The world's oldest crater from a meteorite isn't an impact crater after all

UNIVERSITY OF WATERLOO

Research News

 

Several years after scientists discovered what was considered the oldest crater a meteorite made on the planet, another team found it's actually the result of normal geological processes.

During fieldwork at the Archean Maniitsoq structure in Greenland, an international team of scientists led by the University of Waterloo's Chris Yakymchuk found the features of this region are inconsistent with an impact crater. In 2012, a different team identified it as the remnant of a three-billion-year-old meteorite crater.

"Zircon crystals in the rock are like little time capsules," said Yakymchuk, a professor in Waterloo's Department of Earth and Environmental Sciences. "They preserve ancient damage caused by shockwaves you get from a meteorite impact. We found no such damage in them."

Additionally, there are multiple places where the rocks melted and recrystallized deep in the Earth. This process--called metamorphism--would occur almost instantaneously if produced from an impact. The Waterloo-led team found it happened 40 million years later than the earlier group proposed.

"We went there to explore the area for potential mineral exploration, and it was through close examination of the area and data collected since 2012 that we concluded the features are inconsistent with a meteorite impact," Yakymchuk said. "While we were disappointed that we weren't working in a structure that was the result of a meteorite hitting the planet three billion years ago, science is about advancing knowledge through discovery, and our understanding of the Earth's ancient history continues to evolve. Our findings provide scientific data for resource companies and Greenlandic prospectors to find new mineral resources."

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The study, Stirred not shaken; critical evaluation of a proposed Archean meteorite impact in West Greenland, by Yakymchuk and an international team of scientists from Canada, Australia, Denmark, Greenland and the United Kingdom, appears in the journal Earth and Planetary Science Letters.

The narwhal's tusk reveals its past living conditions

AARHUS UNIVERSITY

Research News

 NEWS RELEASE 11-MAR-2021

 

IMAGE: NARWHALS WITH THEIR CHARACTERISTIC SPIRALLED TUSKS IN DENSE PACK ICE. view more 

CREDIT: PHOTO: ©PAUL NICKLEN / PAULNICKLEN.COM

Every year, a new growth layer is added to the narwhal's spiralled tusk. The individual layers act as an archive of data that reveals what and where the animal has eaten, providing a glimpse of how the ice and environmental conditions have changed over its long life span (up to 50 years).

Same as rings in a tree trunk, every year a new growth layer is added to the narwhal's tusk, which grows longer and thicker throughout the animals life. Because the tusk is connected to the rest of body through blood, each new growth layer records aspects of animal physiology during the year it was formed.

An international team of researchers has now studied each individual growth layer of the tusks from ten narwhals from North-West Greenland. They specifically analysed mercury and stable isotopes of carbon and nitrogen to give information on what the whales have eaten in each year of their life and how the ice cover and the impact of potential toxic compounds such as mercury have changed over time.

A historical archive

Most people are familiar with the narwhal's impressive unicorn-like tusk (a canine tooth) that projects from the left side of the upper jaw of the males.

Researchers do not fully agree on the purpose of the impressive narwhal tusk. Indications from recent years' research suggest that the tusk may be used when the narwhals search for food. But presumably the males also use the long tusk to impress the females. And it is, indeed, impressive - this spiralled, pointed tusk can reach up to three metres long.

Researchers have now shown that each layer of the tusk offers valuable data on the animals' living conditions from when they are born until they die.

"It is unique that a single animal in this way can contribute with a 50-year long-term series of data. It is often through long time series that we as researchers come to understand the development of biological communities, and such series of unbroken data are very rare. Here, the data is a mirror of the development in the Arctic," tells Professor Rune Dietz from the Department of Bioscience and the Arctic Research Centre, Aarhus University, Denmark, who headed the studies.

The sensational data is just published in the journal Current Biology.

CAPTION

Cut-through narwhal tusk displaying the individual year rings. Analyses of the individual layers of narwhal tusks have provided information about their food choice and their exposure to mercury throughout their life.

CREDIT

Photo: Rune Dietz.

Mercury and climate change affect the top link in the food chain

Among the biggest threats to Arctic top predators, such as the polar bear, white whale and narwhal are climate change and the amount of mercury consumed by the animals.

