International scientific review 2013

This review was held at the request of the Minister for Agriculture, Sharon Dijksma, and organised by the Wageningen University and Research Centre. It involved a summarising international review, set up on the basis of the results from a national joint review by a number of Dutch scientists, and a review by a number of individual international scientists. The researchers focused their study on three main issues:

  • The scientific basis for ammonia emission factors related to the application of animal manure
  • The scientific basis for the deposition models as used in the PAS
  • Knowledge gaps


The reviewers concluded that the ammonia emission factors applied in the Netherlands to animal manure application have a sound scientific basis. In addition, they found the scientific basis of the Dutch deposition model OPS also to be sound. OPS is the AERIUS calculation centre. However, use of the model on the national scale would require some adjustments to also be internationally state of the art there. Those adjustments, such as including variable meteorological conditions, could provide an even more robust basis.

In a letter to the Dutch House of Representatives, the Minister for Agriculture, Sharon Dijksma, indicated that the review results did not warrant any changes to the ammonia policy or to the approach by the PAS.

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