Letter: Clarifications on N95 Masks

Dear Editor:
There seems to be a lot of misunderstandings about N95 masks.  I have quoted some information from CDC, NIOSH, OSHA, and the FDA to help clear some of the confusion.

The main issue I hear is that “only medical rated (by the FDA) N95 masks should be used to protect oneself against Coronavirus  and other flu.”  This is not necessarily true.  The “95” part of the N95 stands for the percentage of particulate matter that the mask will filter out.  The size of the test media is .03 micron.  At .03 micron an N95 mask is more than capable of capturing the secretions from the flu patient.  Where the “medical” rated N95 mask comes in is that it has additional safety features such as a fire safety and is rated to not only insure the safety of the person wearing it (surgeon or nurse) but also the patient.  A medical rated N95 will cost more as well.  I suggest that anyone buying N95s look at industrial N95 that have “for occupational use” on the box.

After the quote is a link to each source.  At the end is a standard for eye protection (goggles) that people should be looking for for their PPE needs and a standard for infrared thermometer guns.

National supplies are already limiting orders on healthcare facilities so act quickly.

Sincerely – 3ADscout

N95 Mask:

From OSHA Respirator Types-

There are two main types of respirators:

air-purifying respirators, which use filters, cartridges, or canisters to remove contaminants from the air you breathe, and atmosphere-supplying respirators, which provide you with clean air from an uncontaminated source. Respirators can also be classified as tight-fitting or loose-fitting.

Loose-fitting respirators do not depend on a tight seal with the face to provide protection. Therefore, they do not need to be fittested.

There are filtering facepiece half-mask respirators, sometimes referred to as N95s. A filtering facepiece respirator covers the nose and mouth, and is a tight-fitting, air-purifying respirator in which the whole facepiece functions as the filter. Filtering facepieces may or may not have an exhalation valve to help exhaled breath exit the facepiece. They need to be fit tested, unless you are wearing them under voluntary use conditions. Filtering facepiece respirators filter out particles and do not protect against non-particulate hazards such as gases or vapors.

You may hear someone refer to a respirator as an “N95” or a “P100.” While most people use the term “N95” to refer to filtering facepiece respirators, “N95” actually describes the type of filter material and its protective properties. The filter material can be used in either a filtering facepiece respirator or in a filter cartridge that’s attached to an elastomeric respirator.

The first part of the filter’s classification uses the letters N, R, or P to indicate the filter’s ability to function when exposed to oils.
“N” means Not resistant to oil;
“R” means somewhat Resistant to oil; and
“P” means strongly resistant to oil, or oil-Proof.

This rating is only important in work settings where oils may be present, because some oils can reduce the effectiveness of the filter.

The second part of the classification — the number– refers to the filter’s ability to remove the most-penetrating particle size during “worst case” testing.

Filters that remove at least 95 percent of these particles are given a 95 rating. Those that filter out at least 99 percent receive a 99 rating, and those that filter out at least 99.97 percent – essentially 100 percent – receive a 100 rating.

Using this classification method, an N95 filter is not resistant to oil and removes at least 95 percent of the most-penetrating particles.



Masks and N95 Respirators– from the FDA


Facemasks are not to be shared and may be labeled as surgical, isolation, dental or medical procedure masks.

If worn properly, a facemask is meant to help block large-particle droplets, splashes, sprays or splatter that may contain germs (viruses and bacteria), keeping it from reaching your mouth and nose. Facemasks may also help reduce exposure of your saliva and respiratory secretions to others.

While a facemask may be effective in blocking splashes and large-particle droplets, a facemask, by design, does not filter or block very small particles in the air that may be transmitted by coughs, sneezes or certain medical procedures. Facemasks also do not provide complete protection from germs and other contaminants because of the loose fit between the surface of the facemask and your face.

N95 Respirators

FDA has cleared certain filtering facepiece respirators (N95) for use by the general public.

FDA has cleared the following N95 respirators for use by the general public in public health medical emergencies:

  • 3M™ Particulate Respirator 8670F
  • 3M™ Particulate Respirator 8612F
  • Pasture Tm F550G Respirator
  • Pasture Tm A520G Respirator

These devices are labeled “NOT for occupational use.”

N95 Respirators in Industrial and Health Care Settings

Most N95 respirators are manufactured for use in construction and other industrial type jobs that expose workers to dust and small particles are regulated by the National Personal Protective Technology Laboratory (NPPTL) in the National Institute for Occupational Safety and Health (NIOSH), which is part of the Centers for Disease Control and Prevention (CDC). These products are labeled “For occupational use.”

