Coronavirus can float in air and WHO and CDC should tell people that, experts say
July 06, 2020

專家稱,世衛組織和疾控中心應該告訴人們新冠病毒可以漂浮在空氣中
2020年7月6日


(CNN) Imagine a noisy, crowded bar. Music is pounding, and people are clustered close together, talking loudly or even shouting to be heard. If it''s cold out, doors and windows are shut tight and the heat is on, or if it''s hot out, everything is shut and the air conditioner is recirculating the air.

(CNN)想象一下一個喧鬧擁擠的酒吧。音樂聲震耳欲聾,人們擠在一起,大聲說話,甚至大聲喊叫以便讓別人聽到。如果外面天氣很冷,門窗緊閉,暖氣開著;如果外面很熱,門窗都關著,空調一直開著,空氣在循環。

This, in Donald Milton''s opinion, is the perfect situation for spreading coronavirus.

在唐納德·彌爾頓看來,這種環境更加適合新冠病毒的傳播。

Not only could people pass the virus directly from one to another in the little droplets that we all spray to one degree or another when we talk, laugh or sing; but those little droplets also go up into the air where, Milton says, they can float around for at least some time.

人們不僅可以通過微小的飛沫直接將病毒從一個人傳播到另一個人,而且當我們說話、大笑或唱歌時,我們都會不同程度的噴灑這些飛沫;而這些小水滴也會飛到空中,彌爾頓說,它們至少可以在空中漂浮一段時間。


It''s not a secret, but agencies seem to be afraid to talk about the airborne nature of the virus, Milton said.

這不是秘密,但各種機構似乎害怕談論這種病毒能夠通過空氣傳播的屬性,彌爾頓說。

"The airborne transmission word seems to be loaded," Milton, one of two main authors of the letter, told CNN.

彌爾頓是這封信的兩位主要作者之一,他在接受CNN采訪時表示:“通過空中傳播的文字似乎是不可信的?!?

"The current guidance from numerous international and national bodies focuses on hand washing, maintaining social distancing, and droplet precautions," Milton and colleagues wrote in the letter, published in the journal Clinical Infectious Diseases.

彌爾頓和他的同事在這封發表在《臨床傳染病》雜志上的信中寫道:“目前來自眾多國際和國家機構指導都集中在洗手、保持社交距離和防滴等方面?!?

"Most public health organizations, including the World Health Organization, do not recognize airborne transmission except for aerosol-generating procedures performed in healthcare settings. Hand washing and social distancing are appropriate, but in our view, insufficient to provide protection from virus-carrying respiratory microdroplets released into the air by infected people," they added.

"大多數公共衛生組織,包括世界衛生組織,不承認空氣傳播,除非是在衛生保健設備中形成的氣溶膠產生的過程。適當的洗手和保持社交距離,但在我們看來,不足以保護人們不受感染者從呼吸道中釋放到空氣中的并且攜帶病毒的微滴所感染?!?

''They don''t want to talk about airborne transmission because that is going to make people afraid''

他們不想談論空氣傳播,因為那會讓人們害怕

"I guess we are hoping that WHO will come around and be more willing to acknowledge the important roles of aerosols, whether they want to call it airborne transmission or not," Milton said.

彌爾頓說:“我想我們希望WHO能接受,更愿意承認氣溶膠的重要作用,不管他們是否愿意稱之為空氣傳播?!?

Milton studies the airborne transmission of viruses. The other main author, Lidia Morawska, is a professor of environmental engineering and an expert in aerosol science at the Queensland University of Technology in Brisbane, Australia. Milton said they and a group of other, similar experts have been discussing the potential airborne transmission of coronavirus since February.

彌爾頓研究的是病毒在空氣中的傳播。另一位主要作者莉迪亞·莫勞斯卡是澳大利亞布里斯班昆士蘭科技大學的環境工程教授和氣溶膠科學專家。彌爾頓說,自今年2月以來,他們和其他一些類似的專家一直在討論新冠病毒可能通過空氣傳播的問題。

Milton said the group wants to demystify the word so that health agencies will be less fearful about using it.

彌爾頓說,該組織希望揭開這個詞的神秘面紗,這樣衛生機構就不會那么害怕使用它。


"The best vaccine against fear is knowledge and empowering people to take care of themselves," Milton said. "I want them to understand to what extent washing their hands is important. Why wearing a mask is important is because it blocks the aerosols at their source, when it is easy to block them." It''s harder to block aerosols once they are floating in the air, he said.

彌爾頓說:“對抗恐懼的最佳疫苗是知識和讓人們有能力照顧自己?!薄拔蚁胱屗麄兠靼紫词衷诙啻蟪潭壬鲜侵匾?。戴口罩之所以重要,是因為它能從源頭阻隔氣溶膠,而其實很容易阻隔它們?!彼f,一旦氣溶膠漂浮在空氣中,就很難阻止它們。

The virus is carried on droplets that come out of people''s mouths and noses, and the sizes of those droplets vary. Large droplets fall onto surfaces rapidly and can be picked up on fingers and carried to the eyes, nose or mouth. Smaller droplets can stay in the air longer, and can be inhaled more deeply into the lungs.

