RIVM hoofdgebouw

At the request of the Dutch House of Representatives, RIVM compiled a list of the 100 biggest ammonia emitters in the Netherlands. Recently, the underlying data used to compile this list were disclosed pursuant to a request under the Open Government Act. As a result, it has emerged that the list contained multiple errors. RIVM is reviewing the exact impact.

Disclosure under the Open Government Act

A number of farmers asked RIVM critical questions about their inclusion in the top 100 list. In response, the underlying data were disclosed under the Open Government Act (Wet open overheid, WOO). As a result, it has emerged that, for some of the pig and poultry farms included in the list, RIVM used incorrect emission factors. Consequently, a number of these farms were erroneously included in the top 100 list. 


RIVM sincerely regrets that the top 100 list still contained errors and regrets the confusion this has created among farmers. RIVM is currently reviewing whether it has used any incorrect emission factors in other areas and, if so, what consequences this might have. External parties will be involved in this review. Until a complete overview of the impact has been obtained, RIVM will refrain from publishing any new publications or recommendations related to these spatially distributed ammonia emissions. RIVM will also have an evaluation conducted of how these errors have arisen. 

Emission factors

An emission factor represents emissions of a specific substance per unit of the activity that causes the emission. This could be the emission per unit of fuel consumed, or the emission per kilometre driven.

To calculate emissions, the emission factor is multiplied by the activity data, which measure the activity causing the emissions. To calculate the total annual emissions from vehicles, for example, the emission per kilometre driven is multiplied by the total number of kilometres driven per year.