Dear msrocka and Andreas,
Thank you so much for your information provided and sorry for my delayed anser, I read only now your answers. My question was related to the fact that often, when I am building my model and I am searchng the data, It happens that I don't find any data of the substance I am looking for as input flow (for example a flow from technosphere or flow from ecosphere) but instead I find the substance or a proxy data as emission flow. I bring you another example. I need to insert as input for a chemical process the gallic acid (3,4,5-trihydroxybenzoic acid). There are no data that represent this chemical as input flow but instead there is this chemical as emission flow named as "3,4,5-Trihydroxybenzoic acid".
So if I understood well, the best procedure is to don't insert in the input side because it is an emission flow and could lead to strange results, right? In this case if don't find anything usually how should I proceed to consider it?
Another question also: I checked the impact factors of the flow "3,4,5-Trihydroxybenzoic acid" and it is only considered in the Usetox 2 Impact Assessment method (with impact factor=0). Does it means that if I use CML for example as Impact assessment method, this flow has no impacts in my calculation also if I put it in the outputs as emission flow?
thank you very much for your support.