Significant difficulties in recruiting participants, particularly in the 'cystic fibrosis' group.The constraints placed on participants, in particular the requirement to walk for ten days (5 days in an urban area and 5 days in a green area)

Cystic fibrosis (CF) is the most common autosomal recessive disease that leads to early mortality in Caucasians and affects around 7500 patients in France. Progression of the disease depends on pulmonary exacerbations defined as acute deterioration of respiratory symptoms which ultimately impair lung function and quality of life. Most frequently caused by lung bacterial infections, exacerbations' effects include increased cough, increased sputum production, increased use of antibiotics, dyspnea and decreased lung function. The phenotypic variability of CF suggests the implication of other contributors especially to the CF airway disease. Beside genetic and epigenetic alterations, environmental factors - e.g tobacco smoke, air pollution, temperature changes, food intake - appear as relevant candidates. A previous review has discussed current knowledge on the effects of air pollution on the course of CF disease. Although scarce, the existing epidemiological andexperimental literature suggests a link between exposure to air pollutants and adverse health effects.Although scarce, the existing epidemiological and experimental literature suggests a link between exposure to air pollutants and adverse health effects. The EU sponsored REMEDIA project (Impact of exposome on the course of lung diseases, Grant agreement ID 874753) contributes to the understanding of the influence of the exposome on chronic obstructive pulmonary disease (COPD) and CF. Objective of work package 3 within the REMEDIA project is the development of a mobile environmental sensor toolbox that is capable to assess the external exposome. The biomarkertoolbox was developed and tested in a proof-of-concept study carried out in healthy volunteers. The next step is to validate the collectionof exhaled breath condensate (EBC) in a real-life study. In this aim, the objective of the present study will be to assess the feasibility of EBC collection in CF patients and healthy individuals

Inclusion Criteria:

• Normal blood test
• Negative Cotinine test
• Protocole (RiPH2)
• Normal ECG
• Normal alcohol test
• Lung function with FEV1 predicted ≥ 40% at spirometry.

Exclusion Criteria:

• None