IAQM odour guidance: start with the planning question
The IAQM odour guidance published in September 2026 provides a useful starting point for a planning assessment brief. First, explain the proposal, the potentially affected people and the planning decision. Then choose surveys or modelling to answer that question.
The document is Guidance on the assessment of odour for planning, version 2.0. It addresses planning and amenity. Environmental permitting, health assessment and statutory nuisance involve distinct questions and requirements.
Use this checklist to assemble a focused brief for the appointed assessor. Our odour assessment service guide explains the wider assessment process.
Identify the source, pathway and people affected
First, state whether the proposal introduces an odour source or places a sensitive use near an existing activity. Then show the relationship on a dated plan. Include the whole proposal, rather than only the nearest boundary.
A practical brief should describe what happens, when it happens and where odour might arise. Also record uncertainty explicitly. For example, an indicative process description should not appear in the final assessment as a confirmed operating commitment.
| Brief item | Information to assemble |
|---|---|
| Proposal and decision | Site plan, application stage, intended use, phasing and the authority’s specific question. |
| Activity and operation | Process description, operating periods, materials, handling and storage arrangements, and proposed changes. |
| Surroundings | Nearby and proposed sensitive uses, relevant building layouts and access for any agreed observations. |
| Existing evidence | Earlier assessments, available monitoring or complaint records, their dates and known limitations. |
| Controls and responsibility | Proposed measures, who can deliver them, maintenance responsibilities and remaining design decisions. |
| Scope and output | The assessor’s chosen tools, missing information, programme and the form of conclusion needed. |
Use the IAQM odour guidance to agree suitable assessment tools
IAQM describes a weight-of-evidence approach. Observations, complaints information, predictive assessment and modelling can have different strengths and limitations. Therefore, the assessor should explain how the selected evidence supports the conclusion.
Accordingly, ask for a short scope note before commissioning a fixed package. It should connect each proposed task to an uncertainty in the project. A survey should have a clear purpose, suitable access arrangements and an agreed reporting output.
A model result should not erase convincing evidence of an existing effect. Equally, a brief site visit cannot describe every operating and weather condition. Ask how the assessment will handle gaps and conflicting evidence.
Keep the assessment and management commitments connected
An odour management plan describes controls and operational responsibilities. However, it is not the impact assessment itself. The planning assessment still needs to explain the expected residual effects.
For the project team, the useful check is traceability. Can each relied-upon measure be found in the relevant drawing, specification or operational document? Does the responsible party understand it? If the design changes, who asks the assessor to review the conclusion?
Illustrative example: a proposed waste reception area moves during layout development. Keep the new position, operating description and control proposals together. Ask the assessor which conclusions need review before the application pack treats the change as accepted.
Prepare a focused scoping discussion
Send the current plan, proposal description, relevant authority correspondence and available evidence. Then distinguish confirmed information from assumptions, and identify any dates that constrain access or design decisions.
If your scheme introduces homes near an existing operation, our guide to development near an odour source covers that particular interface. For a project-specific brief, discuss the odour assessment scope with ACP.
Source and scope
Primary source: IAQM, Guidance on the assessment of odour for planning, version 2.0, September 2026. This is professional guidance, primarily for UK planning practice. Apply the relevant national and local policy context. The checklist above is ACP’s practical briefing aid.