How do the sizes of amine molecules affect their volatility and odour?

The size of an amine molecule significantly influences its physical state and sensory characteristics.

Lower-molecular-weight amines are typically gases or easily vaporized liquids at room temperature, which contributes to their high volatility and strong, fishy to putrid odors. As the size of the amine molecule increases, its volatility decreases, meaning the compounds become less prone to evaporation.1

Correspondingly, the intensity of the odor diminishes as the molecular size increases, eventually becoming unnoticeable. However, this trend has notable exceptions; certain larger diamines, such as putrescine and cadaverine, retain distinct and offensive odors associated with decaying organic matter.1