What environmental information is helpful when investigating the causative agent of occupational asthma in an office worker?

I have recently seen an office worker with possible occupational asthma. I have asked her to complete serial peak flows using the OASYS diary. The office is not based in a factory or near an industrial site. The employee does not have any other jobs. The work involves use of display screen equipment in a telephone contact centre. There may be photocopier within the office. If this is occupational asthma what environmental information should I obtain from the employer? I have already thought of the following: cleaning agents [biocides etc], carpet fittings, pesticide applications [what and when and where?], type of ventilation system and its maintenance [including routine cultures for thermophilic organisms etc]. sources of latex. Could you please review my list and recommend what else I should be asking? Thank you.

Occupational Asthma, Health Professional, 6/21/2006, 6/21/2006,

Occupational asthma can occur in ordinary offices, the causes are difficult to find. Your list is good, I might add odorants (the sort that plug into an electricity supply) and perhaps plants (the only cases I know were of workers who serviced the plants, particularly weeping fig, but many of these are now made of plastic)

6/24/2006