This is a pilot cross-sectional study of measured transcutaneous CO-oximetry in children with inflammatory and non-inflammatory conditions.

Children and young adults age 6-24 with the following conditions: asthma, pneumonia, allergic rhinitis, cystic fibrosis, and well child (without inflammatory illness) will be recruited.

Subjects will be asked to complete a brief screening survey to determine if they meet inclusion criteria. Enrolled subjects will be asked to complete questionnaire forms to characterize their health, current symptoms, medications, and common exposures. Transcutaneous carboxyhemoglobin will be recorded.

This study is cross-sectional and will only require one visit coinciding with the clinical visit. Analysis will determine the pairwise differences in SpCO between conditions tested.

Inclusion Criteria:

• diagnosis of asthma, pneumonia, allergic rhinitis, or none of the previous (control group)
• Ability to complete study procedures

Exclusion Criteria:

• Cardiopulmonary disease outside of the specific conditions for inclusion
• Prematurity
• Congenital heart disease
• Current diagnosis of more than one of the following: asthma, pneumonia, allergic rhinitis, cystic fibrosis, or - for controls - any current infection
• Recent serious bacterial infection (except for pneumonia in the pneumonia group)
• Concurrent clinical chest X-ray with findings other those that expected for the group (i.e. normal chest X-ray in pneumonia group or suspected pneumonia on chest X-ray in asthma group). To be determined by attending radiologist's interpretation.

Age range 6-24years old. All genders, races, and ethnicities were sampled, provided they could complete the study requirements.