2014-09-16 Swanport Cafe, Chaoyang District, Beijing
The demo in Beijing was a great success on a Tuesday evening, thanks to Robin and Muren from Totobobo Beijing and the helpful staff from Swan Port Cafe. The session started off with a brief introduction of PM2.5 by Muren, he explained what PM2.5 is, and how it affects our health. Francis, the designer of Totobobo mask, shared how he came up with the idea of a customizable and reusable respirator mask out of the SARS crisis in 2003. The fit-test demo started after a short tea break.
What is “Fit-test”? Why it is important?
Fit-testing is a procedure to determine if a tight seal can be achieved when the user don a respirator mask. This is important because the quality of the seal affects the overall protection against PM2.5 and other airborne contamination. In fact, the NIOSH N95 standard requires a proper fit-test to be conducted before anyone starts using a respirator for the first time. During the fit-test, a particle counting instrument is used to accurately measure respirator fit by comparing the particle concentration in the surrounding air with the particle concentration inside the respirator. The ratio of these concentrations is called the Fit-factor (FF). For N95 mask, a minimum Fit-factor of 100 is required in order to pass the fit test.
TSI Portacount is the best fit-testing machine in the world. (US Army recently purchased 65 sets of the same TSI Portacount fit-tester http://itbriefing.net/modules.php?op=modload&name=News&file=article&sid=571559)
The working principle of the PortaCount 8083 is straight forward: there are two flexible tubes coming out of the machine, one is to draw the air and measure the concentration of particles inside the mask. The second tube is open ended and is used to measure the particle concentration in the surrounding area. The PortaCount fit-tester calculates the particle concentration inside and outside of the mask and report the ratio, or the Fit-factor, in realtime. The higher the Fit-factor, the better is the protection effect of the mask. With the Portacount machine, Francis was able to demonstrate quantitatively how the quality of the seal and the filters can have a great impact on the protection effectiveness of a respirator.
Preparing for the test
Before the fit-test, a “Daily check” on the machine was performed to assure that the ambience air quality is suitable for the test and the machine is in proper operation condition. Amongst the audience, there were members from the China Consumer Association (中国消费者协会), National labor supplies Quality Supervision and Inspection Center (Beijing) 国家劳保用品质量监督检验中心（北京), Austria Embassy, TimeOut Beijing, Aqicn.org and members of the public to monitor the entire process of the fit-test demo.
Fit test demo with PortaCount professional fit-tester
The first Fit-test of Totobobo mask was performed on Faye, a Chinese lady with a slender face shape. Francis first tested a pair of “fake filters” made of cosmetic cotton pad. The “fake filters” looks nearly the same as the original, but the resulting Fit-Factor is only 3.3 which means on a day with AQI 500, the cotton pad can ideally bring it down to 150, just not good enough. After changing into a pair of F96 filters, the Fit-factor shoot up to 150+. In AQI 500 day, ideally it can bring it down to 4-, better than the air you will get in Switzerland!
The second participant was a young girl (Guo Yao) with a fuller face. Francis first conduct the test with the same Totobobo mask without modification. The water-mark-method shown that the seal was not perfect and the initial result was relatively low (below 50). However, after Reshape the mask with a hair-dryer and after a good water-mark is obtained, the Fit-factor reported by the Portacount machine come up to 200+.
Francis also demonstrated the effect of good and poor seal, by the “water mark method”. He applied a bit of water around the nose bridge area. When the matt color mask surface touching the wet skin, it changes to transparent (water-mark).
The third participant was Barbara Grosse from the Austria Embassy. It took Francis few rounds of ReShaping the mask in order to obtain a good water-mark seal. The final Fit-factor was also in the range of 150~200+. All three ladies passed with a clear margin from the minimum requirement of 100 (for N95 mask).
Fit-test demo based on only three users is obviously not statistically sound. However, we have done this nearly a hundred times privately and this is the first time we perform the fit-test in front of a public group.
After Beijing, we went to Shanghai ArtBike to conduct another fit-test demo with their customers. We came to similar observation as in Beijing.
Some interesting facts we can draw from all the fit-tests:
1. Totobobo mask can be ReShaped to fit a wide range of face shapes.
- The same Totobobo mask was used through out the fitting on all three ladies, with significantly different face shapes and all managed to obtain high Fit-factors above 150.
- Many more fit-tests on different users shows the ReShape function can be applied to a wide range of users.
2. The “Water mark” method is reliable to help ensure face fit and protection.
- There was a strong correlation between the water-mark-method and the PortaCount results
- When the water-mark method showed the seal was not perfect, the corresponding Fit-factor dropped to below 50 and sometimes down to single digit value.
- When a clear water mark was formed around the nose bridge and the face, the corresponding Fit-factor shot up to 150+
3. Overall protection against PM2.5 require good quality filter AND a good face-mask seal
- When cosmetic cotton pad is used in place of the Totobobo filters, the Fit-factor dropped to only 3.3.
- When the water-mark shows there is a leak between the mask and the face, the Fit-factor dropped to below 50 and sometime single digit.
- The resulting Fit-factor is consistently good (150+) when Totobobo filter is used and the water mark result is positive.
Above points 1&2 are the strengths and the weaknesses of Totobobo mask, ReShape (and cutting) makes Totobobo mask the most versatile solution to fit a wide range of users, including children and adult. But ReShaping and cutting the mask is more complicated than bending a metal nose clip. With the “Water mark” fit-test method, you can be sure that when the water mark seal up your nose and mouth, the mask is giving you high level of protection. In contrary, ensuring face-seal is much more tricky for many popular masks on the market, as a detail research concluded by Tongji Medical College (Huazhong University of Science and Technology, Wuhan, China) suggested: Fitting Characteristics of N95 Filtering-Facepiece Respirators Used Widely in China . 8 out of 10 popular mask can only fit less than 10% of the 54 Chinese test subjects.
On the other hand, these two features are the limiting factors for Totobobo mask to gain certification approval. It is confirmed that the current testing protocol does not allow mask samples to be reshaped, cut, or perform a water-mark check before the fit. These may well be the reasons why Totobobo mask did not perform well in the published review of 37 masks by Chinese Consumer Association earlier this year. Obtaining the certification is an important step for marketing purposes, but for now we put our focus on the practical protection that can be measured by the professional fit-testing machine (PortaCount 8083).