 The droplets are present in high concentrations (some estimates are as high as 1010 droplets per cm3).Most cigarettes today contain a cigarette filter, which can reduce "tar" and nicotine smoke yields up to 50% by several different mechanisms, with an even greater removal rate for other classes of compounds (e.g., phenols).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).