However, some N95 respirators are intended for use in a healthcare setting. Specifically, single-use, disposable respiratory protective devices used and worn by healthcare personnel during procedures to protect both the patient and healthcare personnel from the transfer of microorganisms, body fluids, and particulate material. These N95 respirators are class II devices regulated by FDA, under 21 CFR 878.4040, and CDC NIOSH.


N95 Respirators and Surgical Masks– from NIOSH Science Blog

Further, the filter’s collection efficiency is a function of the size of the particles, and is not dependent on whether they are bioaerosolsor inert particles.

The FDA does not perform an independent evaluation of surgical mask filter performance, nor does it publish manufacturers’ test results. In many cases it is difficult to find information about the filter test results for FDA-cleared surgical masks. The class of FDA-cleared surgical masks known as Surgical N95 Respirators is the one clear exception to this uncertainty of filter performance. This is the only type of surgical mask that includes evaluation to the stringent NIOSH standards. All members of this class of surgical masks have been approved by NIOSH as N95 respirators prior to their clearance by the FDA as surgical masks. The FDA, in part, accepts the NIOSH filter efficiency and breathing resistance test results as exceeding the usual surgical mask requirements.



Respirator Trusted-Source InformationSection 3: Ancillary Respirator Information

Can we use an N95 that has not been cleared by the FDA in a patient setting?

NIOSH-certified N95 respirators that have not been cleared by the FDA can be used for respiratory protection to reduce the exposures of healthcare personnel in a patient setting to hazardous particulates. These respirators have not been evaluated by FDA to determine whether they meet the fluid and flammability resistance as required for FDA clearance as medical devices. For this reason, they are not intended for use in exposure settings where the performance of a surgical mask to maintain a sterile field is required.

Compiler’s note:  All N95 mask will filter out 95% of the particulate however, medical grade N95 mask have additional capabilities for the healthcare setting such as the fluid and flammability resistance as required by the FDA mentioned above.  You do not have to buy/use an FDA medical N95 mask to protect yourself against germs (coronavirus) unless you work in a medical facility.



Recommended Guidance for Extended Use and Limited Reuse of N95 Filtering Facepiece Respirators in Healthcare Settings



Chemical Splash and Dust Protection For Eyeware:

Eyewear that meets ANSI Z87.1 requirements for droplet (splash) or dust protection will be marked with a code that begins with the letter “D”. For example:

  • Eye protection that provides protection from droplets and splashes is marked with “D3”
  • Eye protection that provides dust protection is labeled “D4”
  • Eye protection that provides fine dust protection is labeled “D5”


Standard Specification for Infrared Thermometers for Intermittent Determination of Patient Temperature:

ASTM E1965-98



  1. Here is a great documentary on the horrific Spanish Flu of 1918 that had a kill rate of 3 to 5% of the world’s population, or 50 to 100 million over a period of almost one year. It thrived in warm and moist environment, and took several months after introduction to peak. The peak was explosive in growth, and lasted for about 45 days. People were literally dropping like flies during this period.

    China is in panic mode. I do not need to understand Chinese to see that this is really big deal. Self quarantine is the best medicine, however, if forced to interact, a full face mask is best. No one knows for sure what we are dealing with, and if they actually do, just like the Spanish Flu, it can mutate, and become worse. Ready Made Resource has the best gear and equipment, and the best advice as to what to buy. Bob is first class all the way. This is my low budget gear for the purpose, but it is far better than a N95 mask, goggles, and gloves. Get the white disposable tyvek suits, duct tape, booties, and the thickest disposal gloves in layers and double up the glove if possible.

    The suit is necessary as if one happens to brush against a contaminated surface with their clothing, or is touched by a person, you can take it home with you and who ever touches the clothing can be infected. All this gear will be gone soon.
    When shopping for a mask, shop for a replacement filter, and then find the mask at another location if necessary. Most gas masks require a bit of effort to breath even when at rest. The Czech M10 mask is a copy of an early U.S GI design that might allow you to breath without as much effort as there are two filters instead of one, however I have no personal experience with this mask other than when I was a youngster. Watch reviews on YouTube, yet any mil-spec mask should serve the purpose. If you are out of shape, or already have trouble breathing, Bob at Ready Made Resource may have a solution for you.

