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Ray Bellia holds up N95 personal protective masks, used by medical and law enforcement professionals, in the warehouse of his Body Armor Outlet store, Wednesday, Dec. 9, 2020, in Salem, N.H. (AP Photo/Charles Krupa)

I decided this week that we should reconsider these because so many of them are being just tossed on the ground. In addition, most of those are the single-use so-called surgical type masks that we get at any medical or health care facility we visit these days. Those single-use disposable masks are the most common but are actually an environmental hazard in several ways. They are manufactured using a three or four layer process. Most of the material is a form of polypropylene plastic that is melted and spun or blown into fine fibers to provide the air filtration needed, while still allowing the wearer to breathe. That layer is covered on each side with a woven or non-woven layer that is usually also a man-made fabric. Between them, those materials shed a large quantity of microfibers when we dispose of them.

To counter that threat, the CDC initially recommended cloth masks for the general population, except where underlying conditions or high risk dictate medical-grade protection. Cloth masks are relatively inexpensive and can be used multiple times, although washing them between uses is highly recommended. A trip through the washing machine has been shown to totally remove any virus that might be on the mask. There is no limit to the number of times a cloth mask can be washed.

Their downside, of course, is that they rarely fit very well, and, when they don’t fit well, they leak, so are less effective. They also stop only the larger particles floating in the air, and the smallest ones seem to do the most damage. Lots better than nothing, but very much not ideal.

Much better, notes a very recent report in Scientific American, is the huge number of high-filtration respirator-style masks on the market, including N95s, Chinese-made KN95s and South Korean–made KF94s. After initially being reserved for health care workers, these masks have been widely available and relatively affordable for months and provide better protection than cloth or surgical masks. That design tends to fit and work better than single-use surgical masks.

Effectiveness, fit, and comfort are the parameters that will determine what we ultimately choose to wear. A mask fits well if it sits snugly against the face and over the chin, with no gaps around the nose or mouth. There are national standards for masks in the workplace, but evidently no standard for N95 use by the public. All provide excellent filtration, so it really comes down to which fits an individual best and is most comfortable. A mask does no good if people simply find it intolerable to wear.

A mechanical engineer at Seagate Technology with a background in aerosol science named Aaron Collins, who calls himself “Mask Nerd,” has offered up some excellent observations on best choices as a result of some experimentation he has done with several of the newer masks. He has even made several YouTube videos to explain his methodology and his findings. The Scientific American article notes that, “in general, [Aaron] recommends KN95s made by a Chinese company called Powecom, as well as some others, or a variety of KF94s such as the Bluna FaceFit and N95s made by reputable brands such as 3M, Moldex or Honeywell. All of these masks had close to 99 percent filtration efficiencies and fairly low pressure drops [i.e. good fit] in Collins’s setup.”

Some other reliable recommendations can be found on the web at shop.project95. The big concern is avoiding fake masks that do not perform as well as others. Collins suggests N95 type mask can be used for up 40 hours with no decrease in their filtration. The virus likely does not survive long on these masks, he adds, but it is not a bad idea to have a few in rotation, reusing one every three days or so.

The Recycle Bin is a weekly column on what to recycle, what not to recycle, and why, in Brunswick. The public is encouraged to submit questions by email to [email protected] Harry Hopcroft is a member of the Brunswick Recycling and Sustainability Committee, though his opinions are his own and do not necessarily reflect those of the committee.

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