The "clean" smell that is sometimes described as similar to the scent air after a heavy rain or thunderstorm. In-fact the scent in both cases is caused by ozone. Ozone occurs naturally after lightning storms, and is also the sanitizing agent we use. If you do not like the smell, just let the tube sit outside the bag for a while. Further, you can run your CPAP for a few minutes before you put it on to further reduce the scent.