"The higher you are in the food chain, the more mercury you accumulate into your body throughout your life. Heavy metals and other environmentally contaminants accumulate at each link in the food chain, so if you are at the top of the food chain, you end up consuming the greatest amount of mercury at each meal" explains Post-Doctoral Research Fellow Jean-Pierre Desforges, Natural Resource Department, McGill University, Canada, who has co-headed the study.

Elevated amounts of heavy metals in the body are toxic and affect the cognitive functions, behaviour and ability of a species to reproduce and defend against infections.

In 2017, the UN adopted the Minamata Convention, which attempts to limit global mercury pollution.

In the Arctic, climate change over the past 30-40 years has led to less sea ice. Many species depend on the ice when searching for food, for example polar bears, while other species use the ice as important breeding grounds, for example seals. For the narwhal, the ice acts as a protection against enemies like killer whales.

Changes in temperature and the cover of sea ice also lead to invasion by new species from warmer areas. This affects the entire Arctic food chain and thus the living conditions of the individual species.

CAPTION

Data on δ13C, δ15N and mercury in narwhal tusks measured in layers corresponding to the period 1968-2010. The cover of summer sea ice for the same period is also shown.

CREDIT

Aarhus University, Denmark

Revealing analyses

"We have been able to trace this development in the narwhals' tusks. In each layer of the tusk, we measured the amount of mercury, just as we measured stable isotopes of carbon and nitrogen - the so-called delta 13C (δ13C) and delta 15N (δ15N)," says Rune Dietz.

The composition of the carbon and nitrogen isotopes in a layer of the tusk provides insight into the diet of each narwhal in the year from which the actual layer originated. Or rather, how high in the food the prey was, and in which part of the ocean the animals lived.

A low δ15N value indicates how high in the food chain the animal sits. A high δ13C value reflects that the prey is closely linked to the surrounding sea ice, while a low delta δ13C value reflects that the prey has lived in the open sea.

Changing conditions for Arctic top predators

The tusks analysed by the researchers were 150 to 248 cm long and contained data from 1962 to 2010.

"What we found in narwhal of Northwest Greenland is consistent with a more general trend across the Arctic where sea-ice is declining and changing the spatial distribution of sub-Arctic and Arctic fish as well as top predators. The big question now is how these changes will affect the health and fitness of key Arctic species in the years to come," says Jean-Pierre Desforges

The analyses of the tusks revealed three things in particular:

Up until around 1990, the narwhals' food consisted particularly of prey linked to the sea ice, such as halibut and Arctic cod. During this period, the ice cover was extensive but varying.

After 1990, the ice cover in North-West Greenland decline consistently year after year and the diet of the narwhals changed to a dominance of open ocean prey like capelin and polar cod. From 1990 until 2000, narwhals also accumulated relatively small quantities of mercury as the new items of prey sat lower in the food chain.

However, from around 2000, the amount of mercury increased significantly in the narwhal tusks without a simultaneous shift in food items. The researchers have also measured higher levels of mercury in other Arctic animals over the past few decades, and they attribute this to extensive emission of mercury primarily from the coal combustion in South-East Asia. The rise in mercury might also be due to changing sea ice conditions in the Arctic as the climate is warming, causing changes in the environmental mercury cycle in the Arctic.

A bank of data

The development worries Rune Dietz and Jean-Pierre Desforges.

"The narwhal is the Arctic mammal most affected by climate change. At the same time, whales lack the physiological properties to eliminate environmentally contaminants. They don't get rid of mercury by forming hair and feathers like polar bears, seals and seabirds, just as their enzyme system is less efficient at breaking down organic pollutants," explains Rune Dietz.

However, the researchers behind the study see it as a positive sign that the narwhal has a greater ability to change its food basis than previously believed.

"With our new discoveries, we now know that there is a bank of data in the narwhal tusks found in museums around the world. By analysing them, we can hopefully get an insight into the narwhals' food strategy from different areas and periods many years back in time. This will provide us with a solid basis for evaluating how the species copes with the changed conditions that it now encounters in the Arctic," says Rune Dietz.

The research team points out that valuable, chronological information is also waiting in other types of biological material, for example from the teeth of other species, hair, whale baleen, whale earwax plugs, shells from shellfish and year rings in trees.

