ASTM Level 3 Surgical Mask

When it comes to protective facemasks, Seattle-based Puraka Masks isn’t reinventing the wheel. Every month, the company mails out tens of thousands of vacuum-packed PM2.5 filters to its subscription customers, who insert them into cotton masks manufactured by Puraka to an exacting regulatory standard known as GB/T 32619. This standard was established in 2006 to regulate a type of pm 2.5 mask designed for particulate reduction. These are the cloth masks known colloquially as “Pollution Masks”. Versus an ASTM Level 3 Surgical Mask, PM 2.5 masks achieve better fitted protection, with filtration comparable to KN95 masks and only a few percentage points less than an N95.

The system combines a form fitting cloth mask with a specially formulated PM2.5 filter to achieve a “best of both worlds” approach, maximizing filtration while minimizing inhalation resistance. The growing body of mask-related research helps to explain why the combination is so effective. Mr. Ansel, who co-founded Puraka Masks in 2018 after the West Coast wildfires, explains that “PM2.5 filters have electrostatic properties, which we now know are crucial to trapping fine particles and aerosols. When you combine them with a cotton mask which excels at filtering larger particulates, you get the kind of hybrid mask that experts are just now recommending, using a set of specifications that have been around for more than a decade.”

The team at Puraka became familiar with the GB/T requirements in 2018, as they worked with licensed Chinese factories to develop a smoke pollution mask for the US market. When COVID started disrupting global supply chains, the company moved much of its manufacturing to the United States, where they applied the same designs. “In this niche industry of fabric particulate masks, China set the standard on everything from materials to fit to testing protocols,” said Mr. Enke, a co-founder and mechanical engineer who worked with a Bellevue-based apparel designer to implement the specifications. “We were able to leverage decades of research on reusable facemasks and filters to achieve an optimal balance of efficiency and resistance

Christophe Rude
Christophe Rude
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