As the winter turns into a second wave and COVID-19 cases begin to pop up across the world, it is clear that by continuing to wear masks in public for the near future, Americans will need to delay the spread. And while surgical masks and cloth masks have become easier to buy, rather than medical ones, many are still opting for handmade or fabric masks.
The consumers of surgical and cloth are drawn to these cloth masks because they are readily available and typically reusable, but what the wearers do not know is that they make a major quality compromise and place the health of others at risk.
The spread of coronavirus is an unprecedented situation, and that means that there has not been enough research on the effectiveness of cloth face masks in slowing the spread of this disease compared to surgical ones. Nevertheless, conclusions can be taken from some of the latest literature on the efficacy of masks.
Surgical masks and its filtration efficacy
Surgical masks are meant to be used to prevent disease transmission from a patient to a health care worker. Sometimes, health care staff depend on them for their own safety. In view of recent developments in preparation for the response of health care workers to global infectious diseases such as H1N1 Influenza, while wearing surgical masks, health care workers may encounter a false sense of protection.
The purpose of this study was to test a double strap tie-on surgical mask's filtration ability. Under FDA testing procedures, the manufacturer claims a 95% performance with a 0.1 um challenge aerosol. Three sizes (polystyrene latex beads: 0.5 um, 1.0 um, 2.0 um) of monodispersed aerosols were used.
The specific objectives were to calculate the selection efficiencies of this mask for the different particle sizes. There were 2 experiments done. Masks were attached to a dummy head in the first one and the edges of the mask were not sealed. In the second one using silicone sealant, the edges of the masks were sealed to the ears, so all penetration was through the mask's filtering content.
Usually, these flat, small, paper-like masks are white and light blue. According to a 2019 report published in Aerosol Science and Technology, about 60 percent of tiny, inhaled particles can be filtered out by surgical face masks.
They are mainly meant to avoid droplets, sprays, and splatters, and studies have shown that it can greatly reduce the spread of respiratory infection by diligently wearing surgical masks in public spaces. Surgical masks are not intended to be used more than once. Ideally, after wearing it you can dispose of a mask.
Cloth masks and its filtration efficacy
For the comparison of the effectiveness of cloth masks with that of surgical masks and controls (standard practice) among healthcare workers in Vietnam, we performed a randomized controlled trial. Among those in the cloth mask group, rates of infection were consistently higher than in the medical mask and control groups. This result shows that those wearing cloth masks were at higher risk of infection. A locally made, double-layered cotton mask was the mask checked.
In a 4-week study period, participants were equipped with 5 cloth masks and were asked to wash the masks daily with soap and water. The poor performance may have been because the masks have not been properly washed regularly or because they have become damp and contaminated.
Some control group participants used surgical and cloth masks, but the poor performance of cloth masks persisted in post hoc analysis when we compared all participants who used medical masks with all participants who used only cloth masks. Cloth mask filtration efficiency varies widely; some materials filter better than others. Cloth mask filtration performance depends on many variables, such as thread count, number of layers, fabric type, and water resistance.
Another study showed that aerosol exposure could also be minimized by handmade cloth masks, but less than surgical masks and respirators. Cotton and towel masks have better security than gauze masks. While cloth masks are often not meant to fit around the face, some materials may fit snugly against the face. One study showed that filtration was increased by the use of nylon stockings around the mask.
Some store-bought masks come with filter pockets; with a pocket for a filter, you can also make fabric masks. As a filter, you can use folded facial tissue; just slip the folded tissue into the pocket of the filter. Adjust the filter regularly for tissues.
May Chu, an epidemiologist at the Colorado School of Public Health, suggests using a polypropylene material filter, a sturdy synthetic fabric that can bear an electrostatic charge, mostly used in upholstery, in an NPR article (which helps it trap small particles). It can improve filtration efficiency from 35 percent to almost 70 percent by applying a polypropylene filter to a two-layer cloth mask.
Surgical masks are more effective infiltration than cloth masks
The different types of cloth masks and surgical masks found that their efficiency of filtration was much lower than that of surgical masks. The authors noted that with handmade cloth masks, where people do not have the expertise or the correct fabric to ensure a tight fit, the risk is even greater. Surgical masks have 70 % more filtration efficiency than cloth masks due to surgical masks manufacturing qualities.