Impact on airborne virus behavior by an electric heat pump (EHP) operation in a restaurant during winter season.

The world is having an unprecedented time due to the pandemic. Currently, more than 93 million people have been infected, and over 2 million people have passed away since 2020. SARS-CoV-2 has forced people to change their lifestyles and patterns. Under the pandemic, buildings are no longer safe shelters. The infected transmit infectious viruses to other occupants by direct contact or indirect contact (i.e., indoor airflow). In addition, the airflow from electric heat pump systems can propel indirect contact in indoor spaces. However, the impact of airflow is still not sufficiently identified to develop virus control strategies in buildings. Therefore, this study selected a restaurant in Seoul, Korea, to experiment with airborne virus transmission of direct airflow in winter using virus-similar particles. The results of this study verified the potential exposure of droplets or aerosols to occupants that can be delivered by air current from heating systems in winter. The effect of kitchen hoods was also confirmed as additional ventilation equipment without additional budget investment in restaurants. The recommendations of this study are expected to improve the guidelines for restaurants to ensure occupant's safety during the COVID-19 period.