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By Peter Bondo

Further information:

Professor Rune Dietz, Department of Bioscience - Marine Mammals Research, Aarhus University; Denmark, E-mail: rdi@bios.au.dk; tel.: +45 2125 4035.

Post-Doctoral Research Fellow Jean-Pierre Desforges, Natural Resource Department, McGill University, Canada; E-mail: jean-pierre.desforges@mcgill.ca.

Cheaper carbon capture is on the way

PNNL-developed solvent breaks barriers, 

captures carbon for less than industrial counterparts

DOE/PACIFIC NORTHWEST NATIONAL LABORATORY

NEWS RELEASE 11-MAR-2021

Research News

     

IMAGE: THIS ANIMATION DEPICTS THE TWO-STAGE FLASH CONFIGURATION, ONE OF SEVERAL PROCESSES DESCRIBED IN A NEW STUDY DETAILING HOW EEMPA, A PACIFIC NORTHWEST NATIONAL LABORATORY-DEVELOPED SOLVENT, CAN CAPTURE CARBON FROM FLUE... view more CREDIT: (ANIMATION BY MICHAEL PERKINS | PACIFIC NORTHWEST NATIONAL LABORATORY)

RICHLAND, Wash.--As part of a marathon research effort to lower the cost of carbon capture, chemists have now demonstrated a method to seize carbon dioxide (CO2) that reduces costs by 19 percent compared to current commercial technology. The new technology requires 17 percent less energy to accomplish the same task as its commercial counterparts, surpassing barriers that have kept other forms of carbon capture from widespread industrial use. And it can be easily applied in existing capture systems.

In a study published in the March 2021 edition of International Journal of Greenhouse Gas Control, researchers from the U.S. Department of Energy's Pacific Northwest National Laboratory--along with collaborators from Fluor Corp. and the Electric Power Research Institute--describe properties of the solvent, known as EEMPA, that allow it to sidestep the energetically expensive demands incurred by traditional solvents.

"EEMPA has some promising qualities," said chemical engineer Yuan Jiang, lead author of the study. "It can capture carbon dioxide without high water content, so it's water-lean, and it's much less viscous than other water-lean solvents."

Carbon capture methods are diverse. They range from aqueous amines--the water-rich solvents that run through today's commercially available capture units, which Jiang used as an industrial comparison--to energy-efficient membranes that filter CO2 from flue gas emitted by power plants.

Current atmospheric CO2 levels have soared higher in recent years than at any point within the last 800,000 years, as a new record high of 409.8 parts per million was struck in 2019. CO2 is primarily released through human activities like fossil fuel combustion, and today's atmospheric concentrations exceed pre-industrial levels by 47 percent.

At a cost of $400-$500 million per unit, commercial technology can capture carbon at roughly $58.30 per metric ton of CO2, according to a DOE analysis. EEMPA, according to Jiang's study, can absorb CO2 from power plant flue gas and later release it as pure CO2 for as little as $47.10 per metric ton, offering an additional technology option for power plant operators to capture their CO2.

Jiang's study described seven processes that power plants can adopt when using EEMPA, ranging from simple setups similar to those described in 1930s technology, to multi-stage configurations of greater complexity. Jiang modeled the energy and material costs to run such processes in a 550-megawatt coal power plant, finding that each method coalesces near the $47.10 per metric ton mark.

Solving a solvent's problems

One of the first known patents for solvent-based carbon capture technology cropped up in 1930, filed by Robert Bottoms.

"I kid you not," said green chemist David Heldebrant, coauthor of the new study. "Ninety-one years ago, Bottoms used almost the same process design and chemistry to address what we now know as a 21st century problem."

The chemical process for extracting CO2 from post-combustion gas remains largely unchanged: water-rich amines mix with flue gas, absorb CO2 and are later stripped of the gas, which is then compressed and stored. But aqueous amines have limitations. Because they're water-rich, they must be boiled at high temperatures to remove CO2 and then cooled before they can be reused, driving costs upward.

"We wanted to hit it from the other side and ask, why are we not using 21st century chemistry for this?" Heldebrant said. So, in 2009, he and his colleagues began designing water-lean solvents as an alternative. The first few solvents were too viscous to be usable.

"'Look,'" he recalled industry partners saying, "'your solvent is freezing and turning into glass. We can't work with this.' So, we said, OK. Challenge accepted."