    Get them while you can. I have mine, an Israeli model with 3 spare 40mm canister filters. Gas masks will disappear fast, and what is left will sky rocket in price. If the canister is used but not exposed to a contagion, it can be used again. Practice with it. Learn how to use it. It must have a good seal. Often smart and savvy business persons will by out a store of it’s stock of emergency gear, wait a bit anticipating panic buying, and then offer them on their site for twice the price. “Panic now and beat the rush.” (Rawles) Seen it happen. Maybe you’ll need one this time, or perhaps it will be next time. Get the mask first, then do not delay, get the suit , ASAP.

    This is a Czech M10. The filter is installed on the inside of the mask. It is easier to maneuver with, but if the filters are clogged, the mask has to come off. However, if used for only short period of time and in a clean environment, it will be fine, and the replacement filters are inexpensive. Here is an example:

    Czech gas mask filters, new $3.99

    Czech gas mask, $29.95: https://majorsurplus.com/czech-m10-gas-mask-with-filter.html

    You Tube review and test using pepper spray:

    Modern respirator is may not be rated for biologicals, but is far better than a N95 mask.:

    Get the 2X or 3X large if you plan on use one for winter camo, so that there is room for a warm coat underneath. Too large is better than a bit too small. If the legs and arms are too long, simply fold it up, and use duct tape to secure the extra material.
    Disposable X large Tyvek suit:

    I’ll use my white Bunny Boots, and tape over the shoe laces, and tape the seam between the boot and pant leg. Yet if you will not have rubber boots, get these to store in the vehicle with your ‘poor man’s disposable bio hazard suit’.

    Disposable boot and shoe cover:

    Heavy duty 5 mil mechanic nitrile gloves, XL size. I would wear a smaller set of gloves under neath in case the top layer is torn. It also aids during the decontamination process. Also, extra large gloves allow one to wear a thin wool, or other material glove liner inside, keeping the hands warmer.

    Standard duct tape:

    One must also learn how to go through a decontamination process. Fail to get that right, and the whole point of getting suited up is defeated. I’ll be using a garden sprayer and a disinfectant, and bucket with a 10% percent solution of bleach for incidentals.

    Level A decontamination process demonstrated:

    1. Most Level 4 and 3 bio workers are wearing large work aprons over their suit to protect the working area of their sealed suit.

      I suggest that is a good thing. The heavy rubberized/nitrile/vinyl ones protect from cuts and wear, thus preserving suit integrity and can be decontaminated.

      I bought Tyvek disposable suits but wish I could afford the full hazmat suit (at $150 last week), assuming it could be decontaminated frequently for a fortnight of use when required.

      1. Hi Wheatley Fisher,

        Readers should consider your recommendations, and get best quality they can afford. What I am suggesting is the low budget option that probably does not meet, or could not be considered to be any certifiable level of protection. IMHO, it is certainly a big step up from an N95 mask and goggles. Even with true level 4 gear, the decontamination process must be followed successfully. Without that training and durable gear and equipment, it is far safer to avoid any kind of risk, and self quarantine. I have this gear should I find myself in unforeseen, and rare circumstance that exposes myself to others. I am already on an extreme low budget, that necessarily requires reoccurring expenses to be correspondingly extremely low as well. There are no checks in the mail to be concerned with. Therefore this ‘life style’ is remarkably sustainable. :O)

        Very few can pull up the draw bridge for long periods of time and wait it out for a period of up to year while there is bills to be paid in a semi functional society. I can fortunately do that. This is the level of true security we should strive for. When, or * if * this storm passes, is unknown. If one has to work for a living, their requirements are far different.

        Disposable Tyvek suits purchased in bulk were about $5 each as of this morning on Amazon, and the Czech M10 mask was also still available on Amazon for $31.00. The suit alone would help to reduce the risk from causal contacts in the work place, and could be donned and shed when leaving, or enter the vehicle in the parking lot. Place the used suit, gloves, goggles, booties, and N95 mask in a trash bag and head home. It would be a better alternative than nothing at all. Use the gas mask for trips to congested stores where the warm moist air is continually contaminated by customers through out the day. It is all about techniques to mitigate different levels of risk.

  2. Another important point is that the masks with the valves should only be worn by people who are not believed to be ill with the virus. As they permit exhalation through them they also allow germs to leave as well. Sick patients or those under quarantine should only wear masks that don’t have the valves.

    1. Ani-
      Correct. The N95 mask (non-medical rated) purpose is to protect the person wearing it. As you point out, IF the N95 doesn’t have valve it works to help capture the secretions of the person wearing it.

      Also, used N95, P100 masks should be handled as CONTAMINATED. Handle with gloved hands and dispose of in a seal bag.

