Tests of masks marketed as N95 from 21 manufacturers show that half of Chinese N95 masks fail quality tests–with some masks filtering no better than a cotton cloth. These tests come at a time that many countries around the world are scrambling for masks and other PPE.
Factories Spring Up to Meet Mask Demand
Factories in China have popped up seemingly overnight to meet the demand. Amid the rush, the high prices masks are commanding have led to what The Wall Street Journal called a “wild west” for mask manufacturing.
Dozens of suppliers contacted Smart Air hawking everything from surgical masks to CE-certified FFP2 and N95 masks. Some suppliers even claimed they could make hundreds of thousands of masks a day.
Putting China’s New Masks to The Test
To find out just how well these masks are performing, we started contacting suppliers and testing their masks from the middle of April. In total, we tested 31 masks from 21 suppliers. The suppliers claimed their masks were N95 or KN95, meaning they filter 95% of particles (similar to the FFP2 standard in Europe). What we found shocked us.
We tested masks’ filtration efficiency using a method that resembled the “particulate filter efficiency” test in the official US test standard. The standard tests normally use a TSI 8130 machine that costs $95,000.
Our engineering team simulated this setup using three Met One particle counters (which cost about $5,000 each). This test provides a reasonable approximation of the official test, although it cannot be used to formally certify masks for government standards.
We adjusted the airflow to 85L/min to match the NIOSH test standard and measured the percentage of particles 0.3 microns and above the masks were capturing. In total, we tested two samples of each mask and repeated the filtration efficiency tests 3 times for each sample.
Read more: How we tested masks and how it compares to NIOSH standards.
Most Chinese N95 Masks Fail Quality Tests
Out of the 31 masks tested, 13 Chinese N95 masks fail quality standards for filtration.
In other words, buying N95 masks in this new supply chain has odds of flipping a coin that buyers will actually get an N95 mask. To meet the N95 (US) or KN95 (China) requirement, masks need to capture 95% of particles. Yet only 18 masks managed to capture more than 95% of tiny particles.
Read more: Here’s exactly what the difference is between N95 and KN95 masks is.
What’s more, many of these failing masks were not just a few percentage points below the standard. On average, the masks that failed the tests captured just 51% of particles. The worst of the worst captured just 24% of particles, which is on par with the filtration ability of a bed sheet.
Masks Show Poor Quality in Straps, Stitching, Noseband
Next, we ran simple tests of the structural quality of the masks. These tests focused only on the masks that met the N95 standard. To start, we pulled the straps of each mask.
Straps on some models broke almost immediately. Straps failed on 11 out of 18 masks. Consequently, these masks are unlikely to last long, especially under conditions where healthcare workers are having to re-use masks.
Next, we tested the masks for fit. This revealed a common issue with the nose pieces and glue. Sub-standard glue meant that metal nose clips on some models came off quickly. In one model, the mask split open in the middle while the engineer was putting it on.
Why this matters: Longevity tests show masks remain effective after 30 days of use.
Only 7 masks – less than one-quarter – passed both the N95 filtration tests and these “wear and tear” tests. Thus, even masks that meet the N95 filtration standard may still prove useless.
New N95 Masks Made in Mobile Phone and IT Factories
To try to understand why so many masks were failing our tests, we did a background check on each of the 21 companies using a company directory for China.
Out of the 21 factories, we found that only 9 of the factories that sent us mask samples worked in the “health and medical” sectors. The other 12 operate in sectors such as mobile phone accessories, sports products, and even software & IT services.
Oddly enough, there was no correlation between factory sector and mask performance. This could be because the companies actually selling masks are just middle men and not actually producing the masks.
Non-medical companies sent us an average of two mask designs versus one for medical companies. Thus, the non-medical companies appear to be merely re-sellers.
New Moves May Help Clean Up Supply Chain
Recent moves may be helping the situation. In an attempt to limit the number of uncertified masks on the market, on April 10th, China tightened the checks on masks leaving the country. It remains to be seen whether these checks will prove useful.
Bottom Line: Buying N95 and KN95 Masks from China
Tests of 31 N95, KN95, and FFP2 mask samples show that Chinese N95 masks fail quality checks for filtration on 42% of samples, with many showing shoddy structural work in the glue and straps. Therefore, we recommend buyers take proactive steps to check the quality of the masks before placing orders. The masks in China’s “wild west” could be endangering healthcare workers around the world.
Why we anonymized factory names: Because we tested masks from only a small handful of suppliers (21 in total), this data represents a fraction of all the companies making masks right now. Therefore, we didn’t set out to name and blame specific factories. Instead, we provide this data as a snapshot of the industry. For more information on the suppliers and tips on how to source reliable masks, check out our tips for sourcing N95 masks article.
Open Data
As always, data at Smart Air is open source. Data and more details on the methodology are in the supplemental data article.
WHAT NEXT?
Along with wearing masks, air purifiers with HEPA filters are also one of the best ways to stay safe from a variety of pollutants in our air including viruses and dangerous PM2.5. A recent CDC study confirmed significantly lower COVID-19 infection rates in schools that used HEPA air purifiers. HEPA filters can significantly lower the risk of a variety of deadly diseases including diabetes, heart disease, cancer, and high blood pressure.

