Simon, out of interest do you sleep throughout the night with air-conditioning switched on?
This may be of interest:- (Google)
Yes, air conditioning can cause bronchitis symptoms:
Mould
A dirty air conditioner filter can lead to condensation, which can cause mould and mildew to grow. Mould can cause respiratory problems like bronchitis, coughing, and sneezing.
Bacteria and dust
The components of an air conditioner can harbor bacteria and dust, which can cause respiratory problems.
I regularly get my air- condition unit cleaned, courtesy of my landlord.