Oxygen increases efficiency in a number of processes by reducing the amount of fuel used and decreasing carbon dioxide emissions. Oxygen is available as a component in many gas mixtures. Oxygen in nitrogen gas mixtures are used as span gas calibration mixtures in engine emissions testing in the automotive industry. These gas mixtures are ISO 17025 accredited and Part 86 compliant. Oxygen gas mixtures are also used in environmental, industrial hygiene and safety and laboratory applications.