Filter/dilution tunnel. A smoke sample is drawn through a tube the place it can be diluted with air, the ensuing smoke/air combination is then pulled by way of a filter and weighed. This can be the internationally regarded technique of measuring smoke from combustion.[66] 1970 – Tobacco companies lawfully https://broadfar.com/non-combusted-cigarettes-a-safer-alternative-or-just-a-myth/