Particle release from human skin and clothing has been identified as an important contributor to particulate matter burden indoors. However, knowledge of modelling the coarse particle release from skin and clothing is limited. This study developed a new empirically validated CFD modelling methodology for particle release and transport from seated occupants in an office setting.

We tested three modelling approaches for particle emissions: Uniform, Uniform + Localised, and Uniform + Localised with Body Motion, applied to four office scenarios involving a single occupant and two occupants facing each other at 1 m and 2 m distance. Uniform particle emissions from skin and clothing underpredicted personal inhalation exposure by as much as 55%-80%. Combining uniform with localised emissions from the armpits drastically reduced the error margin to less than 10%. However, this modelling approach heavily underestimated particle mass exchange (cross-contamination) between the occupants. Accounting for the occupant’s body motion – by applying the momentum theory method – yielded the most accurate personal exposure and cross-contamination results, with errors below 12%.

The study suggests that for accurate modelling of particle release and transport from seated occupants indoors, localised body emissions in combination with simplified bodily movements must be taken into account. Ongoing efforts aim to characterise impact of building, environmental and personal characteristics on the personal exposure associated with particle release from human skin and clothing.

The practical implications of this project are the following:
• Results from this study provide a CFD modelling methodology for particle emissions from human skin and clothing at low computational cost and good accuracy, which is beneficial for refined modelling of human exposure and cross-contamination in various indoor environments.
• The results emphasise the importance of localised body emissions and movement for accurate modelling of particle transport from human skin and clothing.
• The CFD model can be used in future studies for development of improved mathematical models of the dispersal of skin and clothing-associated particles. It can also be used to limit inhalation exposure to particles emitted from the human envelope.