What Is A Sniff Survey? | Odour Assessment Explained
A sniff survey is a field-based odour assessment method which assesses how people experience odours in real-world environments.
Unlike other odour sampling methods which measure emissions at source, a sniff survey focuses on how odour behaves once it leaves the site boundary. It helps identify whether odour is present, how strong it is and how it varies across different locations and conditions.
At Silsoe Odours, we carry out sniff surveys as part of wider odour assessment work, supporting planning applications, operational management and complaint investigations.
Why Use Sniff Surveys?
Sniff surveys help bridge the gap between measured emissions and real-world impact.
They are particularly useful when you need to understand how odour behaves outside the site boundary. They also play an important role in identifying and attributing odour sources where the origin is uncertain.
Sniff surveys are often helpful to:
- Overcome access limitations to an emission source
- Assess potential odour impacts for planning applications
- Identify an odour source from multiple possible sources
- Investigate and provide evidence for odour complaints
- Validate the results of dispersion modelling
- Support odour management planning
- Review whether mitigation measures are effective
To build a complete picture of site impact, sniff surveys often take place alongside odour sampling surveys and dispersion modelling.
How A Sniff Survey Works
A sniff survey involves trained odour assessors visiting pre-defined locations around a site and recording structured observations over a set period.
At each location, assessors evaluate odour conditions at that point in time.
They record:
Odour Character
What it smells like
Odour Intensity
How strong it is
Frequency
How often it occurs
Duration
How long it lasts
Weather Conditions
Wind speed, direction etc
This creates a consistent dataset that shows how odour behaves across space and time. Surveys are often repeated under different meteorological conditions to ensure results are representative.
When Sniff Surveys Are Used
Sniff surveys can support a wide range of industrial and environmental situations.
| Application Area | How Sniff Surveys Are Used | Purpose |
|---|---|---|
| Planning & Development | Assess whether a proposed development will be affected by existing odour sources. | Supports planning applications alongside odour sampling and dispersion modelling. |
| Operational Sites | Monitor boundary conditions and understand how daily operations affect surrounding areas. | Supports ongoing odour management planning and compliance. |
| Odour Complaints | Investigate reported odour events and determine their validity. | Provides structured evidence for planning and regulatory discussions. |
| Validating Dispersion Models | Compare predicted odour impacts with real-world observations at receptor locations. | Improves confidence in modelling used for permitting and planning. |
The Value of Sniff Surveys
Sniff surveys provide context that emission measurements alone cannot. They show how odour behaves in reality and people experience it under different conditions.
They are particularly valuable when decisions depend not just on what is emitted but also on how it is perceived.
In practice, sniff survey data often plays a key role in planning decisions, regulatory engagement and long-term odour management strategies.
Speak to our Team
To find out more about sniff surveys or how they fit into a wider odour assessment, speak to our team of odour specialists.
Call: 01525 860222
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Published May 2022. Last updated May 2026.
2 Responses
Good morning.
I am submitting a comment to Wiltshire Planning concerning a state-of-the-art housing development proposed very near to the Malaby Bigas Ltd plant in Warminster Wiltshire.
I am seeking permission to reference your website and statements contained therin, not necessary for the purposes of objecting or in favour of the submission, but for better containment of odours that emanate from the plant, for the good of all those living nearby.
I can send you a copy of my final submission if requested. May I add your website is very informative even to the lay person and would urge Wiltshire Council to take on board many of the arguments you present.
Ken Plummer – Warminster Resident and retired EMC consultant.
Hello Ken,
We have no objection to you referencing the Silsoe Odours website. Please kindly send your final submission to info@silsoeodours.co.uk.
Many thanks
Joanna