Counterfeit surgical masks: how to recognize a real mask from a fake one?
Text updated on 2020-08-04
Counterfeit or non-compliant surgical masks are being offered for sale on the Internet and in some stores. Here are a few tips to find out if your surgical masks are of good quality.
Real surgical masks are made of three layers of non-woven fabric:
- a hydrophobic outer layer that prevents droplets from entering the mask,
- an intermediate layer that blocks bacteria, body fluids, and particulate contaminants,
- an inner layer in contact with the nose and mouth that absorbs moisture.
The intermediate fiber layer is electret polypropylene: during its manufacture, it was "charged" by a very strong electrical discharge as the fibers solidified. This electrostatic charge greatly increases the efficiency of mechanical filtration. For FFP2/N95 protective respirators, the filtration efficiency is thus increased by 10 to 20 times. For surgical masks, we have not found any quantitative study but the effect of the electrostatic charge on filtration should be comparable.
To check that your surgical masks are of good quality:
- The packaging must state :
- the reference of the NF EN 14683+AC standard
- the type of mask (e.g. type IIR)
There should be a metal bar that bends well over the bridge of the nose to help fit the mask to the nose. The rubber bands should fit the mask over your cheeks. Put your hands (or a plastic bag) on the mask and inhale deeply. If you can breathe effortlessly, it means there are too many leaks on the sides: the mask is bad.
When cutting the mask, you must observe 3 layers.
The middle layer, white and opaque, is "the filter". To test its electret properties, bring it close to dust grains or very small pieces of paper. If static electricity attracts them, the mask is of good quality. If not, it is bad.
To test the mechanical filtration properties of the middle layer, put it in front of a light. If in transparency you detect a regular weave pattern, the mask is bad. If you see felt fibers interweaved across all directions or a homogeneous surface, then the mask is of good quality.
The middle layer should be made of a plastic such as polythene or polypropylene, whereas a counterfeit mask will often use cheaper materials mixed with paper. Try burning the middle layer with the flame of a lighter (in a safe environment). If it burns, the mask is bad. If it curls up, the mask is good quality (made of polypropylene).
One of the layers of the mask is often hydrophobic: make a rectangle holding the edges of the mask, put it under a tap that does not run very much: if the water stays inside as in plastic, the mask is of good quality. If the water passes through or wets the mask, it is bad.
In order to obtain the medical grade label, a mask manufacturer must request that its masks be tested for bacterial filtration efficiency with a filtration efficiency of 0.1 micron particles, pressure differential which measures ease of breathing, and fluid resistance. Some manufacturers, pressed for time and not targeting medical facilities, do not require the label. It is therefore possible that the masks you have purchased are "good" masks even if they do not have the "medical device" label.
The standard that defines the characteristics of surgical masks in Europe is :Standard NF EN 14683+AC (version in French and English).
Salvi, S. S. In this pandemic and panic of COVID-19 what should doctors know about masks and respirators?
For FFP2/N95 protective respirators, the electrostatic charge can increase the efficiency of mechanical filtering by 10 to 20 times.Juang, P. S., & Tsai, P. (2020). N95 Respirator Cleaning and Reuse Methods Proposed by the Inventor of the N95 Mask Material. Journal of Emergency Medicine.
Five tips for recognizing a real surgical mask from a fake one in less than a minute of video. Gearbest.com. March 16, 2020.Video.