Masks have been made from a surprisingly wide range of materials over the centuries, from herb-stuffed leather beaks to electrostatically charged synthetic fibers. The specific material matters because it determines how well a mask filters particles, how breathable it feels, and how long it lasts. Here’s a look at what masks have been made from, starting with the earliest versions and moving through to the high-tech options available today.
Medieval and Early Protective Coverings
The earliest mask-like face coverings weren’t designed to filter particles at all. During the Middle Ages in Europe, plague doctors wore the now-iconic “bird beak” masks made of leather. The elongated beak was stuffed with clove, cinnamon, or fragrant liquids, based on the belief that disease spread through foul-smelling air called “miasma.” The aromatic filling was meant to purify each breath. These masks offered no real filtration, but they represent some of the first purpose-built protective face coverings in medicine.
Cotton Gauze in the 1918 Flu Pandemic
When the 1918 influenza pandemic swept the world, cotton gauze became the standard mask material. Researchers at the time tested how many layers were needed to block infectious droplets, and the results depended on the weave density of the fabric. Gauze with a looser weave (around 24 by 20 threads per inch) required seven layers to adequately protect the wearer, while a tighter weave (32 by 26 threads per inch) needed only five layers. That five-layer version packed roughly 220 strands of cotton fiber per square inch.
These gauze masks were simple, cheap, and widely distributed. By the 1940s, washable and sterilizable versions became standard in Germany and the United States. A few layers of cotton gauze were held together by a metal frame or cotton strings, then reused after disinfection.
The First Modern Surgical Mask
During the 1910 Manchurian plague, a physician named Wu Lien-teh designed what’s widely considered the first modern surgical mask. He improved on existing designs by adding more layers of gauze and developing a better system for tying the mask tightly against the face, preventing gaps where airborne germs could enter. His design was a pivotal step toward the layered, fitted masks used in medicine today.
Modern Surgical Mask Materials
Today’s disposable surgical masks use a three-layer design, and the key material is polypropylene, a lightweight synthetic plastic. Each layer serves a different purpose. The outer layer is hydrophobic, meaning it repels water droplets. The middle layer is a meltblown polypropylene filter that catches tiny particles. The inner layer is a soft, absorbent sheet that wicks moisture away from your face.
Surgical masks are rated at three performance levels under an industry standard called ASTM F2100. Level 1 masks resist fluid penetration at 80 mmHg of pressure and are used for low-risk situations. Level 2 masks handle 120 mmHg, and Level 3 masks withstand 160 mmHg, making them suitable for procedures with significant splash risk. Higher levels also maintain breathability, with all three allowing air to pass through at similar resistance.
N95 Respirators and Electrostatic Filtration
N95 respirators also use meltblown polypropylene, but with a critical twist: the fibers carry a permanent electrostatic charge. This charged layer is called an electret, and it works by attracting particles the way a statically charged balloon sticks to a wall. The charge pulls in tiny airborne particles through direct electrical attraction and also induces a charge on nearby particles, drawing them in as well.
This electrostatic effect is what allows N95s to filter at least 95% of airborne particles while still being breathable. Without the charge, achieving that level of filtration would require packing the fibers so tightly that it would be difficult to breathe through the mask.
Reusable Elastomeric Respirators
Industrial and healthcare settings also use reusable respirators with rigid or semi-rigid facepieces. The body of these masks is made from elastomeric materials, which are flexible, durable rubbers that form a tight seal against the skin. Common options include silicone, neoprene, and ethylene propylene diene monomer (EPDM) rubber, along with proprietary blends. The replaceable filter cartridges inside these respirators typically use the same polypropylene electret technology found in N95s, but the rubber housing can be cleaned and reused indefinitely.
Cloth Mask Fabrics and Their Filtration
During the COVID-19 pandemic, homemade cloth masks became widespread, and researchers tested how well common household fabrics actually filter particles. The results varied enormously depending on the fabric type and weave tightness.
For particles larger than 0.3 microns (roughly the size range of respiratory droplets), a single layer of high-thread-count cotton (600 threads per inch) filtered an impressive 98% of particles. A single layer of natural silk caught about 56%, while chiffon (a polyester-spandex blend) managed around 73%. Flannel, a cotton-polyester blend, filtered only about 44% in a single layer.
The most effective approach was combining different fabrics. Hybrid masks pairing cotton with silk, chiffon, or flannel consistently filtered over 90% of larger particles and over 80% of smaller ones. The combination works because different fabrics use different filtering mechanisms: tightly woven cotton physically blocks particles, while fabrics like silk and chiffon generate a mild electrostatic effect that traps smaller particles the cotton might miss.
Antimicrobial Metals in Mask Filters
Some newer mask designs incorporate copper and silver nanoparticles directly into the filter material. These metals don’t just trap viruses; they actively destroy them on contact. In laboratory testing, surfaces embedded with copper-silver nanohybrids inactivated SARS-CoV-2 within one to five minutes. One approach involves sputter-coating existing respirator filters with a thin layer of silver nanoclusters in a silica composite, which completely eliminated detectable virus in testing. These antimicrobial masks aim to reduce the risk of touching a contaminated mask and transferring the virus to your hands or face.
Transparent Masks for Communication
Standard masks create a real barrier for people who are deaf or hard of hearing, or for anyone who relies on reading facial expressions and lip movements. Transparent masks solve this by replacing part of the fabric panel with a clear plastic window. These windows use fog-resistant coatings to maintain visibility during breathing. The rest of the mask is typically made from the same polypropylene layers as a standard surgical mask, maintaining filtration while allowing face-to-face communication.