Take into account the substance's odor and olfactory threshold

The odor of a substance is a signature that differentiates it from other substances. The detection of this odor is indicative of the presence of this substance in the breathable atmosphere. It can be pleasant or repulsive.

Determining the olfactory threshold of a substance is difficult, as it involves the perception of individuals. However, some highly odoriferous substances are easily detected at thresholds well below human toxicity values.

However, odor detection and its pleasant or repulsive nature can be a stress factor that disrupts people's behavior and increases the risk of accidents.

For example, the olfactory threshold for styrene is between 0.0017 and 1.0 ppm, while the 15-minute occupational exposure limit (15-minute OEL) is 40 ppm. In other words, the olfactory threshold is between 23,500 and 40 times...