 At 4 of the visits, which will happen every 4 weeks, you will be asked to perform spirometry and sputum induction. Spirometry is a breathing test which requires you to take a deep breath in and blow it out as hard and fast as you can. From this we can measure baseline airway function. This takes about 15 minutes, has no side effects and is a routinely performed test on patients in our clinical pulmonary function laboratory. 