Gas chromatography combined with high resolution mass spectrometry (GCHRMS) was used to measure PAH analytes. Seven urinary low molecular weight PAH analytes (1-hydroxynapthol, 2-hydroxynapthol, 2- hydroxyfluorene, 3-hyrdroxyfluorene, 1-hydroxyphenanthrene, 2-hydroxyphenanthrene, 3- hydroxyphenanthrene) and one urinary high molecular weight analyte (1-hydroxypyrene) were measured. Here, PAH is linked to pulmonary arterial hypertension.