The Parties shall, at sessions of the Executive Body, arrange for the preparation, at regular intervals, of revised information on calculated and internationally optimized allocations of emission reductions for the States within the geographical scope of EMEP, using integrated assessment models, including atmospheric transport models, with a view to reducing further, for the purposes of article 3, paragraph 1, the difference between actual depositions of sulphur and nitrogen compounds and critical load values as well as the difference between actual ozone concentrations and the critical levels of ozone specified in annex I, or such alternative assessment methods as approved by the Parties at a session of the Executive Body.
