A CDC microscopic image of the COVID-19 virus.

顯微鏡下的COVID-19新冠病毒

The short answer is we don’t have any direct research to verify if a HEPA air purifier reduces transmission of COVID-19 however, according to Professor Jeffrey Siegel at the University of Toronto, “we can infer from what we know for similar viruses, like SARS, there is reason to think air purifiers might help in some situations.”

簡單的答案是，我們沒有任何直接的研究來驗證HEPA可以減少COVID-19的傳播。然而,多倫多大學(xué)的杰弗里·西格爾教授說,“我們可以從我們所知道的類似病毒,像“非典”病毒,我們有理由相信空氣凈化器在某些情況下是有效的?！?/span>

How many microns in size is the COVID-19 virus?

The COVID-19 virus is approximately 0.125 Micron or 125 nanometers in diameter.? (Source: National Library of Medicine).

However, it often travels in biological aerosols from coughing and sneezing which range in size from 0.5-3 Micron.

COVID-19新冠病毒的直徑有多大？

COVID-19新冠病毒的直徑大約為0.125微米即125納米（來源：美國國家醫(yī)學(xué)圖書館）。

然而，它經(jīng)常通過咳嗽和打噴嚏產(chǎn)生的生物氣溶膠傳播，大小在0.5-3微米之間。

How does HEPA filtration work?

 

HEPA stands for High Efficiency Particulate Air and is a filtration rating that captures microbes, dust, and particulates down to 0.3 Micron.

But what does that really mean and how do they work?

The U.S. Department of Energy first termed?HEPA as a filtering specification for suppliers of filtration products based on how effective they were at particle removal.

HEPA filters consist of a complicated mix of filaments and fibers that carry a static charge which lures various microbes and particles like a magnet.

While the particles travel through the air filtration system, they’re captured and retained within the filter. Additionally, an interesting scientific effect occurs known as Brownian Motion which causes particles in certain media states (such as fluid) to bounce around and become trapped.

 

HEPA（高效過濾器）如何工作？

HEPA是高效空氣過濾的縮寫，是一個過濾等級，可以捕獲小至0.3微米的微生物、灰塵和微粒。

但這到底意味著什么，它們是如何工作的呢?

美國能源部首先將HEPA作為過濾產(chǎn)品供應(yīng)商的過濾規(guī)范，其依據(jù)是過濾產(chǎn)品在微粒去除方面的效率。

高效空氣過濾器由一種復(fù)雜的纖維和細(xì)絲混合而成，帶有靜電電荷，像磁鐵一樣吸引各種微生物和粒子。

當(dāng)微粒通過空氣過濾系統(tǒng)時，它們被捕獲并保留在過濾器內(nèi)。此外，一種有趣的科學(xué)效應(yīng)被稱為布朗運動，它導(dǎo)致某些介質(zhì)狀態(tài)(如流體)中的粒子四處反彈并被困住。

 

How do N95 or KN95 face masks compare to HEPA air purifiers?

You may see or hear about people wearing surgical masks or N95 or KN95 rated masks?to prevent themselves and others from being exposed to Covid-19.? One important thing to note is that these masks are not as effective as HEPA air purifier systems which is more efficient than KN95/N95.

N95 or KN95 face masks capture 95% of particles down to 0.3 micron. This means that 5% still get through the protection. HEPA air purifiers in contrast are 99.97% effective at 0.3 Micron and are much more efficient than face masks.

N95或KN95口罩與HEPA高效空氣過濾器比較如何?

你可能看到或聽說有人戴醫(yī)用口罩或N95或KN95等級口罩，以防止自己和他人暴露于Covid-19新冠病毒之下。需要注意的一件重要的事情是，這些口罩不如HEPA高效空氣過濾器有效，后者比KN95/N95更有效。

N95或KN95口罩能捕捉95%的微粒，微粒大小為0.3微米。這意味著仍有5%的微粒沒有被有效過濾。相比之下，高效空氣過濾器在0.3微米時的過濾效率為99.97%，比口罩的效率高得多。

 

What is the difference between MERV and HEPA filters?

You may have heard the term “MERV” before. It stands for Minimum Efficiency Reporting Value and is a rating system for HVAC air filters created by the American Society of Heating, Refrigerating, and Air Conditioning Engineers or (ASHRAE).

