pardon?

Have realised that the reason I'm so deaf is ten years of travelling by tube. According to this article, decibels average at 88 or 89 db, louder than the level at which employers should provide ear protection. Not sure whether it helps that I normally wear a walkman (or an iPod now!) which blocks out the sound or whether I'm getting more damage by turning up the volume to play over the sound of the tube!