Ventilation as a strategy to reduce indoor transmission of airborne diseases: development of new strategies and a risk assessment model

During the Covid-19 pandemic many people were infected indoors, in most cases in shared homes with family members who had the infection. This is because ordinary buildings are not built to prevent transmissions of airborne infections. This calls for strategies to improve building standards to account for this.

The current project aims to explore ventilation strategies or/and building related measures and develop a new risk assessment model of indoor infection transmission. New concepts on the performance of ventilation in reducing exposure to indoor air contaminants will be explored.

These concepts contribute to development of the risk assessment model for indoor transmission and will be done in cooperation with researchers from Japan.

The approach is that air and contaminants in the room consist of two populations: One leaving the room and the other recirculating. The one recirculating is spreading the infection.

This is quantified by the transfer probability between the source and other locations in the room and by identifying the airflow trajectory.

The ventilation´s ability to dilute the infectious agents is quantified by local purging flow rate and the spread of infectious agents by the visitation frequency. The transfer probability between rooms is determined by airtightness. This makes it possible to identify protected zones, which can be helpful during self isolation.

Mathematical modelling, tests with tracer gas measurements and simulations will be applied.