Does your face mask really protect you?

FFP2 masks with and without valve at a glance

N95 / FFP2 /FFP3- what do those stand for?

Being professional protection, those respirator shave to comply with certain quality standards in order to make sure they deliver the protection they promise. In Europe, this standard is defined by ISO /CEN/ EN. All those standards define, which filtering capacity one respirator has.

-FFP1 (Filtering Face Piece 1) stops at least 80% of the particles that are 0,3 microns or larger.

-FFP2 (Filtering Face Piece 2) stops at least 95% of the particles that are 0,3 microns or larger.

-FFP3 (Filtering Face Piece 3) stops at least 99% of the particles that are 0,3 microns or larger.

Similarly:

-P1 stops at least 80% of the particles that are 0,3 microns or larger.

-P2 stops at least 94% of the particles that are 0,3 microns or larger.

-P3 stops at least 99,95% of the particles that are 0,3 microns or larger.

In USA there is similar standardisation by NIOSH – part of the Center for Disease Control (CDC). According to those:

-N95 stops at least 95% of the particles that are 0,3 microns or larger.

-N99 stops at least 99% of the particles that are 0,3 microns or larger.

-N100 stops at least 99,97% of the particles that are 0,3 microns or larger.

So, to approximate the things, we can say:

FFP2=P2=N95

FFP3=N99

N100=P3

PS: China has their own standard, which approximates to American ones. Those masks carry a sign KN95 and similar.

Here you can find my insta- guide to choosing a mask against Corona:

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A post shared by Dr. Miona Jovanovic Zahnärztin (@jovanovic.miona)

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How big are the viruses and bacteria and can the medical face masks stop them?

According to this research, Corona virus has a diameter of 60 to 140nm (0,06-0,14Microns)

Like we saw earlier, filtering capacity of a mask is measured at 0,3microns, which is more than double the size of the biggest Corona virus!However, the virus does not fly alone. Covid19 virus is within a aerosol that has up to 5micron diameter, or within a droplet that is bigger. But being heavier, droplet should also not be able to float far away so it is less dangerous. So our problem is aerosol drios that are smaller than 5microns. (to be honest, there is a scientific argument going on about how big is the aerosol and how big is the droplet and it gets very weird….so lets keep it simple here and use the WHO standardisation. According to them, up to 5microns is aerosol and bigger drops are called droplets)

One study analysed all the available research in order to compare how effectively can N95 (FFP2) masks and the normal surgical masks stop a virus sized like Covid (for this experiment, researches used Infuenca virus- not because those two offer similar sickness flow, but because they are similar in size and behaviour in aerosol). Based on the data of 6 studies involving 9171 patient, they concluded that the difference is of NO value to general population, meaning: for everyday activities, you should be equally protected, whether you wear a professional N95 mask or a normal medical (“surgical”) mask. Though that was all before covid19. Today we would perhaps want t0 revise this as general population is also facing larger risk.

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OK, so how about the textile masks? Do they stop Corona Virus?

In a recent study researches evaluated 20 different textile masks on how well they can stop different particles. First they put those masks under the microscope in order to estimate the size of the pores. The smallest pore size they found in a textile mask was 51 micrometers (50x bigger than corona virus), and the biggest ones were 569 micrometers (approximately 500x bigger than the Covid19 virus).

This pore size seems to be in correlation with the ability of the mask to stop the small particles. The authors also noted, that those pores also grow when mask is stretched.

As we commonly re-use our textile masks, researchers also washed them and put them under the filtering test again. This time the filtering efficiency was even worse then at the base line. To find the possible cause of change in filtering efficiency with washing and drying, the authors took a photo of the pores under the microscope after every cycle. Below the result:

Another research rightly assumed that our multiple use masks are not all made of same textile. They assumed many people would turn to do-it-yourself solutions once the proper protective masks get sold or too expensive and respirators are left for medical professionals.

So the researchers took a few of house utensils and inspected their ability to help us.

