- Lignin - a natural wood component which replaced higher quality rag paper in the 19th century It releases acetic acid, hexanol and furfurol.
- Rosin (pine tar resin) - hydrophobic compound usually added to paper to make it smoother to write – releases various acidic compounds, such as sulphuric acid, as well as aldehydes and ketones, and 2-ethylhaxanol. The process of adding rosin was called sizing and it was done to prevent blotching.
- Benzaldehyde adds an almond-like scent, vanillin smells of vanilla and ethyl hexanol has a ‘slightly floral’ scent. Ethyl benzene and toluene add sweet notes.
Humans can have some of these compounds in their sweat, breath and urine, after ingesting certain spices and via dermal exposures. They could also react to increased amounts of these compounds in the air by eye and throat irritation.