A Curious Thing Concerning Respirators and Masks

Years ago, I needed to contact MSA about respirators. I needed technical answers, we used their products, I emailed them. No answer. Eventually I made a group emailing. I took key people, reasoned they’d use a first initial, last name, MSA domain, for email. I sent out several in one email, implicit addresses, but not sure. They comeback if undeliverable, if not, they delivered. Someone had their secretary email, she was made my liaison for future communications, and I was given an explanation why they didn’t respond, claiming a “Spam Filter”.

NIOSH is National Institutes of Occupational Safety and Health, they research various things pertaining to work, but respirators are a big part. I noticed you can call, you can write, I think FAX, but in the age of paperwork reduction, you can’t email. So, I’m looking for email addresses online and I find an employee. I send him the email I prepared for NIOSH, told him it wasn’t addressing my attitude towards him, and if he could help, I’d appreciate it. Weeks passed, suddenly a response. By someone else with NIOSH.

Below is what I wrote, what a NIOSH employee wrote back, and my views on their response.

Intent of Email for the NIOSH Employee…..

Dear………. (Name omitted)

Sorry if this is not applicable to you, directly. Please forward to a more appropriate person at NIOSH as needed, all I can find online is Fax and Telephone Numbers.

I see you’re an Industrial Hygienist with NIOSH, even at my former employer, when I was a Union Safety Representative, of all the established Company Safety people that were reluctant to help, yet one Recent Graduate, new IH Employee from Corporate, helped out.

Everything below here was intended for NIOSH and is not written to you specifically. I’m bewildered by the inconsistent ways Respiratory Protection is being handled in light of this pandemic.

My Comments and Questions for NIOSH

I had been involved in Negative Pressure Air Purifying Respirator Training for a number of years in Heavy Industry. Over my career of approximately 25 years, 7+ years were in Instructing 1200+ Employees Per Year, in groups of 30 to 35, on Respiratory Protection. Otherwise, except for the years I was a Union Safety Representative, I worked in Maintenance in the Industry, and as such I wore respirators at work daily for 12+ years and often as needed for the balance.

We had yearly physicals to determine; among other things, if we were physically capable of wearing respirators; fit tests with requisite head movements, speaking, deep breathing, etc., for the same make, model, and size of the respirators that we wore. In Negative Pressure Air Purifying Respirators, I initially wore an MSA ½ Face Respirator and eventually moved to a 3M ½ Face Respirator over the years. I also was Fit Tested for, and wore an MSA Full Face Respirator. Despite all of this, they still leak, that’s why limitations are placed on their use, and the respirators given an assigned protection factor. How much virus can safely be respired, due to face to facepiece seal leakage with tight fitting respirators, and how much more must circumvent the non-seal of a surgical style masks? ”

In addition, for GAS Rescue, escape, and Air-Line Supplied Work, we were Fit Tested for a Scott Full Facepiece for use with the appropriate Air Supplying System and Escape Air Bottles.

Frankly, I must say, from my perspective, the guidance by OSHA, the CDC, and as a subset of the CDC, NIOSH, is conspicuously missing on the covid-19 issue pertaining to the Proper Use of Respiratory Protection Products.

I’m now retired, but was aghast that; due to a shortage (at one time during the Pandemic) of Filtering Facepiece Respirators (FFR); OSHA temporarily suspended the need for a Fit-Test to preserve stock. Would not a Pandemic be the most appropriate time to be sure that FFR Fit Properly to preclude, to the greatest degree possible, infiltration of viral particles?

Masks have, in some areas and/or circumstances, been mandated by govt, and now the CDC; your oversight department; has suggested that Double Masking is safer in preventing covid. Really? Some in the news suggest that wearing a Double Mask approximates an N95. Interesting. Aren’t N95 wearers to be given a Qualitative or Quantitative Fit Test. Are they not required to be cleared, medically, to be able to use an N95? Until this point, I merely thought the CDC to be somewhat ignorant, but now they are bordering on grotesque negligence.

If Respiratory Products are part of a method of successfully combating covid-19, why has there been no outreach to the public? N-95 Respirators are designed for 0.3 Micron and larger particles, and covid-19 is 0.125 Micron and smaller, but clustering of viral particles enlarges their size, and supposedly Electrostatic Attraction is inherent in some Filter Designs, but is this Electrostatic Charge even applicable in an FFR saturated with moisture from exhaled breath? I can see in an Elastomeric Respirator with Filters and an Exhaust Valve (otherwise taboo for Pandemic use), the Filters remain Dry, but not so in an FFR. Does Moisture in an FFR increase force required to inhale and if so, does it not result in additional seal leakage. Has those now required to wear masks or respirators been told about handing them, cleaning them (if appropriate), sterilizing them (another can of worms since the wrong procedure can render them more permeable), when to throw away, etc.

