I have a question for everyone, do you think mucus buildup in the airways and lungs, affects the Pulmonary Function Test numbers that we all do on a regular basis. I have asked many Dr.‘s, Respiratory Teheripists, nurses, etc this question. Some say it (the mucus) has no effect at all. Others say they believe it does. My belief is simple “ If you have an object occluding or blocking a tube or pathway then it HAS to effect the flow of whatever substance liquid or gas. Thank-you.