Vapour
Synonym for the gaseous physical state of a substance that is normally a liquid at usual environmental temperatures. Vapours can like gases easily be dispersed over long distances.
Glossary Source
JRC EU CBRNe Glossary
(
EU Glossary on Chemical, Biological, Radiological, Nuclear, and Explosive risks
)
https://publications.jrc.ec.europa.eu/repository/bitstream/JRC128863/JRC128863_01.pdf