  3. Most sources I’ve checked online are out of stock – Amazon, Home Depot, Grainger. Home Depot has started rationing if they do have them. Anyone have a source that has them in stock? Also, can someone speak to the efficacy of the cartridge-style gas masks such as the Israeli? Even those seem to be in short supply.

    1. Re; Israeli gas masks. They have been designed to protect the civilian population from a variety of threats including biological weapons so I would imagine a corona virus would be handled by this. That said, they are uncomfortable and unwieldy and you would only want to wear one if the threat was large and imminent; not going grocery shopping with one on! I thankfully never had to wear one but many friends did.

      Re sources for regular N95 masks- I needed some more as my son lost his key to my storage unit where I had some stashed (sigh) so I ordered some from Walmart a week ago(just arrived) and through Amazon (on its way). But that was last week. Locally I’ve only seen a single N95 mask sold for about $9 at the hardware store. Maybe check woodworking and agricultural supply sites? Maybe Grainger? Harbor Freight? A site that sells Sheetrock supplies maybe?

      1. I plan for the worst and pray for the best.

        If memory serves, the Israeli mil-surp (military surplus) is a clone of the U.S. GI M-15, and the Israeli ‘civilian’, and other NATO gas mask use mostly 40mm and some, 60mm canisters, that are designed to protect against nuclear, biological, and chemical threats (NBC). It not only filters the air, but also protects the eyes. This virus has reportedly infected medical personnel wear goggles. It appears to be air borne. If so, the potential to a highly dangerous contagion is there.

        In the next few months, some time in the spring, it will prove to be highly contagious and deadly, or not so contagious and only an annoyance. We simply do not know at this time. I would not trust what the media has to say, but study early video of the extreme measures the Chinese are going to, action that portends, or anticipates a worst case threat. Actions speak louder than words. As a sensible prepper, it would be better to have it, or get it while you can, rather than need it, and be without. At some point the availability will be next to zero, and no amount of money will buy what you need if the threat is extreme. The brisk sales of N95 masks prove the point. Good thing I already have a pile of those purchased years ago.

        The disease will go through stages. It will spread, possibly mutates into a mild or severe forms, peaks, and then wanes. It will have similar and different histories depending a variety of variables. It may behave differently in your area than it does in other areas. The Spanish Flu 1918 had different characteristics in different regions of the world, and even after subsiding, emerge once again in another part of the world in a severe form. How it behaves in different parts of the world, and given a particular stage of it life cycle, will dictate how I will deal it. A gas mask may not be necessary, but the use of a tyvek suit with only a N95 mask with goggles nd gloves might be comforting option. It may not be necessary to put oneself though a Level A decontamination process, but to merely, yet carefully strip out of the suit when arriving home, and on the front pouch, submerge the gear in a bucket of diluted bleach including booties, or protective foot wear. Dispose of the masks and gloves if disposable. With a 10% solution of bleach water may kill the virus on a N95 mask. The bleach water may also destroy the mask. I would give it try, or find a way to disinfect it if the masks are scarce. The gear handled carefully, and in this way, might be reused. I would have all the sensible options I afford.

        Because I can, I will self quarantine and carefully watch events as they unfold. Here in NW Montana, the colder weather reduces the air borne viability, and because there is a lower population density, fewer precautions would be needed. I believe we will witness, and be able to better gauge the actually severity of this virus beginning in the next few months, sometime in April, May and June. This disease unfortunately will be carried by asymptomatic vectors, far and wide, and virtually be everywhere when full symptoms manifest.

  4. The masks of any type/designation that you can buy will NOT protect you. They might somewhat filter droplets from the air and they are somewhat effective in limiting airborne emissions from the wearer. The effective masks are generally not available and even if you could get them if you are not wearing them 24/7 you will not be protected. Their use is most effective in a controlled environment for short periods of time.

  5. Great summary 3AD Scout.

    The main thing to keep in mind with all this protective gear is that NONE OF IT WILL GUARANTEE YOUR SAFETY, all it can do is LOWER THE PROBABILITY that you will become infected.

    The South China Morning Post reported five days ago that “Fifteen cases of the coronavirus have been officially reported among medical staff in the city, but doctors say the true number is far higher.” If people experienced with PPE protocols are getting infected, what does that say for the rest of us? If an N95 mask is filtering out 95% of particles, doesn’t that mean that 5% are possibly getting through? Coronavirus particles are so small they are not even measured in microns.

