In the United States and elsewhere, fabric masks are no longer a niche market. This has been both a boon and a barrier for Seattle-based Company Puraka Masks. Since March of 2020, the company has added almost a thousand customers to its filter subscription program, and sold thousands of its “Essential Masks”, based on a PM2.5 filter design regulated by Chinese standards. At the same time, the huge number of entrants into the nascent market has made it difficult for Puraka to showcase an approach its founders believe is distinguished more for its long track record of success than for its novelty.
To educate potential customers about the science behind its masks, Puraka uses articles and apps like its Face Mask Efficiency Calculator, and relies heavily on word of mouth. “A fabric mask that filters 90% of airborne particulates with minimal inhalation resistance is ideal as an everyday face covering, and is also extremely effective against smoke pollution,” the company founder says. “We’re not inventing anything new here, we’re just using what works. For example, a level 3 ASTM mask based on the ASTM F2100 standard filters less than a pm2.5 mask or N95 respirator when accounting for fit. That type of mask is just not appropriate for fine aerosols.”
When it comes to facemasks designed to help keep people safe, Seattle Company Puraka Masks isn’t trying to go back and rehash a problem that’s already been solved. The organization sends out a huge number of flat-packed PM2.5 channels to its membership clients, who embed them into cotton respirators fabricated by Puraka to a demanding administrative standard known as GB/T 32619. This standard was set up in 2006 to oversee the development of pm2.5 inserts. These are the multi-ply cotton respirators referred to conversationally as “Pollution Masks”.
Under US rules, only airtight masks and filters can formally receive N95 certification. Because PM2.5 filters are designed to be used in fitted cloth masks, they are outside the scope of verification. Material-wise, the filters are tested to the same standards as N95 masks, and they tend to get around 98% filtration, closer to N99 than N95. The filters by themselves exceed the 95% requirement by achieving 97.9% filtration. When you combine it with the type of fitted facemask that we produce, the total efficiency is around 90%. Note that it’s important to consider particle size as well. According to researchers, a mask system that filters 90% of fine aerosols is going to filter close to 100% of larger particles.
The group at Puraka got comfortable with the GB/T prerequisites in 2018, as they worked with authorized Chinese manufacturing plants to build up an automated smoke filter distribution system for the US market. At the point when COVID began crippling worldwide supply chains, the organization moved quite a bit of its assembling to the United States, where they applied the same specifications and designs. “In this specialty industry of fabric particulate respirators, China set the norm on everything from materials to fit to testing conventions,” said A Enke, a mechanical engineer and founding member who collaborated with an apparel designer in Medina Washington to implement the specifications for the team’s fabric masks.
Enke, who helped to establish Puraka Masks in 2018 after the Washington State wildfire smoke disasters of 2017 and 2018, clarifies that “PM2.5 inserts have electrostatic properties, which we presently know are required to catch fine particles and vaporized aerosols. When you combine these types of barriers with a multi-layer cotton mask which works to filter bigger particulates, you get the sort of mask that specialists are quite recently suggesting, utilizing a set of standards and specifications that have been around for over 10 years.” The framework consolidates an appropriately sized fabric mask with an electrostatic PM2.5 channel to arrive at a healthy protective solution, boosting filtration with limited breathing resistance.