Over the next decade, the PNNL team refined the solvent's chemistry with the explicit aim to overcome the "viscosity barrier." The key, it turned out, was to use molecules that aligned in a way that promoted internal hydrogen bonding, leaving fewer hydrogen atoms to interact with neighboring molecules.

Heldebrant draws a comparison to children running through a ball pit: if two kids hold each other's hands while passing through, they move slowly. But if they hold their own hands instead, they pass as two smaller, faster-moving objects. Internal hydrogen bonding also leaves fewer hydrogen atoms to interact with overall, akin to removing balls from the pit.

Pivoting to plastic

Where the team's solvent was once viscous like honey, it now flowed like water from the kettle. EEMPA is 99 percent less viscous than PNNL's previous water-lean formulations, now nearly on par with commercial solvents, allowing them to be utilized in existing infrastructure, which is largely built from steel. Pivoting to plastic in place of steel, the team found, can further reduce equipment costs.

Steel is expensive to produce, costly to ship and tends to corrode over time in contact with solvents. At one tenth the weight, substituting plastic for steel can drive the overall cost down another $5 per metric ton, according to a study led by Jiang in 2019.

Pairing with plastic offers another advantage to EEMPA, whose reactive surface area is boosted in plastic systems. Because traditional aqueous amines can't "wet" plastic as well (think of water beading on Teflon), this advantage is unique to the new solvent.

The PNNL team plans to produce 4,000 gallons of EEMPA in 2022 to analyze at a 0.5-megawatt scale inside testing facilities at the National Carbon Capture Center in Shelby County, Alabama, in a project led by the Electric Power Research Institute in partnership with Research Triangle Institute International. They will continue testing at increasing scales and further refine the solvent's chemistry, with the aim to reach the U.S. Department of Energy's goal of deploying commercially available technology that can capture CO2 at a cost of $30 per metric ton by 2035.

This study, "Techno-economic comparison of various process configurations for post-combustion carbon capture using a single-component water-lean solvent," was funded by the U.S. Department of Energy Office of Fossil Energy.

Pacific Northwest National Laboratory draws on its distinguishing strengths in chemistry, Earth sciences, biology and data science to advance scientific knowledge and address challenges in sustainable energy and national security. Founded in 1965, PNNL is operated by Battelle for the U.S. Department of Energy's Office of Science, which is the single largest supporter of basic research in the physical sciences in the United States. DOE's Office of Science is working to address some of the most pressing challenges of our time. For more information, visit PNNL's News Center. Follow us on Twitter, Facebook, LinkedIn and Instagram.

With masks on, three feet is just as safe as six feet apart in Massachusetts schools

Statewide study showed no significant differences in COVID-19 case rates between K-12 districts that implemented 3-feet versus 6-feet of physical distancing

BETH ISRAEL DEACONESS MEDICAL CENTER

Research News

 

BOSTON - As COVID-19 infection rates continue to fall, Massachusetts officials are signaling it's almost time to end remote learning and send all school-aged children back to the classroom. While emerging data suggest young children and schools have not been primary drivers of the COVID-19 pandemic, evidence to guide best practices to prevent the spread of the virus in the school setting has been limited and, as a result, national and international recommendations are inconsistent.

A study led by Beth Israel Deaconess Medical Center (BIDMC) physician-researchers provides new, much-needed data about the optimal physical distancing between students for the prevention of COVID-19 in the school setting. In a retrospective, statewide cohort study, the researchers compared the rates of COVID-19 cases in students and staff in Massachusetts public schools among districts with universal mask mandates but different physical distancing requirements. The team found no substantial difference in the number of cases of COVID-19 among either students or staff in school districts that implemented a distancing policy of three feet versus six feet between students. The findings, published in the journal Clinical Infectious Diseases, suggest that lower physical distancing policies can be adopted in school settings with masking mandates without negatively impacting student or staff safety.

"Prior studies have not directly compared the impact of different physical distancing policies among students attending in-person school," said lead author Polly van den Berg, MD, a fellow in the Division of Infectious Diseases at BIDMC. "This research, which found no substantial difference in the number of cases among either students or staff in school districts that implemented a distancing policy of three versus six feet between students, is important because many school buildings have physical infrastructure that cannot accommodate six feet of distancing and bring all (or most) students back into the classroom."

