UK passengers travel on a range of global airlines. Within Europe, we suggest that any mandatory system to be fitted to commercial passenger aircraft would have to be required and approved by the European Aviation Safety Agency, on the basis of evidence that it was necessary and fit for purpose i.e. capable of detecting any specific items of concern in the circumstances where these might occur. In the UK we are conducting research to ascertain what substances are in cabin air, and at what concentrations, both in normal circumstances and during occasional "fume events". When we have obtained and assessed this information, it may be appropriate for the UK to recommend some kind of detection systems.