In a direct comparison of masks worn by individuals with active COVID-19, the low-cost ‘duckbill’ N95 mask was the most effective, preventing 98% of COVID-19 particles from being released into the air through the breath of infected individuals. The study also found that other masks performed well, with at least 70% of viral particles being blocked from escaping an infected person’s exhaled breath.Researchers from the University of Maryland School of Public Health (SPH) found that various masks performed well, blocking at least 70% of viral particles from escaping an infected person’s exhaled breath. The study, titled “Relative efficacy of masks and respirators as source control for viral aerosol shedding from people infected with SARS-CoV-2,” was published on May 29 in eBioMedicine, a Lancet journal. The study’s senior author, Dr. [Name], emphasized that any mask is better than no mask, and an N95 mask is significantly more effective than other options.Donald Milton, an environmental health professor at UMD SPH and a global expert on airborne virus transmission, conducted a study in May 2020 to examine how viruses spread through the air. The study involved comparing breath samples from individuals with active COVID-19 and testing the effectiveness of four commonly-used masks. Despite not providing fit tests or proper mask-wearing training to the participants, the study found that all masks significantly reduced the amount of virus escaping into the air. The focus of the study was on testing masks as a means of controlling the spread of the virus from the infected person, rather than as protection against COVID-19.The air surrounding us is the focus of a study on the airborne nature of COVID-19. Researchers at UMD’s Public Health AeroBiology Lab (PHAB Lab) are investigating how wearing a mask can reduce the spread of the virus in the air. The study is a continuation of their previous work on how respiratory viruses like influenza can contaminate the air.
To measure the level of viral contamination in exhaled breath, volunteers with COVID-19 were asked to breathe into a specialized device called the Gesundheit II Machine, which was developed by the researchers. The participants spent 30 minutes breathing into the machine and were asked to perform various vocal activities during that time.The researchers conducted various activities such as reciting the alphabet, singing Happy Birthday, and cheering for UMD’s mascot by repeatedly shouting “Go Terps!” In order to measure the amount of viral particles exhaled by volunteers, each 30-minute session of breathing with a mask was compared to a 30-minute session with no mask. “Our study data indicates that a person with mild COVID-19 symptoms who is not wearing a mask exhales just over two infectious doses per hour,” explained Dr. Jianyu Lai, the first author and a postdoctoral researcher at the PHAB Lab.
When a person wears a properly fitting N95 mask with a duckbill design, the risk of particles escaping decreases significantly. The duckbill N95 mask was found to block 99% of large particles and 98% of small particles. According to Milton, the success of the duckbill design can be attributed to its tight seal, effective filter, and spacious air area for breath to circulate.
In contrast, KN95 masks, which are widely used disposable masks, were not found to be more effective than cloth or surgical masks. The study revealed that a popular brand of KN95 masks had more air leakage compared to duckbill or other masks studied, as they do not conform well to the face. Additionally, the powerful filter of KN95 masks with more flow resistance exacerbates this flaw.
It pushes air out of the mask at the sides instead of through the filter, which lets more virus particles escape into the surrounding air.
Cloth masks also performed better than both KN95 and surgical masks. Milton suggests that cloth masks with greater coverage wrap around the face and create a better seal than KN95 or surgical masks. Cloth mask filters also have lower flow resistance, allowing breath to pass through the filter without leaking out the sides of the mask.
Milton stated that limiting the amount of viral particles in the air is a crucial way to control highly contagious respiratory viruses in general. This is especially true for the current situation.The COVID-19 virus has become more transmissible over time, particularly with the Omicron variant breaking through immunity from vaccinations or prior infections. Dr. Milton emphasizes the importance of non-pharmaceutical responses such as wearing masks, and highlights the need for studies to identify the most effective types of masks. The researchers aim for their findings to influence health policies, especially when dealing with potential outbreaks of bird flu or the common flu. They recommend the use of Duckbill N95 masks.As stated by Lai, the use of UV light could become the standard of care in high-risk environments like nursing homes and healthcare settings. This would offer a simple and affordable solution to help control the spread of severe respiratory viruses during future outbreaks. The study involved researchers from the UMD School of Public Health, the UMD A. James Clark School of Engineering, and the World Health Organization Collaborating Centre for Infectious Disease Epidemiology and Control at the University of Hong Kong, China. The research was supported by Prometheus-UMD, sponsored by the Defense Advanced Research Projects Agency (DARPA).Research projects were supported by the Defense Advanced Research Projects Agency (agreement N66001-18-2-4015), the National Institute of Allergy and Infectious Diseases Centers of Excellence for Influenza Research and Surveillance (contract 12-HHSN272201400008C), and the Centers for Disease Control and Prevention (contract 200-2020-09528). Additionally, funding was provided by the Bill & Melinda Gates Foundation and The Flu Lab.
