 Patients in both arms will receive follow-up phone calls to assess duration and amount of oxygen, as well as adverse outcomes. Patients discharged home on room air will receive 1 phone call on post-discharge day 7 range 6-8. Patients discharged home on oxygen will receive a phone call on day 7 range 6-8. Calls will be made for the study by the study investigators or by the Emergency Department ED research assistants. During the follow-up phone call, caregivers will be asked about Primary Care Physician PCP follow-up visits, any future scheduled PCP visits, any adverse events including increased work of breathing, increased oxygen requirement, repeat ED visits to researchers or other institutions, outside hospital admissions, intensive care unit admission or intubations, and any instructions for weaning oxygen given by PCP. If parents have questions or concerns, these questions will be directed to a nurse, fellow, or attending provider. 