In this Guideline@ fundamentals and methods of envi? ronmental Simulation are described which allow the interactions between environment and exposed objects such as humans@ animals@ plants@ materials@ soils and industrial products to be determined. Ethical aspects and laws for protection of animals must be considered. In Order to study these interactions it is necessary to determine the contribution of the individual environ? mental influences and their combined effect. The term environment which is used in this Guideline is more comprehensive than the environmental term which plays a role e.g. in nature and landscape conservation. The environment of an exposed object includes its ambient conditions independently of whether they are natural (e.g. climate@ sunlight) or are caused by anthropogenic effects (e.g. pollution from internal combustion engines). Figure 1 shows by way of example a summary of various environmental influences.