How to choose face masks for Anti-Covid-19?

Technical explanation of the difference between different medical masks

A study published in the Journal of the American Medical Association in September 2019, compared the effectiveness of N95 masks with “medical masks” for protection against influenza for U.S. outpatient medical staff.

In this four-year trial, 8.2% of medical staff wearing N95 masks were infected with influenza, while only 7.2% of those wearing medical masks were infected, showing “little difference between N95 masks and medical masks in protection against most viral respiratory infections, including influenza”.

But after some careful research, we think it is right to say that there is no difference between the protective effect of wearing an N95 mask and a “medical-surgical mask” with the US standard.

N95 face mask

(Image source: CDC)

It is important to note that although the title uses “Medical Mask”, the research team actually has an explanation in the paper: medical masks are often referred to as surgical masks.

Don’t underestimate this phrase, the learning inside the mask is not simple. In China, medical masks are often divided into three levels: disposable medical masks, surgical masks, and medical protective masks, with different protective properties, different applications, and naturally different prices.

Medical-surgical masks have high requirements for blood resistance, while medical protective masks have good filtration efficiency. The focus of the two is different, but the protection ability is definitely stronger than disposable medical masks. These three different masks, corresponding to the three different technical standards.

medical face mask

If you want to buy Chinese standard masks (generally for people from outside Europe and the United States), it is recommended to ask your supplier what Chinese standard their masks follow, and you can also judge what level of masks you have according to the standard number in the above chart.

In addition to the standard number, it can also be distinguished according to the shape. Most protective masks, including N95 masks, are duckbill-shaped or cup-shaped, while disposable masks and surgical masks are mostly rectangular, which is also related to the difference in the functional positioning of the two types of masks.

suigical mask

(Image source: Wikipedia)

In the clinical trial published in JAMA, the “surgical mask” used to compare to the N95 mask was rectangular in shape. According to the technical data of the two “surgical masks”, their protection standards meet the highest level of the ASTM F2100-11 standard recognized by the FDA – Level 3.

BFE and PFE test of the medical mask

Compared with the Chinese standard, the biggest difference between these two masks is that in terms of particle filtration efficiency (PFE) and fluid resistance, the standards for medical surgical masks in China are lower than the ASTM standard level 3, especially the fluid resistance index for medical protective masks is lower, and medical disposable masks have no requirements for this.

Noish Approved N95 Particulate Respirator

This diagram shows the difference between different levels of protection

So put the results of the JAMA test into China, that “medical-surgical mask protection effect = N95 level mask”, in fact, it is still a little bit not rigorous, the two countries’ medical surgical mask standard is not the same yet. And the factors that affect the protective effect can not only look at the mask.

We used to talk to our clients, and they said that the JAMA trial was for influenza, and the flu vaccination rate for outpatient medical staff in the US is quite high. Although in terms of actual protection, the flu vaccine is exhausting every year, and the protection efficiency is only 60% when it is relatively good, there is still a vaccine after all.

The current outbreak of novel coronavirus pneumonia has been developed by scientists in China and the United States as well as in various countries, although vaccination of high-risk populations is now available. However, various problems have emerged, and the effectiveness of the vaccine remains to be proven. And in terms of transmission routes, coronaviruses such as SARS also have aerosol transmission routes, and there are some differences with influenza, which may also affect the data.

vrious Covid 19

(Photo credit: Pixabay)

As for how different masks face coronavirus pneumonia, how different the protection effect is, that still needs test data to prove. The various experts and articles give more empirical advice, even if the protection effect of disposable medical masks is relatively weaker, it is better than no mask.

Besides, the real situation is that at the pharmacies and e-commerce platforms, a variety of masks out of stock or price increases, whether it is medical disposable, medical-surgical, or medical protection, are very good sellers. This kind of time, as a mask purchaser you must be based on the actual application needs of the customer as well as the psychological price to determine what kind of mask to purchase ……


Of course, if you can choose, according to the use of the environment, specific analysis of the specific case, do not have to pursue medical-surgical or N95 level protective masks. For ordinary people with a low risk of contact with patients, wearing a disposable medical mask is also better than not wearing it!

Finally, Mediunion will use this chart again to emphasize how to wear a mask correctly. Wash your hands, use it once, use it and throw it away, don’t touch it again, these common-sense are also important!


(Image source: CDC)

Radonovich L J, Simberkoff M S, Bessesen M T, et al. N95 respirators vs medical masks for preventing influenza among health care personnel: a randomized clinical trial[J]. JAMA, 2019, 322(9): 824-833.

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