Chapter 3 Reporting of Releases

Source categories of unintentional POPs releases under the Stockholm Convention are listed in Annex C Part II and Part III to the Convention. These source categories are also among those considered in the Toolkit, where they are placed into ten source groups to facilitate the development of national release inventories and reporting of POPs releases.

The standard format to report PCDD/PCDF releases through national reports under Article 15 is included in Annex 5, Table III.5.1.

Some countries also report POPs releases to air and a number of other pollutants under the UNECE Convention on Long-Range Transboundary Air Pollution (CLRTAP). For these countries, a brief explanation of source categorization under CLRTAP, including a list of source categories under the Stockholm Convention and their equivalent designations under CLRTAP, is presented in Annex 5, Table III.5.2.

Parties are encouraged to report releases of unintentional POPs in national reports submitted pursuant to Article 15 of the Convention, according to the source categories listed in Annex C of the Convention, grouped into the source groups specified in the Toolkit. By complying with this approach, Parties will ensure that the following conditions are met:

• Estimates of unintentional POPs releases are readily comparable;
• Regional and global release summaries can be easily prepared; and
• Time trends can be readily elaborated for the purpose of effectiveness evaluation under Article 16 of the Convention.

Article 5, paragraph (a) (i) of the Stockholm Convention requires that Parties evaluate current and projected releases, including the development and maintenance of source inventories and release estimates of chemicals listed in Annex C Part I, taking into consideration the source categories identified in Annex C Part II and III of the Convention.

In practice, this means that Parties must prepare their initial release estimates and update these estimates at regular intervals (e.g. every five years). Parties may also find it necessary to revise their initial and subsequent estimates in order to establish and maintain the consistency necessary for discerning meaningful trends in releases over time.

The baseline release estimate is the first inventory of sources and releases of Annex C POPs elaborated by a Party, usually as part of the National Implementation Plan developed under Article 7. This first inventory serves as a baseline against which subsequent updated release estimates are assessed in order to establish trends in releases over time and evaluate the efficacy of the adopted strategies for minimizing and/or eliminating PCDD/PCDF and other unintentional POPs releases.

As schematized in Figure I.3.1, updating of the inventory begins with an examination of the previous/baseline inventory to identify the approach used, including:

• The classification of sources and emission factors used
• Information sources based on which activity rates were estimated
• Assumptions and expert judgment applied to fill the gap.

In a second step, the developer of the inventory should review changes in data since the baseline inventory, in particular by checking for factors that may influence changes in releases over time. These include: economic and/or demographic growth, changes in technologies in particular through phasing in BAT and BEP, building, reconstruction or close down of production facilities, substitution of fuels, introduction of abatement techniques, identification of new sources, and others.

It is also important to check, whether new or revised emission factors have become available or new source categories or classes have been included in the Toolkit. Once these data and information are collected, the developer of the inventory will proceed with the reclassification of sources to reflect the current situation in the particular reference year and with the establishment of activity rates for the reference year.

Once the information is assessed and the inventory is updated to reflect economic, demographic and technical changes, the need to revise the previous inventories, including the baseline, may arise. Revising previous inventories so that new or revised emission factors and new source categories and classes are incorporated is especially important.

Besides such changes in the Toolkit methodology, some specific national factors may also trigger the need for revision. These are usually related to the availability at the country level of new or corrected information/knowledge, e.g. correction of past activity estimates or the discovery of sources that existed in the past but were not considered in previous inventories due to lack of adequate information at that time.

The revision of the previous inventories aims to correct the estimates therein, by including missing information, filling gaps, using the same set of emission factors, applying the same assumptions, expert judgment as in the updated inventory.

Only after this stage, the developer of the inventory will be able to calculate updated releases and establish consistent trends in releases over time. If sources are reclassified and/or emission factors have been revised, new factors must be assigned accordingly; if the source classification has not changed, nor the emission factors, the same factors are applied; releases are finally estimated by multiplying the emission factors with the corresponding activity rates.

Maintaining all these stages of the inventory update and revision process is essential to ensure that coherent trends over time can be computed, based on comparable and consistent results over time. The same approach needs to be applied consistently in all release estimates to ensure consistency of results over time and to enable correct assessment of time trends.

If the approach changes over time, if new or corrected information or knowledge becomes available at the country level, previous inventories need to be revised accordingly and one single approach used for all inventories. Otherwise it would not be possible to compare data from different years and establish consistent time trends.

Projections of future release estimates may be elaborated by Parties using the same methodology, by considering:

• Appropriate emission factors based on planned or expected changes in technologies, raw materials, fuels, abatement techniques or other key parameters which could influence release estimates (e.g. triggered by the action plan developed under Article 5 of the Convention).
• Projections of future activity rates for certain source categories based on e.g. - expected socio-economic development, production plans for a particular source category or source group, etc.

The example inventory 1 shows an illustration of the inventories’ update and revision process.