In a life cycle assessment, which phase collects data on inputs and outputs?

• A. Impact assessment
• B. Goal and scope definition
• C. Inventory analysis
• D. Interpretation

Answer: (C)

In a life cycle assessment, the phase that gathers all the material and energy data and tracks emissions and wastes across the product’s life cycle is the inventory analysis. This step builds the life cycle inventory, listing inputs like raw materials, energy, and water, and outputs such as emissions to air, water, and soil, along with waste and releases from each process in the system. The reason this is the right phase is that it focuses on quantifying what goes into and comes out of the system, creating the dataset that later phases use to evaluate environmental impacts. After inventory, impact assessment translates that data into potential environmental effects (e.g., greenhouse gas emissions, eutrophication), and interpretation examines results, data quality, and conclusions. Goal and scope definition sets the purpose and boundaries of the study, not the data collection itself.