Apart from increasing the air changes and installation of air purifiers, there are simpler and cost-effective ways to fight against the fifth wave of COVID-19 outbreak. A Hong Kong born technology start-up, Nanofil Filtration Technology Ltd., is working hard to expand the range of sizes of their filters for window type and split-type air conditioners in order to suit the larger cassette type air-conditioners commonly adopted in restaurants. Nanofil’s patented nano filter can effectively stop circulation of virus particles within the air-conditioned space in order to reduce the risk of transmission of COVID-19.

The Hong Kong government has tightened the social-distancing rules against the fifth wave of the COVID-19 community outbreak & Omicron infections. There will be a 6pm curfew on dine-in services at restaurants; closures of venues such as bars, karaoke rooms, swimming pools, mahjong parlours; restrictions on large events and social activities.
HongKongers are back to not just coronavirus-induced panic but also serious mental stress especially for business owner.

During this year, the government has announced several requirements on improving indoor air quality (IAQ). Catering premises operators are required to ensure that the air change per hour at seating areas of their premises has reached six, or otherwise installed air purifiers with HEPA filter and UV-C disinfection as a substitute plan. However, from the case of Omicron outbreak tied to a Hong Kong restaurant, it seems not the most effective way of preventing viruses from spread out and protecting employees and customers.
Besides, it is sometimes practically difficult, if not impossible, to comply with the six air changes per hour requirements or huge modification cost on modification of the existing air-conditioning system will incur. In regard to air purifiers, quite many suppliers claim that their air filters meet the standard of HEPA filter, but it is doubted. The required quantity and locations of placing these air purifiers performance are also questioned.
ASHRAE (American Society of Heating, Refrigerating, and Air-conditioning Engineers) reported in their journal of August 2020 that a high efficiency filter of MERV 13 rating or above is effective in capturing airborne virus particles and hence reduce the risk of spread of viruses.
Simple and Effective Way for COVID-19 Protection
Install high quality air filters with MERV 13 rating or above for your business.

Research has shown that the particle size of the SARS-CoV-2 virus is around 0.1 µm (micrometer). However, the virus does not travel through the air by itself. Since it is human generated, the virus is trapped in respiratory droplets and droplet nuclei (dried respiratory droplets) that are predominantly 1 µm in size and larger.
ASHRAE currently recommends using a minimum MERV 13 filter, which is at least 85% efficient at capturing particles in 1 µm to 3 µm size range. A MERV 14 filter is at least 90% efficient at capturing those same particles. High-efficiency particulate air (HEPA) filters are even more efficient at filtering human-generated infectious aerosols but its pressure drop is rather high that might not be able to install on the existing air-conditioning system.
Upgrading of the existing air filters to MERV 13 filtration efficiency could be the simplest and the most cost-effective way to reduce the risk of spread of viruses.