It’s worse than a joke. The government is all rules and little help. Me, I clean shave (I have a goatee at times, and though retired, I shave it when I need to wear a Respirator), and wear an FFR when I have to go out, but I’d rather wear the 3M or MSA Elastomeric Respirator, I feel short of breath (on occasion) in the FFR, I never felt that way with the Elastomeric Respirators. And now, without Medical Screening, without Training, Without Fit Testing, the CDC Recommends Double Masking.

  • Does NIOSH Support Double Masking?
  • Is Double Masking over a Beard Really Protecting anyone?
  • Is NIOSH on Board with Requiring People to Wear Respiratory Protective Products without Training or Oversight?
  • Does NIOSH believe that employees should be assiduous about wearing Respiratory Protection but it’s OK for the Public to Haphazardly Wear them?

All those things I learned and taught about Respiratory Protection are being thrown out the door for political expediency. None of this makes any sense from the original premise of wearing a facial covering to reduce droplets expelled by people that are sick. As the CDC, and I would presume, NIOSH, make Mask Scenarios Increasingly restrictive, other issues will arise. People wearing them below the nose, for instance. It’s especially concerning when I see the studies on the flu that have been pulled (one of note was done at a Dental Organization and their findings were that Masks don’t stop the flu, but magically they stop covid so they pulled their own study).

Before anyone flies off the handle and labels me as an Anti-Masker, re-read my Email. I said I clean Shave and Wear a Filtering Facepiece Respirator and I took the time to be sure that it is authentically approved for its NIOSH labeling. I am saying that the public aren’t being given guidance that would render their Respiratory Products significantly effective according to long established requirements for Industry, nor are they being given advise on the possibilities of their infected masks for becoming a vehicle for the spread of the virus, through careless wearing or handling. The CDC has been virtually idiotic on this issue, and I had hoped that NIOSH would set them straight.

NIOSH Response Below:

Thank you for contacting NIOSH about your concerns around mask recommendations during the pandemic. You raise many important questions and issues that can impact the performance of masks and respirators in protecting the public against the transmission of SAR-CoV-2. NIOSH has years of history and science to support recommendations on respirator use in workplaces. We have drawn from this science to help support CDC in the development of mask recommendations and have initiated new research to help fill gaps where possible.

CDC does not recommend the use of N95 respirators for protection against COVID-19 in non-healthcare settings. N95 respirators should be reserved for healthcare personnel and for other workers who are required to wear them for protection against other hazards. CDC recommends following guidance to protect yourself and others from COVID-19 by wearing a mask when going out in public. Correct and consistent mask use is a critical step everyone can take to reduce their risk of getting and spreading COVID-19. How well a mask fits, how well it filters the air, and how many layers it has are all important to consider when choosing which mask to wear.

No federal agency has regulatory authority over mask use by the public and CDC is limited to providing guidance. Currently OSHA does not consider masks to be personal protective equipment and they are not required under OSHA’s PPE standard (29 CFR 1910.132). As the scientific community learns more about the effectiveness of masks and the role they play in slowing the spread of COVID-19, CDC will refine the guidance we provide to the public. I encourage you to follow the CDC’s Use Masks to Help Slow Spread and OSHA’s Coronavirus Disease (COVID-19) pages as these are updated frequently.

Additionally, please see below for information on respiratory protection topics you mentioned in your inquiry.

Fit Testing and Training

  • Respirators used in workplace need to be used in the context of complete respiratory protection program per the OSHA regulation 29 CFR 1910.134 (https://www.osha.gov/pls/oshaweb/owadisp.show_document?p_id=12716&p_table=STANDARDS). A complete respiratory protection includes fit testing which indicates that the proper size facepiece is being worn.
  • Respirators, when required to protect workers (e.g., healthcare personnel) from airborne contaminants such as some infectious agents, must be used in the context of a comprehensive, written respiratory protection program that meets the requirements of OSHA’s Respiratory Protection standard. The program should include medical evaluations, training, and fit testing.
  • On March 14, 2020, the U.S. Department of Labor’s Occupational Safety and Health Administration (OSHA) issued new temporary enforcement guidance for respirator fit testing in healthcare during COVID-19 Outbreak. The March 14 guidance, which applied to healthcare, now applies to all workplaces covered by OSHA where there is required use of respirators. This temporary enforcement guidance temporarily suspends the annual fit testing requirement of N95 filtering facepiece respirators. However, initial fit tests with the same model, style, and size respirator are still required.


