A2. Epping Forest Special Area of Conservation

• Natural England 
• Essex County Council 
• City of London Corporation 
• Epping Forest District Council 

Epping Forest is one of London’s largest open spaces and is managed by the City of London (CoL) as the conservators of Epping Forest. Epping Forest Special Area of Conservation (SAC) lies within Epping Forest and comprises a large and ecologically distinctive ancient woodland that extends for around 19km from Manor Park in the south to Epping in the north. Epping Forest is crossed and bordered by several major transport routes, including the M25, A104 and A121. Its location at the urban– rural fringe means it is uniquely exposed to traffic-related air pollution while simultaneously supporting habitats of international importance.  

Large parts of Epping Forest have been designated as a SAC due to the presence of wet and dry heaths and Beech forest which provides habitat for its population of stag beetle. Epping Forest SAC is underpinned by the Epping Forest SSSI. 

The Interim Air Pollution Mitigation Strategy (APMS) has been developed to provide a strategic approach to mitigating the effects of development in relation to atmospheric pollution at Epping Forest SAC. The Strategy has been developed to support policies set out in the Epping Forest District Council Local Plan (Epping Forest Council, 2023). The Strategy was developed in response to concerns raised by Natural England regarding the impact of new development on the integrity of Epping Forest SAC. At the time, the council faced a two-year backlog of planning applications, as no net increases in dwellings could be approved without a strategic mitigation approach in place. 

The strategy covers all growth allocated in the Epping Forest Local Plan alongside a small allowance for windfall sites. It provides a structured, evidence-based approach to air quality mitigation and represents one of the first strategic schemes in the UK designed specifically to address traffic-related air pollution impacts on a SAC 

Under the Epping Forest Interim APMS, financial contributions from all relevant development proposals are taken to fund the implementation of strategic air quality mitigation measures, monitoring and comparative assessments to be delivered by the Epping Forest District Council and its partners. The APMS lists a package of measures for delivery over the Local Plan period (up to 2033). The strategy outlines the measures to be delivered, how they will be monitored, and the responsibilities of developers and the council. For sites allocated within the Local Plan, compliance with APMS measures allows projects to bypass individual project-level Habitats Regulations Assessments (HRAs), streamlining planning approvals. In contrast, speculative developments or projects exceeding the Local Plan growth must undertake a shadow HRA and design a bespoke mitigation package aligned with the strategy’s principles. This ensures that any development can demonstrate, beyond reasonable scientific doubt, that it will not adversely affect the integrity of the SAC. 

The APMS includes a contingency provision for a Clear Air Zone (CAZ) covering roads within and immediately adjacent to the SAC. The CAZ would only be introduced if monitoring demonstrates that traffic-related emissions remain above safe thresholds, serving as a backstop to ensure protection of the Forest’s habitats. 

It would place a charge on non-compliant vehicles, while ULEVs would be exempt, incentivising a reduction in emissions. In the meantime, the APMS relies on measures such as ULEV promotion, restricted vehicle parking in new developments, and encouragement of remote working to mitigate traffic impacts. It provides an option for a strategic safeguard rather than an automatic or immediate measure, and its introduction would only occur if monitoring demonstrates that introduced mitigation measures alone are insufficient to prevent adverse effects on the SAC, serving as a strategic backstop to protect the Forest’s habitats. 

The APMS also includes a series of measures that are intended to encourage the uptake of ULEVs which include: 

• Ensuring that the necessary infrastructure for ULEVs is widely and easily available across the District; 
• Incentivising the replacement of petrol cars with ULEVs, targeted at people who live in areas from which the most frequent trips on roads in close proximity to the Epping Forest SAC arise; 
• improvements to broadband infrastructure to support remote working, particularly for new dwellings, intended to reduce commuter vehicle trips through and near the Forest; and, 
• Undertaking awareness-raising of both the issue of air pollution and the things that residents and businesses can do to contribute to improving air quality (Epping Forest District Council, 2020a). 

