Public Lab Research note

How to Describe Odors Using FIDO, illustrated by Sara Sage

by joyofsoy , sarasage | June 27, 2019 22:33 27 Jun 22:33 | #19902 | #19902

These illustrations by Sara Sage were featured in the centerfold in Public Lab's Community Science Forum, Issue 16.

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An odor log can help you keep a record of the environmental odors you smell in your neighborhood so you can report your findings to suspected offenders, community groups, health officials, and/or code enforcement officials.

The Agency for Toxic Substances and Disease Registry (ATSDR) recommends collecting "FIDO" characteristics when keeping an odor log: information about the odor's frequency, intensity, duration, and offensiveness.

* First determine how offensive the odor is. Would you rate it: not unpleasant, unpleasant, offensive, or highly offensive? Use the diagram to the left to help determine the rating. Use the chart above for ideas on how to describe the specific smells or types of odors you notice.

* Next, determine the duration. How long does the odor last? One minute, ten minutes, one hour, four hours, more than 12 hours?

* Then choose the intensity level. Describe how strong the odor is: very strong (VS: makes you feel sick), strong (S: can't go outside), moderate (M: you can smell it, but it doesn't affect normal life), or light (L: barely noticeable).

* Choose the frequency of the odor. How often do you smell it? Once, daily, weekly, monthly, every few months?

For further reading from the ATSDR on odor logs, their uses, how to determine if an odor is considered a nuisance, and other resources, visit

Building on previous work by @sarasage and other organizers around the world, community group IMVEC created Odor Log 1.0, PDF odor logs that can be printed and filled in by hand. They suggest collecting data about date, time, and location, as well as type of odor, intensity, temperature, wind (speed and direction), effects on people, and other observations (including weather conditions). Learn more about their history and download the logs at


@joyofsoy has marked @sarasage as a co-author.

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