In these sentences, I'd say they are interchangeable.
If you use "help with" instead of "help" though, the sentence will change a little bit.
1. If you get rid of your car you could help with the environment.
2. Listening to music while I'm working helps with my concentration.
3. I swam gently back and forth in the pool and i really helped with my back.
This is honestly just one of those things no one will be able to teach you, in my opinion.
Some people will use "help with" others prefer "help." In these sentences, both are acceptable.
Good question. :)