 While there are Health Canada licensed washout systems available that can determine LCI; these devices have not been adequately validated; thus their use in routine lung function testing is controversial. As part of an international effort to validate multiple breath washout testing to measure LCI, the specific device is licensed in Europe, but as of yet is not Health Canada approved. Thus, testing with this device is considered research. This study will utilize technology to assess lung function in patients undergoing routine lung function testing for clinical indications. In addition, healthy controls of different ages will be asked to perform this lung function test to gain reference data that can be used to interpret LCI in patients with lung disease. 