Ventilation Design in High-Rise Residential Buildings and Infectious Disease Spread

In the SARS epidemics in 2003, cluster of cases occurred in high-rise residential(HRR) building blocks, especially in Hong Kong, which gave rise to the concern of the possible roles of air flow. In this paper, the multiple parallel airborne transmission routes are discussed. In particular we closely investigated one of the most likely virus-spread paths, which is related to single-side ventilation air flow through open windows caused by buoyancy effects. Both tracer gas and CFD (computational fluid dynamics) techniques have been employed, and tt was found that the upper floor air can contain up to 7% of exhaust air directly from the lower floor. The results can well explain the RNA fragments of Corono-Virus (CoV) found within the sampled deposits on the window sills of the upper floors of the two index patients flats during the SARS outbreak. Implication for ventilation design and infection control in HRR will be discussed.