As described in Table 1, uniform and triangular functions were used to model the analyzed parameters. Uniform distribution was used, when data within the same range have the same probability. For instance, air quality improvement varies depending on many conditions. Thus, green roof air pollution removal cannot be described as a deterministic value. Further, the landfill cost is related to the weight of the polymeric layers. The plastic layers weight of an intensive green roof varies depending on the thickness of each layer; however, one specific thickness is often repeated in many intensive green roofs. Therefore, a triangular distribution was used.