Is a Filter Needed for Face Masks?
At this point in the evolution of the 2020 COVID-19 pandemic, it's well understood that a face mask is an essential part of any personal protection strategy. Many states have required people to wear face masks out in public, and recently the CDC has also announced that a fabric face mask reduces the spread of covid-19 by up to 80%, a very important statistic to note to help stop the spread and give us enough time for the scientists and disease prevention specialists to develop a cure or vaccine.
Benefits of Face Mask Filters
Many people have asked “is a filter needed with a face mask?” The answer is “yes”—that is, if you want to improve the mask’s efficacy. Depending on the material that the face mask is made out of, a face mask filter insert can be a very helpful addition to any face mask by significantly increasing the protection the mask itself offers. Face mask filters boost the performance of a face mask and can allow wearing masks which otherwise wouldn’t have adequate protection. This is great because as new masks are designed, there are fun or fashionable masks that look great but may not have the best protection.
Face Mask Fabrics
Face masks come in all shapes and sizes and are made of many different materials. As recommended by the CDC and found by the latest scientific studies being done, the best-performing materials are generally tightly woven natural fibers such as a high thread count cotton. For example, cotton flannel which has a fuzzy pile and tight weave, acts as a great filter. Other fabrics that are found to be effective are blended fabrics or fabrics with a lot of fibrous material that acts as a mechanical filter to catch particles. Blended fabrics do well because they have a variety of fibers that form a more intricate network to catch particles. Finally other fabrics that have been found to be effective are high electrostatic (think static cling!) fabrics such as a 90% polyester 10% spandex chiffon which creates static to help attract particles to it in the air.
This all said there are still certain limitations with fabrics and other materials that generally don't allow fabric face masks the same level of protection as an N95 mask. A good way around this is wearing a filter in the mask. Many masks are now made with a filter pocket so that you can add your own filter. A filter adds another layer of protection to trap particles and liquid that might not be caught by the face mask alone. Therefore, consider the following about any filter how well it:
- Blocks harmful particulates and moisture
- Allows adequate breathing
- Can be washed or sanitized and reused
Levels of Filtration
There are many kinds of face mask filters available for purchase. One of the most common types of filters seen is the PM 2.5 filter. These filters offer some additional protection but are not always effective at preventing against COVID-19 spread because they haven’t shown effectiveness when it comes to particles smaller than 1 micron and the coronavirus comes in at 0.1 microns. Also these filters tend to be small and not offer full coverage without air leakage. Therefore the PM 2.5 filter is not the best option.
Other newer technology filters have appeared in the market since the pandemics beginning. Some advertise different levels of protection based on the HEPA or MERV scales, two different ways of describing the level of particles that a material catches. These ratings are commonly used in household filter systems as well as face masks. The most important thing about any filter to keep in mind is to get a high level of particle filtration and make sure that the filtration covers particles of 0.3 microns or smaller. 95% and higher are the best efficiencies and are in line with an N95 face mask. This consideration will necessitate a HEPA rating of 11 or higher and a MERV rating of 16 or higher.
Blocking Moisture
Another great function for a face mask filter to have is to block moisture. COVID-19 is spread through wet particles that come from people's sneezing and coughing and other bodily fluids that may be expelled into the air. Scientists have found that blocking moisture droplets is just as important as blocking particles. If a droplet contacts your body there's going to be more virus exposed to your system.
Breathability
Just as important as a high level of filtration is a high level of breathability. If a material is not breathable then the airflow will be harder with more resistance through the material and will cause the airflow to go around the sides as opposed to through the material, thus defeating the purpose of the mask. Also, if a mask has a good seal but the material is not breathable, it can cause serious medical issues for the wearer.
As we know, oxygen is an important part of breathing and maintaining healthy lung function so a restricted intake of oxygen can cause lung pain or issues especially in patients who might have respiratory or other health issues that reduce their lung function or oxygen levels.
