A wet face mask is less effective because water restricts airflow and cuts the amount of viral filtering, scientists have warned.
The World Health Organization says dry three-layer masks – the now-common blue surgical masks are the most recognisable of these – worn over the mouth and nose can protect people from catching coronavirus.
But a former senior WHO official has urged users to change their face covering if it gets wet because 'moisture makes masks porous', meaning 'all types of mask are essentially vulnerable in damp weather'.
<<Print>>