Discarding Respirators

  • An N95 respirator should be discarded when it becomes damaged (e.g., broken straps, broken nose piece) or deformed; no longer forms an effective seal to the face (i.e., fails a user seal check); becomes wet or visibly dirty; breathing becomes difficult; or if it becomes contaminated with blood, respiratory or nasal secretions, or other bodily fluids from patients.
  • The CDC recommends that the fit of reused FFRs should be monitored by the respiratory protection program manager or appropriate safety personnel. One way to monitor fit for FFRs that are used more than five times is to conduct a qualitative FFR fit performance evaluation. A qualitative FFR fit performance evaluation is not the same as a qualitative fit test but can be conducted using the same agents and exercises used for qualitative fit testing, however, each exercise is conducted for 15 seconds as opposed to the 1 minute specified in the actual OSHA-accepted fit test. This will help limit the time it takes to assess respirator fit and allow healthcare workers more time to focus on patient care. This process is described at the following webpage https://www.cdc.gov/coronavirus/2019-ncov/hcp/ppe-strategy/decontamination-reuse-respirators.html

Size of COVID-19 and NIOSH-Approved N95 Filtration Efficiency

  • The size of COVID-19 particles is around 100 nm diameter. When worn correctly with a good fit, a NIOSH-approved N95 respirator with 95% efficiency is expected to filter these particles.
  • The N95 filters are highly efficient at collecting small aerosol particles smaller and larger than 0.3 micrometers (microns, aerodynamic diameter). NOTE: the efficiency of collection by inertial impaction and interception drops as particles become smaller. The efficiency of collection by diffusion mechanism drops as particles become larger. The minimum for the combined collection efficiencies for inertial impaction and diffusion is somewhere between 0.1 – 0.3 micrometers, which is why NIOSH tests particulate N, P and R type respirators in its certification tests with particles in that most challenging size range, around 0.3 micrometers.

The Public Wearing Respiratory Protection

  • The purpose of masks is to keep the wearer’s respiratory droplets from reaching others, also known as source control.
  • Again, CDC does not recommend the use of N95 respirators for protection against COVID-19 in non-healthcare settings. Currently, N95 respirators are critical supplies that should be reserved for healthcare workers and other medical first responders to prevent supply shortages. Also, respirator use by the general public is not subject to regulations required of employers in workplaces. Consequently, wearers will not have the benefits of formal training, fit testing, or medical evaluation to ensure they can wear a respirator properly and safely.

My Comments for this Blog on NIOSH’s Response:

3 - Respirator Comparison

NIOSH is likely correct in saying that OSHA, due to a shortage of Filtering Facepiece Respirators (FFR), suspended the yearly Fit Testing requirement, but still required the Initial Testing Requirement for the Respirator, I appreciate the difference. It would be madness to just hand out FFR in hospitals without the Initial Fit Test.

Yet, I just found this:

United States: OSHA Extends Suspension Of N95 Annual Fit Testing To All Industries

“Finally, OSHA noted that “[m]ost respirator manufacturers produce multiple models that use the same basic head form for size/fit,” and have a list of respirators with equivalent fit (known as “crosswalks”).  “Therefore, if a user’s respirator model (e.g., model x) is out of stock,” the memo states, “employers should consult the manufacturer to see if it recommends a different model (e.g., model y or z) that fits similarly to the model (x) used previously by employees.”


The memorandum is a welcome relief for those employers outside the healthcare industry that still have N95s. Since annual fit testing often results in destruction of the respirators tested, OSHA’s guidance will help those employers preserve their limited supply and improve the N95 shortage. Still, some employers had hoped that OSHA might excuse initial fit testing requirements (which also destroys respirators) or provide alternatives for medical evaluation.”

I’m still a little less than impressed, not concerning NISOH, but OSHA, since the emphasis is on preservation of N95 Respirator Stock and not an assured Fit Test for the employees expected to work around covid patients. This excerpt, above, went so far as to suggest that Employers hoped the Initial Fit Test would have been eliminated as well, this seems to show a complete disregard for the employee. The employee should be provided with the same Make, Model, and Size FFR that they were Fit Tested with. The excerpt above indicates that “Crosswalks” exist, they explain these as “Different Models that Fit “Similarly” to the desired model. This does not seem like a good policy when it is so important to reduce or prevent exposure to the greatest degree possible. 

I was amazed at the CDC still insisting that “CDC does not recommend the use of N95 respirators for protection against COVID-19 in non-healthcare settings. N95 respirators should be reserved for healthcare personnel and for other workers who are required to wear them for protection against other hazards.”  Personally, if there is a chance to prevent my family or friends from being exposed to covid, I’d want them to correctly wear an N95 rather than a Surgical Mask, Cloth Mask, etc.

