Owner EnviroCalc Consulting South Charleston, West Virginia, United States
Revised ABSTRACT: Humans with asymptomatic or mild coronavirus disease 2019 (COVID-19) have been reported to transmit the disease without direct dermal contact. This leads scientists to suspect that inhalation is the primary exposure pathway. The recent COVID pandemic has increased the need for simple tools to assess the potential inhalation exposure to COVID aerosol. This paper developed a workaround to apply the common well-mixed room (WMR) model to predict exposure in units of virus copies/m3. The WMR model applicability to aerosols is discussed. This study referred to the work of Riediker and Tsai (2020) for the key input; the COVID aerosol released by a symptomatic individual breathing or a coughing into the room air. The WMR model predictions were compared to the model predictions by Riediker and Tsai (2020) and the differences were explained. A case study estimated the potential COVID exposure in a dining bubble, the igloo-like structure being used to allow outdoor dining during cold weather. Many restaurants are using outdoor dining to stay in business during the COVID pandemic. These structures are being used in U.S. cities where colder weather may inhibit outdoor dining. The model can predict the exposure for the first step in a risk assessment. For the second step, COVID hazard levels have not been proposed that would enable one to complete the risk characterization. This paper is directed to risk assessors who want a practical, scientific analysis but do not want to become an expert in exposure modeling.
