Capture of aerosolized spores from air streams impinging onto fabrics

• We blew 1–2-µm spores over samples of 10 fabrics at 3 speeds and 3 incident angles.
• Removal by filtration was more efficient than by deposition.
• Surface texture affected capture efficiency more than surface composition did.
• Our CFD model predicted 2–10× less capture on an inert surface than we observed.
• An empirical fabric–particle interaction term will improve predictive capability.

The zero-volume airlock concept minimizes the volume of air in and transiting through the airlock by effusing air from the clean area through spaces between deformable air bladders. An individual transiting through the airlock into a shelter displaces the bladders and creates ephemeral regions of varying dimensions and air velocities, which affect deposition and reaerosolization of particles. Properties of the aerosols and bladder surfaces are also influences, so the airlock may be treated to shed or retain particles and possibly to promote decontamination of them; the uniform material determines the protection from or exposure to these particles that the wearer experiences. To initiate evolution of a predictive computational model for the deposition and disposition of airborne particles in an airlock, this study presents measurements of deposition rates of Bacillus atrophaeus spores, a common simulant for anthrax spores, on a variety of fabrics as a function of airspeed and angle of incidence at ~22 °C and ~55% RH in a laboratory-scale aerosol tunnel. A computational model using inert surface properties consistently underpredicted experimental results by a factor of 2–10, suggesting that the variation in results across the test panel can be exploited to generate empirical parameters that can be substituted into the model to improve its predictive capability. Factors and possible approaches to computational descriptions are considered.