Dr. Rand Paul, on “Louder with Crowder’s” show on Thursday 11 March 2021, said he was unsure of the impact of masks, “if any”, but said that of all the options, the N95 would be the most likely to help protect against covid. 

It’s over a year since the pandemic began, nearly a year since it became an issue in the U.S. and there is no reason that Manufacturers have not been geared-up to produce massive quantities of N95 so that they would commonly be available for the general public and available in sufficient numbers for Front Line Workers. 

Concerning which particles are most likely to successfully make it through an N95 Respirator, I found this page: 

Respirator Filtration Mechanisms & MPPS

MPPS = Most Penetrating Particle Size (I never heard this term before) 

Regardless, reading the article, and I suggest it’s worth a look, they discuss 4 Principles of Filtration. Particles smaller than the porosity of the Respirator Filter can be removed, but not at 100% all the time, and face to facepiece leakage accounts for still more particle infiltration. But reading the article, I came to the conclusion that covid is more likely to get through due to it’s size, and am not convinced by the NIOSH response on the issue. In the comments to the article is this: 

“Do you know how this relates to SARS-CoV2 specifically? On the face of it, the virus is pretty close to the optimal size to sneak through filters, as it is about 0.12 μm. However, that’s the bare virus and I imagine the virus isn’t usually floating in the air ‘naked’. It is in droplets of water/saliva/mucus, which are bigger.

For instance, the following paper says sneezes produce droplets of 100 μm, which filters should find much easier to take out. However, it says coughing produces droplets of around 1μm, which is still in the MPPS zone.”

Despite this reliance on the virus riding a wave of saliva or mucus, I have read elsewhere in technical material for Respirator Filters that the moisture adherent to the virus evaporates very quickly. Dr. Merritt, in a presentation she did on Masks, feels that in infectious environments, the virus tends to permeate the room, ergo it is not laden with moisture to help it become entangled in the filtering media. Something not mentioned in the Filtration Article is Clustering, something I saw in, if memory serves, in a 3M article on Respirator Filters. Clustered viruses take on a size that permits them to become entangled in the Filter Fibers, and I believe that that is the case to a degree. 

No matter what one wears, in terms of Negative Pressure Air Purifying Respirators, some viruses will get in, either at the face to facepiece seal leakage or some will permeate the filtration media successfully.

Of Negative Pressure Air Purifying Respirators, Certainly Tight Fitting Respirators will seal the best (Elastomeric, i.e. rubber or silicone facepieces usually with 2 external filters), but due to the Exhaust Valve, are not suitable to wear to protect others from the wearer. But due to the exhaust and intake valves, they prevent exhaled air from going through the filter, the filter becoming saturated with moisture, and the loss of the Electrostatic Filtration mentioned in the aforementioned article. 

N95 Filtering Facepiece Respirators (FFR) will seal the best after that, they must not have an exhaust valve when used for protection from pathogens, as any pathogens the wearer has exit unfiltered. The Exhaust Valve makes breathing more comfortable, when used for non-pathogen control, such as used against Dust and Fibers in Industry, but the Exhaust Valve will not, in the case of FFRs, prevent the filter from becoming saturated with moisture, though they likely will delay it. 

Respirator Fit Testing / Mask Fit Testing∣ Intrinsic Analytics 

The above video demonstrates a Quantitative N95 Fit Test and the wearer is being given instructions on the use of the Respirator, notice she pulls the hair away from the Respirator to prevent leakage at the face to facepiece seal. 

Surgical Masks have no seal. And Double Masking is being pushed by some to approximate wearing an N95. Yet, according to OSHA, Employees that are required to wear an N95 must be given a medical evaluation before being Fit Tested for the Respirator, as even an N95 can impose additional burdens on the human body due to alterations in respiration. I’m not convinced that Double Masking is as effective as the CDC would have us believe, and I’m not convinced that it doesn’t impact the body as a whole based on altered respiration. In any case, the issue of Double Masking was not addressed in the response from NIOSH. 

In any case, I’d like to thank the NIOSH employee that received my email and the one that responded to it. I have an appreciation for the work NIOSH does in protecting employees. I’m sure that readers of this Blog Entry will find the official Links provided by NIOSH useful, they refer to the CDC and OSHA. 

3 - Respirator Comparison 4

Author: Dr-Artaud

A Doctor that is not a Doctor, but named after a character in the movie "No Such Thing", as is the Avatar.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

%d bloggers like this: