Saturday 15 August 2020
And the US Centers for Disease Control (CDC), in a new guide to wearing masks, said that face coverings with valves or breathing holes – which construction workers wear largely in pre-pandemic times – do little in terms of transporting a person with “Covid-19.” 19 “, for the virus to others.
In an update published last week, the CDC said: “Masks with valves or one-way vents allow air to be exhaled through a hole in the material, which could expel respiratory droplets that could reach others. Therefore, CDC does not recommend By using masks to control the source, if it has an exhalation valve or a ventilation hole, “according to Russia Today.
Instead, the agency urges people to wear cloth masks, noting that cotton prevents most infectious respiratory droplets from escaping.
A recent Duke University experiment tested 14 different types of face masks to determine how effective each was at stopping the respiratory spray.
The study found that medical N95 masks were the most effective, followed by disposable surgical masks, and polypropylene and cotton mixed masks in the top three.