Epping Forest is bisected by a number of roads which serve communities in Epping Forest District and beyond. The Interim APMS was developed to provide a strategic approach to mitigating the effects of development on the integrity of the Epping Forest SAC in relation to atmospheric pollution. Without appropriate mitigation, development proposed through the adopted Epping Forest District Council Local Plan (Epping Forest Council, 2023), in combination with other plans and projects, would have an adverse effect on the integrity of the Epping Forest SAC as a result of atmospheric pollution, particularly from vehicles (Epping Forest District Council, 2020a). 

The APMS is specifically designed to address growth forecasted in the Epping 

Forest District Local Plan (13,400 new homes plus a small windfall allowance). Speculative development beyond these allocations cannot rely solely on the APMS; developers must produce a shadow HRA with bespoke mitigation measures. This ensures that all proposals demonstrate, beyond reasonable scientific doubt, that they will not adversely affect the SAC when considered in combination with other plans and projects. 

Traffic emissions, primarily nitrogen oxides (NOx) and ammonia from vehicles, are the main sources of pollutants affecting the air quality of Epping Forest SAC. Its location means it is exposed to traffic-related air pollution on extensive areas of ancient semi-natural woodland, wood-pasture, grassland and wetlands, with a rich assemblage of veteran trees, fungi, lichens and invertebrates which are sensitive to nitrogen deposition and other airborne pollutants. 

Evidence underpinning the Interim Air Pollution Mitigation Strategy was collated through the Habitats Regulations Assessment process that supported the adopted Local Plan (Epping Forest Council, 2023). This evidence included traffic modelling and air quality modelling of mitigation solutions (Aecom, 2022). 

The projected scale of development within Epping Forest District up to 2033, particularly in the form of new housing and employment growth, is a fundamental driver of increased traffic and associated emissions that threaten the integrity of the Epping Forest SAC (Epping Forest District Council, 2020a). 

The planned development set out in the Local Plan, both residential and economic development, will result in additional vehicle movements on key routes that bisect and border the SAC, such as the A104 and A121. Evidence shows that this cumulative growth in vehicle flows, when combined with background traffic increases from existing commitments and national trends, will lead to higher local concentrations of nitrogen oxides (NOx) and ammonia along the roads adjacent to the Forest (Epping Forest District Council, 2020a). 

The Interim Epping Forest Air Pollution Mitigation Strategy is not a cross-boundary solution but focuses on addressing the impact of the adopted Epping Forest District Local Plan up to 2033. The traffic modelling undertaken in support of the Local Plan shows that average daily traffic flows on all modelled sections of road are dominated by people who either live or work in Epping Forest District, particularly the settlements that surround the SAC, and that neighbouring LPA contributions would make a negligible contribution to the ‘in combination’ effect. 

“A. The Council will expect all relevant development proposals to assist in the conservation and enhancement of the biodiversity, character, appearance and landscape setting of Epping Forest and the Lee Valley. The Council will expect all relevant development proposals to ensure that there is no adverse effect on the site integrity of the Epping Forest Special Area of Conservation and the Lee Valley Special Protection Area. 

2. New development for which it is not possible to conclude no adverse effect on the integrity of the Epping Forest Special Area for Conservation or the Lee Valley Special Protection Area, either alone or in combination with other plans or projects, will not be permitted. Where development would have likely significant effects, mitigation measures, on-site and off-site as appropriate, will be required to ensure that it will have no adverse effect on the integrity of these areas. In designing mitigation measures, regard should be had to the Air Pollution Mitigation Strategy for the 

Epping Forest, the District’s Green Infrastructure Strategy and Epping Forest Strategic Access Management and Monitoring Strategy. 

Contributions towards off-site measures to mitigate the likely impacts air pollution and adverse recreational effects arising from a development will be sought where these are necessary to make the development acceptable, are directly related to the development and are fairly and reasonably related in scale to the development. 

3. In recognition of the risks posed to the Epping Forest Special Area of Conservation from urbanisation effects over and above that resulting from recreational pressures (including from fly-tipping, the introduction of non-native plant species and incidental arson) planning applications for development will not be permitted within 400 metres of the boundary of the Epping Forest Special Area of Conservation unless it can be demonstrated through project level HRA that the development would not generate any such impacts.” 

