Hospitalised Patients  Inclusion Criteria:  Hospital admission with an acute respiratory diagnosis Participant is willing & able to give informed consent for participation in the study Aged 18 years or above Able (in the Investigators opinion) & willing to comply with all study requirements  Exclusion Criteria:  Unstable or life-threatening cardiac disease including myocardial infarction or unstable angina during current admission. Any other significant disease or disorder which, in the opinion of the Investigator, may either put the participants at risk because of participation in the study, or may influence the result of the study, or the participant's ability to participate in the study. Known pregnancy  Matched Controls  Inclusion Criteria:  Aged 18 years or above Patients with stable chronic respiratory conditions or healthy volunteers Able (in the Investigators opinion) & willing to comply with all study requirements  7.3.2 Exclusion Criteria:  Hospitalised due to an acute respiratory illness in the last 6 weeks prior to consent Any other significant disease or disorder which, in the opinion of the Investigator, may either put the participants at risk because of participation in the study, or may influence the result of the study, or the participant's ability to participate in the study. Known pregnancy