With the outbreak of the 2019 novel coronavirus, interest has surged in Japanese Pitta masks. Smart Air has received a flood of questions about how well they filter the coronavirus and other viruses.
The Japanese Pitta masks are sleek and incredibly popular, but there’s little information available on how well they filter out tiny virus-sized particles.
How Big Are Coronavirus Particles?
The 2019 Novel Coronavirus, or 2019 nCoV, is a new respiratory virus first identified in Wuhan in China’s Hubei Province. Scientists have already taken electron microscope images to measure the size of coronavirus “virions” (or particles). The virions are spherical particles with diameters of approximately 125 nm (0.125 microns). The smallest particles are 0.06 microns, and the largest are 0.14 microns.
That makes the coronavirus particles smaller than PM2.5 particles, but bigger than some dust particles and gases.
How Well Can Japanese Pitta Masks Capture Virus-sized Particles
To test how well the Pitta masks can capture tiny particles, Smart Air engineer Kang Wei purchased a pack of Pitta masks and tested them against 3M N95 masks.
To measure particles, we used a Met One 531, which measures particles as small as 0.3 microns. That’s about 3 times bigger than the coronavirus. Research shows that particles 0.3 microns in diameter are the hardest to capture. So if a mask does a good job at capturing particles 0.3 microns in diameter, then we can be confident it can also capture smaller, 0.1 micron particles.
Pitta Mask Effectiveness
We compared the Japanese Pitta mask with two other 3M 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. Maybe the result is a fluke? Separate tests from AQ Blue found similar results.
This result strongly suggests that the Pitta mask does a very poor job of capturing 0.1 micron particles, like the coronavirus particles. Meanwhile, the 3M masks captured over 90% of 0.3 micron particles.
In fact, data shows even a surgical mask would provide more protection from the coronavirus than the Pitta mask. Tests from researchers at the University of Massachussets found that a surgical mask they bought on the streets of Nepal captured over 60% of 0.1 micron particles. A 3M N95 mask captured over 80%.
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.
Does Pitta Claim It Filters Viruses?
But the Pitta mask isn’t all bad. First off, their official store never claims that it is effective against PM2.5 or smaller particles for that matter.
The Pitta masks claim to be 99% effective at filtering out pollen and dust particles, which range from 5-100 microns in size. The Pitta mask might be great at capturing pollen, but for viruses such as the coronavirus and flu, the Pitta mask doesn’t cut it.
Bottom line: Pitta masks can capture large pollen particles and are stylish to boot! However, they are completely ineffective against 0.3-micron particles.
This means they do a very poor job of capturing the coronavirus or any other virus for that matter. A far more effective and affordable solution to filter out viruses such as the coronavirus would be to use any of one of the high-scoring, scientifically validated masks.
Paddy graduated in aeronautical engineering from Bristol University, and now runs Smart Air’s operations from Beijing. He’s an advocate for open data, free information and transparent business.