
Paper, cotton masks appear ineffective stopping Covid-19 - doitLP
https://annals.org/aim/fullarticle/2764367/effectiveness-surgical-cotton-masks-blocking-sars-cov-2-controlled-comparison
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doitLP
TL;DR

 _Discussion: Neither surgical nor cotton masks effectively filtered
SARS–CoV-2 during coughs by infected patients. Prior evidence that surgical
masks effectively filtered influenza virus (1) informed recommendations that
patients with confirmed or suspected COVID-19 should wear face masks to
prevent transmission (2). However, the size and concentrations of SARS–CoV-2
in aerosols generated during coughing are unknown. Oberg and Brousseau (3)
demonstrated that surgical masks did not exhibit adequate filter performance
against aerosols measuring 0.9, 2.0, and 3.1 μm in diameter. Lee and
colleagues (4) showed that particles 0.04 to 0.2 μm can penetrate surgical
masks. The size of the SARS–CoV particle from the 2002–2004 outbreak was
estimated as 0.08 to 0.14 μm (5); assuming that SARS-CoV-2 has a similar size,
surgical masks are unlikely to effectively filter this virus._

