Classification by shape
Masks are divided into three types: flat, foldable, and cup-shaped. The flat mask is easy to carry, but has poor adhesion; the folding mask is easy to carry; the cup-shaped breathing space is large, but it is not convenient to carry.
Classification by wearing method
Head-mounted: Suitable for workshop workers who wear for a long time, troublesome to wear.
On-ear style: easy to wear, suitable for frequent wearing.
Neck-wearing type: S hook, some soft material connecting parts, connecting ear straps are converted into neck-belt type, suitable for long-term wearing, and more convenient for workshop workers such as wearing hard hats or protective clothing.
Classified by material
Gauze masks: Gauze masks are still used in some workshops, but they follow the GB19084-2003 standard, which does not meet the GB2626-2019 standard, and can only protect large particles of dust.
Non-woven masks: Most disposable protective masks are non-woven masks, which are mainly based on physical filtration and electrostatic adsorption.
Cloth masks: Cloth masks only have a warming effect and have no effect of filtering very small particles such as PM.
Paper mask: suitable for food, beauty and other industries, with good air permeability, easy to use and comfortable, etc., the paper used follows GB / T22927-2008 standard.
Other material masks, such as new materials for bio-protection filtering.
Classified by scope
Medical masks: domestically divided into three categories, medical ordinary masks, medical surgical masks, medical protective masks.
Particulate Matter Protective Mask: Industrial use meets GB2626-2019 standard, special labor protection products safety mark certification (LA certification), in 2015 changed from mandatory certification to voluntary certification. If you need to use the insert type for anti-fog and haze, it must meet the GB / T32610-2016 standard. Civil use meets G B / T32610-2016 standard
Insulation masks: Insulation masks are suitable for winter wear, as long as they meet the relevant standards of fabrics.
Other special industries: such as chemical industry.
By protection level
Different countries and industries have formulated different standards, which are divided into different protection levels according to different particle filtration efficiency, which will be introduced in detail in the standard section.
other
Respiratory protective masks can be divided into filter type and isolation type, and filter type can be divided into air supply filter type and self-suction filter type, the latter can be divided into half masks and full masks; isolation type can be divided into air supply and air carrying , Both include positive pressure and negative pressure.
Technical standards for masks
China
Different types of masks follow different standards, and different masks have different scopes of application. Several major standards for Chinese masks are GB2626-2019 Breathing protective self-priming filter anti-particulate respirator, GB / T32610-2016 daily protective mask technical specifications, YY / T0969-2013 disposable medical masks, YY0469-2011 medical surgery Technical requirements for masks, GB19083-2010 medical protective masks, the main standards are described in detail below.
GB2626-2019
The first version of the standard was released in 1981 (GB2626-1981), and three updates were made in 1992, 2006, and 2019. The 2019 version was changed to "respiratory protective self-priming filter anti-particulate respirator" without "supplies" word. The GB2626-2019 version was released on 2019-12-31 and implemented on 2020-07-01. The standard specifies the classification and marking, technical requirements, detection methods and identification of self-priming filter anti-particulate respirators. This standard was proposed by the State Administration of Work Safety and is under the jurisdiction of the National Technical Committee for Standardization of Personal Protective Equipment (SAC / TC112). Relative to the 2006 version, based on the basic principles of scientificity, standardization, coordination, timeliness, etc., according to scientific progress and product development trends, adjust the respiratory resistance index and improve the detection method without reducing the protective ability , Optimize the lower vision of the half mask, and improve the comfort of the product.
This standard filter element is divided into two categories (KN and KP) according to the filtering performance. The KN category is only suitable for filtering non-oily particles, including KN90 (≥90%), KN95 (≥95%), and KN100 (≥99.97%) level. The KP type is suitable for filtering elements of oily and non-oily particles, including KP90 (≥90%), KP95 (≥95%), and KP100 (≥99.97%). The numbers after KN and KP refer to the level of filtering efficiency. The higher the number, the better the filtering effect. KN masks do not test synthetic blood penetration and surface moisture resistance. Therefore, this type of mask can block the virus for a short time, but it cannot be used to contact patients who may have splatter or contact the patient for a long time.
GB / T32610-2016
The technical specifications of daily protective masks are standards for civilian masks. This standard was proposed by the China Textile Industry Federation and is under the jurisdiction of the National Textile Standardization Technical Committee (SAC / TC209).
According to the filtration efficiency: Ⅰ, Ⅱ, Ⅲ, corresponding filtration efficiency: salty medium is ≥99%, ≥95%, ≥90%; oily medium is ≥99%, ≥95%, ≥ 80%. The protective effects of masks are classified into A, B, C, and D grades from high to low. The ambient air quality applicable to masks at all levels is severe pollution, severe and below pollution, severe and below pollution, and moderate and below pollution. Masks at all levels should reduce the inhaled particulate matter (PM) concentration to ≤75μg / m (air quality index category is good or above) under the corresponding air pollution environment. When the protective effect level of the mask is level A, the filtering efficiency should reach level Ⅱ and above; when the protective effect level of the mask is level B, C, and D, the filtering efficiency should reach level Ⅲ and above.
YY / T0969-2013
This standard is an industry standard for single-use medical masks. It was released on 2013-10-21 and implemented on 2014-10-01. Ordinary medical masks meet this standard and are suitable for general protection of medical personnel. They are only used in ordinary medical environments (see Figure 6). Ordinary medical masks have many names, and they belong to this category of medical care and disposable medical treatment. Medical masks without the words "protection" and "surgical" are ordinary medical masks. The core indicators of this level of masks include bacterial filtration efficiency and ventilation resistance. It does not require blocking effect on blood, and there is no requirement for tightness. See Table 3.
YY0469-2011
Medical Surgical Masks (YY0469-2011) is the industry standard for medical surgical masks. It was released on December 31, 2011, and implemented on 2013-06-01. The first edition of the medical surgical mask industry standard (YY0469-2004) has been replaced by the 2011 edition. Disposable masks suitable for clinical medical personnel during invasive operations (see Figure 6). They are commonly used medical masks in operating rooms and other environments where there is a risk of bodily fluids or blood splashes. The outer packaging must be clearly marked as medical surgical masks. The core indicators of this type of mask include bacterial filtration efficiency, particle filtration efficiency, synthetic blood penetration resistance, and ventilation resistance (see Table 3). There is no strict requirement for facial tightness like the standard of medical protective masks, and the filtration efficiency of bacteria ≥ 95%, the filtration efficiency of particles is limited (≥30%).
GB19083-2010
The technical requirements of GB19083-2010 medical protective masks were released on 2010-09-02, and implemented on 2011-08-01. The first version was GB19083-2003, which was formulated under the national situation of combating SARS. It was released on April 29, 2003 and Implementation, there is no medical protective mask before SARS. This standard is applicable to filtering particulate matter in the air in the medical work environment, blocking droplets, blood, body fluids, secretions, etc., including various infectious viruses (see Figure 6). The core indicators of this type of mask include particle filtration efficiency, synthetic blood penetration resistance, ventilation resistance, surface moisture resistance, good adhesion, and total fitness factor (see Table 3). Medical protective masks have a good fit with the wearer's face. According to the filtering efficiency of non-oily particles, medical protective masks are classified into 1 grade (≥95%), 2 grade (≥99%), and 3 grade (≥99.97%). Medical protective masks require that the filter's filtering efficiency for non-oily particles is ≥95%, which is in line with N95 or FFP2 and above.
The protective capabilities of medical masks in China are, in order from highest to lowest, medical protective masks, medical surgical masks, and general medical masks.

