Effects of HVAC System and Building Characteristics on Exposure of Occupants to Short-Duration Point Source Aerosol Releases

This paper presents results from the simulation of localized, short-duration bioaerosol releases in a hypothetical building similar to a dormitory or barracks using public domain multizone air flow and contaminant dispersion modeling software. The primary purpose of the modeling was to generate example exposure data to be used in the development of a comprehensive microbial risk assessment methodology. However, these results are also of intrinsic interest for what they reveal about the contribution of various building characteristics to risk from airborne contaminants. A variety of parameters were varied, including building construction, heating, ventilating, and air-conditioning (HVAC) system design, and release characteristics, among others. Results of these simulations demonstrate the variability of exposure possible under different scenarios and, more particularly, the impact that HVAC design decisions can have on risk. Although a single building and restricted set of scenarios was investigated, several general conclusions could be drawn regarding factors, such as HVAC zoning and filter maintenance, that intrinsically contribute to vulnerability reduction.