A 58-year-old man is brought to the physician because of a non-productive cough for 2 months. He has not had fever, wheezing, orthopnea, paroxysmal nocturnal dyspnea, or chest pain. He had a non-ST elevation myocardial infarction 3 months ago that was managed medically. Current medications include aspirin, ticagrelor, ramipril, metoprolol, and rosuvastatin. He has smoked one pack of cigarettes daily for 30 years. The lungs are clear to auscultation. There is no pedal edema. Which of the following is the most likely cause of his cough?