The Air-MEPCA indicator is an ongoing project (initiated in 2025) to improve how we assess whether management of protected sites is effective in addressing air pollution impacts.
It adapts the Management Effectiveness of Protected and Conserved Areas (MEPCA) indicator to focus specifically on air pollution, providing a structured approach to evaluate management actions and support evidence-based decision-making.
Background
Nature recovery depends on understanding whether management actions are effectively addressing environmental pressures.
Air pollution remains a significant pressure on many UK habitats, with nitrogen deposition exceeding critical loads across large areas of protected sites.
Figure 1. Atmospheric nitrogen deposition (kg N ha-1 yr-1) across the UK for moorland (short vegetation), highlighting widespread pressure on sensitive ecosystems. Source: Air Pollution Information System (APIS), UKCEH.
While existing indicators assess exposure to pollution, they do not show whether management actions are in place or working. The Air-MEPCA indicator addresses this gap by focusing on management effectiveness, linking site-level actions to conservation outcomes.
The indicator also supports UK commitments under international frameworks, including Target 7 of the Kunming-Montreal Global Biodiversity Framework, by helping demonstrate progress in reducing pollution impacts on biodiversity.
Why this matters
The Air-MEPCA indicator helps show whether action on the ground is making a difference, providing evidence to support better decisions for nature recovery and pollution management.
The Air-MEPCA Indicator
The Air-MEPCA indicator is a structured framework for assessing how effectively protected area management is addressing air pollution pressures. Building on the existing MEPCA indicator, it focuses on whether management actions are in place, being implemented, and contributing to conservation outcomes, specifically in relation to air pollution.
What does the indicator assess?
The indicator collates multiple lines of evidence to assess management effectiveness at a site level. It considers:
- Risk status: Is air pollution a risk to the site (e.g. critical load exceedance)?
- Management and planning: Are there management plans in place?
- Measures: Are appropriate measures in place to reduce impacts?
- Monitoring: Does site condition monitoring take place?
- Outcomes: Is the site achieving, or moving towards, its conservation objectives for air pollution?
What does the indicator provide?
The indicator is applied through a set of metrics, scored and weighted using the best available evidence and data. It provides:
- A structured, site-level assessment of management effectiveness, complementing existing data and indicators that focus on air pollution pressure.
- A method for linking management actions to conservation outcomes, helping to understand whether interventions are supporting nature recovery.
- A repeatable and scalable framework that can be applied across different protected areas.
- Evidence to support decision-making, including planning, regulation, and site management.
- A tool to track progress over time, including early indications of improvement where nature recovery may take longer to detect.
Development of the Indicator
The Air-MEPCA indicator framework is in development and is being refined through testing, stakeholder engagement, and iterative updates.
Testing and Application
The indicator is being tested using case studies across UK protected areas. These have been selected to represent a range of air pollution pressures, habitat types, and management strategies.
The case studies are being used to explore how the indicator could be applied in practice, by assessing the availability of supporting evidence and identifying where to improve clarity and usability. The findings from the case studies have been used to inform subsequent stakeholder discussions and identify areas for refinement.
Stakeholder Engagement
Stakeholder engagement has been an important part of the development of the Air-MEPCA indicator. Feedback has been sought from air pollution experts, nature conservation bodies, government departments and other key stakeholders across the UK through workshops, discussions and ongoing collaboration.
This engagement has helped to refine the indicator and ensure it is scientifically robust, relevant to policy and practical for use in assessing air pollution impacts on protected areas. Stakeholder input continues through established forums, including the Inter-Agency Air Pollution Group (IAPG) and the Air-MEPCA Steering Group, supporting the ongoing development and application of the indicator. The Air-MEPCA Steering Group includes representatives from JNCC, Natural Resources Wales (NRW), the Department for Agriculture, Environment and Rural Affairs (DAERA), Natural England (NE), NatureScot, the UK Centre for Ecology & Hydrology (UKCEH), and the Department for Environment, Food and Rural Affairs (Defra).
Indicator Refinement
Feedback from case study testing and stakeholder engagement has informed targeted refinements to the indicator, including:
- Clarifying metric definitions, particularly around air pollution risk and conservation outcomes.
- Improving the distinction between management actions and monitoring, to support consistent interpretation.
- Refining the structure and usability of the indicator, including simplifying metrics and reviewing how components contribute to the overall assessment.
These changes help ensure the indicator can be applied consistently using available evidence, while remaining adaptable to different site contexts.
Future Development
Future work will focus on:
- Expanding testing and application, including engagement with site managers and broader use across protected areas.
- Refining the indicator framework to consider off-site air pollution pressures, including updating metrics, scoring, and supporting guidance.
- Exploring opportunities for global application and comparison, to provide insight into whether the Air‑MEPCA framework could serve as a transferable model.
- Enhancing evidence and policy alignment, ensuring the indicator is supported by robust data and relevant to decision-making processes.
Contacts
To learn more about the project please contact us.
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