Van den Berg and colleagues looked at publicly available data from 251 Massachusetts school districts, encompassing 537,336 students and 99,390 staff who attended in-person instruction during a 16-week study period from September 2020 to January 2021. Using a combination of information - including individual district infection control plans, the number of infections reported to the Commonwealth by districts, and community rates of COVID-19 from a non-partisan, not-for-profit data dashboard - the scientists found no significant difference in the rate of COVID-19 cases among students and staff in districts that mandated six feet of distancing versus in districts that mandated three feet of distancing. The scientists note that physical distancing was only one of several infection prevention measures taken by school districts.

"These data can be used to inform and update how infection control plans are implemented in school settings," added corresponding author Westyn Branch-Elliman, MD, MMSc, an infectious disease specialist at BIDMC and a clinical investigator at VA Boston Healthcare System. "It is important to remember that distancing was just one of a number of interventions adopted in the districts included in our analysis. Across the districts included in our study, there was a near-universal masking mandate, thus our study addresses the question of the effectiveness of three versus six feet of distancing among students and staff who are wearing masks."

The team's findings also showed that, in general, schools had lower overall rates of infection than their surrounding communities, lending support to the idea that in-person learning is not a major driver of the pandemic; however, district case rates were tightly linked to those of the community, particularly among staff.

"Early in the pandemic, infection control plans for schools and other settings were developed based on the best available evidence at the time -- which, early on, was limited," said Branch-Elliman, also an Assistant Professor of Medicine at Harvard Medical School. "We hope that our findings can be used to update current recommendations about distancing policy, and ultimately, to help return more students to the classroom."

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Co-authors include Elissa M. Schechter-Perkins, MD, MPH, of Boston University School of Medicine and Boston Medical Center; Rebecca S. Jack, MPP of COVID-19 School Response Dashboard; Isabella Epshtein, MPP, of VA Boston Center for Healthcare Organization and Implementation Research; Richard Nelson, PhD, Veterans Affairs Salt Lake City Healthcare System and University of Utah School of Medicine; and Emily Oster, PhD, of COVID-19 School Response Dashboard and Brown University Watson Institute for International and Public Affairs.

The authors received no financial support for the research, authorship, and/or publication of this article. WBE is the site PI for a grant funded by Gilead pharmaceuticals (funds to institution). EO and RJ are affiliated with the COVID-19 School Dashboard, which is funded in part by the Chan Zuckerberg Foundation and the Arnold Foundation. All other authors have no conflicts to report.

About Beth Israel Deaconess Medical Center

Beth Israel Deaconess Medical Center is a patient care, teaching and research affiliate of Harvard Medical School and consistently ranks as a national leader among independent hospitals in National Institutes of Health funding. BIDMC is the official hospital of the Boston Red Sox. For more information, visit http://www.bidmc.org.

Beth Israel Deaconess Medical Center is a part of Beth Israel Lahey Health, a health care system that brings together academic medical centers and teaching hospitals, community and specialty hospitals, more than 4,000 physicians and 35,000 employees in a shared mission to expand access to great care and advance the science and practice of medicine through groundbreaking research and education.

New study shows impact of mask wearing on patient trust and perception of surgeon

This study is the first to examine the effect of a surgeon's mask on communication with patients in the clinic setting.

UNIVERSITY OF NORTH CAROLINA HEALTH CARE

Research News

 

IMAGE: NORMAL MASK VS. CLEAR MASK, DEMONSTRATED BY IAN KRATZKE, MD view more 

CREDIT: UNC SCHOOL OF MEDICINE

CHAPEL HILL, NC - A first-of-its-kind study out today in JAMA Surgery suggests that patients have a more difficult time understanding and building trust with their surgeons when they cannot see the surgeon's entire face due to masking requirements. These findings have major implications for not only how surgeons are viewed and rated by their patients, but also how well a patient does during and after a surgical procedure.

"At beginning of pandemic I had a patient say, 'Dr. Kapadia, it's odd you've taken out a big part of my colon and I don't even know what you look like,'" Muneera Kapadia, MD, the study's senior author said. "It made me realize we don't have much information on how masks are effecting surgeon-patient communication and relationships."

