The sum of the impacts does not give the total.

Question

Hello,

I have a question about impact visualization.

I am finishing the impact assessment phase of an EPD and in the EP-Marine impact category, it gives me a score of 60% in stage A3. However, when I view the details of this stage, the sum of all the impacts does not add up to 60%.

Do you know why this is? Could the rest of the impact be from air emissions that are not represented? 

Answer 1

Are you referring to the contribution tree? If yes, be aware that the "sub-branches" e.g. below an A3 branch do not contain the direct impacts happening in an A3 process. Maybe add an image to make it more clear. For The LC stages modeling in EPDs, I would recommend the analysis groups that we added recently to openLCA.