Forgot to mention that I'm an ex-smoker too, (quit in 2003), but it would seem that would be more related to one's lungs. I initially had my lungs x-rayed and they were clear. However, I had two older brother that passed away developing lung cancer after invasive surgeries. One of them never smoked, the other had quit for more than 10 years. I asked my doctor to enter me into the lung screening program here in Ontario, Canada and they do a much better job examing your lungs using a scanner and determined that my lungs were clear and fine. So no impact from that either. I've wondered if an allergy might be something to look into, although over the years I've only discovered allergies to wood dust from Rosewood, Spalted Maple, and instant glues like Crazy Glue (cyanoacrylate, an acrylic monomer that turns into plastic when it cures) so far. I stay away from those things and have done so since 2013. I might ask my doctor to refer me for allergy tests.