What are medical face masks? No matter common blue/green ones or fancy printed ones, medical face masks have been proven effective in reducing the spread of Covid-19. Now the advent of vaccines has brought the disease outbreak under control, but wearing masks has become a daily habit (at least in Asia). When face masks have become day-to-day necessary commodity, the supply has gradually exceeded the demand with the increase in production of various brand manufacturers, and consumers have also changed their attitudes from just wanting to have it to carefully comparing its efficiency, appearance, and comfort before purchasing.

This article will first introduce the structure of medical face masks, and then integrate the information of various medical mask styles currently available on the market. The purpose is to compare and analyze their differences, advantages, disadvantages, and wearing experience, and provide all the useful information for those who have difficulties in choosing the best medical masks.

Note: Masks without filtration effects (such as: general cotton/gauze masks, activated carbon masks) are not included in the content of this article, because they can only prevent dust or air pollution particles, and do not belong to the category of medical masks.

Structure of Medical Face Mask

Generally, medical mask is composed of three layers of nonwoven fabrics as listed below.

1. Outer layer of face mask (Surface)

The first layer of the mask is mostly using polypropylene spunbond (PPSB) nonwovens. The material is water-repellent and can block larger particles like droplets and dust (Surgical mask level can block blood splash).

2. Middle layer of mask (Melt-Blown)

Middle layer is the main filtering layer of the mask, so it needs to use high-density melt-blown non-woven fabric to achieve the filtration effect. Polypropylene (PP Melt-blown, also called MB or PPMB) is the commonest material for melt-blown fabrics. Using “electrostatic electret technology” in the melt-blown process can make the fabric generate static electricity and make the middle layer of face mask have electrostatic adsorption function, which can filter bacterial particles and pollutants.

3. Inner layer of face mask (Skin Friendly)
Because people have to wear face masks all day during COVID-19 pandemic and the inner layer of face mask will be in contact with our facial skin for a long period of time, it is better to use a material that is soft and not hairy. Some mask manufacturers use polypropylene spunbond (PPSB) nonwoven fabrics, same material as the outer layer, to be the inner layer of face mask in order to reduce the cost, but PPSB is hairy and will make face itchy and irritated. Also, hydrophilic treatment on the inner layer is also not good for allergy-prone skin. Therefore, ES composite fibers (Ethylene-Propylene Side By Side) spunbond non-woven fabric are more commonly used in Taiwan as inner layer material of masks now.

Extra layer of face mask–Activated carbon (Only in 4-Ply face mask)

There are also “4-ply” masks on the market. In addition to the above-mentioned three-layer structure, an activated carbon layer is added between the surface layer and the filter layer(Melt-blown), which is the so-called the fourth layer. Although the activated carbon layer and the filter layer are also located in the middle layer of the mask, the activated carbon layer does not have the function of filtering bacteria or dust, and its main functions are deodorization and adsorption of organic gases. The price of the 4-ply activated carbon mask is relatively high, but the filtration effect is not better than 3-ply medical face masks. Also, under the same conditions, its breathing resistance will be higher than that of the 3-ply mask, so 3-ply mask is still the main commodity on the market.

Note: Regarding the types of non-woven fabrics used in the 3-ply medical face masks, and the selection of non-woven fabric materials suitable for different printing methods of the mask pattern, we have a separate column providing you a professional advice. Welcome to the following article for reference and advice!

What are the types of non-woven fabrics for face masks? Difference between 5 types of non-woven fabrics and 11 types of mask raw materials!
https://www.illumeinternational.com/en/non-woven-fabrics-for-face-masks/

Style of Medical Face Mask

After introducing the structure of medical face masks, you should be very clear about the function of each layer of the mask. Next, we will analyze various styles and special features of medical masks on the market, such as wearing comfort, suitability for low or high-risk environment and other considerations, and then provide some advice for you when purchasing masks.

<Flat Face Mask>

Flat 3-ply face masks are the cheapest and most commonly seen style on the market. You can buy them from pharmacies, supermarkets, or even grocery stores. The following is a complete introduction to the styles of flat face masks.

1.「3-Fold mask」v.s.「4-Fold mask」

According to the design of face mask machine, there are two types of masks, “three-fold”(3-fold) and “four-fold”(4-fold). A special reminder here is, do not confuse the “4-fold” mask and the “4-layer” (4-ply) activated carbon mask! What is introduced here is only the appearance – “fold” of the mask. In terms of structure, there are still only 3-layers of non-woven fabric. No matter whether it is folded in three or four, it will not affect its filtration effect. However, 4-fold mask is far better than 3-fold one in terms of wearing comfort. The reason is that after the mask is opened and worn, 4-fold mask will form larger three-dimensional breathing space, and it will not press the nose and mouth, and does not move up and down with the mouth when speaking. However, there are relatively few machines for making 4-fold mask on the market, so the most common one is still 3-fold medical masks.

