Hey Tracey, measuring the air temperature will only tell you half of the story, you need to consider all the other factors that add to comfort levels to arrive at the right solution.

WorkSafe have produced this guidance document on Workplace Discomfort which you may find of use.

Safe and Sound advertise Biological Exposure Monitoring services within their brochure.

I'm not sure how far outside of Christchurch they operate though.

Best to follow WorkSafe's advice contained within their Safe Use of Machinery Best Practice Guidelines by engaging with a competent person (experienced at working with and using AS 4024 or equivalent or higher standards).