigation measures are required for the loss of functionally linked land. Any changes in habitat suitability on the allocation site should also be assessed. We advise that the DPD policy wording should be amended to include a requirement for detailed bird surveys and a HRA to be conducted at development management stage. Provided that this is added to the DPD wording, we would agree that the DPD would have no adverse effect on the integrity of the sites due to loss of functionally linked land.

Annex 3: Standard Advice for Air Quality Impacts for Local Plans

Local Plans are likely to generate increased emissions of nitrogen oxides (NOx) and ammonia, and additional nitrogen deposition as a result of increased traffic generation associated with new development. As impacts from individual development management proposals would be difficult to quantify without an overarching assessment of the cumulative impacts from Local Plan development, it is necessary for this to be considered strategically at plan level. Natural England would expect the environmental assessment of the plan including the Sustainability Appraisal (SA) and the Habitats Regulations Assessment (HRA) to consider any detrimental impacts on the natural environment from these emissions. It should also suggest appropriate avoidance or mitigation measures where applicable. Technical guidance about the ecological impacts from road transport can also be found in the Natural England research report The ecological effects of air pollution from road transport: an updated review' (NECR199).

Protected sites are 'sites of special scientific interest' (SSSIs) and 'habitats sites' (also called 'European sites'). For the purposes of this advice, Habitats Sites are Special Areas of Conservation (SACs), possible SACs, Special Protection Areas (SPAs), Potential SPAs, Ramsar sites, and sites identified, or required, as compensatory measures for adverse effects on Habitats Sites.

Although their regulatory frameworks differ, the general principles and approach for air pollution assessment outlined for Habitats Sites are also relevant for SSSIs. Where the following advice applies to both, we use the term protected sites. Where the advice or approach differs, the individual terms are used.

Habitats Sites and SSSIs at risk from local impacts are those within 200m of a road with increased traffic, which feature habitats that are vulnerable to nitrogen deposition and/or acidification.

Natural England provides the following standard advice on air pollution. This advice relates to the protection of protected sites under the Conservation of Habitats and Species Regulations 2017 (the Habitats Regulations) and the Wildlife and Countryside Act 1981 and should also be taken as Natural England's formal representation under the Town & Country Planning (Local Planning) Regulations 2012. This standard advice is applicable to all stages of the Local Plan process. This includes advice on information that is required to assess air quality and how to interpret the results of air quality modelling for your LPA to conclude whether air quality impacts would have an adverse effect on the integrity of a Habitat site or a SSSI. Detailed guidance on how to undertake a Habitats Regulations Assessment for air pollution impacts generated from traffic can be found here Natural England's approach to advising competent authorities on the assessment of road traffic emissions under the Habitats Regulations (NEA001).

You should also consider any relevant caselaw that could affect how you carry out any air quality assessments.

Air pollutants

This advice covers the following air pollutants:

ammonia (NH3)
nitrogen oxides (NO, NO2 or NOx)
nitrogen deposition
acid deposition
sulphur dioxide (SO2)
Standing advice on air pollution and development is also available here: https://www.gov.uk/guidance/air-pollution-and-development-advice-for-local-authorities

Whilst the standing advice does not cover Local Plans, it does include additional technical advice which may prove useful. However, in summary, Table 1 provides the steps that we advise should be taken by local planning authorities.

Table 1: Sequential approach to air quality assessments
(See attachment)

Additional advice

For many protected sites, the current background pollution may already be exceeding the relevant critical load/level from a different source type to the project being assessed (e.g. the main source of background exceedance is due to agriculture, but the proposal is a road scheme). Proposals must consider their own impacts against the relevant environmental thresholds. There are many reasons why background levels are high, but the conservation objective is to 'maintain or restore' air pollutants to within these benchmarks. The objective would be undermined by proposals that add further emissions, including if it compromises any strategic initiatives to reduce air pollution levels.

Where an air quality report concludes that only a very small area of the site will be impacted, the assessment of effects on integrity or damage to the site, should take into account the interest features of the site, their distribution and how they will be impacted by proposals rather than on specific percentages of site. Dependent on features being present in the area to be impacted, this could have a disproportionate impact on the site if an area of a rare habitat type were lost rather than a judgement just on the percentages of habitat.

Improvements in vehicle technology and a move to further electrification of the vehicle fleet will, over time, result in lower background levels of nitrogen deposition and Nitrogen Oxide pollution near to roads. As most sites are currently over the relevant thresholds and have a "restore" objective, this should be noted as a "retardation" of the restore objective and expressed in months and years. Retardation of less than one year is acceptable as air quality is considered against an annual average. Please note that ammonia impacts cannot be assessed in this manner as there is no certainty of a declining trend.

Common Standards Monitoring is used to define the ecological condition of a protected site. It is undertaken on a broader level and does not currently consider air quality impacts. The relevant benchmark for assessing impacts is the critical thresholds. Therefore, the existing status of a designated site should not be the sole reason for judgement on potential impact.

Defra Emissions Factor Toolkit

The Defra Emission Factor Toolkit (EFT) allows for gradual introduction of electric vehicles into the fleet (cars and LGVs) up to 2050. These are the emission factors we advise that Local Plans should be using (which we advise should also consider ammonia emissions as well as NOx - using one of three sets of emission factors available). However, the User Guide to the EFT highlights that calculation tools only support assessment years 2018 up to 2030, reflecting that predictions and assumptions beyond then become less certain. Where EFT calculated emissions are to be used after 2030 to inform air quality assessments, the EFT indicates that appropriate caveats around the limitations of the analysis must be included to accompany the assessment.

We therefore advise that emission factors no later than 2030 are used for HRAs- which would mean percentages of EVs are at predicted 2030 levels. A key concern is that, although EVs themselves have no tailpipe emissions, and the percentage of them will increase, the remaining combustion engine vehicles on the road may become more polluting as they age as selective catalytic reduction technology may create 'ammonia slip' over time. Ammonia slip is the unreacted ammonia (NH₃) that escapes from a selective catalytic reduction (SCR) or selective non-catalytic reduction (SNCR) system used to reduce NOx in exhaust gases. Motorways within the affected road network There is potentially an added complexity to the need for in-combination assessments when considering traffic on motorways, as including these roads can mean that the assessment takes account of traffic growth related to strategic factors or long range (external) trips that are independent of the specific plan or project and neighbouring plans or projects. These roads are strategically important and tend to have high volumes of traffic as well as being well represented in traffic models. The air quality assessment should therefore include traffic flows on these roads, but the external trips can be excluded from the initial screening assessment. A justification and explanation of which journeys are included and excluded in the traffic model should be provided. The conclusions reached on the air pollution impacts of the HRA must be incorporated into the wider HRA conclusions for other impact pathways identified for the local plan. How to Use this Advice in Decision Making Provided you have followed the above advice and have been able to conclude there would be no adverse effects on any protected sites we would be able to agree with the conclusions of your HRA in relation to air quality impacts and that the Local Plan is sound in this regard.