Most blue surgical masks ineffective against COVID-19 — Canada study
Most blue surgical face masks used by many during the pandemic are not enough to avoid people from being infected with COVID-19, a study from the University of Waterloo in Canada found. – MedicalBrief (2 September 2021) According to the study, the blue cloth surgical masks that have become popular during the pandemic were found to filter only 10% of aerosol droplets, as they do not cover the face properly. The N95, filtered more than 50% of aerosol droplets while the other half is dispersed above the wearer's head.
Even modest ventilation rates were found to provide about the same level of protection as the highest quality masks, the lead author noted.
The Centre for Disease Control & Infection has been criticised for its confusing stance on masks after it reversed its mask guidelines. But cities and states say they need to see the evidence before revising their own policies.