< Flat Face Mask – 3-Fold >

< Flat Face Mask – 4-Fold >

2. 「Normal Wrapping」 v.s. 「Reverse Wrapping」 & 「With Strips」

v.s. 「Without Strips」

The more supply of masks on the market, the more requirements of the customers are raised. Besides filtration effect, being fashionable and beautiful is also important. That’s why there are so many kinds of customized and colorful masks on the market. In order to print delicate patterns on the outer layer of the mask, manufacturers have begun to seek for raw material which can be dyed or printed easily. To make the pattern fully presented, manufacturers have also tried to adjust the wrapping style of the four sides of the mask:

Normal Wrapping:

The inner layer of the mask (usually white) is folded outward to cover the outer layer, so you’ll see the upper and lower edges of the mask are white. The disadvantage is that the patterns shown on the upper and lower sides of the outer layer would be covered by the wrapping.
Reverse Wrapping:

The outer layer of the mask is folded inward to cover the inner layer, which can keep the mask pattern from being covered in appearance. The disadvantage is that there are two edges on the upper and lower sides of the inner layer, which may make your face itch.

< Flat Face Mask – Normal Wrapping >

< Flat Face Mask – Reverse Wrapping >

With Strips:

The left and right sides of the mask are covered with strips (usually white PPSB). The strips can cover the rough welding points of earloops and avoid itching your face. In order to protect child’s delicate face, children’s masks are often wrapped with the strips.
Without Strips:

There are no additional strips covering the left and right sides of the mask, which can maintain the completeness of the appearance and pattern of the mask. The disadvantage is that the two edges may be easy to itch the skin, and the welding points of earloops are also easy to break.

< Flat Face Mask – With Strips >

< Flat Face Mask – Without Strips >

3. Mask with Ties (Tie-on mask)

Mask with ties is commonly used in operation room, and are mainly worn by physicians and nursing staff when performing operations or caring for patients. The advantage is that wearers can adjust the tightness according to the their head shape and size, so it can avoid ear pain after wearing it for a long time. It is more suitable for those who need to stay in a high-risk environment all day, such as operation room. Because it’s not easy to wear tie-on masks, most consumers would still prefer flat masks with earloops.

< Mask with Ties >

Note: There are quite a variety of earloops for masks. You can choose the most comfortable style according to your needs. We have a more detailed introduction and analysis of the types, materials and comfort of earloops. Welcome to the following articles to continue in-depth discussion~

Which types of facemask earloop are most comfortable? 5 key points that affect the comfort of mask earloops! A good earloop will make your ears no longer hurt!
https://www.illumeinternational.com/en/types-of-facemask-earloop/

< Three-Dimensional Mask – 3D Mask >

After Omicron was confirmed and found to be highly infectious, the public began to feel anxious about the protection of flat masks. As the protection of medical masks mainly comes from two aspects: one is the filtration efficiency of the mask, and the other is whether the mask fits your face. Because the left and right sides of flat mask cannot completely fit the face, this gap may make people worry that the protection is not comprehensive. However, N95 masks that fit closely to the face are less comfortable and are not suitable for long-time use, and also they are generally reserved for front-line medical staff. Therefore, three-dimensional masks (3D masks) will be a better choice for the public. That’s why there are more and more 3D masks launched on the market. The following are some 3D mask styles that are available in retail channels.

Note: About N95 masks, there is a more detailed discussion in the next paragraph: <N95> !

1. Traditional 3D mask

Traditional 3D masks include earloops style and all-in-one style (the mask body and earloops are cut from the same non-woven fabric). Generally, 3D masks with earloops are usually small, and it may cause ear pain after wearing for a long time. The all-in-one 3D mask can fit the face better and does not need to worry about breaking the earloops, but it is not suitable for consumers who wear glasses. Due to the design, 3D mask can fit the facial curve of most people, so the advantage is that the pressure caused by the nose wire is reduced, and the space inside the mask is larger, which improves the breathing and wearing comfort. However, when purchasing a 3D mask, you must find a size that really suits your face shape as it’s usually made one size for all, unlike flat mask which can be extended to cover the whole face and chin. If you fail to choose a 3D mask that matches your face shape, the mask is easy to move while speaking, which would cause the risk of infection.

< Traditional 3D mask >

2.2 4D mask

This style of mask is also known as ”Fish mouth mask or KF94 mask” which is originated from South Korea. Under the blessing of the cultural prosperity of the Korean entertainment industry, the Korean food, clothing and products their stars eat, wear and use always form strong cultural output very quickly, and masks are of course no exception. Due to the exposure effect of wearing by many star entertainers on IG, the inquiries of the Korean version of 4D masks have risen with the tide, and the patterns of the masks has become more and more fancy and fashionable. This also makes 4D/KF94 masks become the first choice for those who treat masks as part of their outfit. In addition to fashion factors, 4D masks do have their practical advantages. For example, the special fish mouth style increases the breathing space of the mask, which improves comfort of wearing. Also, your make-up like lipsticks and foundation won’t be rubbed off. The disadvantage is that the output of 4D masks is comparatively low, and the unit price is 5-10 times more expensive than that of flat mask.

