1) Hazardous air pollutant 
(from the article `chemical industry`) The three isomeric xylenes (isomeric means that they have exactly the same number and kind of atoms but are arranged differently) occur together, and ...
C8H10 Molar mass: 106.165
A component of gasoline, but also a major breakdown product or pyrolsis product given off when certain polymers are heated
a colorless liquid, CH, used chiefly as an intermediate in the manufacture of styrene and as a solvent and diluent for paints and varnishes.