The sight of individuals donning surgical masks are common sight as fears of coronavirus grows. The perennial question is, if this measure is really worthwhile.
Firstly, surgical masks were created to avoid droplets from the surgeon’s nose and mouth from contaminating the wound area during surgery. When the droplets are trapped in the masks, the bacteria and viruses which stays within the droplets are prevented from travelling further.
The smallest diameter that a surgical mask will trap is about 0.1 micrometer in size. A virus is about 20-400 nanometers and the size of a coronavirus is about 100 nanometers or 0.1 micrometers.
A study in 2010 looked at the efficiency of surgical masks, sums this up quite well. This study was done following the move of using surgical masks to protect oneself from infection following the influenza H1N1 outbreak in 2009.
The analysis revealed that the filtration efficiency for 0.5 um particles ranged from 3% to 43% for the unsealed masks and 42% to 51% for the sealed. For 1.0 um particles, the efficiency was 58% to 75% for unsealed and 71% to 84% for sealed masks. For 2.0 um, the efficiency was 58% to 79% for unsealed masks and 69% to 85% for the sealed masks. The data were statistically significant and indicated that surgical masks were associated with very low filtration efficiency. This suggests that they may be inadequate against airborne viruses and bacteria.
A coronavirus is much smaller than 0.5 micrometers.
So the proper advise is for those who are unwell, especially those coughing and sneezing to wear masks and to sanitise or wash their hands to avoid contaminating more surfaces. For those who are well, please sanitise or wash your hands before touching your eyes, nose or mouth. Wearing a surgical mask may only give you a false sense of security.