Last month, 13 people who stayed at the Mandarin Orchard Singapore hotel were confirmed to have Covid-19. And Crowne Plaza Changi Airport hotel was found to have three unlinked Covid-19 cases.
Is it a good idea to spend long hours in an enclosed space in this pandemic?
Air-conditioning systems play a significant role in hotels because many hotels do not have operable windows. People are more vulnerable in these air-conditioned enclosed spaces because they are rebreathing the air in the room and from one another.
To save energy, typical air-conditioning systems in hotels use only 10 per cent to 20 per cent fresh air, while the remaining is recycled air coming from different hotel rooms since the air goes through the same air exhaust ducts.
In non-pandemic conditions, this air is sufficiently clean for occupants. However, airborne transmission can happen quickly if an infected person is staying in one of the rooms.
Lessons can be learnt from aircraft cabins that deliver higher percentages of fresh air (50 per cent), and which use high-efficiency particulate air (Hepa) filters for their air-conditioning systems, which can remove 99.7 per cent of airborne microbes.
Alternatively, ultraviolet-C (UVC) radiation, commonly used in hospitals, is a proven disinfectant for viruses and pathogens and shown to minimise the viability of the Covid-19 virus on surfaces and in the air.
A simple and cheap solution could be to install UVC lamps in the air ducts of these buildings.
Though UVC lamps are relatively inexpensive and installing them in air ducts is non-intrusive, each of these solutions may inevitably lead to some increased costs.
The question is how much increased costs and inconvenience is considered "too much" for the sake of our health and safety? If we are unwilling to pay the costs, then we might have to pay in other ways - possibly even tighter safe management measures.
Many good measures have been implemented, and most Singaporeans have been socially responsible in adhering to them.
However, as we gradually allow greater access to enclosed spaces, let us also ensure that our building services are regulated and maintained in this fight against Covid-19.
Zheng Kai (Dr)