<4D mask >

<N95 Mask>

Recall that in the beginning of the pandemic, in order to keep ourselves more assured, everyone began hoarding N95 masks instead of flat masks, which made the supply of N95 masks insufficient. So at that time the government always urged the public not to overstock N95 masks and reserve them for medical staff. Yes, N95 should be given priority to frontline healthcare workers due to its high breathing resistance, and compared with flat masks, the production and supply of N95 are indeed less no matter from local or from imported. Previously, due to the insufficient supply of N95, the United States has opened its market for foreign-made masks and respirators through the Emergency Use Authorization (EUA) application during the emergency period of the pandemic. After the peak of the pandemic, the supply of anti-epidemic materials have gradually stabilized, so consumers can easily buy N95 in the market now. The Centers for Disease Control and Prevention (CDC) has also updated its mask guidelines (2022), which suggest that the public choosing N95/KN95 for pandemic protection purposes without worrying about the shortage of masks. N95 refers to a protective mask that has passed the NIOSH certification in the United States, which can filter non-oily particles and has a minimum filtration efficiency of 95%. The following three different styles of N95 masks that meet this specification are introduced, with their characteristics and functions for comparisons.

1. Bowl-Shaped N95

This model is the original and the most common model of the N95 series. It is often used in the environments with severe air pollution or dust, such as mining, construction, or paint industry. During the epidemics, such as the Severe Acute Respiratory Syndrome (SARS) epidemic in 2003, front-line healthcare workers in medical facilities were at high risk of infection. In order to prevent Covid-19, N95 masks have become a necessary means of protection for healthcare workers because it completely fits the face. Even if N95 masks would leave bruises and cause skin irritation on the face after countless hours of wearing, it is still the most important anti-epidemic equipment.

Compared with disposable flat masks, N95 can actually be reused if it is not used in a high-risk medical environment. But we still recommend to replace it regularly, and do not try to washing or cleaning the masks, as the filtering efficiency may be reduced.

In addition, although bowl-shaped N95 mask is tighter than flat mask, sometimes it’s too big and can’t fit the face shape of wearers. Wearers have to fasten the masks tightly by rubber ear straps, so the comfort of wearing is not as good as flat masks. Therefore, it is not recommended for people with beards or with breathing difficulties and children who can not wear masks for a long time.

< Bowl-Shaped N95 >

2. < Duckbill N95 >

Compared with the traditional bowl-shaped N95 mask, the duckbill N95 mask has more exhalation space in the front end of the mask, and the resistance is smaller. The problem of bowl-shaped N95 (easily leaving bruises on the face) is also improved, which is more suitable for medical personnel who need to wear the mask for a long time. The edge of the bowl-shaped N95 mask is hard, which is not easy to fit completely with the curve of the human face. So in order to fit the face completely, the ear straps need to be tightened. The duckbill N95, on the other hand, has a softer edge which can fit the face more closely without tightening the ear straps. The duckbill N95 not only ensures the tightness, but also maintains the comfort when wearing it all day long.

< Duckbill N95 >

3. < N95 With Air Valve >

N95 respirator with air valve is mainly used to improve the wearer’s comfort by reducing the wearer’s expiratory resistance. The exhalation valve on the mask is closed when the wearer inhales, and the air inhaled from the outside will still be filtered through the filter material in the mask before entering the mask, so the protection efficiency is no different from that of the mask without the exhalation valve. But when the wearer exhales, the exhaled air will be directly discharged through the exhalation valve, which reduces the resistance of exhalation and keeps the inside of the mask dry and cool. Therefore, it is more comfortable to wear N95 with air valve. At the same time, the internal pressure of the mask is greater than external, so the unfiltered air from the outside will not enter into the mask through the exhalation valve.

Will my N95 respirator with exhalation valve protect both me and others? Some people have concerns about wearing N95 respirators with air valve because the valves are not covered. However, CDC’s answer is “Yes” as “a NIOSH-approved N95 filtering face piece respirator with an exhalation valve offers the same protection to the wearer as one that does not have a valve”. Even if the N95 has an exhalation valve, “findings from NIOSH research suggest that it still provides the same or better source control than surgical masks, procedure masks, cloth masks or fabric coverings even without covering the valves.” Although “an N95 respirator with a valve may not provide the same level of source control as an N95 without a valve”, people should not be asked to use one without an exhalation valve or cover the valve. Note that N95 respirators with air valve is not recommended to use in operation room or the situations where a fluid resistant respirator is indicated because it’s not fluid resistant. It’s better to wear a surgical N95 without valve or cover the valve by a surgical mask or a face shield (don’t compromise the fit of the respirator).