Authors: Melissa Markoski (@melmarkoski) and Thomaz Arruda (@thomazaw)
Reviewed by: Mateus Falco (@mateuslfalco) and Larissa Brussa Reis (@laribrussa)
Translated from portuguese by: Isaac Schrarstzhaupt (@schrarstzhaupt) and reviewed by Mellanie Dutra (@mellziland) and Marcelo Bragatte (@MarceloBragatte)
During COVID-19 pandemic days, we realized that it would be fair that Luke Skywalker has his mask. Even if he didn’t manage to get a “professional” mask as his father’s, Darth Vader, he got a cloth mask that matches with his black suit and allows him to perform all the moves he needs at this lightsaber fight. For our concern, that is the best lightsaber fight of all, indeed! But…what if the Death Star was going through a SARS-CoV-2 surge, would this cloth mask protect Luke?
From a galaxy far, far away to our reality, we brought here a friendly (like Han and Chewie) text to help clarify if cloth masks are effective and the quality of their protection from aerosol (particles smaller than 0.5 µm) contamination. Before the empire strikes back, we highlight that this text is based on the article published, in this week JAMA Internal Medicine journal (impact factor of 18.65) [1], which brings an analysis of the filtration efficiency in different types of cloth and surgical face masks being used as PPE (personal protection equipment) by the general population in the COVID-19 pandemic. A new hope, perhaps?
Well, if you’re landing here with the Mandalorian jetpack, we suggest that you take a look at these texts from our COVID-19 Analysis Group (they’re in portuguese, but we can translate them for you, if you ask to!) that also explain about face masks. The first stands out the importance of the protection that face masks give to everybody else, the second argues relation between face masks, distancing and the filtrating capacity of the professional face masks. Finally, the third focuses on physical distancing, especially regarding the use of face masks to the airflow and particle retention. And now, please, leave baby Yoda on its crib and join us on this new mission. You’ll receive something as protective as Beskar: information.
Before we discuss the study itself, here’s a question: do you know what FFE (Fitted Filtration Efficiency) stands for? Well, FFE is the analysis of a material’s resistance to bacterial, viral or chemical penetration. It’s made on filtration materials, cloths, capes and protection designed devices. It’s a bit like the situation where Han Solo was frozen in carbonite, just to test the machine that was meant to freeze Luke…So, the higher the FFE value, the better the protection barrier is. What about an example? The N95 mask has this name because it has a 95% filtration efficiency. The Jama Internal Medicine journal published an article in august [2] evaluating the FFE of different professional masks, like N95 and surgical ones. The study, made in North Carolina, showed that N95 masks that passed through a sterilization procedure with ethylene oxide and hydrogen peroxide didn’t have their efficiency altered after this procedure, pointing out the possibility of reutilization. Considering nowadays, when money spent on masks is high and the residues pile up in our environment, reutilization, as Yoda would say, important it is!
After the New Republic, we mean, the World Health Organization (WHO) recommended the use of face masks for the general population, we developed face masks from different materials and origins (homemade, improvised), spreading this knowledge through the Galaxy (and we saw several Jawas profiting with this). With all these choices, many questions started to show up about the filtration efficiency of these options. You can see, in the case of the face masks, the analysis in the Figures 1 and 2 from the following study. All masks had their FFE analyzed based on OSHA (Occupational Safety and Health Administration) methods. They’re a kind of Jedi council of occupational safety. The experiment was made in a particle generation chamber that shoots sodium chloride (NaCl) in aerosol form, in a median size of 0.05 μm (between 0.02 e 0.6 µm). Remember the asteroid field that Solo blasted through in the Millennium Falcon and almost scared Leia to death (Figure 3)? It’s sort of that, but on a microscopic scale (actually nanoscopic!)…
Well, the test applied to evaluate the FFE reflects an environment with particles of different sizes and slightly smaller than the SARS-CoV-2 virus. But here, we need your attention: no biological material was used in this test. They used salt particles (no relation whatsoever with the red salt that we find in Crait) to test the efficiency hypothesis in the filtration of the mask materials. Another point that must be cleared is the article evaluated the efficiency regarding the face mask user and not others.
Back to the tests: a device that looks like a small “door” that collects samples is put behind the mask (you can see how it’s done here), then the same person wears the different kinds of masks from the experiment and perform the same moves (head, torso and facial muscle movements) during 3 minutes for each 12 masks. This test measures the proportion of particles present in the chamber where the person is placed and how many of them could penetrate inside the mask. The result is presented as percentage, as mentioned, and the devices are attached to an equipment that performs the measurements.