Think of it this way—if you go to high altitudes but you are used to being at sea level there's less oxygen in the air. When there's less oxygen in the air it's harder to breathe. People living at higher altitude have already adapted to pulling more oxygen from the air and using it more efficiently. Wearing a mask that does not allow enough oxygen to your body is similar to going up to high altitudes if you are not acclimated to it. Your lungs and body have to work harder to get the essential oxygen into your system.
Reusability
Finally, the ideal face mask filter will be able to be washed or sanitized so that it can be reused. Many people have more restrictions on their finances right now in this difficult time with layoffs, furloughs and economical struggles. Everyone, even those without financial strain should appreciate a face mask filter that is reusable which saves a lot of money, especially with the high price tag of protective and cleaning supplies during the pandemic. Aside from being affordable and economical, reusable filters are environmentally friendly and help cut down on precious resources used in manufacturing and landfill garbage.
Best on the Market
Taking all of this into account, there are a couple of face mask filters that shine out as the best available in the market. One of these filters is made by a company called DragonWise, a small USA-based woman, veteran-owned company who embraces the ideals of small business and helping others. The Dragonscale MERV 16 Face Mask Filters, use a brand new technology that rival the efficacy of N95 masks. They are sold online on DragonWise’s website as well as on Etsy alongside other protective products including handmade and custom fabric face masks.
The Dragonscale Face Mask Filters have an extremely high MERV and HEPA ratings, and block 95% of 0.3 micron particles. Worn in a face mask, they will boost the mask’s filtration efficiency to over 99%. They also have the moisture repelling layer that will block cough & sneeze droplets before they hit the face. Finally, they are the gold standard for reusable face mask filters. With their unique DragonWise Filter Care Method, the filters can be washed or sanitized up to 8 times, bringing the cost of use down to under $0.39 per day. Other comparable filters will cost three to five times that per day because they are not reusable.
Therefore, DragonWise’s Dragonscale Face Mask Filter is rated as our number one face mask filter insert. For those who are interested in making their own filters, see our analysis of the best and worst DIY face mask filter materials.
In conclusion, although a face mask filter isn't required, the right filter can potentially boost well-fitting fabric face masks to the same level of protection or even higher than an N95 mask. Since many people do not find themselves in places where they might need the protection of masks such as the N95, KN95, or surgical masks, using a filter in an ordinary 1- or 2-ply cloth mask allows the home user security and a very high level of protection. Therefore, medical face masks required for medical personnel and first responders will remain in abundant supply when the need arises.
References
Aydin, Onur, et al. Performance of Fabrics for Home-Made Masks Against the Spread of Respiratory Infections Through Droplets: A Quantitative Mechanistic Study. 20 July 2020, https://www.medrxiv.org/content/10.1101/2020.04.19.20071779v2.
CDC. “Coronavirus Disease 2019 (COVID-19).” Centers for Disease Control and Prevention, 11 Feb. 2020, https://www.cdc.gov/coronavirus/2019-ncov/prevent-getting-sick/diy-cloth-face-coverings.html.
Centers for Disease Control and Prevention (CDC). “Laboratory Performance Evaluation of N95 Filtering Facepiece Respirators, 1996.” MMWR. Morbidity and Mortality Weekly Report, vol. 47, no. 48, 11 Dec. 1998, pp. 1045–1049, https://pubmed.ncbi.nlm.nih.gov/9869077/.
Konda, Abhiteja, et al. “Aerosol Filtration Efficiency of Common Fabrics Used in Respiratory Cloth Masks.” ACS Nano, 24 Apr. 2020, https://pubs.acs.org/doi/10.1021/acsnano.0c03252.
US EPA, OAR. “What Is a HEPA Filter?” US EPA, 19 Feb. 2019, https://www.epa.gov/indoor-air-quality-iaq/what-hepa-filter-1.
US EPA, OAR. “What Is a MERV Rating?” US EPA, 19 Feb. 2019, https://www.epa.gov/indoor-air-quality-iaq/what-merv-rating-1.
Cherrie, John W, et al. “Effectiveness of Face Masks Used to Protect Beijing Residents against Particulate Air Pollution.” Occupational and Environmental Medicine, vol. 75, no. 6, 2018, pp. 446–452, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5969371/.
