We’ve all been told to wear face masks to reduce the spread of coronavirus, but it turns out the material your mask is made of may affect your risk, a new study suggests.
An N99 mask, which filters out almost all major and minor particles, reduced the risk of contracting COVID-19, the disease caused by the virus, by 99 percent.
But a simple cotton T-shirt or scarf tied around the face was much less effective and only reduced the risk by about a quarter.
The University of Arizona team says the findings prove that not all face masks are created equal and can advise Americans on what to wear and what not to wear when going out in public.
N99 masks (shown) that filter 99% of the particles reduced the risk of coronavirus infection by 99% in 30-second settings and by 94% in 20-minute scenarios
Scarves reduced the risk by 44% after 30 seconds and by 24% after 20 minutes, and cotton T-shirts were just a little better than not wearing a mask. Pictured: a man wearing a raccoon mask in an area called the Capitol Hill Autonomous Zone (CHAZ)
For the study, published in the Journal of American InfectionsThe team looked at 12 different types of masks and collected data from various studies on the effectiveness of masks.
They then created a computer model to simulate how well different masks would protect short 30-second and long 20-minute scenarios.
Researchers took into account the volume of air that a person breathes over time and the amount of virus concentration in the air.
Unsurprisingly, wearing any type of face cover reduced infection risk by between 24 percent and 99 percent.
The results showed that N99 masks, which are designed to prevent 99 percent of the particles from entering, were the most effective.
After N99 masks, the next most effective N95 masks were surgical masks and vacuum filters that can be placed in fabric masks (above)
They reduced the average risk by 99 percent in 30-second settings and by 94 percent in 20-minute scenarios.
“N99 masks, which are even more efficient at filtering airborne particles than N95 masks, are clearly one of the best options for blocking the virus,” said lead author Amanda Wilson, a PhD student in environmental health sciences the University of Arizona, in one statement.
‘But they can be hard to come by and there are ethical considerations, such as leaving them available to medical professionals. ‘
The next best options were the well-known N95 mask, a surgical mask and – unexpectedly – vacuum filters, which can be placed in fabric masks.
Vacuum filters reduced infection risk by 83 percent in 30-second scenarios and 58 percent in 20-minute settings.
Among other things, non-traditional materials were the materials that the researchers found most effective tea towels, cotton mix fabrics and antimicrobial pillowcases.
Scarves only reduced infection risk by 44 percent after 30 seconds and by 24 percent after 20 minutes, and cotton T-shirts were just a little better than not wearing a mask.
Wilson explained that dense fibers filter better than fabrics that are thinner.
Therefore, higher thread counts lead to higher effectiveness. There’s just more to block the virus, ”she said.
“But some masks (such as those made of silk) also have electrostatic properties, which can attract smaller particles and prevent them from passing through the mask.”
For a mask to be effective, Wilson says it has to squeeze the nose to form a seal and never sit under the nostrils.
“Good use of masks is so important,” said Wilson.
“We also focused on masks that protect the wearer, but they are most important to protect others around you if you are infected. If you put fewer viruses in the air, you create a less contaminated environment around you. ‘
Wilson points out that no mask can reduce infection risk to zero, so it’s important to remember to socially distance, wash your hands, and wear a mask in public.