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Local experts hail report of upcoming standards for COVID-19 masks

Are those masks working? Green Line passengers wearing masks earlier this month.David L. Ryan/Globe Staff

New England experts welcomed news that a division of the US Centers for Disease Control and Prevention is developing standards and labels for the myriad face masks out there on the market intended to protect people from getting and spreading the coronavirus.

“This is a welcome development. Creating minimum standards can help inform and guide everyone at a time when the simplest prevention decisions can get very complex,” said Dr. Howard Koh, a professor at the Harvard T.H. Chan School of Public Health and a former top Obama administration public health official.

“The news is also timely since President-Elect Biden has pledged to make mask usage a unified national strategy for his first 100 days instead of relying solely on states alone,” Koh, who is also a former Massachusetts public health commissioner, said in an e-mail.


Dr. Abraar Karan, an internal medicine physician at Brigham and Women’s Hospital, said the development was “both welcome and overdue,” adding, “We’ve known ... really since the beginning of the epidemic that masks are critically important.”

The National Institute for Occupational Safety and Health is working to develop minimum filter efficiency standards, and labels showing which products meet them, for the vast market for masks and other face coverings, The New York Times reports.

NIOSH, a division of the CDC, has been quietly writing guidelines with an industry standard-setting organization, ASTM International (formerly the American Society for Testing and Materials), that are expected to be made public next month.

“By having a standard in place you will be able to know what level of protection is being achieved and you’ll have a consistent way of evaluating these products,” Maryann D’Alessandro, director of the NIOSH National Personal Protective Technology Laboratory, told the Times.

Since the pandemic began, there has been little federal oversight of masks and other face coverings.


The US Food and Drug Administration, which regulates medical devices, shares authority with NIOSH for oversight of N95 respirators, which are the most protective devices available. But most of the masks worn by the general public are just pieces of cloth and don’t come under any regulatory oversight.

The effectiveness of masks can range “from 0-80 percent, depending on material composition, number of layers and layering bonding,” Dale Pfriem, president of Protective Equipment Consulting Services and a member of the standards development working group addressing mask guidelines, told the Times.

Shan Soe-Lin, a lecturer at the Jackson Institute for Global Affairs at Yale University and managing director of Pharos Global Health Advisors in Boston, welcomed the prospect of new standards, noting that it would still be important to continue wearing masks even as the nation’s vaccination effort is underway.

“Wearing ones that are known to be effective is a good thing for everybody as long as the standards are simple and easy to understand,” she said, citing the SPF number on sunscreens as a good model.

She also emphasized that “it’s still better to wear something rather than nothing.”

“It would be a shame if people thought, ‘I can’t afford to wear this NIOSH mask so I’m just not going to wear anything,’” she said.

Joseph Allen, a professor of exposure assessment science at the T.H. Chan School, had similar concerns, saying he wondered what message would be sent by the new mask standards.

“Will people feel like they’ve been misled and their current mask is no good? I hope that’s not the case because the reality is that for most people in low-risk settings, just about any mask will provide benefit. Remember, the real power of masks come from everyone wearing them,” he said.


At the same time, he said in e-mail, “That’s not to say we don’t want better masks. Ideally everyone should be wearing a 2- or 3-layer mask by now, and that is what I would recommend.”

Allen noted that he had written an article in early April observing that the debate on the importance of masks was over. “How is it that it’s December and plans are just being made by the government to standardize guidance on masks?” he said.

The current CDC recommendation is to wear a mask to prevent yourself both from getting the virus and transmitting it. The agency says the mask should have two or more layers of “washable, breathable fabric” and it should “fit snugly against the side of your face and not have gaps.”

In a scientific brief last month, the CDC called for further research on masks to “identify the combinations of materials that maximize both their blocking and filtering effectiveness, as well as fit, comfort, durability, and consumer appeal.”

The Times reported that a working group of federal and industry officials has proposed one high and one low filtration requirement that manufacturers and distributors can adopt and list on their labels. The lower standard is a 20 percent filtration barrier and the higher is 50 percent.


Those numbers are more protective than they sound. The filtration efficiency percentages are based on a product’s efficiency at filtering particles measuring 0.3 microns, which, as the generally most penetrative particles, are standard for NIOSH tests.

“Twenty percent efficiency at 0.3 microns would translate to 50 percent efficiency at 1 to 2 micron particles, and 80% efficiency at blocking particles that are 4 to 5 microns or larger,” said Linsey Marr, a professor of civil and environmental engineering at Virginia Tech and a leading expert on airborne viruses. “I think it will be useful.”

According to Marr, the coronavirus itself is 0.1 microns, but it is carried in aerosols of about 0.5 microns or larger.

Jeffrey Stull, a member who is assisting in writing the standards, said the group would also rate masks and face coverings for “breathability.”

Manufacturers who want to note that they meet the ASTM standard must first have their products tested by an accredited laboratory. They should also be able to show that their masks provide a reasonable fit to the population at large. Those who do comply with the standards can then note that they meet the ASTM standard on the product or the packaging. There is no enforcement mechanism, however.

Jill Crittenden, a scientific adviser at the Massachusetts Institute of Technology and member of the mask expert group n95decon.org, said she was “delighted” at the news of the upcoming standards.


Karan, the Brigham doctor, said he welcomed the government’s effort to “get Americans the information they need to select better masks.”

But he said, “They should be making it easier for us to get access to those masks.”

In an ideal world, he suggested, the government would go further, even creating an Operation Warp Speed-type effort and manufacturing effective, comfortable, and reusable “good masks for everyone.”

Jeremiah Manion of the Globe staff contributed to this report. Material from Globe wire services was used in this report.

Martin Finucane can be reached at martin.finucane@globe.com.