Smells play an important role in today's densely populated world. Many products have smelling substances added in the production process. Some are unintentional, since the process causes them, while others are added to give the product a flavour that appeals to the consumer.
In either case, some kind of production monitoring is required to check the odour. This can be done either by the human nose, or using an analytical instrument. When analytical instruments are used they need to be calibrated, and Linde has a wide program to create the necessary calibration mixtures.