This research showed that vacuum cleaner bags have the best filtering capacity, 94,35% just slightly lower than normal surgical masks(96,35%). Kitchen towel also showed surprising results, filtering 83,24% when placed in double layer. But, authors also conclude that:

1. An improvised face mask should only be used as the last alternative if the normal surgical masks and respirators are not available

2. The improvised masks could potentially help your surrounding not get infected by you.

3. However, textile and other improvised masks can provide wearers little protection from other infected persons.

4. Finally, any mask, no matter the filtration potential and fit, will have little to no effect unless used in conjunction with other protective measures, such as physical distancing, washing your hands and, should washing be unavailable, disinfecting them.

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More important than any research: our habits or, how it all looks in reality?

For one reason or the other, many governments took up ordering the obligation of wearing (any kind of) face mask in all the publicly accessible areas. Additionally, the masks that, as we saw, actually provide protection against COVID (FFP2&FFP3) were in shortage, and it is appealed to public not to hord them but leave the available quantities for medical professionals.

Simultaneously, the price of surgical masks rose from 10 cent to anywhere from 1- 7e per piece in March 2020. Naturally, this left many families without the possibility to protect their own health using the mask. They were only focused on preventing getting fined. And so the use of the cotton masks started, although we saw that the protective effect they offer is extremely limited, even in the laboratory circumstances.

5 months later, in August 2020, another interesting experiment was published here. Admittedly, it is not the scientific article I usually go for, but I deemed their test legit and consider the findings very relevant.

For this experiment, random masks were taken from random people. Those were the masks they were about to (re)use. and the results were more than worrying: every re-used mask contained various bacteria and fungi, that can be very dangerous for the wearer!

These results are easy to explain: we put the mask on and off our face many times a day, many days in a row. In the meantime she is in the pocket, in the bag or any other place we quickly find for it. Until the next occasion when we grab it with the unwashed hands and put it back on the face. All the while, we know we will get fined if we don’t wear it, but were scarcely told how to actually place the mask and how to dispose of it.

What does it all mean, should we just give up on masks?

Absolutely not -it would just be irresponsible.

But I am a huge fan of doing things right. If wearing a mask: then knowing which one to wear and how to do it right..

So here is my mini guide to choosing a mask in Covid19 pandemics

Choose one of the masks that will protect both you and people around you. That would mean FFP2 or FFP3 with no filter

Remember that protective effect of the mask depends not only on the material, but also on how tight the edges of the mask adapt to your face. This prevents income of the aerosols from the side.

Never touch the inside of the mask.

In my dental practice the high quality practice is: place the mask before the first treatment and keep it as long a s possible. Once taken off, the mask has to be thrown away… Yes, it is harder to breathe in those long periods but it is a low price to pay for protecting my clients and myself. Consider this practice for yourself if you are having intensive social contacts during the workday,

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Personal view

I wish the government worked quickly and stimulated raising facilities that could produce the right protection. This would add to Austrian independence on imported protection masks, help the unemployment, reduce the enological imprint of imported masks and retain the earnings of the mask sales in the country.

I also wish everyone had been informed right from the beginning what the scientific facts were. That could had perhaps spared some of confusion after people had obediently worn masks for months and still witnessed that peak in Autumn. Perhaps some people listened to the governmental instructions to wer a mask, but as they had not been told which one, they wasted money and still got infected.
Instead we had to listen to the ridiculous baby elephant commercials. And talking about baby elephant: in next post we will check the physical distancing: is at least this based on research?

Finally, I have to make a clear statement. I only reflected on the evidence available in madical sciences. I am aware that the governmental decisions should also be supported by sociocultural and epidemiological evidence

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Sources:

Effectiveness of Surgical and Cotton Masks in Blocking SARS–CoV-2: A Controlled Comparison in 4 Patients, DOI: 10.7326/M20-1342

COVID-19 and use of non-traditional masks: how do various materials compare in reducing the risk of infection for mask wearers?, DOI: 10.1016/j.jhin.2020.05.036

A Novel Coronavirus form patients with pneumonia in China, DOI: 10.1056/NEJMoa2001017

Optical microscopic study of surface morphology and filtering efficiency of face masks, DOI: 10.7717/peerj.7142

Testing the Efficacy of Homemade Masks: Would They Protect in an Influenza Pandemic?, DOI: 10.1017/dmp.2013.43

N95 vs FFP3 & FFP2 masks – what’s the difference?

DIY Masks: Worth the Risk? Researchers Are Conflicted

Gesichtsmasken sind voll von Bakterien und Pilzen

Considerations for Wearing Masks