Department Seminar - Speaker: Tami Bond
Description
Speaker
Abstract:
The last six months of the COVID-19 pandemic have provided many lessons in thinking about contaminant transport. One of the lessons is that the principles of aerosol dynamics are not fully integrated into recommendations to protect public health and reduce exposure. A group of CSU faculty has been working over the summer to identify some of the important principles, and this presentation summarizes some of the findings. We defined a metric, Effective ReBreathed Volume (ERBV), that quantifies how infectious pathogens transport through air, distinguishing environmental characteristics from other factors in the chain of infection. Particle size is a key factor in transport, removal onto surfaces, and elimination by mitigation measures, so ERBV is presented for a range of exhaled particle diameters: 1 μm, 10 μm, and 100 μm. Two separate but interacting effects—proximity and confinement—govern pathogen transport. Distancing can reduce the proximity effect, but confinement in enclosed spaces overwhelms that protection after about 15 minutes for 1-μm and 10-μm particles. Changes in standard ventilation and filtration can reduce person-to-person transport of 1-μm particles (ERBV1) by 13-85% in residential and commercial situations. Deposition to surfaces competes with intentional removal for 10-μm and 100-μm particles, so the same interventions reduce ERBV10 by only 3-50%, and ERBV100 is unaffected. The analysis identified some important uncertainties in quantifying transmission and the benefits of mitigation: transport very near emitters and indoor deposition rates.
The EAS seminar series continues in its new virtual form this semester. Seminars are loosely organized around the theme of “Hazards.”
Every Wednesday from 12:40-1:30 pm.