Read More: Four Steps to Choosing the Best Air Purifier
Smart Air is a certified B Corp committed to combating the myths big companies use to inflate the price of clean air.

Experience breathing truly clean air with gimmick-free, effective air purifiers that won’t break the bank. Join the clean air movement.

Currently using two brands of ASTM level 3 masks, one 3-layer, one 4-layer. Both are made in China. (1) Have you tested such masks for performance & if so, how did they do? (2) What US fabricators are producing these masks?
Why NOT list the factories that failed? if you state its an “unofficial” test anyway… ..you may save peoples LIVES!!! Please list the factory names and let the consumers decide if they wish to buy/use from that factory!! Lives are on the line! Seriously!
Hi Fred! Song here.
We are willing to provide the list on a case by case basis if you want the specific names. Please contact [email protected]
Guess you do not understand what a baseline is for. By using an actual N95 NIOSH mask like from 3M you validate your testing methodology.
What US Made certified N95 masks did you use for your baseline to make sure your test was properly calibrated
Hi Donald. Song here.
We didn’t use any mask as our baseline. We tested their filtration ability as N95 masks are supposed to filter 95% of particles.
While this research is invaluable, it would important to know which masks not to wear. Please do so!
Can i share this on the social media?
Aslo could you tell how do you put your testing sample on the devcie? The testing section seems closed.
Hi Max. Song here. Feel free to share these information as long as for non-commercial purpose with attribution. This is what we meant to be. As for testing methods, please check here: https://smartairfilters.com/en/blog/testing-china-kn95-n95-masks-supplemental-data/
Hi, bought a 3M Half facepiece respirator from China, its marked as GB2626-2006 and the Particulate filters are marked as NIOSH approved N95. This is for non medical use only, DIY, Spray jobs etc, does this conform to UK standards and is it Ok to use?
Hi Stewart, Liz here. Here is an article on the differences among mask grades: https://smartairfilters.com/en/blog/comparison-mask-standards-rating-effectiveness/
Short answer to your question would be yes, an N95 mask should give you good protection against Covid. If you have a pre existed pulmonary condition, ask your doctor if you can wear a N95 mask. Stay safe!
Thank you Liz, appreciate the answer. As stated I don’t have a medical condition, the mask is just for DIY dusty jobs etc.
Many Thanks
Stewart
GB2626-2006 is out of date. It should be marked GB2626-2019. If you have further questions have a lok at the above document on P2 respiratory protection.
https://www.fda.gov/medical-devices/coronavirus-disease-2019-covid-19-emergency-use-authorizations-medical-devices/personal-protective-equipment-euas#appendixa
https://www.cdc.gov/niosh/npptl/usernotices/counterfeitResp.html
This link is no longer working: https://www.tianyancha.com
Is there another way to check on the company in China that is making the masks? Any updates on whether China’s tightened checks on the mask is working to remove all faulty N95/KN95 masks? Was there some sort of stamping/approval of which ones meet China’s tightened checks?
You’re right, it’s a pain! That website doesn’t seem to work outside of China. Here’s the link to a website that does: https://www.qcc.com/
Paddy, You seem credible. Problem is that after reading your article there is more fear as we have no way of knowing who in the hell made masks that are from China. We also have had major issues with Chinese food products.
I think you should source and test the masks yourself and sell them or at least lot test a source that you trust and “approve” them…..kind of like a Rabbi certifying Kosher food.
Besides being very resentful of China’s antics with the virus and hoarding I have also used KN95s where the strap fell off! There are so many vendors and the prices are high.
You are there on the ground and know how corners are cut in China and can discern shady producers from quality producers.
We need a recommendation.
thanks for performing this testing and sharing the results!
Hi Paddy, do you or anyone else you know offer testing services for N95 masks?
Thank you
Hi Latha! We do have testing services for N95 masks, however they can’t be used as official government certifications. I’ve heard that the companies which can offer N95 certifcation have a backlog of several months’ worth of orders.
More info on our testing service can be found here: https://smartairfilters.com/cn/en/product/mask-effieicncy-test-certification/
Other than that, you could try getting hold of a particle counter similar to the Met One and perform tests using the test setup in our supplemental data.