The Three-Layer Defense in Masks: The Truth About Disposable Medical Masks
The disposable medical mask hanging behind
the ears is actually a sophisticated "micro defensive structure", and
the collaborative design of its three-layer structure holds the core wisdom to
fend off pathogens.
The outer blue water-repellent non-woven
layer serves as the first barrier. Adopting the "lotus leaf effect"
technology, it can block splashing droplets like an umbrella and also prevent
reflections from shadowless lamps from interfering with medical staff's
operations. The middle melt-blown fabric filter layer is known as the
"heart" of the mask. Ultra-fine fibers, only 2 microns in diameter,
form an electrostatic field after electret treatment. Through four mechanisms
including diffusion deposition and inertial interception, it can capture over
95% of 0.3-micron particles — a size that is a common carrier of viruses. The
inner white hydrophilic non-woven layer is responsible for absorbing moisture
exhaled, keeping the wearer dry during long periods of use.
However, the protective effect is often
greatly reduced due to common misuse. Experiments show that spraying alcohol on
the mask or soaking it in boiling water damages the structure of the melt-blown
fabric, causing the protective layer to fail and allow leakage. Wearing two masks
overlappingly not only fails to improve the basic 95% filtration rate but also
doubles the breathing resistance. Moreover, wearing the mask inside out (white
side out and blue side in) makes the water-repellent layer absorb droplets
inward, which instead increases the risk of infection.
Choosing the right mask is also crucial:
ordinary medical masks complying with the YY/T0969 standard are suitable for
daily protection, while medical surgical masks meeting the YY0469 standard can
resist body fluid splashes of over 16kPa, making them suitable for medical
scenarios. A mask should be replaced after 4-6 hours of single use, and must be
"used and discarded immediately" in high-risk environments.
Every detail in the design of these thin
three layers is a vital line of defense to block the spread of viruses.
