家禽養殖戶因佩戴 N95 口罩而面臨風險

馬丁博士首頁 論壇 觀鳥、保護、旅行 H5N1 家禽流感和候鳥 家禽養殖戶因佩戴 N95 口罩而面臨風險

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  • #3364

    This was sent to me by a microbiologist in Washington and he has informed me that N95 masks being used by poultry farmers although very cost effective is completely useless against H5N1 virus. He refers it to trying to filter sand with a pasta strainer! The H5N1 virus is so much smaller than .3um. Why on earth would anyone want to wear a N95 mask which is only 95% effective? Would it not be more prudent to wear a mask that is 99.99% effective? Would it not be wiser to actually use a mask that’s been tested with biological agents instead of salt particles? It’s kind of like building a boat and spraying it with a hose then telling everyone it will float. I understand that N95’s are inexpensive and yes better than nothing. But why is everyone so quick to accept it as being the best or only solution. Their are masks out there that will give you 99.99% protection. I’ve read that the H5N1 virus is attached to droplets and that the N95 will stop it from passing through. What about the 5% that might get through. How long will the 95% efficiency of the mask last? Not all face masks provide the same level of performance hour after hour of use. Studies show that when subjected to bio-aerosols, the performances of most face masks deteriorate significantly over time unless there is a antimicrobial agent which protects it against microbial deterioration of the filtration media. What is N-95? Filters and infectious particles Particles greater than 5 microns fall out of the air Particles 1 – 5 microns in diameter can enter upper airways 0.1 – 1 micron particles enter lower lungs and alveolar ducts Examples of particle size:  Viruses 0.02 to 0.3 microns – N95 mask not effective  Bacteria 0.5 to 10 microns – N95 mask effective  Mold spores 1 to 70 microns – N95 mask effective  Fungi 2 to >200 microns – N95 mask effective Particulate filter efficiency is based on ability to remove particles greater > than 0.3 microns in diameter (medial aerodynamic diameter of 0.3 um) It is also very important to note, that although the CDC recommends these products as suitable levels of protection against the H5N1 virus, the testing criteria used to certify these products does not include any biological agents. NIOSH only tests the filtration efficiencies of N95 facemasks against salt particles, and does not currently employ any standards to test against live agents. http://www.cdc.gov/niosh/pt84abs2.html 42CFR part 84 Under the new particulate filter tests, NIOSH will certify three classes of filters, N-, R-, and P-series, with three levels of filter efficiency, 95%, 99%, and 99.97%, in each class. All filter tests will employ the most penetrating aerosol size, 0.3 µm aerodynamic mass median diameter. The N-series will be tested against a mildly degrading aerosol of sodium chloride (NaCl). The R- and P-series filters will be tested against a highly degrading aerosol of dioctylphthalate (DOP): http://www.health.state.mn.us/divs/idepc/dtopics/infectioncontrol/ppe/comp/n95.html http://www.cdc.gov/niosh/npptl/usernotices/pdfs/Nanoguard062906.pdf Nanoguard Mask Warning 

    #4327
    馬丁
    參加者

      N95 口罩在 SARS(一種病毒)期間使用並且有效,除非——比如說——有人推起口罩來抓癢的鼻子。

      我在疫情爆發期間嘗試過一次:非常不舒服;濕熱空氣,甚至比香港正常的濕熱空氣還要糟糕。嘗試過幾乎沒用的紙口罩(除非你自己恰好患有疾病並且不想將其傳染給他人)。否則,由於SARS主要發生在醫院,所以沒有戴口罩。

      無法想像在實際受 H5N1 病毒影響的地區(而非受 H5N1 病毒影響)的人數會超過極少數。 禽流感恐嚇)會使用口罩;那些可能在工廠化農場裡做的事情,那裡的口罩等應該由公司提供,或者獸醫支持等也應該提供口罩。

      否則,這些口罩對於真正受禽流感影響的地區的人們來說肯定是遙不可及的;而且不太可能被磨損。
      如果目標是向偏執狂銷售:那麼,viraldefender.com 真是丟人了。

      另請參閱 CDC 網站上這篇關於用 T 卹製作口罩的摘要論文;不理想,但被認為有效:
      http://www.cdc.gov/ncidod/EID/vol12no06/05-1468.htm

      #4611
      匿名的

        I raised this issue at work and this is what I was told: in order for viral particles to become airborne and capable of traveling through the air, they need to attach themselves to something (i.e, dust particles, respiratory droplets, mold spores, et etc), that has enough mass to be lifted by air currents, and viral particles are too small to travel through the air by themselves.

        I’m still pondering the explanation that I was given.

        I previously thought, perhaps erroneously, that getting sick had to do with the amount of viral particles to which one was exposed, and it wasn’t exposure per se that made one sick, but rather the amount of viral particles that one was exposed to, and respiratory droplets measuring 0.3 microns or larger contained enough viral particles to make one sick.

        I am not a virologist or researcher, I’m just your average layperson, and I do not know the correct answer to these questions.

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