What is formaldehyde – and how are we exposed to it?

Formaldehyde is a chemical with no colour and an unpleasant smell. At room temperature, formaldehyde is a gas. It also comes in a liquid solution called formalin. Formaldehyde is widely used in various industries and as a preservative and disinfectant. Formaldehyde is also found in smoke and exhaust from sources like cigarettes, vehicles, gas or wood-burning stoves and forest fires.