Many people are asking the question, “can I use a MERV filter in a mask”?

While there have been no scientific studies we could find for this, the answer is likely no.

Here’s why…

MERV stands for Minimum Efficiency Reporting Values, or MERVs, report a filter’s ability to capture larger particles between 0.3 and 10 microns (μm). (Per the EPA)

HEPA and MERV filters are usually not the same.? MERV rated filters are typically used in air conditioning systems, including systems found in most homes.

MERV filters have a rating system… MERV 7, 8, 10, and so on—up to MERV 20.

MERV filters are not effective at filtering microbes and viruses until they are rated at 17 or better.

MERV(最低效率報告值)和HEPA（高效空氣過濾）過濾器有什么區(qū)別?

你可能聽說過“MERV”這個詞。它代表了最低效率報告值，是由美國供暖、制冷和空調(diào)工程師協(xié)會(ASHRAE)創(chuàng)建的HVAC空氣過濾器評級系統(tǒng)。

很多人都在問這個問題，“我可以在口罩中使用MERV過濾器嗎?”

雖然我們還沒有找到相關(guān)的科學(xué)研究，但答案很可能是否定的。

這是為什么…

MERV代表最小效率報告值，或MERVs，報告過濾器捕捉0.3-10微米(中值m)大顆粒的能力。

HEPA和MERV過濾器通常不一樣。MERV過濾器通常用于空調(diào)系統(tǒng)，包括大多數(shù)家庭使用的系統(tǒng)。

MERV過濾器有一個評級系統(tǒng)…MERV 7, 8, 10，等等，直到MERV 20。

MERV過濾器在過濾微生物和病毒時，只有當(dāng)它們被評為17或17以上時才會有效。

What is the difference between N95 and KN95 face masks?

N95 face masks are examples of personal protective equipment, or PPE, that are used to protect the wearer from airborne particles and liquid contaminating the face.

They are regulated by the FDA and NIOSH (U.S. National Institute for Occupational Safety and Health). The N is for “Not resistant to oil” and the 95 refers to the minimal is efficiency level at 0.3 microns (of which is it 95% efficient).

Similarly, KN95 masks are also a form of PPE used to protect the wearer from similar hazards though they are not regulated by NIOSH. These masks are often identical to N95 masks and are the “N95 equivalent” for medical usage in China.

In the US, they are primarily used in industrial settings and offer the same filtration as N95 face masks with a rating of 95% at 0.3 Micron. In fact, these masks are often produced from the same assembly line as N95 masks however are not sent for NIOSH regulation.

On April 3rd of this year, the FDA approved the use of KN95 masks for healthcare professionals in an effort to increase the available PPE face masks and lower the spread of the COVID-19.

N95和KN95口罩有什么區(qū)別?

 

N95口罩是常見的個人防護(hù)裝備(PPE)，用于保護(hù)佩戴者免受空氣中的微粒和液體污染面部。

它們由FDA和NIOSH(美國國家職業(yè)安全和健康研究所)監(jiān)管。N表示“不耐油”，95表示在0.3微米時的最低效率水平(95%的效率)。

同樣，KN95口罩也是PPE的一種形式，用于保護(hù)穿戴者免受類似的危害，盡管它們沒有NIOSH的規(guī)定。這些口罩通常與N95口罩相同，是中國醫(yī)用的“N95等效物”。

在美國，KN95主要用于工業(yè)場合，并提供與N95口罩相同的過濾功能，在0.3微米的評分為95%。事實上，這些口罩通常是由生產(chǎn)N95口罩的同一生產(chǎn)線生產(chǎn)的，但KN95沒有發(fā)送NIOSH進(jìn)行標(biāo)準(zhǔn)認(rèn)證。

今年4月3日，F(xiàn)DA批準(zhǔn)醫(yī)療專業(yè)人員使用KN95口罩，以努力增加防護(hù)口罩的可用性，并降低COVID-19的傳播。

 

How do viruses like COVID-19 spread through the air?

By nature, viruses are sub-micron in size-we’re talking 500nm (0.5 micron) and below.? Not to mention viruses only require a small amount to enter your body in order to start an infection.

The sad truth is that some viruses will inevitably pass through any HEPA filter.