    IMO, all this PPE will lull too many people into a false sense of security. Anybody with the IQ of celery can put a suit and mask on, but can they fit the mask properly? And there is a whole list of protocols to follow once it is on, and just as importantly, protocols to follow on how to get it off, and where, and how not to get infected in the process. That’s where a lot of inexperienced people will get infected. And even experienced people who are tired and overworked get infected, such as those medical workers in Wuhan. Those of us who haven’t shaved our mugs since the Reagan Administration will have to be clean shaven for any of these masks to work.

    Hopefully, all this talk is for naught and this virus will not become epidemic in the US. And if it does, hopefully it will not have a high death rate. But if it does make it here, and does have a high death rate, two big IF’s, then JWR’s advice from the other day is applicable: Don’t mess with the Wuhan. Be prepared to hunker down in isolation and let this contagion burn itself out.”

    The only time you’d want to don your PPE would be to take care of some family member you had to tend to, not to go out in public if those two big IF’s (epidemic in US + high mortality rate) happen to come to pass. You can’t depend on your PPE to keep you safe, only to lower the probability that you’ll become infected.

    Just my 2¢ worth.

    1. ST. Funogas,

      Oh you are so right on the doffing of the gear. Back when we had the few Ebola cases it was the doffing process were the medical staff became contaminated. Locally here our hazmat team was offered to assist any hospital or EMS service that had a suspect case. We are not too far from Cleveland where the one infected nurse went to buy her wedding dress. We had several people arrive in our city that flew on the same plane so the “pucker” factor was a little high.

      My assumption is that people would be using the gear in their homes. I would personally be using a TyVek suit and would decon myself in the home shower before doffing. A pump sprayer with a bleach solution would be very handy too.

  6. https://www.thelancet.com/pb-assets/Lancet/pdfs/S0140673620302117.pdf

    Here’s an interesting epidemiological paper just published in the Lancet, hot off the press. These are the statistics on the first 99 patients at the Wuhan Jinyintan Hospital from Jan 1 to Jan 20, 2020. They followed these patients until January 25th when the report was written so these percentages are as of that date.

    57% of the patients were still in the hospital
    31% had been discharged
    11% had died.

    Some of those 57% might still die so that means the mortality rate is above 11% for this group of 99 people. That is a very small sample size so difficult to determine how it will correlate to the larger group and since it will be impossible to get real numbers from the Chinese government, we may never know until it spreads elsewhere. If that turns out to be a real death rate, or even close to it, that is definitely something to be concerned about.

    Two other coronaviruses SARS and MERS each had mortality rates of >10% and 35% respectively.

    Another important finding of the study was that the virus affected men (67%) more than women (33%), just as SARS and MERS do, and 51% of the patients had some kind of other chronic illness, with cardiovascular and cerebrovascular diseases and digestive problems being the majority of the cases.

  7. One item from past training that no one seems to mention, the non surgical use masks are compromised after 15-20 of use due to moisture in exhaled air. Once the mask is compromised by moisture you’re breathing in everything like you weren’t wearing one. Things may have changed in the past decade to address this, but worth thinking about.

    In other news, CDC researchers accomplished a Reconstruction of the 1918 Influenza Pandemic Virus, articl and citations at omthetrenchesworldreport.com/reconstruction-of-the-1918-influenza-pandemic-virus/261252?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+fromthetrenchesworldreport%2FWQjf+(_From+the+Trenches+World+Report) and to help you sleep better, Joe Biden Suggests Making Michelle Obama Running Mate, Appointing Barack to Supreme Court at https://fromthetrenchesworldreport.com/joe-biden-suggests-making-michelle-obama-running-mate-appointing-barack-to-supreme-court/261257?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+fromthetrenchesworldreport%2FWQjf+(_From+the+Trenches+World+Report).

    Remember the ROTC soldier at the end of Animal House-“All is well!” Sleep soundly.

    1. What me worry,

      Are you referring to a surgical mask or an actual N95 mask there is a difference. The N95 is NOT compromised as you describe. If you have some source that says other wise I would really like to see it, but if I had to guess this was in reference to a surgical mask only NOT an N95 rated mask.

  8. Ready Made Recourses has a Bird Flu Kit for $22.
    I had already stocked up a few months back on protective gear but I ordered 6 of these kits a few minutes ago so I can have extra.
    Plus I can keep a couple in my vehicles just in case
    So if you don’t have any supplies and don’t want to be gouged on Amazon give them your business, it’s a nice all in one kit at a great price and they are a great company deserving of your business

Comments are closed.