You fail to say whether this is your email account provided by the internet provider or a throw away space based account.

If you have your account set to preview emails then change it so only he headers are on show. That way the email is not opened and you simply highlight and delete.

For you to know it is porn perhaps you are opening them? NEVER open anything from anyone you do not know, opening it often sends back a message that they have reached a valid address. Hence the large volume of unwanted mail

If this is a space based throw away account then create a new account, notify your contacts and abandon the old accont which will die after a given time frame.

You should have at least 1 or 2 "junk" email accounts to use for anything that you do not want to clutter up your primary email with. Yahoo-GMail-Hotmail are all good for this purpose. Avoid giving out your primary email to all but your most important and trusted contacts.

First off don't just delete them instead with out opening them send them to the junk mail folder that is how your email program learns what you think is junk, by simply deleting them it is not teaching that this is to be considered junk mail.
Definitely if you have your email set so you have a preview pane visible you need to change that, in the settings, it is dangerous to use this.
Do you get and send emails with lists of people's email addresses showing? If so you just answered why you get tons of spam mail. Each of those emails with all those addresses get harvested by the spanner, and they know it is an active email address, so they sell it to other spammers.

What email are you using? Hotmail? Yahoo Other?

If using Hotmail, it has a nice "Sweep feature that both deletes spam emails without opening them and also blocks them.