What are N95 masks?

A standard N95 respirator is a tight-fitting respiratory protective face mask, designed to help reduce the user’s exposure to airborne particles including very small particles (0.3 microns) and large droplets. N95 respirator face mask literally has a filtration efficiency of at least 95% against non-oily particles.

What’s the difference between N95, KN95, FFP2 and KF94 mask rating?

The N95 mask has a full name of NIOSH-approved N95 respirator, which means these respirators are tested of 95% filtration and certified by the U.S. National Institute of Occupational Safety and Health (NIOSH). And the KN95, FFP2 and KF94 mask is as effective as NIOSH-certified N95 mask with the same filtration efficiency, but are tested by different nation criteria. The KN95 respirator is a particulate-filtering mask tested using the China criteria. The FFP2 is a filtering facepiece score of 94% filter capacity approved by Europe, and the KF94 is tested by Korea criteria.
To simply put, we could put these respirators into an equation as below:
N100 (99.97%) = FFP3 (99.95%) > N95 (95%) = KN95 (95%) = FFP2 (94%) = KF94 (94%) > KN90 (90%).
According to a study by respirator company 3M,all these respirators offer nearly the same level of protection.

Certification	N95	FFP2	KN95	KF94(Korea 1st Class)
Filter performance	≥ 95%	≥ 94%	≥ 95%	≥ 94%
Test agent	NaCl	NaCl and paraffin oil	NaCl	NaCl and paraffin oil
Flow rate	85 L/min	95 L/min	85 L/min	95 L/min
Total inward leakage (TIL)	N/A	≤ 8% leakage	≤ 8% leakage	≤ 8% leakage
Inhalation resistance	≤ 343 Pa	≤ 70 Pa (at 30 L/min) ≤ 240 Pa (at 95 L/min) ≤ 500 Pa (clogging)	≤ 350 Pa	≤ 70 Pa (at 30 L/min) ≤ 240 Pa (at 95 L/min)
Flow rate	85 L/min	Varied – see above	85 L/min	Varied – see above
Exhalation resistance	≤ 245 Pa	≤ 300 Pa	≤ 250 Pa	≤ 300 Pa
Flow rate	85 L/min	160 L/min	85 L/min	160 L/min
Exhalation valve leakage requirement	Leak rate ≤ 30 mL/min	N/A	Depressurizatio n to 0 Pa ≥ 20 sec	visual inspection after 300 L /min for 30 sec
Force applied	-245 Pa	N/A	-1180 Pa	N/A
CO2 clearance requirement	N/A	≤ 1%	≤ 1%	≤ 1%

Based on this comparison, it is reasonable to consider KN95(China GB2626-2006), KF94 (Korea KMOEL - 2017-64) as “equivalent” to N95 (United States NIOSH-42CFR84) and FFP2 (Europe EN 149-2001) respirators, for filtering non-oil-based particles such as those resulting from wildfires, PM 2.5 air pollution, volcanic eruptions, or bioaerosols (e.g. viruses). Therefore, if N95 masks or FFP2 masks are out of stock, you could buy KN95 or KF94 masks instead.

What is the N95 mask used for?

A standard N95 mask, designed as an air-purifying facepiece respirator (particulate filtering dust mask), is mainly intended for use by healthcare professionals who work in the frontline of widespread outbreaks of infectious respiratory diseases like influenza and coronavirus, to reduce their risks of exposure to the infectious illness. 

What’s the difference between a surgical N95 mask and a standard N95 filtering mask?

A surgical N95 mask is literally a combination of standard N95 particulate respirator and a disposable surgical mask. Different from standard N95 filtering respirators, N95 surgical masks include a static-electricity melt-blown filter layer, which makes the N95 surgical masks fluid-resistant to stop the viruses on the mask surface from entering the mask.

How to know if a surgical N95 respirator is real or fake?

Firstly, check the package or the printing on the N95 mask if there is a mark of surgical or medical. Secondly, cut open the N95 mask to check if there is a melt-blown filter layer. 3 steps help you to identify a melt-blown layer: ① The melt-blown layer looks very different from the other two transparent non-woven layers, it looks more like a white paper.
② Different from a paper, the melt-blown layer of very low flammability melts in case of fire but does not flame. Instead, paper burns when it comes to fire. 
③ There is the static electricity in the effective melt-blown layer. If you tear the melt-blown layer into strips, you will feel the electrostatic adsorption effect, and you can also adsorb the melt-blown layer on stainless steel.

What’s different between N95 masks with a valve and without a valve?

Literally, a venting valve would not make the N95 mask better or worse in filtering viruses, but help the wearer breathe in and out easier. As a tight-fitting protective facepiece, the N95 mask without valve is not recommended to use by those who are suffered from CVD or difficult breathing. The N95 mask with an exhalation valve is recommended for people who wear glasses to avoid warm breath rise from the mask to fog the glasses. Please bear in mind, the valved N95 mask shouldn’t be used by an infected person, because the one-way venting valve couldn’t keep the wearer’s illness to himself.  Besides, the N95 mask with a breathable valve is pricier than the one without a valve. 

