The most common source of argon is an air separation plant. Air contains approx. 0.93% (vol.) argon. A crude argon stream containing up to 5% . oxygen is removed from the main air separation column via a secondary. Characteristics Colorless , odorless , non-inflammable , completely inert and extremely gas . Grade Industrial grade:99.5%Min, Weld grade: 99.997% Min, High Purity grade: 99.999% Min. Typical Applications Used for Atomic Absorption spectroscopy . Used as a pure or in mixtures is a shielding gas for arc welding . Argon is used in blends with . For example, fluorine and helium in excimer lasers .