Mask Resources and Recommendations

Resources and Suggested Best Practices for Mask Wearing for the TRS ECC Community and Congregation


In keeping with the CDC’s call to members of the public to “Improve the Fit and Filtration of Your Mask to Reduce the Spread of COVID-19,” the TRS COVID Advisory Group (CAG) put together a supplemental resource document to provide the TRS ECC Community and Congregation with a consolidated list of some options and best practices for mask wearing. Especially as we return to TRS for community and worship activities, ensuring that each person is wearing the best mask for their protection and others will be crucial.

Upgrade your mask with the 3F’s: Filter + Fit + Function

If you are currently using a cloth mask and would like to know more about how to upgrade, three helpful characteristics to consider are the 3 F’s: Filter, Fit, and Function. Upgraded masks are better able to filter small particles that carry viruses because they are made of special materials like multiple layers of nonwoven/electrostatic fibers or nanofibers. One measure scientists use for this is % VFE (Viral Filtration Efficiency). Cloth masks can vary widely between 20-70% VFE while N95s use materials with 99% VFE. But to be more protective, a mask needs to fit the face tightly, covering the nose and mouth, and creating as best a seal to the face as possible without gaps. (For example, while N95s use 99% VFE material, they must fit the face closely to provide a certified 95% VFE level of total protection.)  Finally, a mask needs to function, it needs to be comfortable and breathable so you can actually wear it for longer periods of time. The following infographic illustrates the 3Fs and where different upgraded masks fall on a spectrum of effectiveness:

Beware of counterfeit masks

There are a lot of counterfeit masks circulating. Please be cautious if purchasing masks from Amazon, e-bay, or other e-commerce sites because these sites do not effectively screen out counterfeit products. Also, please avoid KN95 masks that are not FDA EUA approved (you can check the list here:

Additional Information on Mask Options and Resources

The links below contain suggestions of particular products and brands that have worked well for members of the TRS community, and that are reputable brands. TRS does not endorse or promote buying any one particular brand or company over another, but has pulled together these suggested links in case they are of interest for the community. These resource links are for masks that can promote effective filtering, fit, and function, but there are also many other types and brands of masks available as well.

For adults

  • KF94 masks (the Korean equivalent of N95s), are becoming more widely available in the US. The biggest trusted distributor in the US is, and some TRS community members particularly like the Bluna Facefit. The Bluna Facefit tends to work well for women or men with smaller faces. For those with larger faces, the BOTN brand tends to work well.
  • KN95s (the Chinese equivalent of N95s), have been widely available in the US for months, but there are a number of counterfeit masks circulating, even in stores. Your best bet for a trusted KN95 is the Powecom brand, available here:
  • Nanofilter masks are a newer technology, some have KF94 or the European equivalent FFP2 certification. While they are not as proven over time as the standard protective mask material that is nonwoven/electrostatic, they are more cleanable/washable/reusable. This nanofilter mask has a 90% VFE, and this is an FFP2 nanomask. Some masks have nanofilters sewn inside of cloth – this one is liked by some in the TRS community (has kid sizes too).
  • If you want to double mask using a surgical mask inside of a tight-fitting cloth mask, please make sure you use one that is rated ASTM 2 or ASTM 3. Here is a high quality ASTM 3 surgical mask made in the USA: To improve fit, double masking with a tight fitting cloth mask, a mask fitter, knotting/looping, etc is needed. Info about mask fitters is here:

For kids

  • A KF94 that fits age 4+ well is Bluna Facefit Small, and the behealthy site has a few other kid-sized options.  For the 3+ crowd, this Blue 2D mask might fit better as it is a little smaller. For 2 year olds, these options may be too big to fit well, but fit can be improved with a tightening head strap accessory like this one.
  • The Happy Masks nanofilter cloth mask that is available for adults also has kid sizes.
  • Armbrust surgical masks come in a child size, but they work better for older children.
  • Taiwan Masks sells ASTM 2 or ASTM 3 surgical masks that can fit 2-6 year olds or 6+ year olds.

Can I Reuse Masks?

Upgraded masks can be more expensive. What can help with per-use cost is reuse. While most of these masks were originally designed for single use, preliminary research indicates it is possible to reuse them on a limited basis without major degradation of VFE. For nonwoven/electrostatic filters, a maximum of 40 hours of total use is recommended.[1] If wet or soiled the mask should be discarded.  Keep masks in a clean, breathable container, like a paper bag, between uses.[2] Rotate between 3-4 masks to allow 3-4 days between reuse, ensuring virus die-off.[3]

Nanofilters vary but in general are reusable for a longer period of time. For example, the SoomLab HPB mask has no hour limit but can be reused up to 10x (with an ethanol or isopropyl alcohol spray cleaning step, do NOT use soap), and the Happy Mask has a 250 hour limit and a 50x wash limit (hand wash, soap and water). For these two masks, follow manufacturer instructions.

Additional Information Sources to Learn More

If you have any questions about resources and best practices for mask wearing for the TRS ECC Community, please contact Parents Committee Member Angie Boyce (, 650.793.5499)

If you have any questions about resources and best practices for mask wearing for the TRS Congregation, please contact TRS Executive Director Jessica Ingram (, 703.676.3871)