VOC’s or Volatile Organic Compounds have a high vapor pressure and low water solubility. 

- Many are human-made chemicals that are used and produced in the manufacture of paints and lacquers, cleaning supplies, disinfectants, cosmetics, degreasing fluids, hobby products, paint strippers, pesticides, building materials and furnishings, office equipment such as copiers and printers, correction fluids and carbonless copy paper, graphics and craft materials including glues and adhesives, permanent markers, and photographic solutions.

- VOC's typically are also all industrial solvents, such as trichloroethylene; fuel oxygenates, such as methyl tert-butyl ether (MTBE); or by-products produced by chlorination in water treatment, such as chloroform. 

- VOC's are also common ground-water contaminants.

- Concentrations of many VOC's are consistently higher indoors (up to ten times higher) than outdoors.