Mask Wearing-the Scoop

April 22, 2020

 

 

As nurses who own and operate Discovery Garden, we prioritize your health and feel a duty to help our customers wade through all the information (and mis-information) regarding the coronavirus. This article compares 4 different types of masks/respirators, (cloth, surgical, N95 respirator, and surgical N95 respirators). Your health is paramount to us and we want you to understand the facts surrounding mask wearing so you can make an informed decision for yourself and your loved ones.

 

Stay safe and be well!

 

Masks types

 

Homemade cloth masks-  Unlike surgical masks or N95 respirators, cloth face coverings have not been tested to any government performance standards for filtration.  According to a study done in Vietnam in 2015, penetration of cloth masks by particles was almost 97% while surgical masks allowed only 44% of particles (surgical masks are primarily designed to prevent transmission of bodily fluids).  Contrast that to an N95 respirator that filters out 95% of airborne particles. The 2015 study also found that wearing a cloth mask increases your chances of contracting a viral illness due to moisture retention, reuse of the mask, and the inherent poor filtration of particles (BMJ open).  It may also cause people to relax social distancing under a false pretense of safety.  Another 2017 study comparing performance of a standard N95 mask to cloth masks suggest that cloth masks are only marginally beneficial in protecting individuals from particles <2.5 microns (size of the coronavirus is about 0.1 micron).  Compared with cloth masks, disposable surgical masks are more effective in reducing particulate exposure (j expo sci environ epidemiol). A 2013 study on cloth masks used several household materials to evaluate the capacity to block bacterial and viral aerosols.  The number of bacteria and viruses isolated from the coughs of volunteers wearing cloth masks were compared to those wearing a standard surgical mask. This study showed the surgical masks were 3 times more effective in blocking bacterial and viral transmission than the homemade mask and concluded that a homemade mask should only be considered as a last resort (disaster med public health).

 

Surgical masks-  These have been tested, FDA-Cleared, and designed to be worn by healthcare professionals during surgery and other procedures to help prevent contamination of the surgical field and/or the patient by capturing liquid droplets that are exhaled by the wearer.  A key performance requirement for this mask isn’t filtering out viruses, but rather fluid resistance which is the ability of masks to resist penetration by high-pressure streams of liquid, such as those that might result from an artery being punctured during surgery.

 

N95 respirators-  These are respirators designed specifically for those exposed to a potential hazard of airborne droplet containing viruses and bacteria, such as those generated by coughs and sneezes.  N95-rated respirators have been approved based on their tested ability to remove 95% of particles that are 0.3 micron in size.  The coronavirus is 0.1 micron in size but is actually easier to filter than 0.3-micron particles due to the N95 mask design which includes an electrostatically charged microfiber filtering system.  Particles both larger and smaller are easier to filter, leaving the 0.3 micron-sized particle the most difficult to filter, thus the rating targets this size particle.  In China, during the 2019 coronavirus outbreak, 10 out of 213 medical staff with no mask contracted Covid-19 from SARS-CoV-2 (coronavirus), while none of the 278 medical staff wearing an N95 respirator were infected (China 2020).  These masks are able to filter out 95% of particles, both larger and smaller than its 0.3 micron rating which includes the coronavirus (3M) (3M) 3M).

 

According to the CDC, N95 respirators are the PPE most often used to control exposures to infections transmitted via the airborne route, though their effectiveness is highly dependent upon proper fit and use.  A common mistake mask wearers make is a loose fit that allows air to flow around the mask rather than through the mask.  Not covering your mouth and nose snugly allows air flow and contaminant flow to bypass the mask through the point of least resistance, the poor seal between mask and face.

 

Surgical N95 respirators-  Strictly for healthcare workers, this device is used by those working in an environment containing both particles, such as the coronavirus, and where exposure to body fluids such as blood and saliva is likely, such as in surgery.  These are not used by the general public or those health care workers not working in environments where contact with bodily fluids is likely.

 

In light of a global N95 respirator shortage, where the public often has no other option than to wear a homemade cloth mask, it is important to continue to maintain a 6-foot separation from others as well as hand washing prior to eating or touching the face. Actually, even with either a surgical mask or an N95 respirator, it is still important to practice social distancing as none of these facial protection devices are 100%.  A 2020 study by Konda, et al comparing various fabrics and their filtration effectiveness indicates that a combination of high thread count cotton combined with chiffon or silk takes advantage of an electrostatic particle grabbing effect created between different fabrics making these masks almost as effective as an N95 respirator.  Though an N100 respirator would offer more protection than an N95 mask as well as other face coverings (JR Soc Interface).

 

For future reference if you have access to an N95 respirator, you may be interested to know that researchers at Stanford University who heated N95 masks to 167°F x 30 minutes at a humidity of 85% found the masks uncompromised, even after 20 heating cycles (Stanford Medicine).  To increase humidity when heating these masks, placing a pan of water in the oven will help.  Avoid touching the mask to heating surfaces.  One tip is to suspend the mask with a wooden stick.  This reuse method has not been approved by National Institute of Occupational Safety and Health (NIOSH) or the Centers for Disease Control (CDC). 

Freezing the virus doesn’t kill it as cold temperatures will keep the coronavirus alive for days and if frozen it can stay alive up to two years! (Kampf, J Hosp Infect, 2020, WHO, COVID-19 Situation Report 32, 2020)

 

References

Davies, A., Thompson, K. A., Giri, K., Kafatos, G., Walker, J., & Bennett, A. (2013). Testing the efficacy of homemade masks: would they protect in an influenza pandemic?. Disaster medicine and public health preparedness, 7(4), 413-418.

Kampf, G., Todt, D., Pfaender, S., & Steinmann, E. (2020). Persistence of coronaviruses on inanimate surfaces and its inactivation with biocidal agents. Journal of Hospital Infection.

https://www.who.int/docs/default-source/coronaviruse/situation-reports/20200221-sitrep-32-covid-19.pdf?sfvrsn=4802d089_2

Lai, A. C. K., Poon, C. K. M., & Cheung, A. C. T. (2012). Effectiveness of facemasks to reduce exposure hazards for airborne infections among general populations. Journal of the Royal Society Interface, 9(70), 938-948.

MacIntyre, C. R., Seale, H., Dung, T. C., Hien, N. T., Nga, P. T., Chughtai, A. A., ... & Wang, Q. (2015). A cluster randomised trial of cloth masks compared with medical masks in healthcare workers. BMJ open, 5(4), e006577.

Shakya, K. M., Noyes, A., Kallin, R., & Peltier, R. E. (2017). Evaluating the efficacy of cloth facemasks in reducing particulate matter exposure. Journal of exposure science & environmental epidemiology, 27(3), 352-357.

Wang, Q., & Yu, C. (2020). The role of masks and respirator protection against SARS-CoV-2. Infection Control & Hospital Epidemiology, 1-2

https://multimedia.3m.com/mws/media/1794572O/surgical-n95-vs-standard-n95-which-to-consider.pdf

http://multimedia.3m.com/mws/media/1102295O/electrostatic-media-dr-white-paper-en.pdf

https://multimedia.3m.com/mws/media/956213O/differences-between-respirators-and-masks.pdf?fn=Respirator%20vs%20Surgical%20Mask%20flye

https://www.fda.gov/medical-devices/personal-protective-equipment-infection-control/n95-respirators-and-surgical-masks-face-masks#s3


 

 

 

 

 

Share on Facebook
Share on Twitter
Please reload

Featured Posts

I'm busy working on my blog posts. Watch this space!

Please reload

Recent Posts
Please reload

Archive