Wear a mask made of cotton, not only effective anti-virus, but also
Save the environment
Author | leaflets
2021 Northern Hemisphere has been going into the V, and keep track of new virus variants crown remains a threat to the human world, we have to continue to adhere to the “three-piece protection”: wear masks, social distancing and personal hygiene.
At home, wear a mask has become most people’s daily habits. Currently on the market a wide range of masks, an adequate supply of disposable protective masks, anti-fog and haze N90, N95 masks, washable reusable masks and so on. But at the beginning of the epidemic, there was a period of global masks in short supply. At that time, a group of scientists who find a way to homemade masks, as well as to find the best fabrics can effectively resist new viral particles crown.
The new crown epidemic forced many people to turn home remote mode, the scientists are no exception. Edward Vicenzi is to protect the United States Smithsonian Institute Museum
(Smithsonian Museum Conservation Institute, hereinafter referred to as MCI)
Fellow scientists, the main work before the epidemic is to use a variety of sophisticated equipment inspection items of rare ancient relics. Jamie Weaver is the US National Institute of Standards and Technology
(National Institute of Standards and Technology, hereinafter referred to as NIST)
Chemists, chemical properties investigation before the Viking era Swedish glass products.
The two scientists are proficient in materials research, at the beginning of the epidemic, they and two other with aerosols in the Earth’s atmosphere NIST scientists working James Radney and Chris Zangmeister form teams, academia and the health sector response to the call, play to their professional knowledge and skills while DIY masks, while research can effectively resist mask fabric virus particles.
In 2020, the US Centers for Disease Control and Prevention
(Centers for Disease Control and Prevention, hereinafter referred to as CDC)
The official website has three ways to demonstrate and teach simple homemade cloth masks. In order to enhance the protective effect, it is recommended then wear a disposable surgical masks in homemade masks.
Once hung in the official website of the US CDC mask production steps. But each person ability, personal effects DIY masks uneven, and later adequate supply of masks available in the market, and now the CDC is no longer recommended homemade masks, also canceled DIY masks page.
Weaver employed methods is shown in FIG. Need to use a sewing machine stitching, but the production process is quite simple:
1. Cut the two rectangular cloth
(Sheets, old T-shirts can)
, About 25 cm, width 15 cm;
2. be stacked together, vertically and horizontally inwardly folded four sides, and then sewn together with a sewing machine;
3. Then, taking two long rubber band, passing through the two short sides of the mask and tied, finished knot squeezed seam edge;
4. Adjust the position of the mask and the rubber band, the bonded face masks, face masks fixed shape;
5. Finally, the rubber band with the seam sewn securely to prevent sliding. In this way, a simple cloth masks on the production well.
Self-made masks, Weaver’s family background played no small role, Weaver is her last name, “Weaver” means. Indeed, the ancestral home of the Five people are sewing masters, a collection of various types of textiles. This time, Jamie stepping on my own grandmother used sewing machines, masks made of various fabrics, collections from home to craft shops scouring cloth. For added security, Weaver sew three layers of fabric, also made a patch near the nose, to prevent facial masks do not fit.
Figure on four DIY masks worn by scientists first published a study in the journal mask material, from left to right: Jamie Weaver, James Radney, Edward Vicenzi and Christopher Zangmeister Shu Source: NIST
Cloth mask production process is simple, but finding an excellent protective effect masks the fabric is not easy. It also focuses on the four-member team, they read a lot during the 1918 flu masks related articles. In fact, it is also the 1918 flu outbreak, masks let into public life from private medical surgical instruments.
A 1919 described in the literature at the time of the medical staff wearing surgical masks homemade, masks and production methods, the method of CDC given similar. Shu Source: George H. Weaver, Droplet Infection and its Prevention by the Face Mask, The Journal of Infectious Diseases, Volume 24, Issue 3, March 1919, Pages 218-230, https://doi.org/10.1093/infdis/ 24.3.218
So let Vicenzi home away from Weaver and advanced laboratory equipment. However, since the DIY masks beat them, naturally mention DIY laboratory. They from Wal-Mart for less than $ 30 each to buy a number of simple microscope. Vicenzi and the Internet to find a high-resolution microscope, we can clearly see the details of the characteristics of the fabric fibers, accuracy of up to 2μm. Later, the team published articles, many high-definition fine fiber structure microscopic view of it is from Vicenzi hands. Further, Vicenzi hands will be transformed further into the beer cooler simple humidifier, the fabric fixed thereto with adhesive tape. All of these simple experimental apparatus was examined by two scientists help of various samples of fabric properties: porosity, thread count, line thickness and composition of the fabric, so as to reveal how the cloth against small virus particles.
Vicnezi from April last year started working to build a home lab Shu Source: Ed Vicnezi
They compared and, Radney and Zangmeister much more lucky, they get special permission to go to work in the laboratory during the outbreak. During that time, the two constantly back and forth to both Weaver and Vicenzi home, to bring home a bag scientists fabric samples. In laboratory units, they simulate a new crown chloride virus, using “magic spray bottle” small particle emitting aerosols of different sizes or diameter from 50 nanometers to 825 nanometers range, these particles were observed to penetrate the fabric tube closed case, the measurement of the ratio of the number of particles on both sides of the cloth, so that the filtering effect is determined for each fabric.
Fast forward to June 2020, the results of 4-person team quickly published
( “ACS Nano”)
, Setting off a wave of no small concern. According to statistics, after the line on this article views so far it has more than 6.4 million times, making it the headline journal article in 2020.
