Tracer gas is a suitable surrogate of exhaled droplet nuclei for studying airborne transmission in the built environment

Sustainable design of courtyard environment: From the perspectives of airborne diseases control and human health

“…In the User-Defined-Scalar (UDS) equation, particle size was considered in determination process of Brownian diffusivity ( Zhao et al, 2009 ). Based on the previous literature on diameter of droplet nuclei ( Ai, Mak, Gao, & Niu, 2020 ), the size of respiratory droplet nucleus was set as 1 μm in the current numerical simulation.…”

Adaptive Wall-Based Attachment Ventilation: A Comparative Study on Its Effectiveness in Airborne Infection Isolation Rooms with Negative Pressure

“…A pressure outlet at –10 Pa is used for the outlets. The tracer gas (i.e., contaminants) is assumed to be released from the heads of the patients in the ward [24] , [44] . Based on the literature, given the most unfavorable conditions for the environment of medical staff in an isolation ward, the rate of contaminants generated is 0.7 L·s -1 under steady conditions [45] , [46] and 10 L·s -1 for 2 s with a frequency of 40 counts per hour under unsteady conditions [47] , [48] , [49] .…”

Assessing and controlling infection risk with Wells-Riley model and spatial flow impact factor (SFIF)

“…Tracer gas is a suitable surrogate of exhaled droplet nuclei for studying airborne transmission in the built environment ( Ai, Mak, Gao, & Niu, 2020 ). Indoor air pollutants and exhaled droplets (or droplet nuclei, the residual of evaporated droplets) are usually a very small fraction of air.…”