<qa>  What is the maximum amount of salbutamol?After the initial enrolment and confirmation of the entry criteria, subjects will perform spirometry before and following bronchodilation with salbutamol up to 400 ug. They will then enter a 4-week run-in period during which all subjects will be withdrawn from inhaled corticosteroid containing products. They will then be treated with formoterol via Turbuhaler 12 ug BID and short-acting beta-2 agonists as needed PRN. Subjects may also have LAMA either tiotropium 18 ug once daily or glycopyrronium 50 ug once daily at the discretion of the attending physician. At the end of the run-in phase, eligibility will be confirmed and then subjects will undergo pre and post-spirometry, low-dose thoracic computed tomography CT and bronchoscopy. One week post-bronchoscopy, the subjects will be randomized to a 12-week treatment period. Subjects may also have LAMA at the discretion of the attending physician. At the end of the 12 week treatment period, the subjects will undergo pre- and post-spirometry and 2nd bronchoscopy. The subjects will be re-evaluated one week following bronchoscopy and then discharged from the study. All subjects with pulmonary nodule requiring follow-up will be evaluated by the attending physician and the pulmonary nodule will be investigated as per guidelines of the Fleischner Society. 