口罩有效防疫的定義
By: Health Ecoforum
Tags: Masks, Covid 19, Health, Virus

第二種方式：是透過可以長期或是相對長時間漂浮於空氣中的更小微粒(<1μm微粒)去傳染。醫學界尚未證實，這是傳染的途徑之一，但是值得我們重視透過這種方式傳播的可能性。一般來說，>3μm微粒在空氣中的運動，我們假設是可以用牛頓力學中的慣性運動來說明，也就是說，微粒的運動可以假設成直線，而過濾的效果則可以假設成為過篩式的慣性阻隔效果。然而，1μm~3μm微粒的空氣中運動開始受到少許的空氣分子碰撞所產生的布朗運動所影響，會在原本的運動之中，呈現隨機的擾動，而在空氣中產生比較長時間的停留。

Second method: It is transmitted through smaller particles (under 1μm) that can float in the air for a long time or relatively long time. The medical profession has not confirmed that this is one of the ways of transmission, but it is worthy of our attention to the possibility of transmission through this method. Generally speaking, the motion of particles over 3μm in the air can be explained by the inertial motion in Newtonian mechanics. That is to say, the motion of the particles can be assumed to be a straight line, and the filtering effect can be assumed to be a sieve type of inertial blocking effect. However, the movement of 1μm~3μm particles is starting to be affected by the Brownian motion by the collision of a few air molecules, and will exhibit random disturbances in the movement, and cause a longer stay in the air.

當微粒直徑小於1μm時，布朗運動的效益愈來愈大，於是我們可以將這種粒淨的氣懸膠分成以下兩種運動的方式：

When the particle diameter is less than 1μm, the benefit of Brownian motion becomes greater and greater, so we can divide this clean aerosol into the following two motion modes:

● 0.3μm~1μm微粒大小: 屬於相對長時間懸浮於空氣中的氣懸膠微粒。

Particle size between 0.3μm~1μm: It belongs to aerosol colloidal particles suspended in the air for a relatively long time.

● <0.3μm微粒大小: 屬於永久懸浮於空氣中的氣懸膠粒子

Particle size under 0.3μm: It belongs to aerosol particles that are permanently suspended in the air.

沒有醫學證據目前證實以上兩種懸浮在空氣中的細小微粒，可以傳染CoV-19病毒。但是在病毒在空氣中存活的時間變長，以及無症狀感染者的人數不斷增加的客觀風險之下，按照邏輯去推測後續的發展，這些細小微粒所可能造成的潛在傳染風險，值得重視。幸好這些微粒經過空氣碰撞而產生的隨機運動，大幅提升了這些微粒被口罩織物所捕捉的機率，也因此，讓口罩設計者，根據此一現象，做出了提前佈署的規劃。

There is no medical evidence that the above two kinds of fine particles suspended in the air can infect the CoV-19 virus. However, under the objective risk that the virus survives longer in the air and the number of asymptomatic infections continues to increase, according to logic to speculate the subsequent development, the potential risk of infection caused by these fine particles is worthy of our attention. Fortunately, the random movement of these particles caused by air collision has greatly increased the probability of these particles being captured by the mask fabric. Therefore, mask designers are allowed to make advance plans based on this phenomenon.

口罩設計的提前佈署

Advance plan of mask design

好的口罩設計，在微粒過濾上，必須考量以下三種情況:

For a good mask design, the following three situations must be considered in terms of particle filtration.

● 直徑>5μm大小微粒的過濾效果

Filtering effect of particles with diameters over 5μm.

● 直徑介於1μm到5μm微粒的過濾加阻擋的綜合效果

The combined effect of filtering and blocking particles with a diameter between 1μm and 5μm.

● 直徑小於1μm微粒的阻擋效果

The barrier effect of particles with diameter under 1μm.

在設計上，要產生足夠的過濾效果，就是透過口罩表面織物的空隙大小來做規範。如果要有效的過濾5μm直徑的微粒，口罩表面織物的空隙就要控制在比5μm小一點即可，無需太密造成透氣性的問題，造成過度的呼吸阻礙。對於更小的微粒(<1μm直徑)，我們必須考量如何阻攔與”沾附”這些以布朗運動隨機飄浮在空氣中的微粒。而沾附的兩個基本的辦法，其一是透過靜電吸附，其二則是透過纖維本身的吸附能力。

In the design, to produce sufficient filtering effect, is through the pore size of the fabric on the surface of the mask to make specifications. If you want to effectively filter 5μm particles, the pore of the fabric on the mask surface should be controlled to be smaller than 5μm, there is no need to be too dense to cause air permeability problems and excessive breathing obstruction. For smaller particles (under 1μm), we must consider how to block and adhere these particles that are randomly floating in the air with Brownian motion. There are two basic methods of adhesion, one is through electrostatic adsorption, and the other is through the adsorption capacity of the fiber itself.