I WRITE to support the views in a letter (March 19) putting the case that we should all be wearing Covid-19 protecting respirators. These are also know as half face masks.

Research from a number of institutions around the world identify the virus having a mean diameter of 0.125 microns, within a range 0.06 microns to 0.14 microns.

This dimension is comparable with suspended airborne dust.

Transmission of the virus is then by contact (direct and indirect via an infected surface); by way of droplets from coughing or sneezing propelled into the air; and by way of air suspended virus particles.

Importantly, modern research papers give good evidence that virus carries on the breath of those who are infected. There is a mix of airborne transmission: propelled droplets, and airborne aerosol particles.

The case is then overwhelming, we should all be wearing masks, or if we can FFP2 or FFP3 respirators.

Simple medical fabric masks will help lower infection spread from infected exhaled breath. Better still an FFPs respirator, rated to filters down to 0.03 microns, will protect the wearer from most particles of 0.125 Covid-19.

The reason then we are not in the UK wearing protective masks is that government has no stockpiles to issue. Nor do we have the capacity to manufacture, nor can we procure on the world market. The vast majority of manufacturing in China, also in Korea, USA, and Germany, is overwhelmed.

There is, categorically, in principle, mass protection for a population. That we are not protected is because we do not have the resources: masks and respirators. Further to this I am sure readers can make their own judgements.

GRAHAM FURGUSON PHD

Enviro Science Research Student, Bristol University

Huntly Road, Winton