Figure 1. Customized face masks and improvised facial coverings (adapted from Clapp et al., 2020).
Figure 2. Surgical masks and modifications projected to improve the comfort of the mask to its user (adapted from Clapp et al., 2020).
Figure 3. The Hoth asteroid field (Star Wars Episode V – The Empire Strikes Back) represents the different sizes of particles in a particle generator.
In the results session from the study, the researchers showed that the FFE analysis for the different types of masks varied between 27 and 79% efficiency, where the 2 layered nylon mask (Figure 1A) had the highest efficiency, and the 3 layered cotton mask (Figure 1G) had the lowest. The bandanas had an average performance value about 50%. Strikingly, the modifications made on surgical masks to improve the fit (using the nylon pantyhose, the hair clips, etc.) improved the filtration efficiency by almost 20% and, in some cases, even 80%. Therefore, the face mask’s grip can be compared to the Millennium Falcon’s hyperdrive, which improve it to reach lightspeed! And before you say that the efficiency was low in some cases, we remind you that the barrier provided by any mask is important and must be addressed to hand/surface cleaning and physical distancing. Besides, have you ever seen Darth Vader or any stormtrooper without their masks in one of those Imperial Star Destroyers (closed spaces, crowded with people)? By the way, Vader is an expert in physical distancing… And, he simply doesn’t touch anybody! Figure 4, our “teaser” is a summary of the study.
Figure 4. Filtration efficiency analysis according to Clapp et al., 2020 study [1].
While we’re under the new coronavirus attack, just like when the Sith army attacks the Jedi, we must use the Force. The Force, in the Star Wars universe, according to Jedi Master Obi-Wan Kenobi, is “an energy field created by all living things. It surrounds us and penetrates us; it binds the galaxy together”. The Force that we need right now is the resilience to keep the prevention measures against COVID-19, and this resilience needs the union and effort of all the Galaxy living beings. We can party with the ewoks after we have many of us vaccinated. May the Force be with you.. always!
P.S.: We can notice that, in the initial image, Palpatine isn’t wearing a mask. One does simply guess that he’s from the dark side… have you imagined an old man like him without a mask? 😉
Melissa Medeiros Markoski
Biologist, Jedi master and doctor in Cellular and Molecular Biology by the Universidade Federal do Rio Grande do Sul, with post doctoral internships in Immunology on the Pontifícia Universidade Católica do Rio Grande do Sul and Universidade Federal de Ciências da Saúde de Porto Alegre (UFCSPA); Lecturer at UFCSPA in the field of Biosafety, studying immunotherapy and regenerative processes with stem cells (Lattes resumé link: http://lattes.cnpq.br/1872859400316329).
Thomaz Arruda Wioppiold
Industrial chemist, Jedi master and doctor in Chemistry by the Universidade Federal de Santa Maria, with a sandwich period in Freie Universität Berlin (Germany); Former lecturer in the Instituto Federal Farroupilha (IFFar) – Panambi Campus currently developing courseware to distance learning companies.
References
[1] Clapp PW, Sickbert-Bennett EE, Samet JM, Berntsen J, Zeman KL, Anderson DJ, Weber DJ, Bennett WD; US Centers for Disease Control and Prevention Epicenters Program. Evaluation of Cloth Masks and Modified Procedure Masks as Personal Protective Equipment for the Public During the COVID-19 Pandemic. JAMA Intern Med. 2020 Dec 10. doi: 10.1001/jamainternmed.2020.8168. Epub ahead of print. PMID: 33300948.
[2] Sickbert-Bennett EE, Samet JM, Clapp PW, Chen H, Berntsen J, Zeman KL, Tong H, Weber DJ, Bennett WD. Filtration Efficiency of Hospital Face Mask Alternatives Available for Use During the COVID-19 Pandemic. JAMA Intern Med. 2020 Aug 11:e204221. doi: 10.1001/jamainternmed.2020.4221. Epub ahead of print. PMID: 32780113; PMCID: PMC7420816.
Images:
Cover image: adapted from https://www.quora.com/;
Image 3 – https://starwarsforce.wordpress.com/2014/06/29/millenium-falcon-asteroid-field/
