Masks Work. Really. We’ll Show You How
Date Posted: November 3, 2020
Posted In: Discussion,
From NY Times: The public health debate on masks is settled, said Joseph G. Allen, director of the Healthy Buildings program at Harvard. When you wear a mask, “you protect yourself, you protect others, you prevent yourself from touching your face,” he said. And you signal that wearing a mask is the right thing to do.
With coronavirus cases still rising, wearing a mask is more important than ever. In this animation, you will see just how effective a swath of fabric can be at fighting the pandemic.
Masks come in many styles and materials, but they generally work in the same way. Layers of fibers capture large respiratory droplets and smaller airborne particles known as aerosols that can carry the coronavirus.
This process is known as filtration, and a material’s ability to trap particles is called filtration efficiency.
Tightly woven cotton outperforms most common fabrics. A nonwoven material like that of an N95 respirator is most effective.
Let’s take a closer look at how filtration works at the microscopic level.
Here is how the fibers of a cotton mask compare with aerosol particles of different sizes. The coronavirus is about the size of the smallest particles, but it usually travels inside the larger ones.
The fibers present a dense forest that the particles must navigate as they move with the air stream. The laws of physics influence how the particles interact with the fibers and how well the mask can capture them.
Larger particles are easier to trap. They slam straight into the fibers and get stuck when the air stream brings them within touching distance, or when their momentum causes them to veer off course.