Kapadia, an associate professor of surgery in the UNC School of Medicine, found a way to study how the new masking protocols during pre-operative meetings are affecting patients' perception and trust of their surgeons. Study organizers utilized clear masks so that patients could see a surgeon's entire face, while still following safety protocols.

The randomized clinical trial included 200 patients that were recruited from 15 surgeon's clinics, spanning seven subspecialties. Surgeons were randomized to wearing clear masks versus covered masks for each new patient clinic visit. After the clinic encounter, patients completed a verbal survey including validated Clinician and Group Consumer Assessment of Healthcare Providers and Systems (CG-CAHPS) questions, and additional questions about surgeon empathy and trust, and the patient's impression of the surgeon's mask.

"When surgeons wore clear masks as opposed to traditional masks, patients rated their surgeon significantly higher in how well they provided an understandable explanation, knew the patient's history, demonstrated empathy, and built trust," said Ian Kratzke, MD, a resident in the department of Surgery at the UNC School of Medicine, and first author of the study.

Patients reported improved communication when surgeons donned a clear mask, suggesting that not seeing the surgeon's face may have negative consequences on the surgeon-patient relationship. And simply put, patients prefer to see their surgeon's face.

While donning clear masks for these interactions can be a solution, Kapadia says the study is more about raising awareness.

"Our face is how we connect with other people," Kapadia said. "We react to people with facial cues, which are being covered by the masks, and that's having a big impact on communication."

"We need to be cognizant that patients are having more difficulty connecting with us as providers. I think knowing that before interacting with them will help mitigate the issue by reminding us to spend more time getting to know our patients, and making sure they understand what we are trying to convey."

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This study was sponsored by the Department of Surgery in the UNC School of Medicine.

Invited Commentary

March 11, 2021

Benefits of Clear Masks in Communication With Patients

Margaret L. Schwarze, MD¹; Elle L. Kalbfell, MD¹

Author Affiliations Article Information

JAMA Surg. Published online March 11, 2021. doi:10.1001/jamasurg.2021.0848

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Adapting to new safety standards during COVID-19 has likely been easier for surgeons who are accustomed to wearing a mask. Although wearing masks outside the operating room has become the new normal, it may not be as easy for patients as it is for us. In this issue of JAMA Surgery, Kratzke et al¹ demonstrate that patients whose surgeon wore a clear mask were significantly more likely to give a top-box rating (4 on a Likert scale of 1-4) for providing easy-to-understand information, knowledge of patient information, displaying empathy, and generating trust.¹ Although there was no significant difference in patient-reported comfort with the surgeon operating on them, it is unclear whether this study was powered to detect such a difference.

This evidence should motivate us to consider why patients reported a striking difference in communication, particularly in a field (clinical communication research) that is chronically hamstrung by measurements with high ceiling effects. Because each surgeon served as their own control, the content of communication about disease and treatment, ie, information and knowledge, was presumably the same in each group. Thus, information transfer may not be as important as we think; technical details about illness or treatment may be less salient for patients than developing an interpersonal connection. Surgeons might view the surgical consultation as transactional, a time to exchange information, but patients may be inclined to see it as relational. Because human expressions are a critical component of emotional exchange, visual cues such as a smile, frown, or other facial gestures likely contributed to patient-perceived rapport and higher ratings despite similar informational content.

The findings may also point to what covered masks lack rather than what clear masks provide. When surgeons wear covered masks, patients may sense a lack of transparency, viewing the mask as a form of disguise or concealment. With limited visual cues, patients are left to determine how the surgeon is thinking or feeling. Many also noted it was easier to hear the surgeon, suggesting compensation for hearing loss or sensory preferences with visual cues. Study findings may also reflect pandemic fatigue. Masks are a reminder of innumerable hardships over the past year, and clear masks represent extra effort by surgeons to mitigate patient discomfort and increase engagement.

Alongside the disastrous effects of COVID-19 on everyday life, do clear masks really matter? They might. Trust is the cornerstone of surgical care. Without it, patients would not let us operate on them or trust our judgment to forgo surgery. And how we speak may be more important than what we say. As surgeons, we do many bold things because they improve patient care, and wearing a clear mask with new patients should be one of them.

