We know this is a HOT topic among parents sending their kids back to school right now, and we wanted to share some recommendations from aerosol scientist and Nerdy Girl favorite Dr. Linsey Marr and her colleague Dr. Aaron Prussin from Virginia Tech.
We are posting their advice below:
“The most important factors to consider for kids masks are:
1) COMFORT. If your kid won’t wear the mask because it’s uncomfortable or hard to breathe through, then it’s not helping.
2) FIT. The mask should fit tightly with no gaps. Gaps are most common at the sides of the cheeks and around the nose. If there are gaps, air can easily pass through them rather than the mask material, so viruses will, too. A bendable nose bridge is key for ensuring a good fit.
3) FILTRATION. Certain materials, such as the meltblown non-woven polypropylene used in surgical masks and high efficiency particulate air (HEPA) filters, are designed to remove small particles. They do this not by sieving out particles but rather by mechanisms that make particles collide with and stick to the fibers of the material.
Masks are categorized below according to our judgment, based on a combination of effectiveness (lab performance + real-world use) and kid-friendliness. We are parents of kids ages 4-13 and experts in virus transmission, aerosol science, and mask performance.
Any cloth or surgical mask is better than no mask.
Double mask with an ASTM-certified surgical mask and a tight-fitting cloth mask; or use an ASTM-certified surgical mask with a fitter, such as the Badger Seal Mask or Fix the Mask, to seal the mask to the face. A surgical mask is an excellent filter, but by itself fits poorly and leaks. The cloth mask or fitter is intended to improve the fit of the surgical mask.
a) A genuine KN95 or KF94 made to fit kids. These have very high filtration efficiency, like an N95, and are designed to seal to the face. Fit is critical! These appear to be widely available online, so we are not compiling a list of them. Unfortunately, counterfeiting is a problem, and we do not have information about reliable brands.
b) Masks that meet the ASTM F3502 standard are tested for filtration efficiency, breathability, and leakage. The standard was introduced in spring 2021, so there are not a lot of masks in this category yet. Level 1: ≥20% filtration efficiency for submicron (0.1 μm) particles and airflow resistance ≤ 15 mm H2O. Level 2: ≥50% filtration efficiency for submicron (0.1 μm) particles and airflow resistance ≤ 5 mm H2O. Seek a mask with a higher filtration efficiency, lower airflow resistance, and less leakage.
c) A tight-fitting cloth mask with a high-quality filter can be very effective. Many cloth masks with a pocket for a filter are available. Here, we only list those that come with a well-described filter that spans the mask. Smaller filter inserts are less effective because it is easier for air to flow around them rather than through them.”
Aaron J. Prussin, II, Ph.D. (@ajprussin on Twitter)
Linsey C. Marr, Ph.D. (@linseymarr on Twitter)
Civil and Environmental Engineering
Another resource with specific kids mask brands created by Dr. Eva Enns from the University of Minnesota School of Public Health