\u25cb\u300c\u7e4a\u7dad\u306e\u9699\u9593\u3088\u308a\u5c0f\u3055\u3044\u7c92\u5b50\u306f\u30de\u30b9\u30af\u306e\u30d5\u30a3\u30eb\u30bf\u30fc\u3092\u901a\u904e\u3059\u308b\u300d\u306f\u9593\u9055\u3044<\/mark>
\u25cb \u5927\u4e8b\u306a\u3053\u3068\u306f\u300c\u30de\u30b9\u30af\u306e\u30d5\u30a3\u30eb\u30bf\u30fc\u6027\u80fd\u3088\u308a\u3001\u30de\u30b9\u30af\u306e\u7e01\u3068\u9854\u8868\u9762\u3068\u306e\u9699\u9593\u304b\u3089\u306e\u6f0f\u308c\uff08\u4fb5\u5165\uff09\u3092\u5c11\u3057\u3067\u3082\u306a\u304f\u3059\u3053\u3068\uff01\u300d
\u2192\u3000\uff3b\u898b\u89e3\uff08\u5168\u6587\uff09\u306f\u3053\u3061\u3089\u3092\u3054\u89a7\u4e0b\u3055\u3044\uff3d\uff082020.2.21\u63b2\u8f09\uff0c2020.3.26\u4e00\u90e8\u4fee\u6b63\uff09<\/p>\n\n\n\n
<\/a>On Mask Wearing for COVID-19 and Hay Fever<\/p>\n\n\n\n <\/a><\/p>\n\n\n An English translation of the Japanese statement (PDF) from the society (JAAST) regarding mask use for COVID-19 and pollen allergy.<\/p>\n\n\n\n (Revised on March 26, 2020)<\/strong><\/p>\n\n\n\n Masks are essential not only for people with colds but also for those with pollen allergies. However, there is often misinformation about mask use in media reports and online articles. A typical example is:<\/p>\n\n\n\n \u201cBecause viruses or pollen allergens are small, they pass through the gaps in mask fibers, so only special masks for viruses (such as N95 masks) are effective.\u201d<\/p>\n<\/blockquote>\n\n\n\n This type of statement was also commonly seen in reports about high concentrations of PM2.5 in Beijing (Jan\u2013May 2013), with \u201cvirus\u201d or \u201callergen\u201d replaced by \u201cPM2.5.\u201d As explained below, this is scientifically incorrect in two ways. Here, \u201cmasks\u201d refer to medical or surgical masks commonly available at drugstores.<\/p>\n\n\n\n If viruses or pollen allergens remained as spherical particles of about 0.1 \u03bcm in diameter in the air, they would indeed be about 1\/300th the size of typical cedar pollen (30 \u03bcm diameter). However, the mechanism by which filters (including those in masks) capture airborne particles is fundamentally different from simply sieving out particles larger than the mesh size.<\/p>\n\n\n\n For example, for a 0.1 \u03bcm spherical particle, even an N95 mask filter has gaps much larger than the particle\u2019s diameter. So, how are particles captured? The mechanisms are:<\/p>\n\n\n\n Particles adhere to the surfaces of the fine fibers in the filter (see diagram). Brownian diffusion becomes dominant as particle size decreases. Contrary to common belief, particles around 0.1 \u03bcm or smaller are actually more easily captured by the filter due to this effect. Some mask filters also use electrostatic forces to enhance the capture of small particles. In many cases, regular mask filters capture small particles with high efficiency (for example, Mask-1 captured 97% or more of particles 0.025\u20130.21 \u03bcm in diameter). Therefore, the explanation that \u201cviruses or allergens are small and pass through mask fibers\u201d is fundamentally incorrect.<\/p>\n\n\n\n The behavior of airborne aerosol particles is governed by physical principles, regardless of whether they are biological or non-biological. Cedar pollen (30 \u03bcm), droplets (10 \u03bcm), or viruses (0.1 \u03bcm) all exist as stable liquid or solid particles in the air and are all considered aerosols. N95 masks and Japanese disposable dust masks (e.g., DS2) are tested using sodium chloride particles. For those concerned about biological particles, organizations in Japan and the US also test masks for their Bacterial Filtration Efficiency (BFE) and Viral Filtration Efficiency (VFE), using aerosols of Staphylococcus aureus or bacteriophages. These tests follow standards such as ASTM F2101. However, the mist particles used in these tests are 1 \u03bcm or larger, not targeting particles as small as 0.1 \u03bcm. This should be kept in mind.<\/p>\n\n\n\n Even when wearing an N95 or DS2 mask to block particles around 0.1 \u03bcm, the proportion of particles inhaled depends on the presence and size of gaps between the mask\u2019s edges and the face\u2014i.e., leakage. The filter\u2019s capture performance is secondary. Air containing particles will flow more easily through gaps than through the mask\u2019s fibers. While N95 and DS2 masks fit more tightly, even regular medical or surgical masks can be effective against various particle sizes if worn to minimize leakage around the nose and chin.<\/p>\n\n\n\n This statement refers to N95 masks and medical\/surgical masks with performance indications, not all masks. While this is not direct evidence, from the perspective of cough etiquette, even masks without performance indications, such as cloth masks, are necessary to prevent the direct spread of droplets. People with symptoms such as coughing or sneezing are recommended to wear masks.<\/p>\n\n\n\n \u25cb\u300c\u7e4a\u7dad\u306e\u9699\u9593\u3088\u308a\u5c0f\u3055\u3044\u7c92\u5b50\u306f\u30de\u30b9\u30af\u306e\u30d5\u30a3\u30eb\u30bf\u30fc\u3092\u901a\u904e\u3059\u308b\u300d\u306f\u9593\u9055\u3044\n
![\"\"](\"https:\/\/jaast.xsrv.jp\/jaast\/wp-content\/uploads\/2020\/03\/image.png\")
<\/figure>\n<\/div>\n\n\nJAAST\u2019s View on Mask Use for COVID-19 and Pollen Allergy<\/h2>\n\n\n\n
\n
1. Particle Capture by Masks<\/h2>\n\n\n\n
\n
2. What Are \u201cVirus-Specific Masks\u201d?<\/h2>\n\n\n\n
3. Points to Note When Wearing Masks<\/h2>\n\n\n\n
4. In Conclusion<\/h2>\n\n\n\n
References<\/h2>\n\n\n\n
\n
https:\/\/www.niid.go.jp\/niid\/ja\/kansennohanashi\/9303-coronavirus.html<\/a><\/li>\n\n\n\n
https:\/\/www.mhlw.go.jp\/stf\/seisakunitsuite\/bunya\/0000187997.html<\/a><\/li>\n<\/ol>\n","protected":false},"excerpt":{"rendered":"
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