Which masks have good filtration efficiency?

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asked Oct 8, 2021 in 3D Segmentation by freeamfva (39,060 points)

Singapore updated its guidance for the use of masks on Tuesday (May 18) on the back of rising COVID-19 infections in the community. To get more news about CE antiepidemic mask, you can visit tnkme.com official website.

The Ministry of Health (MOH) is advising that members of the public use masks with better protection, such as those with better filtration efficiency, to mitigate the higher risk of infection.
This is because the recent COVID-19 clusters “suggest a higher level of transmission, likely attributed to new virus variants”, the ministry said.The bacterial filtration efficiency (BFE) of a mask refers to the degree of barrier protection provided by the material or fabric of the mask.

A mask with a higher BFE would be more effective in preventing bacteria-containing droplets from reaching the wearer.Masks that meet the requirement for medical and surgical standards have a BFE of 95 per cent - blocking 95 per cent of droplets it is exposed to.

This is often indicated on the packaging or product description of the masks sold.Suitable face coverings include surgical masks or reusable masks that are made of at least two layers of fabric, said the MOH.

Reusable masks such as those issued by the People’s Association and Temasek Foundation also have good filtration efficiency, said the ministry.It's not just wearing a cloth mask, but wear one with high filtration capability - a surgical mask or one of those with the filter inserts," said Finance Minister Lawrence Wong, who co-chairs the COVID-19 Multi-Ministry Task Force, on Tuesday.

This is especially so if one is going to an enclosed space with people in close proximity, he said.Infectious diseases expert Leong Hoe Nam said on CNA on Tuesday that masks have certifications and one can look for its ASTM rating.

These are issued by ASTM International, an organisation that develops and publishes standards on materials and products, including personal protective equipment.

Before, ASTM guidance only applied to masks used in medical settings, but in February 2021 it issued standards on consumer face masks. To get such ratings, the masks have to be tested for bacterial and particulate filtration capability and fluid resistance, among other things.

ASTM mask gradings vary from one to three and all can filter particles of 0.1 micron and above, said Associate Professor Richard Sugrue from the School of Biological Sciences at Nanyang Technological University.

"Most masks do not filter out individual virus particles (which are too small), but act by preventing large aerosol droplets from reaching the wearer," he said.

Dr Leong, who practises at Rophi Clinic, added: "If you were to use cloth masks which are made on your own, you don't know how good they are.Director of Medical Services Kenneth Mak on Tuesday also reminded people to wear their masks properly.

“Good quality masks worn well and properly provide an excellent form of protection for all of us against how the virus spreads, irrespective of whether it spreads by droplet or some form of aerosolised transmission,” he said.MOH advises people to ensure that the mask closely and completely covers their nose and mouth.

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