Yes: open the “Notification Preferences” (User → Preferences → Notification Preferences) and activate the “Disable Notifications” tick just below the title. This way you will no longer receive any notifications from any courses, either by e-mail or within the site.

If you wish to disable only email notifications, but not those within the site, from the “Notification Preferences” page change all status indicators under the e-mail column from On to Off.