**4.2 Selected impact categories**

One of the most important parts of life cycle assessment (LCA) is the outputs, in other words the environmental impacts of the product. With SimaPro software, it is possible to calculate over 100 environmental impact categories. For that reason, the academic- and industry-specific life cycle assessment (LCA) studies' guidelines and standards were surveyed to determine the environmental impacts for our study (**Table 2**).

With this taxonomy (**Table 2**), the commonly used environmental impact categories are listed for textiles. Consequently, based on the taxonomy given in **Table 1** and the raw material need for a denim fabric, five impact categories are selected. These impact categories, their definitions, and calculation methodologies within the SimaPro software are presented in **Table 3**.

#### **4.3 Environmental impact as a rationale for denim fabric recycling**