“A. The Council will seek to ensure that the District is protected from the impacts of air pollution. Potential air pollution risks will need to be properly considered and adequate mitigation included in the design of new development to ensure neither future, or existing residents, workers, visitors, and other sensitive receptors are adversely impacted as a result of the development. 

2. Any required mitigation measures will be determined by the scale of development, its location, the potential to cause air pollution, and the presence of sensitive receptors in the locality. 
3. Larger proposals or those that have the potential to affect air quality, will be required to undertake an air quality assessment that identifies the potential impact of the development together with, where appropriate, contributions towards air quality monitoring. Assessments shall identify mitigation that will address any deterioration in air quality as a result of the development and these measures shall be incorporated into the development proposals together with financial contributions to support the implementation of off-site measures and the monitoring of their efficacy. Such assessments should include an assessment of emissions (including from traffic generation) and calculation of the cost of the development to the environment. All assessments of air quality impacts shall be undertaken by competent persons.” 

The measures contained within the Strategy will be secured through a number of mechanisms including: 

• The use of planning conditions and/or legal agreements to secure financial contributions for the implementation of off-site measures as part of the determination of planning and other development related applications; 
  • The development of Strategic Masterplans; and 
  • Strategic initiatives to be implemented by the Council and its partners. 

Funding sources vary for each of the mitigation measures set out in the APMS.  Some mitigation will be funded by individual developers, others through financial contributions from relevant planning applications and a number will be funded by Epping Forest District Council. 

A tariff per dwelling is applied for air pollution mitigation as a financial contribution, in accordance with the Council’s Interim Strategy (‘Air Pollution Contribution’) (Epping Forest District Council 2020a). The required contributions for residential development are as follows: 

• The Garden Communities (GCs): £232 per dwelling. 
• North Weald Bassett Masterplan Area and South of Epping Masterplan Area: 

£641 per dwelling. 

• Smaller sites (including windfall sites) and the Waltham Abbey Masterplan Area: £335 per dwelling. 

 Varying levels of financial contributions are also set for specific development areas and non-residential development. These are only sought for development proposals on the proposed employment allocations at North Weald Airfield and Land north of A121, both set at £206,017. 

Financial contributions are secured through the use of planning obligations or securing S106 planning obligations on individual planning permissions, the development of Strategic Masterplans and strategic initiatives to be implemented by the Council and its partners.  

The Interim APMS itself is primarily a technical and policy framework and does not constitute a formal public communication strategy or plan. Its main purpose is to provide a district-wide approach for mitigating traffic-related air pollution affecting the Epping Forest SAC, ensuring compliance with the Habitats Regulations and supporting Local Plan policies (DM2 and DM22). 

The Interim APMS establishes a framework for ongoing monitoring to ensure that mitigation measures are effectively reducing traffic-related emissions of nitrogen oxides and ammonia, and thereby protecting the Epping Forest SAC. Monitoring is implemented through a combination of continuous air quality monitoring stations at key locations near roads adjoining the Forest, supplemented by passive diffusion tubes to measure NO₂ concentrations along smaller roads not covered by automatic stations. In parallel, traffic flows are tracked and emissions modelling is maintained to estimate nitrogen deposition rates across sensitive habitats. Traffic is measured using average daily traffic (ADT), with attention to the distribution of vehicle movements along roads adjacent to the forest. This allows the council to assess cumulative (“in combination”) effects of multiple developments on the SAC. Air quality monitoring supplements traffic data to track nitrogen deposition and other key pollutants. These methods together provide a continuous dataset, enabling the Council to compare pollutant concentrations and deposition rates against baseline levels measured prior to mitigation implementation, also allowing for an adaptive management approach, whereby mitigation can be adjusted over time based on realworld monitoring results. 

