Which type of odor is considered the most difficult to deal with?

Psychological odor is regarded as the most challenging type of odor to manage because it is more about a person's perception and memory than about the physical substance causing the smell. This type of odor can trigger emotional responses and is often tied to personal experiences or trauma. For instance, someone may associate a specific scent with a past event, which can lead to a strong psychological reaction, even if the odor itself is no longer present.

In contrast, biological odors result from living organisms, food odors are generated from cooking or spoiled food, and chemical odors originate from synthetic substances. These can generally be identified, treated, and eliminated through physical cleaning or removal of the odor source. However, psychological odors are tied to individual experiences and may not be resolved merely by physical means, making them much more challenging to address effectively in restoration scenarios.