In recent months, the Japanese Pitta masks have seen a surge in popularity in Chinese cities like Beijing and Shanghai, as well as in India, the US and South Korea.
They look sleek, but I wanted to review whether the Pitta masks actually work, and how effective is the Pitta Mask at filtering PM2.5, bacteria and viruses such as the flu? Data shows that Japan’s air quality is much better than China’s, so it’s possible that they were designed for things other than the tiny PM2.5 particulates that are considered most dangerous to our health. Maybe these Japanese Pitta masks are more about fashion, larger pollen particles, or sickness.
To review the Pitta masks, I first purchased a pack of 3 Pitta masks on the Pitta mask official Tmall/Taobao for 64RMB (US$9.20) — or about 21RMB or US$3 each. That makes them rather pricey compared to a 3M 9010 mask, which data has shown to be highly effective but costs just 3 RMB.
Initial Review of The Pitta Masks
When the Pitta mask first arrived, it looked and felt totally different from any of the 3M air pollution masks we had.
The Pitta mask has no filter inside and is made completely of polyurethane, the same material used to make sponges. The Pitta official store has a graphic explaining this:
Conversely, N95 masks like the 3M ones have an electrostatic filter inside.
I tested the particle capture effectiveness of the Pitta and 3M’s 9502 and 9010 masks. In these tests, I burned cigarettes in a sealed room to simulate outdoor air pollution. Using a fan, I blew air through the mask and tested the particle count of the air coming out. I tested for 0.3-micron and 2.5-micron particles as particles this size is considered the most dangerous to our body – small enough to penetrate our lungs and enter the bloodstream.
Test Results for The Pitta Masks
The results weren’t pretty.
The Pitta mask captured an astounding 0% of 0.3-micron particles and only 64% of larger 2.5-micron particles. In fact, even a surgical mask would provide more protection from PM2.5 than the Pitta mask! Meanwhile, the 3M masks captured over 90%.
Is this a fluke—maybe some sort of problem with the testing method? AQ Blue, a company that produces air pollution masks, tested the Pitta masks with different equipment and came up with nearly identical results.
In short, this data shows the Pitta mask is not effective at capturing small particles. That means it won’t do a good job filtering things like PM2.5, viruses, bacteria or fine particles.
Merits of The Pitta Masks
But the Pitta mask isn’t all bad. First off, their official store never claims that it is effective against PM2.5.
The Pitta masks claim to be 99% effective at filtering out pollen and dust particles, which range from 5-100 microns in size.
Our particle counter doesn’t report 10-micron particles, but it does report 5-micron particles. The Pitta captured 86% of 5-micron particles. For larger 10-micron particles, the Pitta will likely be even more effective, so there is a decent chance it lives up to that claim.
However, we didn’t test how well the mask sealed on people’s faces, so users should be careful.
Pollen allergies are a big deal in Japan, so the Pitta may serve those users well. The problem is many people in China use masks for air pollution, so they could easily be misled into think they’re protected with the Pitta masks.
The Pitta makers also claim that the mask’s material can be washed and reused up to 3 times which might justify the much higher cost of the mask, although they don’t provide any evidence of it. There’s a reason to be skeptical because our tests of washing HEPA filters found it actually decreased effectiveness.
Bottom line on the Pitta mask: if we review the data, we see that the Pitta masks capture large pollen particles and are stylish to boot! However, they are completely ineffective against 0.3-micron particles. That means things like PM2.5, bacteria and virus cannot be captured by the Pitta mask. Moreover, the Pitta should be considered safe to use in China, India, Thailand or any other country with high PM2.5 levels. A far more effective and affordable solution for countries with air pollution problems like China and India would be to use any of one of the high-scoring, scientifically validated masks.
Kang Wei is a chemical engineer from the National University of Singapore. He’s currently working on R&D and engineering at Smart Air.