Hope Lanter explains how noise damages hearing by destroying hair cells in the cochlea. Loud sound bends these cells like grass in wind, and when they break, the damage is permanent. Higher pitches suffer first because of how the cochlea is structured.
Why is noise so bad for our hearing? It seems pretty obvious, it's loud sounds causes hearing loss, but why? If you think about the cochlea, that's our hearing nerve, it has little rows of hair cells. They look a lot like grass, basically little blades of grass. What I've always thought about with this is that if you were to basically run across your grass every single day in the same place, or you ran back and forth many, many times in the same day, you're going to see that that grass eventually starts to die. You create a damaged path there that can't be reversed. So what happens is that the longer we're exposed to those sounds, the less likely it is that we'll have any hearing ability in those places where the damage is occurring. The shape of the hearing nerve, the cochlea, is basically one where the first curve of that is where we get most of the damage. It's a fluid-filled space, and so the first wave crashes in one specific area, and that's why you oftentimes see that the hearing loss happens in the higher pitches regardless of the pitch of the sound that you've been exposed to. So if you're in a loud factory with a boom kind of sound, doesn't matter, it's still damaging that one area the most. And so what we see is that over time hearing loss is irreversible and the damage is so great that it can create pretty significant hearing loss for people who are exposed to noise over time.