Here’s why…

Typically, viruses like COVID-19 or even H1N1 are spread through the air via?biological aerosols.? These tiny moisture droplets are expelled whenever you sneeze, cough, or go ACHEW!

They carry bacteria and viruses through the air and ultimately your respiratory system.

Overtime, with enough volume or use, particles will eventually separate and penetrate the filter due to their sub-micron size.

像COVID-19新冠病毒是如何通過空氣傳播的?

病毒的大小是亞微米級別——我們說的是500納米(0.5微米)及以下。病毒只需要少量進(jìn)入你的身體就會引起感染。

令人悲哀的事實是，一些病毒將不可避免地通過任何HEPA過濾器。

這是為什么…

通常，像COVID-19甚至H1N1這樣的病毒是通過生物氣溶膠在空氣中傳播的。當(dāng)你打噴嚏、咳嗽或疼痛時，這些微小的飛沫就會被排出。

這些飛沫攜帶著細(xì)菌和病毒通過空氣，最終到達(dá)你的呼吸系統(tǒng)。

隨著時間的推移，當(dāng)過濾器里病毒積累到一定數(shù)量或過濾器過度使用后，粒子最終會因其亞微米大小而分離并穿透過濾器。

How can a HEPA air purifier help lower the spread of the COVID-19 virus?

Research studies have been conducted to test the efficacy of HEPA filtration on moisture droplets containing viruses.? Most biological aerosols range in sizes from 0.5-3 micron. HEPA air purifiers,? captures aerosol particles in that size range.

On paper, it is impossible for any HEPA filter to be 100% effective since many microbes are less than 0.03 micron in size—but that’s in an isolated form where they typically can’t survive long.

Plus, research is still being done on the subject.

An interesting study performed by NASA indicated that HEPA filters were able to capture sub-micron particulate down to 0.1 micron!

Additionally, all testing is performed using brand new filters. HEPA filters actually work better the “dirtier” they get (up to the point where airflow is restricted).

HEPA高效空氣過濾器如何幫助降低COVID-19病毒的傳播?

對高效空氣過濾對含病毒微粒過濾的效果進(jìn)行了研究。大多數(shù)生物氣溶膠的大小在0.5-3微米之間。HEPA高效空氣過濾器，捕獲該大小范圍內(nèi)的氣溶膠顆粒。

研究發(fā)現(xiàn)，任何高效空氣過濾器都不可能100%有效，因為許多微生物的直徑小于0.03微米——但這是微生物獨立個體存在時的尺寸，這種形式存在時它們通常不能存活很長時間。

另外，關(guān)于這個課題的研究還在進(jìn)行中。

美國宇航局進(jìn)行的一項有趣的研究表明，高效空氣過濾器能夠捕捉到0.1微米以下的亞微米微粒!

 

此外，所有測試都使用全新的過濾器執(zhí)行。高效空氣過濾器實際上工作得越好就“越臟”(直到氣流受到限制)。

 

Not only can HEPA air purifiers capture viruses, but they also create a cleaner work area in general.

If you work in an area with potential airborne hazards or particles, then the HEPA air purifier is an excellent piece of equipment to promote better air quality and health.

But please keep this in mind, a HEPA air purifier is not an end all solution.? It can only filter particles it captures-many airborne particles can still be present in the air and land of surfaces or travel around before getting captured by an air purifier.

This is why proper disinfecting procedures are required, wearing masks, gloves, and following procedures to regularly disinfect are all key factors in reducing the spread of any contagion.

 

高效空氣濾過器不僅可以捕捉病毒，還可以創(chuàng)造一個更清潔的工作區(qū)域。

如果你工作的空間有潛在的空氣危害或微粒危害，那么高效空氣濾過器是一個很好的設(shè)備，提高空氣質(zhì)量，為健康保駕護(hù)航。

但請記住，HEPA高效空氣過濾器不是解決所有問題的辦法。它只能過濾捕捉到的微?！S多空氣中的微粒在被高效空氣過濾器捕獲之前仍然存在于空氣和地面表面或四處傳播。

這就是為什么需要采取其它適當(dāng)防護(hù)措施如消毒，戴口罩、戴手套和遵循定期消毒是減少任何傳染病傳播的關(guān)鍵因素。