In April 2020, we were told to use face coverings made from any random bit of cloth to stop droplets, thereby reducing the spread of Covid-19.

Droplet transmission requires a direct hit on someone else’s nose, mouth or may be hands (which later touch the nose or mouth), or fomites – that is, particles on surfaces to transmit an infection. The CDC has since said fomite transmission is rare.

The paper, discussed in the thread below, finds that aerosol transmission is primary mechanism of disease spread.

Which means we’ve been using (mostly) the wrong kind of masks all this time – masks that have little impact on airborne transmission. To reduce airborne transmission we need to use air sealed respirators such as N95/FP2/KN95 masks, not surgical masks or cloth masks. This likely explains why cases skyrocketed after high compliance mask mandates went into effect – we were using ineffective masks.

We also need to improve ventilation – yet modern building design has done the opposite – with more sealed buildings without windows and fresh air.

Link to published paper.

By EdwardM