▲ Main standards and scope of Chinese masks (quoted from "Chinese Journal of Infection Control")
United States
The American NIOSH standard has classified the filter material and filtration efficiency of masks, and the standard is highly recognized worldwide. According to the filter material of the middle layer of the mask, it is divided into three types: N, R, and P series, and each of them can be divided into three levels according to the filtering efficiency (see Table 4). N is used to protect non-oily suspended particles. Generally, non-oily particles refer to coal dust, cement dust, acid mist, microorganisms, etc. The droplets produced by talking or coughing are not oily. In the haze pollution currently raging, suspended particles are mostly non-oily. Oily particulate matter refers to oil fume, oil mist, asphalt fume, etc. The oil fume produced by cooking is oily particulate matter. R and P are used to protect non-oily and oily suspended particles. Compared to the R series, the P series has a relatively long service life. The specific use time is according to the label of different manufacturers. The N95 mask is a type of mask in the N series with a filtering efficiency of ≥95%. When the wearer's face is tightly tested, ensure that air can pass in and out through the mask under the condition of the close face. Certification number. In the special period of preventing SARS, the WHO temporarily recommends medical staff to use N95 certified N95 masks. N95 masks are not equal to medical protective masks. Medical protective masks require that the filtering effect of the masks must meet the N95 requirements, and they have surface moisture resistance and blood barrier capabilities.
The ASTMF2100 standard is a medical standard that divides masks into three levels: low protection (Level1), medium protection (Level2), and high protection (Level3). The higher the level, the better the protection. Level1 and Level2 masks are usually called procedure masks; Level3 masks can be used in the operating room, also called surgical masks. When exposure to viruses is particularly high, a higher level of protection should be selected.
ASTM certification requires masks to meet relevant standards in four aspects: bacterial filtration efficiency, particle filtration efficiency, synthetic blood penetration resistance, and pressure difference. See Table 3. Level 1 can block 95% of bacterial particles, even if only low protection standards are met, it is enough to protect the general community users; Level 2 and Level 3 (medium to high protection standards) require masks to block at least 98% of bacteria and particles, and the pressure difference is only It needs to be lower than 49.0Pa / cm, and the lower protection standard is a little looser, because it is more difficult to maintain better breathability while achieving better protection. The main difference between medium and high protection standards is that the high protection (Level 3) standard has higher requirements for the ability to block liquids. Medical N95 masks need to meet both the FDA Surgical Masks-Premarket Notification Submissions Guidance for Industry and FDA Staff standards, as well as the NIOSH requirements for N95 masks. The synthetic blood penetration and surface moisture resistance have been tested, and the FDA standard is basically Follow ASTMF2100 standard.
Europe
The European Union (CE) certification standards for masks include BSEN140, BSEN14387, BSEN143, BSEN149, and BSEN136. Among them, BSEN149 is widely used as a filter-type half mask that can protect against particles. It is divided into P1 according to the tested particle penetration rate. (FFP1), P2 (FFP2), P3 (FFP3) three levels, FFP1 low filtering effect ≥80%, FFP2 low filtering effect ≥94%, FFP3 low filtering effect ≥97%. FFP2 masks are very close to the filtering efficiency of the aforementioned medical protective masks, KN95 masks, and N95 masks. Medical masks must follow the BSEN14683 standard (Medical face masks-Requirement sand test methods), which can be divided into three levels: low standard Type I, then Type II and Type IIR. See Table 3. The previous version was BSEN14683: 2014 and has been replaced by the new version BSEN14683: 2019. One of the main changes in the 2019 edition is the pressure difference. The pressure differences for Type I, Type II, and Type IIR have increased from 29.4, 29.4, and 49.0 Pa / cm in the 2014 edition to 40, 40, and 60 Pa / cm, respectively.
Australia
AS / NZS1716: 2012 is the standard for respiratory protection in Australia and New Zealand. This standard specifies the procedures and materials that must be used in the manufacture of anti-particulate masks, as well as certain test and performance results to ensure their safe use. The standard is divided into three categories, P1: low filtering effect ≥80%; P2: low filtering effect ≥94%; P3: low filtering effect ≥99%. The Australian medical mask standard is AS4381: 2015, which is divided into Level1, Level2 and Level3 according to the core indicators, see Figure 3.

