Mask protection against COVID-19: N95 vs Surgical mask vs SonoMask

Photo by Jonathan J. Castellon

Categories of Personal Protective Equipment (PPE) Explained

A common concern when choosing personal protective equipment for everyday use is that will the face-mask of choice have effective action of blocking COVID-19 transmission.  N95 respirators, surgical masks & fabric face-covers are examples of personal protective equipment that are used in order to help protect the wearer from airborne particles..

It should be noted that currently NO face-mask is clinically validated to be 100% effective against blocking COVID-19 transmission, there does exist however considerable variability between different types of units and it must also be recognised that correct wear and practicality of for constant use is of vitally important consideration. 

An N95 mask is a type of respiratory protective device, typically intended for medical workers and first-responders; it is designed to achieve a very close facial fit and approximate 95% filtration efficiency of airborne particles (around 0.3 microns). Note that the edges of the respirator are designed and should form a seal around the nose and mouth. In short, N95 masks meet the US standards of NIOSH for respirator masks; KN95 masks are the Chinese standards for masks, very similar also is FFP2 for Europe. These are the requirements that the US National Institute for Occupational Safety and Health requires manufacturers to meet in order to label their masks as N95s.  Despite significant differences related to airflow which will be explained later, the categories of “N95” are at least the equivalent or nearly equivalent upon the filtration features that most people are concerned about.

 A surgical mask is a loose-fitting, disposable device that creates a physical barrier between the mouth and nose of the wearer and potential contaminants in the immediate environment. These are often referred to as face masks, although not all face-masks are regulated as surgical masks.  Note that the edges of the mask are not designed to form a seal around the nose and mouth.

Face shields:  It is unknown if they provide any benefit as source control to protect others from the spray of respiratory particles. CDC does not recommend use of face shields for normal everyday activities or as a substitute for cloth face coverings. Some people may choose to use a face shield when sustained close contact with other people is expected. Disposable face shields should only be worn for a single use.  Reusable face shields should be cleaned and disinfected after each use.

A cloth face mask is a mask made of common textiles, usually cotton, worn over the mouth and nose. Cloth face masks are recommended by public health agencies for disease “source control” in epidemic situations to protect others from virus laden droplets in infected mask wearers’ breath, coughs, and sneezes.  The CDC recommends wearing a cloth mask anytime you’re in a public setting where maintaining social distancing is challenging.

The SonoMask is an advanced-defense textile unit fashioned from high GSM cotton-polyester fabric, double layered and filtering to 5 microns.  What makes it unique it that it has undergone a patented sono-mechanical process that was affirmed by independent laboratory bodies to retain its antimicrobial activities against bacteria and fungi with log 5-7 reductions for over 65+ washes.  As well as this it has lab-verified anti-viral activity against COVID-19 meaning the fabric is able to destroy the virus contact.  Coming in ear-loop and head-strap designs which are fully adjustable ensures that the product will fit almost any one securely, with a conforming nose-clip to ensure an effective seal.  This face-mask is cleared for FDA Marketing under the non-medical use as the metallic nano-particles are regarded as GRAS by FDA, used only in minute but effective quantities that stay permanently bound to the fabric fiber.  The SonoMask is also in the process of being submitted for Medical FDA Testing as a new category of PPE for health-care workers.

Filtration Comparison:

To explain the point of how SonoMask filtration compares with its 5 micron particle efficiency to N95/FFP2 filtration let’s explore a few possible scenarios following exposure at 1 metre distance from an infected individual. 

According to the most recent journal pertaining to COVID-19 and Public Health (June 13th 2020), Entitled “Transmission of COVID-19 virus by droplets and aerosols.”

Without any mask worn, a susceptible host exposed to infected persons coughs inhales the resultant plume of droplets, the host without a mask worn receives a considerable payload of viruses so that it is very likely that they get infected.  However, with an ordinary face-cover they may, during inhalation, filter in 20–30% of the payload of viruses with a lower propensity of getting infected. Such a payload may have more than a couple of hundreds of SARS-CoV-2, which is believed to be adequate to instill the COVID-19 amongst exposed people. The host wearing N95 may not receive in more than 5%, which may however, scientifically still constitute more than a few hundreds of payloads of the virus, ergo the same potential risk.

With SonoMasks’ lab-verified anti-COVID-19 fabric however, there is not only 5 micron filtration, the approximate size of infective droplet causing conventional COVID-19 transmission according to WHO and this cited governmental journal, but over 90% lab-verified elimination of the virus upon contact which therefore indicated mitigation of the risk to even less than N95-use without any of the uncomfortable impracticality of wearing a medical-respirator upon a routine-basis.

