Investigation of Airborne Contaminant Transmissions in Senior Care Facilities: Covid-19 Outbreaks and Architectural Features

During last three years, many COVID-19 outbreaks occurred in senior care facilities. Senior care facilities are nursing places for long-term treatment and care of senior citizens, and thus, in facilities, they are prone to be exposed to risks when an infectious disease spreads into the buildings. Therefore, this study investigated airborne contaminant transmissions based on outbreak cases in senior care facilities in Korea and analyzed the potential impact of architectural features in a selected senior care facility using network simulations. In the results, COVID-19 outbreaks in 85 senior care facilities represented that the staff accounted for the largest proportion of the index cases, which means that the staff would be a primary virus carrier in the initial process of the virus transmission in senior care facilities. In addition, network simulations indicated that the (reverse) stack effect could significantly influence airborne contaminant transmission in summer and winter. The indoor airborne contaminant exposure can be changed according to the seasonal indoor airflows, and a long-distance airborne contaminant transfer through shafts (e.g., elevator, staircases) can be possible in the senior care facility. Also, when operating available mitigation strategies, it can be helpful to lower the potential risk of airborne transmission, but some poor spaces should be improved or controlled for safety. The results of this study can be used as a reference to develop customized countermeasures for senior care facilities.