List pros and cons of lowering the capabilities of my ears by listening to loud music (70-75db) in order to withstand the incredibly loud sound of screaming kids at school.
Yikes!  I do not recommend that you intentionally damage your hearing.  If you need to block out the incredibly loud sound of screaming kids at school, I suggest that you wear earplugs. 

To humor your request, here are the pros:
* None.

Cons:
* Permanent hearing damage.