• Nurse or physician fluent in English and employed full-time by the hospital, affiliated practice, or affiliated university who cared for bronchiolitis patients on a unit participating in the trial during at least 5 days of the most recent bronchiolitis season - Hospital administrator fluent in English who oversaw the care of bronchiolitis on a local level (e.g. nurse manager) or a hospital level (e.g. Chief Quality and Safety Officer)

• Under the direct supervision of study or site principal investigator(s) Population 1b: Hospital staff who participate in qualitative interviews In Aim 2, we will conduct semi-structured interviews with physicians and nurses who provide care to bronchiolitis patients in participating units at the 5 hospitals with the highest and 3 hospitals with the lowest sustainability (8 hospitals total; up to maximum of 8 interviews/hospital). Maximum anticipated enrollment 64. Inclusion criteria: - Nurses or Physicians who cared for bronchiolitis patients on a unit participating in the trial during at least 5 days of the most recent bronchiolitis season - Employed full-time by the hospital, affiliated practice, or affiliated university - Fluent in English Exclusion criteria: • No exclusion criteria Population 2a: Bronchiolitis patients directly observed while not receiving supplemental oxygen ("in room air," for primary trial outcome) Inclusion Criteria: - Infants and children 2 months through 23 months old - Hospitalized on non-ICU wards participating in the trial - Cared for by generalist inpatient services (e.g. general pediatrics, hospital medicine) - Primary diagnosis of bronchiolitis in most recent physician progress note - Not actively receiving supplemental oxygen ("in room air") - Last documented receipt of supplemental oxygen >1 hour prior to direct observational data collection Exclusion Criteria: - Documented apnea or cyanosis during the current illness - Extreme prematurity (<28 weeks completed gestation) - Cardiac disease - Pulmonary hypertension - Chronic lung disease - Home oxygen requirement - Neuromuscular disease - Immunodeficiency - Cancer - Severe Acute Respiratory Syndrome Coronavirus 2 (Covid-19 / SARS-CoV-2)-related illness (known or suspected, including multisystem inflammatory syndrome in children multi-system inflammatory syndrome in children (MIS-C) Population 2b: Bronchiolitis patients directly observed while receiving supplemental oxygen (for underuse evaluation). Inclusion Criteria: - Infants and children 2 months through 23 months old - Hospitalized on non-ICU wards participating in the trial - Cared for by generalist inpatient services (e.g. general pediatrics, hospital medicine) - Primary diagnosis of bronchiolitis in most recent physician progress note - Actively receiving ≥2 Liters/minute (2L/min) supplemental oxygen or 21% room air flow Exclusion Criteria: - Extreme prematurity (<28 weeks completed gestation) - Cardiac disease - Pulmonary hypertension - Chronic lung disease - Home oxygen requirement - Neuromuscular disease - Immunodeficiency - Cancer - Severe Acute Respiratory Syndrome Coronavirus 2 [Covid-19 / SARS-CoV-2 (known or suspected)] Population 3: Parents or guardians of bronchiolitis patients who participate in qualitative interviews. Inclusion Criteria: - Their child was hospitalized for bronchiolitis on a unit participating in the trial during the most recent bronchiolitis season - Their child was found to be in room air during Aim 1 data collection - Fluent in English Exclusion criteria: • They are an employee of the hospital or a hospital volunteer