Oxygen will enhance nitrous and there is really not that much difference between welding O2 and medical grade except the paperwork. It usually comes from the same bulk tank and they are pretty careful with it because contaminants tend to go boom. I certainly trust O2 from the welding store more than "food grade" nitrous from China and that is one of the biggest sources, no matter where it got carted up. I use a pretty good filter (0.3 micron particulates and an oil absorber)