Clean Air for Rare MUcociliary Clearance dIsorders

Inclusion Criteria: * Age ≥6 years * Physician-confirmed diagnosis of CF or PCD, based on internationally accepted criteria. PCD diagnosis will be based on either a) a positive genetic test (bi-allelic disease-causing mutations) or b) TEM class 1 defect, as defined by the European Respiratory Society and American Thoracic Society guidelines for the diagnosis of PCD. CF diagnosis will be based on the diagnostic criteria of the European Cystic Fibrosis Society Patient Registry including: (a) two sweat chloride test values of at least 60 mmol/L, or (b) one sweat chloride test value of at least 60 mmol/L and two disease-causing CFTR mutations, or (c) typical CF features at clinical presentation and two disease-causing CFTR mutations if sweat chloride test value was less than 60 mmol/L or not reported. * Residing in a main household in Cyprus for at least 5 days per week during the study period. * Willingness and ability to provide informed consent (or approval with guardian consent for minors). Exclusion Criteria: * Active smoking * Hospitalization for any condition during the study period or lack of internet access, which is required for continuous data transmission