Claimed is a method of delivering nitric oxide comprising non-electrolytically generating a first gas from a nitric oxide precursor that includes a precursor salt, wherein the first gas includes nitric oxide and is substantially devoid of nitrogen dioxide and transporting the first gas. Precise delivery of nitric oxide at therapeutic levels of 20 to 100 ppm and inhibition of reaction of nitric oxide with oxygen to form toxic impurities such as nitrogen dioxide can provide effective inhalation therapy for pulmonary hypertension.
