在大家对防护口罩的争夺大战中,中国的工厂在一夜之中涌现出来,并且供应了很大数目的口罩,并且满足大家的需求。然而,对21家生产商的口罩测试显示,在市场上销售的N95口罩中,有一半未能达到N95的标准,其中一些口罩的性能甚至不及棉布制品。
口罩工厂如雨后春笋般地出现
在这场风波之中,口罩的价格久高不下。这导致华尔街日报把现在的这口罩产业现象称为,“狂野西部“。
数十家口罩制造商和供应商已与Smart Air联系,出售种类从外科口罩到获得CE认证的FFP2和N95口罩等各种产品。一些供应商甚至声称每天生产数十万个口罩。
测试中国新型口罩的性能
为了弄清楚这些口罩的性能如何,我们从4月中旬开始与供应商联系并尝试测试他们的口罩。总共,我们测试了21家供应商的31种口罩。供应商声称他们的口罩是N95或KN95,这意味着他们过滤了95%的颗粒(类似于欧洲的FFP2标准)。我们接下来发现的一切足以震惊大家。
对来自中国21家工厂N95口罩进行测试
我们使用类似于美国官方测试标准中的“微粒过滤效率”测试方法来测试口罩的过滤效率。 标准测试通常使用TSI 8130机器,价格为$ 95,000。
我们的工程团队使用三个Met One粒子计数器(每个成本约5,000美元)模拟了这种设置。 尽管不能用于正式的政府标准口罩测试,但该测试可以无限接近官方的口罩测试。
Met One粒子计数器测量N95口罩的过滤效果
我们将气流调节至85L / min以符合NIOSH测试标准,并测量了口罩捕获的0.3微米及以上颗粒的百分比(完整的测试方法及其与NIOSH标准的比较)。 我们至少测试了每个口罩的两个样品,并对每个样品重复进行了3次过滤效率测试。
结果发现大多数口罩不符合N95标准, 在测试的31个口罩中,有13个(几乎一半)未达到N95标准。
42%的口罩不符合N95规范标准
换句话说,在这个新的供应链中,购买者实际上会得到符合标准的N95口罩的概率就像是,扔出一枚硬币,之后得到正面的概率一样。
为了满足N95(美国)或KN95(中国)的要求,口罩需要捕获95%的颗粒。 然而,只有18个口罩有足够能力去捕获95%以上的微小颗粒。
而且,许多不合格的口罩不仅仅是只比合格口罩低几个百分点。 平均去计算,未通过测试的口罩仅捕获了51%的颗粒。 最差的最坏的仅捕获了24%的颗粒。 24%这个捕捉效率就跟我们之前测试DIY口罩材料里面的床单的过滤效率相似
口罩在挂耳绳,缝线,鼻带上显示出较差的质量
我们对口罩的结构质量进行了简单的测试。我们首先拉动每个口罩的挂耳绳。我们仅测试了符合N95标准的口罩上的绑带。
Smart Air的佩戴磨损测试
一些型号的表带几乎立即断裂。 18个口罩中的11个挂耳绳没有通过测试。这些口罩不可能反复持续佩戴很长时间,尤其是当一些医护人员不得不反复使用同一个口罩的情况下。
轻轻拖拉后,许多口罩的挂耳绳断裂
接下来,我们测试了口罩的贴合度。这意味着鼻梁金属和胶水经常会出现很多问题。不合格的胶水意味着某些型号口罩上的金属鼻夹很快就会脱落。在某一个口罩中,当工程师尝试配戴上时,口罩的中间竟然裂开!
这些简单的结构测试表明,即使对于符合N95过滤标准的口罩,它们的质量依旧不过关。只有7个口罩(不到四分之一)通过了N95过滤测试和这些“磨损”测试。
手机和IT工厂尝试制造N95口罩
为了进一步了解为什么有这么多口罩未能通过我们的测试,我们使用中国公司背景介绍网站对21家公司中的每家进行了背景调查。
在这21家工厂中,我们发现向我们发送口罩样品的工厂中只有9家在“健康和医疗”领域工作。其他12个行业在手机配件,运动产品,甚至软件和IT服务等行业中运作。
大多数销售口罩的公司不在医疗产业经营
奇怪的是,工厂以前的生产行业与口罩性能之间没有必要的关联。这可能是因为实际销售口罩的公司只是中间商,而不是实际生产口罩的厂家。
非医疗公司向我们寄送了更多口罩,相比医疗产业有关的工厂。非医疗公司平均给我们发送了两种口罩版本。而医疗公司则给了我们一种。这表明非医疗公司不过是代理商。
新举措可能有助于供应链的正确成长
最近的举动可能正在帮助局势。为了限制并减少市场上未经认证的口罩的数量,4月10日,中国对从中国出口的口罩的检查更加严格并且谨慎。但是这些所谓的检查是否真的有效,还有待观察。
划重点:从中国购买N95和KN95口罩
对来自中国的31个N95,KN95和FFP2口罩样品进行的测试发现,有42%的过滤效果达不到95%的过滤标准,其中许多胶水缝合位置和挂耳绳的结构与质量十分差强人意。我们建议买家在下订单之前采取积极的措施检查口罩的质量。中国“狂野西部”之下的面具可能正在危害全球的医护人员。
关于我们为何将工厂名称和口罩名称匿名化的说明:我们仅测试了少数供应商(总共21个)的口罩。这只是目前所有制造口罩的公司的一小部分。我们并没有指出特定的生产工厂,而是提供数据来帮助人们在这种大环境中确保自己的安全以及权益。有关供应商的更多信息,以及如何购买可靠口罩的小提示,请查看我们的N95口罩购买技巧。
开放数据测试:
作为Smart Air开放数据政策的一部分,这些实验的测试数据将以开原形式发布。可以从我们的补充数据文章中下载。

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.