Argon 0.0001 or 1 ppm; carbon dioxide 0.00005 or 0.5ppm; carbon monoxide 0.00005 or 0.5 ppm; carbon tetrafluoride 0.00001 or 0.1 ppm; hydrogen 0.0002 or 2 ppm; krypton 0.0005 or 5 ppm; nitrogen 0.0001 or 1 ppm; oxygen 0.0001 or 0.1 ppm; total hydrocarbons as methane 0.0001 or 0.1 ppm; water vapor 0.00001 or 0.1 ppm