New research presented at this year’s European Congress of Clinical Microbiology & Infectious Diseases (ECCMID), held online this year (9-12 July), shows that wearing a surgical face mask can provide a similar degree of protection against aerosols as wearing a respirator. Face shields, however, provide little or no protection.To get more news about Quality Medical Mask, you can visit tnkme.com official website.

The efficacy of personal protective equipment (PPE), including face masks, has been the focus of scientific and public interest since emergence of the SARS-CoV-2, a virus which is mainly transmitted through droplets and aerosols in poorly ventilated settings. It is crucial to provide healthcare workers with high-quality face masks or respirators to protect both themselves and their patients. However, at start of the pandemic, some experts, particularly in Europe, said that while surgical face masks protect others, they provide no significant protection for the wearer. Moreover, many newly produced masks seem to be of poor quality.

The study, by Dr. Christian Sterr and colleagues at Philipps University Marburg, Marburg, Germany, compared 32 types of mask intended for use in hospitals, including cloth and surgical (medical) masks, respirators and face shields. The surgical masks included some with EN 14683 certification (the EU quality standard) and others that were non-certified. Both FFP2 and KN95 respirators were tested. KN95 respirators, which meet Chinese standards, were subject to EU RAPEX safety warnings from April 2020.

The first experiment measured the filtration efficacy of the mask material. Each mask was fixed to an air-collecting tube inside an airtight tank. An aerosol of the chemical di-ethyl-hexyl-sebacat (DEHS) was pumped into the tank and the aerosol particles in the collecting tube counted by a particle counter.

The average filtration efficacy was lowest for the cloth masks (28%), followed by the non-certified surgical masks (63%) and the certified surgical masks (70%). The KN95 respirator material filtered out 94% of particles and the FFP2 mask material, 98%.

The second experiment measured the air pressure on either side of the mask. Surgical face masks produced the lowest drop in pressure and so would provide the least resistance to breathing—type II surgical masks produced a pressure drop of 12.9 Pa/cm2, while non-certified surgical masks produced a pressure drop of 16.2 Pa/cm2.Respirators produced pressure drops that were two to three times higher (26.8 Pa/cm2 for FFP2 and 32.3 Pa/cm2 for KN95). The results for the cloth masks ranged between 6.9 and 149.3 Pa/cm2.

The third experiment measured the filtration efficacy of the masks as worn. It used a similar set-up to the first experiment but the masks were mounted on a dummy head with an artificial trachea or windpipe, instead of being fixed to the air-collecting tube. The artificial head was the size of the average person in the US and had a skin-like coating, to provide a more realistic mask fit.

The cloth masks and the non-certified surgical masks had the worst as-worn filtration efficacies, filtering out just 11.3% and 14.2% of the particles, respectively. Remarkably, the type II surgical face masks had similar as-worn filtration results (47%) to the KN95 respirators (41%) and FFP2 respirators (65%). The face shields did not have any significant effect.