Odour Threshold 2 : The minimum concentration of a substance in air which is capable of being detected by the human sense of smell. This is normally expressed in parts per million or milligrams per cubic metre
Peter Koob (Compiler & Typesetter, Tasmania State Emergency Service), Emergency Management Australia (Ed & Pub), Australian Emergency Management Glossary (Australian Emergency Manuals Series Part I: The Fundamentals, Manual 3), ISBN0642476152, Tasmania, Australian 1998. http://www.em.gov.au/Documents/Manual03-AEMGlossar y.PDF, (Emr Mgt/ ND and Other Dzstr - Brit) {53}