04/01/2020
With the ongoing debate in both Canada and the USA on the merits of wearing a face mask, I would like to provide some useful information on this topic from the perspective of a subject specialist in occupational health and safety.
In general there are two types of "masks" being mentioned as personal protective equipment for the front line healthcare practitioners including the EMS, the nurses, the doctors and the housekeeping staff in hospitals.
One is the surgical mask and the other is the N95 respirators.
The surgical mask serves the primary function of reducing the droplets generated during sneezing, coughing and talking by the wearer. This is the reason why the Chief Medical Officer of Canada, Dr. Theresa Tam repeatedly mentioned that if you are sick, or symptomatic, you should wear a mask. Would the mask completely stop the droplets from being released by the wearer during sneezes or coughs? The answer is it is unlikely to completely stop them from being generated because the mask does not form an airtight seal with the face of the wearer and hence a portion of the droplets would still be released but at a shorter distance.
The next question is does the surgical mask protect the wearer from an environment where there are droplets containing the Covid19 virus? The short answer is no it does not. The simple explanation is because the mask does not form a seal with the wearer's face and hence air containing droplets can enter the breathing zone and eventually enter into the lung.
This is one of the reasons why the infection specialists are not recommending the wearing of surgical masks by the general public.
Others reasons are it gives the wearer a false sense of protection which can be dangerous as he or she is more likely to be closer to an infected person.
Still another reason is for some people the wearing of surgical mask would increase the likelihood of touching the face as it is uncomfortable with prolonged wearing. Some proponents would argue that it would reduce the touching of ones face as it firms a barrier.
Only the N95 respirator would provide protection against droplets. Frontline healthcare practitioners must use the N95 respirators while being exposed to patients with Corona virus, provided that the respirator is worn properly which can be achieved by qualitative and or quantitative fit tests. The wearer must also be trained in performing the user seal tests each time the respirator is being used.
As a certified industrial hygienist, I provide the qualitative respirator fit test (QLFT) to workers whose job requires the use of respirators. More on the QLFT and the N95 respirators on my next posting. If you have any comments or questions, please let me know.
