https://www.lifecycleinitiative.org/applying-lca/lcia-cf/

There is not an straight answer to your second question. CF are calculated by the authors (yoo need to look for thier publicactions) and the implmented by Databases (e.g. EcoInvent https://www.ecoinvent.org/support/faqs/methodology-of-ecoinvent-3/did-the-characterisation-factors-of-a-specific-lcia-method-change-why-is-the-lcia-score-of-a-certain-product-not-the-same-in-the-ecoinvent-database-and-in-my-software-tool.html?most) and/or software. So you need to look along all the way to find why a certain CF is given and what is the reasoning behind. E

Hi Edwin,

Thank for your advice, I'm using different methods implemented in SimaPro regularly and am often surprised by some values (e.g. CF=0 for nitrate for Aquatic eutrophication in IMPACT2002+, which is obviously wrong). Coming back to NH3 release in the atmosphere, there is no need to make long reasonings to know that it should counterbalance the acidification , therefore having a CF

Dear Didier

I have not look in details but through experience I have found many of these "weird" CF. The advantage of SIMApro, for instance, is that you can edit your evaluation method and CFs. It is also good to report it to the software and DB developers, some are just simple mistakes that someone overlooked. If you opt for changing your CF make sure that the systems as whole stays in balance.

E

1. The mentioned gases have a very short lifetime and thus unimportant as Greenhouse Components

2. NH3 is acidifying because in the soil it is oxidised, by bacteria, to nitric acid