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Article Information

Corresponding Author: Margaret L. Schwarze, MD, Department of Surgery, University of Wisconsin-Madison, K6/134 CSC, 600 Highland Ave, Madison, WI 53726 (schwarze@surgery.wisc.edu).

Published Online: March 11, 2021. doi:10.1001/jamasurg.2021.0848

Conflict of Interest Disclosures: Dr Schwarze reported grants from the National Institutes of Health and Greenwall Foundation and reports that her spouse has ownership interest outside the submitted work. No other disclosures were reported.

References

1.

Kratzke IM, Rosenbaum ME, Cox C, Ollila DW, Kapadia MR.  Effect of clear vs standard covered masks on communication with patients during surgical clinic encounters: a randomized clinical trial.   JAMA Surgery. Published online March 11, 2021. doi:10.1001/jamasurg.2021.0836
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Assessment of Use and Fit of Face Masks Among Individuals in Public During the COVID-19 Pandemic in China

Xiangbin Pan, MD^1,2; Xi Li, MD^2,3; Pengxu Kong, MD¹; et alLin Wang, MD⁴; Rundi Deng, MD¹; Bin Wen, MD¹; Luoxi Xiao, PhD^5,6; Honglin Song, PhD^5,6; Yi Sun, PhD⁵; Hongmei Zhou, PhD⁵; Jiang Lu, PhD⁵; Yang Wang, PhD¹; Qiuzhe Guo, MD⁵; Lin Duo, PhD⁵; Chengye Sun, PhD⁷

Author Affiliations Article Information

JAMA Netw Open. 2021;4(3):e212574. doi:10.1001/jamanetworkopen.2021.2574

Original Investigation 

Public Health

March 11, 2021

Key Points

Question  What proportion of people in public places are wearing face masks without proper airtight seals, what factors are associated with face mask protection efficacy, and can they be improved?

Findings  This cross-sectional study, including 6003 participants wearing face masks in public places, found that face mask airtightness was commonly suboptimal, mostly secondary to gaps at the upper face mask edge. Using simple and tolerable approach of sealing the upper face mask edge with an adhesive tape was associated with significant improvement of face mask airtightness.

Meaning  These findings suggest that compromised protection due to suboptimal face mask airtightness was common, and use of adhesive tape to seal the upper edge was associated with easily and quickly improving the airtightness of existing masks.

Abstract

Importance  Face masks are recommended to prevent transmission of coronavirus disease 2019 (COVID-19); however, there is scarce evidence on their protection efficacy and ways to improve it.

Objective  To determine the proportion of improper face mask use, the factors associated with face mask protection efficacy, and ways to improve efficacy.

Design, Setting, and Participants  This population-based cross-sectional study was conducted in China from July to August 2020 in 5 kinds of public places. Participants included convenience samples of individuals wearing face masks and able to taste the check solution.

Exposures  Demographic and socioeconomic characteristics, including sex, age, and education level; information on face mask model and the worn duration was recorded.

Main Outcomes and Measures  The main outcome as airtightness, assessed by detecting face-to-face mask gaps, movement of cotton fiber placed at the face mask edges, and using a qualitative fit test with a bitter solution spray. Masks were further assessed for whether sealing the upper face mask edge with an adhesive tape strip was associated with improved face mask airtightness.

Results  Among 6003 face mask wearers enrolled, the mean (SD) age of participants was 31.1 (13.7) years, and 3047 participants (50.8%) were female. The first qualitative fit test found air leakage in 2754 participants (45.9%; 95% CI, 44.6%-47.1%), which was mostly attributable to gaps at the upper face mask edge. After sealing the upper face mask edge with an adhesive tape strip, 69.7% (95% CI, 68.0%-71.5%) of masks that had exhibited leakage became airtight in the second qualitative fit test, and the rate of airtightness reached 96.2% (95% CI, 95.4%-96.8%) in a third qualitative fit test after new surgical face masks with tape on the upper edge were provided to those who had not converted initially. The tape was well tolerated; overall, 6 participants (1.2%) reported a rash and 24 participants (5.8%) reported significant discomfort.

Conclusions and Relevance  In this study of face mask fit among participants in China, although most people used face masks in public places, compromised protection due to suboptimal airtightness was common. The simple approach of sealing the upper edge of the face mask with an adhesive tape strip was associated with substantially improved its airtightness.

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