病毒通過人的口鼻飛沫傳播,飛沫大小不一。大的液滴迅速落在表面上,可被手指撿起,帶到眼睛、鼻子或嘴巴。更小的飛沫可以在空氣中停留更長時間,也可以更深地吸入肺部。

"There is significant potential for inhalation exposure to viruses in microscopic respiratory droplets (microdroplets) at short to medium distances (up to several meters, or room scale), and we are advocating for the use of preventive measures to mitigate this route of airborne transmission," Milton and his colleagues wrote.

“我們有很大的能力阻止人們在短距離到中等距離接觸時吸入空氣中帶有病毒的微小飛沫,同時我們提倡預防措施,以減輕這種空氣傳播”彌爾頓和他的同事寫道。


"For example, at typical indoor air velocities, a 5 nanometre droplet will travel tens of meters, much greater than the scale of a typical room, while settling from a height of 1.5 metres (about five feet) to the floor."

“例如,在典型的室內空氣速度下,一個5納米的液滴將移動數十米,而這個距離比一個典型房間的尺度大得多,同時從1.5米(約5英尺)的高度沉降到地面?!?

What''s not clearly understood is how important droplet size is to coronavirus transmission, Milton said.

彌爾頓說,目前尚不清楚的是,小水滴的大小對于新冠病毒的傳播有多大影響。

But studies show it''s a factor, Milton added. "A lot of people crowded close together indoors where it is poorly ventilated -- that is what drives the pandemic," he said. A loud bar, where people must raise their voices to be heard, is a perfect storm of close contact, poor air circulation and people generating a lot of virus-carrying particles by talking, laughing and shouting.

但研究表明這是一個因素,彌爾頓補充道。他說:“很多人擠在通風不良的室內,這是導致疫情蔓延的原因?!币粋€嘈雜的酒吧,在這里人們必須提高自己的聲音才能被聽到,密切接觸,空氣流通不良,人們說話,笑,大喊產生大量攜帶病毒的顆粒。


Advice to avoid coronavirus transmission

避免新冠病毒傳播的建議

But Milton said there are other ways, too, including improved ventilation, as well as distancing and mask use. And that''s information the average person, as well as health care professionals, can use and act on.

但彌爾頓說,還有其他方法,包括改善通風、保持距離和使用口罩。這是一般人,以及衛生保健專業人員都可以使用和采取的行動。

"I am very much concerned about the general public and schools and ventilation in school buildings and in dorms on college campuses and in bars and in churches and where people sing and where people congregate," he said.

他說:“我非常關注公眾、學校、學校建筑、大學校園宿舍、酒吧和教堂的通風情況,以及人們唱歌和聚集的地方?!?

The group gives practical advice in its letter.

該小組在信中提出了切實可行的建議。


· Supplement general ventilation with airborne infection controls such as local exhaust, high efficiency air filtration, and germicidal ultraviolet lights. (These would be placed high up in the ceiling to avoid damage to people''s eyes and skin)

·通過局部排氣、高效的空氣過濾和紫外線燈殺菌等空氣感染控制措施來補充一般的通風。(這些將被放置在天花板的高處,以避免傷害人們的眼睛和皮膚)

· Avoid overcrowding, particularly in public transport and public buildings.

·避免過度的擁擠,特別是在公共交通和公共建筑。

"Such measures are practical and often can be easily implemented; many are not costly," they wrote.

“這些措施是切實可行的,往往很容易執行;很多并不昂貴,”他們寫道。

"For example, simple steps such as opening both doors and windows can dramatically increase air flow rates in many buildings."

“例如,在許多建筑中,一些簡單的步驟,比如打開門窗,可以顯著增加空氣流量?!?

In a car, Milton advises, open windows and make sure the air conditioning or heat is not recirculated but set to include outside air.

彌爾頓建議,開車時打開窗戶,確??照{或暖氣沒有再循環,而是將外部空氣流動進來。

In buildings, carbon dioxide monitors can help managers know if the air is being refreshed properly, Milton said. Outdoors in an urban area, he said, carbon dioxide levels are about 350 parts per million in the air. Exhaled breath carries about 38,000 parts per million of carbon dioxide. Indoors, he said, if the air has 1,000 parts per million carbon dioxide content or less, "that''s pretty good," Milton said.

彌爾頓說,在建筑物中,二氧化碳監測器可以幫助管理者了解空氣是否得到了適當的凈化。他說,在城市戶外,空氣中的二氧化碳含量約為百萬分之350。人們呼出的空氣中含有大約38,000 ppm的二氧化碳。他說,在室內,如果空氣中的二氧化碳含量低于百萬分之一千,“那就很好了,”米爾頓說。