Dilution-based Evaluation of Airborne Infection Risk - Thorough Expansion of Wells-Riley Model

Abstract

Evaluation of airborne infection risk with spatial and temporal resolutions is indispensable for the design of proper interventions fighting infectious respiratory diseases (e.g., COVID-19), because the distribution of aerosol contagions is both spatially and temporally non-uniform. However, the well-recognized Wells-Riley model and modified Wells-Riley model (i.e., the rebreathed-fraction model) are limited to the well-mixed condition and unable to evaluate airborne infection risk spatially and temporally, which could result in overestimation or underestimation of airborne infection risk. This study proposes a dilution-based evaluation method for airborne infection risk. The method proposed is benchmarked by the Wells-Riley model and modified Wells-Riley model, which indicates that the method proposed is a thorough expansion of the Wells-Riley model for evaluation of airborne infection risk with both spatial and temporal resolutions. Experiments in a mock hospital ward also demonstrate that the method proposed effectively evaluates the airborne infection risk both spatially and temporally.

Simple quantitative assessment of the outdoor versus indoor airborne transmission of viruses and covid-19

“…Evaluating the airborne infection risk considering spatial resolution is much more challenging as discussed by Zhang and Lin (Zhang and Lin 2020 and references therein). Some attempt in this way have been made and can involve Computational Fluid Dynamics (Li et al ., 2018; Vuorinen et al ., 2020; Zhang and Lin, 2020). However in essence inhomogeneous models are devoted to particular situations, then drawing general conclusions on the relative outdoor versus indoor case seems beyond their possible field of applications.…”

Simple quantitative assessment of the outdoor versus indoor airborne transmission of viruses and COVID-19

“…Evaluating the airborne infection risk considering spatial resolution is much more challenging as discussed by Zhang and Lin ( Zhang and Lin 2020 and references therein). Some attempts in this direction have been made and can involve Computational Fluid Dynamics ( Li et al , 2018 ; Vuorinen et al , 2020 ; Zhang and Lin, 2020 ). However, in essence inhomogeneous models are devoted to particular situations and drawing general conclusions on the relative outdoor versus indoor case seems beyond their possible field of applications.…”

Recent research on expiratory particles in respiratory viral infection and control strategies: A review

“…The Wells-Riley model has been extensively used. It allows simple and quick evaluation, based on the quantum concept that implicitly considers the infectivity, infectious source strength, and biological decay of pathogens; the dose-response model is less frequently used because it requires information that is costly to obtain through experimental and on-site studies ( Sze To & Chao, 2010 ; Zhang & Lin, 2020 ).…”

“…(2020) also considered the time-varying viability of viruses. Zhang and Lin (2020) proposed a dilution-based evaluation method. This expansion of the Wells-Riley model can assess the airborne infection risk for both spatial and temporal resolutions.…”