The outputs of this monitoring programme include detailed air quality data, nitrogen deposition estimates relative to critical ecological loads, and assessments of developer compliance with mitigation requirements, such as electric vehicle infrastructure provision or contributions to district-wide CAZ initiatives. While the Strategy is still at an interim stage, it provides for adaptive management, whereby mitigation measures can be adjusted in response to monitoring outcomes if reductions in emissions are found to be insufficient. In this way, the approach allows for a continuous evaluation of effectiveness, comparing pre and post-mitigation data to ensure that air quality improvements are achieved over time, while also informing future planning decisions and refinements to the Strategy (Epping Forest District Council, 2020b). 

Links to multifunctional benefits 

Although the primary aim of the Interim Epping Forest APMS is to mitigate trafficrelated nitrogen oxide and ammonia emissions affecting the Epping Forest SAC, the document recognises that the proposed measures can generate wider environmental and social benefits. For instance, the APMS promotes sustainable transport measures, including walking, cycling, and public transport, alongside the uptake of ultra-low emission vehicles (ULEVs) and electric vehicle infrastructure. The APMS notes that these measures reduce vehicle emissions and traffic-related pollutants, which contributes to cleaner local air and supports community health and well-being, though the APMS does not explicitly quantify these benefits (Epping Forest District Council, 2020a).

Lessons leant 

While the APMS has been effective in providing a novel strategic framework for air quality mitigation, lessons have been learnt throughout its implementation. Coverage of employment or commercial developments is limited, with only two strategic sites included in the current strategy. Modelling of traffic and nitrogen deposition is technically complex, requiring specialist input and significant resources, which can limit the frequency of updates. Estimating headroom and vehicle fleet composition adds further uncertainty, particularly as fleet mixes evolve over time. Speculative and windfall developments beyond the Local Plan allocation require bespoke HRAs and mitigation strategies, as they cannot rely solely on measures outlined in the strategy. 

A key strength of the APMS is its evidence-led approach.  It is based on traffic modelling, air quality and nitrogen deposition data, and supported by the Local Plan HRA. The APMS is designed to be adaptive, with ongoing monitoring of air quality, nitrogen deposition, traffic flows, and developer compliance enabling mitigation measures to be adjusted if reductions in emissions are insufficient. This ensures that the strategy remains proportionate and effective in protecting the SAC from development pressures while supporting sustainable transport initiatives.

A key success of the APMS is its clarity and accessibility. The APMS is written in plain English, enabling developer teams and decision-makers to understand requirements and apply mitigation measures effectively. 

The APMS also integrates mitigation with broader environmental and social benefits, promoting sustainable transport, ultra-low emission vehicles (ULEVs), and electric vehicle infrastructure, contributing to cleaner air, community well-being, and reduced traffic impacts around the SAC. This holistic approach demonstrates that mitigation strategies can simultaneously address biodiversity protection, air quality, and climate adaptation objectives. 

Aecom (2022) Epping Forest District Local Plan 2022 Habitats Regulations Assessment. 

Epping Forest District Council (2020a). Interim Air Pollution Mitigation Strategy for Epping Forest SAC. Available at: https://www.eppingforestdc.gov.uk/app/uploads/2021/02/Interim-Epping-Forest-AirPollution-Mitigation-Strategy.pdf (Accessed: 23/01/26) 

Epping Forest District Council (2020b). Decision by Portfolio Holder.  Adoption of the Interim Air Pollution Mitigation Strategy. Available at: 

https://www.eppingforestdc.gov.uk/app/uploads/2024/02/EB154-Adoption-of-theInterim-Air-Pollution-Mit-Strategy-v2-1.pdf (Accessed: 23/01/26) 

Epping Forest District Council (2023) Epping Forest District Council Local Plan 2011 – 2033 Party One Adopted March 2023. 

Epping Forest District Council (2025) 2025 Air Quality Annual Status Report. Epping Forest District Council. Available at: 

https://www.eppingforestdc.gov.uk/app/uploads/2025/08/Final-ASR-2025.pdf (Accessed: 12/02/26). 

Epping Forest District Council (n.d).  Guidance for applicants on EFSAC impacts. Available at: https://www.eppingforestdc.gov.uk/planning-and-building/efsacguidance-for-applicants/ (Accessed: 12/02/26).