What is N95 mask fit testing?

An N95 mask fit testing mainly tests the secure fit between the respirator’s facepiece and your face. It’s originally a basic requirement for any worker who needs to use a tight-fitting respirator. Not everyone can get a good fit with one specific respirator, however, the respirator can’t protect you if it doesn’t fit your face. So before you wear a tight-fitting N95 respirator, you must be fit tested to make sure that the respirator fits you without difficult breath and leakage.

How to perform a respirator fit testing?

A fit test should only be conducted if there is:
- No hair growth (beards)
- No apparel
- No jewelry
- Any other condition or object that may compromise the fit or prevent contact of the respirator with the skin.
1. Prepare the qualitative fit test apparatus:
①Attach the hood to the collar by placing the drawstring between the flanges on the collar.
②Tighten the drawstrings and tie it with a square knot or bow.
③Pour approximately 1 teaspoonful or 5ml, of the sensitivity solution into the nebulizer labeled “Sensitivity Test Solution”.
④Pour the same amount of fit test solution into the second nebulizer labeled “Fit Test Solution”.
Sensitivity Test Purpose: To assure the subject can taste a dilute version of the Sensitivity Test Solution.
⑤Avoid eating, smoking, drinking or chewing gum for at least 15 minutes before the test and during the test at all times. This does not include water.
⑥Instruct the test subject to place the hood and collar assembly over their head without a respirator.
⑦Position the hood assembly forward so there is about six inches, or 15 centimeters, between the subject’s face and the hood window.
⑧Instruct the test subject to breathe normally through their mouth with their tongue slightly extended. Both plugs on the nebulizer must be removed during use.
2. Tips for Qualitative Fit Test
The respirator to be tested shall be worn for at least 5 minutes before the start of the fit testing.
The nebulizer must be held in an upright position to ensure the aerosol generation.
3. Simple Steps for Fit Testing:
- 60 seconds each
- half the number of original squeezes every 30 seconds.
1. Normal breathing - continue for 60 seconds
2. Deep breathing - continue for 60 seconds
3. Turning head side to side - repeat for 60 seconds
4. Moving head up and down - one nod per second for 60 seconds
5. Talking - for 60 seconds
6. Bending at the waist (repeatedly) - for 60 seconds
7. Normal breathing - for 60 seconds
The fit testing must be completed successfully before a health care worker can be allowed to wear a respirator.

How to clean and reuse the N95 mask?

During a shortage of face masks, knowing how to safely clean and reuse an N95 respirator will help you save more. Besides, keeping your N95 mask clean and well maintained will help ensure better protection as well as extend the lifespan of your respirators. 
How to clean the N95 mask?
1. Store your used N95 in a dry and well-ventilated area (avoid to touch the surface of the respirator) after going out (when if you didn’t go to the crowded places) 
2. Disinfect your used N95 mask by 30-minute oven-dry heat at 70 degrees Celsius or sterilize the face mask with the ultraviolet sterilization for 30 seconds.
Please do not clean the respirator masks with steam air, hot water, alcohols, disinfectants, or detergents of any kind as they will damage the integrity and reduce the filtration efficiency of the N95 masks.
How to reuse the N95 mask?
If the inside of the respirator mask is clean, not visibly damaged and breathing has not become more difficult, you can continue to wear the masks.
1. Clean hands with soap water or an alcohol-based hand sanitizer before and after touching the respirator;
2. Use a pair of clean gloves when putting on or adjusting a used N95 respirator. Discard the gloves after finished and ensuring the respirator is fitting securely and comfortably on your face.

What is an N95 mask made of?  

An effective surgical mask for virus protection is at least 3-ply, made of SMS material. SMS material is basically referred to as Spunbond (outer Polypropylene hydrophobic non-woven layer), Melt-blown (middle Polypropylene filter layer), Spunbond (inner Polypropylene soft absorbent non-woven fabric). 

An N95 mask is generally made of needle-punched cotton, melt-blown cloth, and non-woven fabric. The melt-blown cloth usually weighs 40 grams or more, coupled with the thickness of needle cotton, the N95 mask looks thicker than an ordinary flat mask in appearance, and its filtration efficiency can reach up to 95%. A surgical N95 mask is composed of 5-ply SMMMS material, and a standard N95 particulate respirator is at least 3-ply but the filter layer is not made of melt-blown cloth.

How to make N95 masks at home?

1. Prepare the melt-blown non-woven cloth as one to three middle filter layers.
2. Prepare the needle punch cotton as the outer layer.
3. Prepare the ES (Ethylene-Propylene Side By Side) non-woven fabric or medical gauze as the inner layer for soft contact to the skin.
4. Prepare some plastic surgery nose splints to get a secure fit if possible.
5. Prepare the ear loops or headband drawstrings.
6. Layer all the fabrics, stick the nose splint on the top of layers and sew them together.
7. Sew the ear loops or headbands on the sides of N95 masks.