Air Swallowing Leading to Flatulence

I have an odd problem. I use a nebulizer that contains albuterol and iprotropium for treatment of COPD. To use it you inhale through your mouth. It seems I am swallowing the mist as well getting it to my lungs. This results in flatulence, unrelated to undigested food. By the way, I have never had a digestion problem and have an "iron stomach."

What am I doing wrong that I am swallowing air (and the medication)? Is there some trick to avoid this from happening? Also, is the swallowing of the mist harmful?

Many thanks to anyone who can help.