The use of activated carbon in cigarette filters is well established. It is known that the activity of the carbon is reduced when incorporated into a cigarette filter. There are several factors that influence the activity of carbon in a cigarette filter; these include triacetin, tobacco volatiles and exposure to particulate matter during smoking. This study looks at the effect of changing the amount and source of particulate matter presented to the filter. The first stage of this work uses a two level factorial design which looks at the effect of keeping the Dalmatian filter constant and changing the tobacco column length, ventilation level and charcoal loading to understand the effect of amount of particulate matter presented to the filter. Both a Virginia blend and US blend were evaluated under this design. The second stage investigates the effect of changing the length and tar efficiency of the upstream segment within the filter in a cavity construction to vary the amount of particulate matter presented to the carbon. The tobacco column and overall filter length is maintained. The third stage explores removing the particulate matter prior to the filter and exposing the filter only to the vapour phase. This is achieved by placing a Cambridge filter pad in between the tobacco column and filter to remove the particulate matter before the vapour phase smoke is presented to the filter. The methods of smoke analysis will be discussed and the effects of the tar removal and dilution on the vapour phase activity of the carbon. All three stages showed little or no effect on vapour phase efficiency of the carbon by changing the amount of particulate matter presented to the filter.