WITH regard to Greg Russell and his exclusive about air ionisers: during my time as a Royal Army Medical Corps medic, I spent time on the staff of the High Dependency Unit at the Cambridge Military Hospital in Aldershot. One of the items of electrical equipment, which was left permanently running, was a little machine, not unlike in appearance a small fan heater. This machine, we were told, was an “ozone generator”. We medics, of course, thought it was just a bit of kit which reduced the very unpleasant smells which inhabit units like this one. But no, we were told, there was an anti-microbial benefit to ozone and this machine was helping keep the bugs down. This was in the 70s.