Tor does a good job and very simply.
Your IP has nothing to do with emails. Email is a different system than browsing, the 2 are not related.
It depends on where you get your emails from, IE your ISP or hotmail/google/yahoo type.
If you use outlook for offline emails (POP3) then your emails come from your ISP and the spammers would send them to that IP address, not your PC's IP address. Same with online emails like google (gmail) yahoo or hotmail, the spam gets sent there.
Spammers work by sending email to 1000's of email addresses randomly. So they would say start at "fred1@yahoo . com" and keep adding numbers or characters like "fred2@yahoo . com" they dont target by IP address because that IP address would have to have an email server running in order to recieve emails.
Also you can never fully hide your IP as it's fixed by your ISP and cannot bechanged unless you disconnect from the internet or your ISP renews it for another one.