Hi there...I have asthma as well and like you, it only really bothers me in the winter...I did have a incident in training while doing firefighting...I had to put on the PBE (smoke hood with concentrated O2) and "fight" a fake fire...I was running up the aisle with the PBE on and started gasping for breath and had a full blown asthma attack...I think it was the combination of stress, running and the fact that I had on a PBE (with limited O2) right in my face- I had never had an attack like that before or since...My company hadn't known about my asthma before this but they were great...At my new company (been here 3 yrs) I told them upfront and they have been excellent...I would be honest since you never know what the situation will bring, particularly in a stressful situation! Good luck!
Cdn