Numerous papers have been presented at previous conferences examining the characteristics of filter cigarettes containing activated carbons on the removal of vapour phase compounds from smoke. All these studies have been carried out on triple granular or active acetate ("dalmation") type filters in which the carbon granules are evenly spread across the body of the filter. Innovations in filter manufacture now enable the carbon to be localized in particular cross-sectional regions of the filter, notably around the periphery (as in "Active Patch" filters) or more recently within a centrally located pocket (as in "Smooth Core" filters). This leads to the question of the extent to which the vapour phase retention of such carbon filters is affected by the localized position of the carbon granules. The vapour phase retention will not only be affected by the smoke flow paths relative to the position of the granules, but also by diffusional mechanisms occurring as the smoke travels along the filter. This paper examines the interaction between the position of carbon granules and the overall vapour phase removal efficiency of the filter. Experimental findings are presented of the relative retentions of vapour phase compounds, notably carbonyls and hydrocarbons, and semi-volatile compounds, notably phenol and cresols, by four different types of carbon filters - 'Active Acetate', 'Triple Granular', 'Active Patch' and 'Smooth Core'. The results demonstrate that the weight, rather than the position, of the carbon within the filter is the dominant factor affecting retention.