This is an open label phase 2 pilot study designed to evaluate the safety, tolerability and device performance of the GeNO nitrosyl delivery system during right heart catheterization (RHC) in participants with pulmonary arterial hypertension (PAH). All participants will receive inhaled nitric oxide in oxygen or nitric oxide in air delivered by nasal cannula. Hemodynamics, clinical laboratory and clinical assessment data will be collected on all participants to evaluate safety.