Without correct training, N95 masks may not even protect workers on the Covid-19 frontline

Health care workers are considered to be a high risk group of contracting Covid-19 for several reasons: exposure to many patients with Covid-19 who are shedding the virus, lengthy exposure during extended shifts, and increased frequency of exposure because of repeated shifts caring for Covid-19 patients.  This is compounded by a lack of capacity to treat all Covid-19 patients in what are known as “airborne infection isolation rooms.”  Wearing a respirator incorrectly poses a dual risk.  Firstly, an incorrectly worn mask will fail to protect the user as described above from respiratory hazards such as SARS-CoV-2.  Secondly, an improperly worn mask can give health care workers a false sense of security that they are being protected in a high-risk environment when they do not have the protection they think.  Moreover, assuming that this type of limited PPE was not intended only for medical workers, the kind of fit-testing to ensure that medical respirator is working properly, is not available to implement by the average person at home:  It involves choosing and trying a personal size from a wide range that creates the necessary sealing and then being exposed to noxious stimuli to see if the user can smell/taste it. 

Not all N95s are created equally either.

Valved N95 masks pose a real danger to others, Healthline reports:

The virus can be transmitted through the valves, which offer no filtration at all,” said Dr. Ali Raja, executive vice chair of the department of emergency medicine at Massachusetts General Hospital and an associate professor at Harvard Medical School.  Moreover, “In the spirit of ‘your mask protects me and my mask protects you,’ a mask with a valve virtually makes that impossible,” said Jessica Malaty Rivera, MS, a microbiologist and contributor at the COVID Tracking Project.  If you don’t have anything filtering what’s going out, it’s kind of like your mouth is an open air exhaust, and that’s the danger,” she told Healthline.  This stems back to the principle that many masks that tick the “N95 box” are in-fact designed for construction workers to use to keep out dust and other debris particles and were NOT intended for infection control.

To elaborate further, in fact our SonoMasks perform substantially better in three main areas over the N95 respirator; Function, Longevity, and Price.

Additionally, the N95, typically being a valved respirator and not a mask, does not filter exhalations.  In any type of environment where the safety of others is at stake, the N95 will do nothing to protect others. However, our Zinc-oxide infused masks have a particle filtration above 98% of 5 microns (according to ASTM F2299M and EN 14683:2019) filtering both inhalations and exhalations.  Moreover, unlike N95s our SonoMasks are convenient to wear and easy to apply correctly.  The adjustable straps available in ear-loop and head-ties make it easy to find a style that fits correctly, moreover the nose-piece which molds to the users-face ensures that there are no gaps with exposed air, as can easily happen with incorrectly applied N95 masks.

As mentioned, the main route of infection is through infective aerosol droplets of size 5 micron and above, which the SonoMask is an effective barrier against. Our advanced nano-particle embedded technology is capable of deactivating viral units on contact according to our lab-verified studies.  In comparison, the N95 simply filters the virus instead of de-naturing it, creating a valid risk for handling.  One of the considerable differences between the two is the longevity of our product.

Unrivalled Longevity

Currently our SonoMasks have been verified by current lab-certifications to be used for 90 industrial wash cycles with 12 hours use between cycles, equating a total of 1080 hours of wear.  The CDC has reported that N95 respirators can only be used for up to 5 rotations or around 8 hours of use, barring hospital visits or heavy traffic. Most N95 respirators are marked as single use only meaning they cannot be reused once removed.

Peak into our dramatic lab-findings

Sonovia previously received the following test reports made by an independent tier one laboratory, Hygcen Austria servicing the EU medical industry & healthcare institutes: Determination of antiviral activity of textile products according to ISO 18484 –

Sonovia’s Sono finished ZnO based fabric, rated with a good( ( 99.8877%) virucidal effect as significant reduction of vaccine virus was detected after an exposure time of 24 hours.

Determination of antibacterial activity of textile products according to ISO 20743 – Sonovia’s sono finished ZnO based fabric, rated with a strong antibacterial effect, more than 99.9999% biocidal activity was detected for both gram positive and gram negative bacteria types after multiple laundry cycles.

Now we have just received a preliminary report back from Microspectrum (Weipu Jishu) lab in Shanghai that has demonstrated that the early test fabri neutralised more than 90% of the coronavirus (SARS-COV2) to which it was exposed.

This is now concrete evidence that our SonoMask is a vital tool in preventing disease transmission in the current pandemic.  Since this test material was submitted several months ago, our Zinc oxide nanoparticulate formulations have been optimised even further at our technical laboratory in Tel Aviv, these are the formulations on which are commercially available SonoMasks are imbibed with and we anticipate a 99% SARS-COV2 (COVID-19) with a fast-tracked full test application with an EU authorised laboratory imminently.  This will demonstrate that we are providing the public with the highest level of anti-viral protection.

Dr Jason Migdal MRes

Dr Jason Migdal MRes

Sonovia Microbiology R&D Team ​