The rapidly rising traffic volume significantly contributes to the overall air pollution. In most countries of the world, exhaust emission standards and limit values have been established in order to mitigate this issue. In Europe, there are emission standards for each type of vehicle. These regulations are the basis for the design approval of new developed vehicles and for the periodic proof of compliance with emission limits (“emission inspection”) of registered vehicles. The emissions of carbon monoxide, carbon dioxide and hydrocarbons are measured. The analytical instruments for car exhaust control measurements have to be calibrated according to country-specific regulations at regular intervals with high-precision calibration gases in accordance with prescribed concentrations of sample components. In some countries, the national regulations require the use of calibration gases with a certificate from a laboratory accredited according to ISO/EN 17025. Messer offers these calibration gases as Lambdamix gases with optional certificate from an accredited laboratory.