 None of the standard clinical assessment tools provide information regarding underlying airway inflammation, the control of which is central to an effective asthma management strategy. Therefore this study will evaluate the impact of FeNO assessments on asthma treatment decisions in approximately 40-50 subjects 7-60 years of age with asthma. This pilot study will also provide information regarding the ability of physicians to correctly assess airway inflammation using standard clinical assessment tools i.e., prior to FeNO measurement. Finally, this pilot study will allow the cost consequences of changes in asthma management following FeNO determinations to be estimated. 