When burnt, which fiber smells like burning hair?

Wool is a natural fiber that, when burnt, emits a smell reminiscent of burning hair. This characteristic is due to the structure of wool, which is primarily made of keratin, a protein also found in human hair. When wool is exposed to flame, it tends to smolder and produces a distinct odor that can be compared to that of singed hair, often described as unpleasant but identifiable.

In contrast, the combustion of other fibers such as acrylic typically produces a chemical smell due to its synthetic nature, while cotton usually burns with a smell similar to burning paper or wood. Polyester, also a synthetic fiber, tends to emit a sweet and plastic-like odor when burnt. Each fiber has its unique burning characteristics, making it important to differentiate them based on these olfactory cues, especially for professionals in carpet cleaning and textile care.