A study of 10 coronavirus cases from three families who dined at the same restaurant in southern China has suggested that air conditioning aided droplet transmission between them.

“Strong airflow from the air conditioner could have propagated droplets” between three tables, according to the report of the research, based on the infections in the city of Guangzhou in late January. Droplet transmission alone could not explain the infections, it concluded.

Restaurants should increase the space between tables and improve ventilation to reduce the risk of infection, according to the report of the research, led by Jianyun Lu of the Guangzhou Centre for Disease Control and Prevention.