▲ Figure 3: Core indicators of medical masks in China, the United States, Europe, and Australia

Cited from "Chinese Journal of Infection Control"

▲ Figure 4: Classification of particulate protective masks by the US NIOSH standard
Cited from "Chinese Journal of Infection Control"
Japan
Japan JIST8151: 2018 standard is the standard of respiratory protection device, and also the verification standard of Japan ’s Ministry of Health, Labour and Welfare (MHLW). The common discarded salty particle filtration specifications are as follows, DS1: low filtration effect ≥80%; DS2: low filtration effect ≥ 99%; DS3: Low filtering effect ≥99.9%. See Figure 7 for grades of masks.

▲ Figure 4: Japanese mask classification
Cited from "Chinese Journal of Infection Control"
Korea
Korean mask standard KF (Korean filter) series, the KF series standard is the Korean mainstream mask standards (Regulations on the Approval, Notification, and Evaluation of Quasi) issued by the Ministry of Food and Drug Safety (MFDS) -Drugs). KF series are divided into KF80, KF94, KF99. KF80: ≥80% (salinized medium only); KF94: ≥94% (oily and salty medium); KF99: ≥99% (oily and salty medium).
Mask core materials and raw materials manufacturers
Medical surgical masks are generally made of three layers of non-woven fabric, as shown in Figure 8. Material is spinning

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