The series of guidelines VDI 4280 describes the planning and evaluation of ambient air quality measurements and is an important element of quality assurance in monitoring and assessing air quality in the sector regulated by law [G1 to G11]. Not only measurements, but also dispersion models and statistical analyses are used for assessing air quality. Usually, the air quality is not only assessed for a point, but for a whole area. However, the air quality is generally only determined and measured at single points of this area. Different methods can be used for representing the air quality in an area. The present guideline VDI 4280 Part 5 allows checking the quality of such model calculations.