Textile fibres in the respiratory tract part 2: Transfer during smothering vs legitimate activities

In a follow up to a previous paper [6], this article continues the exploration of fibres recovered from the respiratory tract in smothering cases. Specifically, this second part examines the transfer of fibres when smothering has occurred as compared to legitimate exposures to the textile in question. In order to simulate these activities, volunteers breathed through textiles of various levels of shedding under conditions of strain and at rest. Fibres were then self-recovered from the nose and mouth for the counting of target fibres that have transferred. The results demonstrate a noticeable difference between the two activities in terms of the quantity of fibres transferred. This difference is increasingly marked for higher levels of shedding. The findings from this paper and from part 1 were then utilized to assign probabilities which were subsequently used to evaluate findings of two hypothetical scenarios meant to represent commonly encountered case disputed issues. The results further highlight the potential for such traces to aid in suspected smothering cases. In general, low number of fibres (<5) support propositions of non-smothering whereas larger quantities (>15) typically support those of smothering. The count of fibres at which the support switches is highly dependent on the shedding of the textile. It is thus important to consider shedding and the quantity of fibres recovered in such cases.