People often question how a mask with filter openings larger than the size of the particles work. This sketch demonstrates how layers of large filter opening can still stop small particles.
Do note, it is still possible for some particles to get through, similar to how most air filters are not 100% efficient.
This does not simulate other filtering mechanism like Brownian motion and electrostatic charge.
Click on the black spaces to generate particles. Click on the appropriate button to turn on and off breathing simulation.