Tobacco smoke may be grouped into a particulate phase (trapped on a glass-fiber pad, and termed "TPM" (total particulate matter)) and a gas/vapor phase (which passes through such a glass-fiber pad). "Tar" is mathematically determined by subtracting the weight of the nicotine and water from the TPM. However, several components of tobacco smoke (e.g., hydrogen cyanide, formaldehyde, phenanthrene, and pyrene) do not fit neatly into this rather arbitrary classification, because they are distributed among the solid, liquid and gaseous phases.
Tobacco smoke may be grouped into a particulate phase (trapped on a glass-fiber pad and termed "TPM" (total particulate matter)) and a gas/vapor phase (which passes through such a glass-fiber pad) "Tar" is mathematically determined by subtracting the weight of the nicotine and water from the TPM However several components of tobacco smoke (eg hydrogen cyanide formaldehyde phenanthrene and pyrene) do not fit neatly into this rather arbitrary classification because they are distributed among the solid liquid and gaseous phases