When oxygen is delivered through nasal catheter, mask or non-invasive ventilation (NIV), substantial exhaled air is released into the air, which can increase dispersion of the virus, and subsequently increase the risk of nosocomial infection [4]. Prior studies have suggested that the application of high-flow nasal cannula (HFNC), NIV through the specific mask with optimised vent holes or the helmet with a double-limb circuit may lower the risk of airborne transmission [5, 6]. Performing non-invasive respiratory support in a single, well-ventilated, negative pressure ward is also considered a safe option. Currently, however, the majority of patients are still receiving respiratory support through nasal catheter or common mask in general wards or emergency departments with limited medical resources. The potential for airborne transmission in this population has not received enough attention. Furthermore, a significant proportion of suspected patients with mild to no symptoms who are managing at home may also require long-term home oxygen or NIV treatment (e.g. patients with advanced staged COPD). These patients may increase the risk of family cluster infections by the widespread dispersion of exhaled air in their homes.