Has anyone noticed a gaseous odor upon exhalation?

I have been diagnosed with COPD and/or asthma. I also had chemo and SBRT radiation for malignant tumors in my lungs. My last scan in Oct. did not show any more malignancy.
I seem to wheeze when I exhale, breathe better through my mouth as I have rhinitis and breathing through my nose often does not provide sufficient oxygen.
My chest felt heavy with mucus when I woke up and this morning I seemed to smell a gaseous odor which dissipated after using Albuterol.
Has anyone experienced this? I’m not quite sure if this was my imagination as the odor was not strong and almost vague.