Jul 24, 2020

FIDOR: A practical tool for assessing odour emission risks

  • Article
  • odour emissions
  • odour emission risks
  • fidor
  • air quality
  • social licensing

It can be challenging for decision-makers to operate an existing plant, to start up a plant or to integrate a new process. These challenges include risks associated with odour and social acceptability, which are sometimes overlooked. However, nearly 70% of citizen complaints about air quality are odour-related. So, it is important to carefully plan operations, as poor odour emissions management can lead to complaints, inspections from the Ministère de l’Environnement or the Lutte contre les changements climatiques and even lawsuits.

  1. Provide a clear snapshot of the situation

    To prevent such issues, it is important to be aware of the potential your facility has to emit odours, which is no small task. Fortunately, an analytical tool such as FIDOR[1], or “FIDOL”, allows industrial companies to better determine the impact their facilities have on the surrounding olfactory landscape.

    What is FIDOR?

    FIDOR, a term used around the world, was introduced by the United Kingdom Environment Agency. The acronym comes from “Frequency, Intensity, Duration, Offensiveness, Receptor”, which are the parameters used to estimate a facility’s odour emissions risk. This decision-making tool was developed to help industrial companies assess and manage the factors that affect odour pollution levels. FIDOR provides a ranking for each parameter, making it possible to quantify the risk of nuisance and identify the most appropriate and efficient approach to reducing an industrial site’s risk of odour pollution. Each parameter’s ranking applies to a specific industrial facility.

    Under FIDOR, odour risk is measured by: the frequency of odour-related events, the intensity of the detected odours, the duration of exposure to odour-generating events, the level of offensiveness of the detected odours, and receptor sensitivity in the environment where the odours are detected.

    What do these parameters measure?

    Frequency: the number of odour-generating events that are noticeable in the vicinity and that occur within a given timeframe.

    • The detected frequency of events is linked to a variety of factors, such as the plant’s production schedule and weather conditions.
    • Optimizing the airflow parameters of odour exhaust stacks is an effective way of reducing the frequency of events associated with odours detected in ambient air.
    • Some authorities rely in part on limiting the frequency and intensity of odour-related events when setting regulations.

    Intensity: the concentration of odours detected in the surrounding environment

    • Olfactometric analyses and ambient air odour measurements are used to determine the intensity of odours detected in the surrounding environment.
    • Reducing odours at the source is the best way to reduce the intensity of events in the surrounding environment.
    • Reducing odour concentration in the vicinity reduces the risk of citizen complaints.
    • The air dispersion model is used to predict the intensity of detected odours.

    Duration: the exposure duration of each event detected in the surrounding environment

    • The duration of odour-generating events is often closely linked to plant production processes and weather conditions.
    • Some odour-emitting processes can be scheduled for times when they are less likely to disturb the surrounding community.

    Offensiveness: an odour’s level of pleasantness or unpleasantness

    • Pleasant smells are less likely to cause complaints from the surrounding community.
    • This parameter is closely linked to a person’s olfactory memory.
    • Improving an odour’s quality can reduce the risk of odour nuisance.

    Receptor sensitivity: the environment in which odour-generating events are detected

    • Receptor sensitivity is related to the immediate environment and plant location.
    • It measures the individual or collective level of tolerance for odours detected in the surrounding environment.
    • The risk increases with the number of people affected by the odours.
    • A residence or a school is more likely to be sensitive to odours than an industrial area or highway.
    • Industrial companies that are already established and in operation have the least influence over this parameter.
    • Improving community relationships promotes greater social acceptability toward the company’s industrial activities.
    • Public participation in a plant’s environmental plan can help reduce a community’s sensitivity to harmful odours.
    • Urban sprawl increases proximity between residential neighbourhoods and industrial areas, creating a higher risk of odour nuisance.
    • For new industrial facilities, it is recommended to conduct a study of the existing and future receiving environment.


    Decision-makers can control FIDOR parameters to varying degrees, meaning each company has its own odour management measures.

    Proper odour risk management helps maintain positive relationships with neighbouring communities. It also improves the company’s brand image, helps sustain operational activities and facilitates discussions with government authorities.

    Calling on odour management experts is highly recommended to adopt best practices. These experts will be able to suggest which actions to take to reduce your impact in a sustainable way. BBA can help you diagnose, measure and prioritize the necessary actions for determining the extent of odour pollution in an area and can recommend specific measures.

    1. Environmental Agency (2011). Environmental Agency. Government of United Kingdom. Additional guidance for H4 Odour Management – How to comply with your environmental permit. GEHO0411BTM-E-E. Retrieved from: https://assets.publishing.serv...

This content is for general information purposes only. All rights reserved ©BBA

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