Find a letter in the Independent from the Director-General of the Cosmetic Toiletry Perfumery Association. He is absolutely right to say that the presence of fragrances in the air is not proven to cause allergic reactions, because, in science, nothing is capable of being proven. So the "not proven" is a good standby to continue doing exactly as you please irrespective of any consequences. It took 20 years and 20,000 scientific studies to "prove" that smoking caused lung cancer.
The major problem with perfumes is not allergy, although classical allergic skin reactions are indeed possible to perfumes, but intolerance reactions. There is now good statistical evidence from the Children of the 90's study, as well as my general practice based observations, to indicate that some people are better off in a perfume free environment.
Industry is naturally responding to this with denials, but it would do better by making perfume free options available for consumers. And the challenge for public health authorities is for creating perfume free public spaces. In this regard California is about 50 years in advance of the UK.