Several microscope best protective cloth enlarged image:. A 100% cotton towels, B1 and B2 are 100% cotton, flannel outer surface and the inner surface of light, 100% polyester C, garment fabric. , D.100% cotton, linen, E.100% polyester staple fiber Shu source: ACS Nano 2020, 14, 7, 9188-9200
The paper describes, the four scientists selected 32 kinds of fabric, measuring their filtration efficiency
And structural parameters
. Also with seven kinds of surgical masks and N95 masks polypropylene fiber filter material used was compared. It was found that virus particles against the effect of 100% cotton flannel best performance, and less than N95 masks, it is immediately followed by a woven synthetic fiber. If you add one or two layers of filtration layer on the basis of flannel, such as a HEPA
(High efficiency particulate air filter)
Filters, filter cloth or other coffee can capture tiny aerosol particles of material, the mask is a higher level of defense capability.
Well, N95 masks is how to do it? N95 masks prototype from the 1958 US fashion editor Sara Little Turnbull lingerie cup design ideas, through constant transformation, eventually forming masks can block 95% of new virus particles crown sizable aerosols. In general, single viral particle diameter of about 110 nm, but the data recording Zangmeister new crown viral pneumonia patient breath group wrapped in protein and salt, up to twelve microns in diameter. The production of industrially N95 masks, melt blown extrusion process will
, Plastic fibers so that deformation of the N95, a result, the thickness of the fiber bundles of varying mixed together to form different shapes and textures of the woven so messy mixing the aerosol can not pass through the mask.
N95 masks chaotic internal structure Shu plastic fiber sources: Ed Vicenzi
Vicenzi team of structural imaging reveals the mechanisms of anti-virus particles are not inferior cloth masks N95 masks. This common fabrics like flannel, internal structure between N95 and polyester. Despite its fiber is woven together according to a certain pattern, but still very irregular. This is because during the weaving flannel, the fiber bundle will be raised from the surface, a so-called “fluff.” The researchers speculate that this surface fluffy cloth not only to provide a soft touch, but also as N95 masks as capture more of aerosol particles. Vicenzi said: “
Flannel is N95 textile industry.
Second only to the effect of N95 masks flannel microstructure Shu Source: Ed Vicenzi
March 8, 2021, the team’s second article published in the
ACS Applied Nano Materials
( “The ACS nanomaterials”)
Further reveals another advantage of cotton masks:
Humidity strengthen the effectiveness of the protection masks
They simulate a high humidity environment when people breathe, found that droplets containing the new virus struck crown, hydrophilic fabric
(E.g. cotton fabrics)
The filter effect will be enhanced. Principle easier to understand: we exhale humidity of 100% cotton masks but also has water absorption, after a substantial expansion thickening fibers absorb water, the small interior space is more narrow, aerosol increasingly difficult through the mask into the nasal cavity.
In contrast, synthetic plastic fibers N95 masks employed is hydrophobic, we exhale water vapor will condense on the inside surface of the mask. Vicenzi cited the following example: “…… like a fly buzzing insects hit a fly fishing net, a catenary surface was firmly trapped.” Similarly, in the interior of the cotton masks a very humid environment, air sol particles due to water absorption becomes large, and finally trapped trapped in a narrow space.
In contrast wet material, filtering cloth masks and protective effect simulation FIG. Shu particle source is visible through the dryer fabric (a map) of the aerosol particles to be more wet fabric by (b panel): Hydration of Hydrophilic Cloth Face Masks Enhances the Filtration of Nanoparticles
However, this does not mean that it needs to be soaked in water before wearing masks, but that
If you’ve been wearing cotton masks, with time, in the wet filter mask layer enhances virus protection effect.
All week, at the beginning of the new crown spread of the disease, whether the issue must wear a mask, which has caused widespread controversy in the world. Vicenzi research team reveals the structural mechanisms masks blocking viral particles, proved that China has always insisted on doing the right thing: During the outbreak, everyone should wear a mask to protect the health of themselves and others.
The recently published
Study in the Journal
Once again it proved their daily lives wearing masks to reduce the spread of the new virus crown theoretical point of view. In a public environment, we can not avoid inhaling others exhaled air, especially at the highest hospital virus concentration, even the protective effect most surgical masks, if you do not wear protective clothing, maintain ventilation, can not provide adequate protection effectiveness. But in ordinary people’s living environment, the new crown virus concentration in exhaled aerosols people is not high, is a virus-limited settings
As long as we all wear masks, even the simplest of disposable surgical masks, can effectively reduce possible exposure to the virus, but also better residual virus filtering to further reduce the infection rate. All in all, to achieve the best protective effect, patients and healthy people should wear face masks, while maintaining good ventilation and social distance.
The virus is limited environment where ordinary people living environment, wear a mask and do not wear masks differences, the red dots represent the new crown contains a virus aerosol particles, while the green dots represent not contain a virus aerosol particles. Shu Source: Tinu CA from www.freeicons.io, distributed under CC-BY 3.0.
Global fight against SARS is an extremely complex disease activity, make small changes in human behavior, could dramatically change the trajectory and the effect of viral transmission. Epidemic is not over yet, and constantly mutated new virus crown at any time may bring new threats to us, will be summer rates, we might as well make yourself desirable color of cloth masks, both to protect themselves, but also to protect the environment. After all, life science research and practice have proved the practical significance wear a mask, which is indeed one of our most powerful weapon against the epidemic of the general public.
OriginalReference: https: //www.smithsonianmag.com/smithsonian-institution/using-store-bought-microscopes-and-eye-detail-heres-what-smithsonian-scientists-have-learned-about-mask-effectiveness-180977216/