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BC emissions inventories

Action 2.4: Improve methodological guidance and external support for black carbon inventories

Within this action focused on methodological guidance and external support for the inventories, two components have been identified. Component 2.4a addresses potential improvements in the existing guidance documents under the Air Convention and UNFCCC, relevant for black carbon emission inventories. Component 2.4b highlights the need for external support for national experts in applying these methodologies while compiling the emission inventories.


Area of Action
BC emissions inventories
Improve methodological guidance and external support for black carbon inventories
2.4a Improve and develop methodological guidance for black carbon emissions inventories
2.4b Emissions inventory capacity-building
Type of intervention
Establishment and improvements of monitoring and inventories
Information and guidance
Time perspective
2.4a Medium- to long-term: 2020-2030
2.4b Short-term (ongoing capacity building)
Structural change
Jurisdictional scope
2.4a International
2.4b International, national
Policy forum
2.4a UNECE Air Convention: TFEIP, IPCC: The IPCC's Task Force on National Greenhouse Gas Inventories, IMO
2.4b UNECE Air Convention, EU, national authorities

Component 2.4a. Methodological guidance for black carbon emissions inventories

The EUA-BCA technical report on emission inventories (EUABCA 2019b) highlighted deficiencies in the 2016 EMEP/EEA (European Environment Agency) Air Pollutant Emission Inventory Guidebook[1] and the reporting guidelines - such as lack of higher Tier inventory methodologies and outright lack of Tier 1 emission factors for some source sectors. Improvements have since been made in the 2019 EMEP/EEA (European Environment Agency) Air Pollutant Emission Inventory Guidebook[2], but still further work is required. Further developing guidance on reporting of emissions of BC is one of the items in the 2024–2025 draft workplan for the implementation of the Convention (ECE/EB.AIR/GE.1/2023/6−ECE/EB.AIR/WG.1/2023/6)[3]. The lack of a clear working definition for black carbon is also an important issue to resolve as also reflected in the conclusion of the Report on the review of the Protocol to Abate Acidification, Eutrophication and Ground-level Ozone, as amended in 2012 that scientific and policy work on setting metrics for BC should be continued (see component 2.3a)




The EMEP/EEA Air Pollutant Emission Inventory Guidebook is normally updated every 3-4 years; with the most recent update published in 2023[4]. Impetus from the EMEP is likely needed to give the Task Force on Emission Inventories and Projections (TFEIP) the mandate and allocate resources for substantial updates and improvements in black carbon inventories. Such action will likely need to be elaborated first in proposals for the Air Convention’s 2-year work plans. An expert group on black carbon within TFEIP was however set up to review current EMEP/EEA Air Pollutant Emission Inventory Guidebook with respect to BC. The expert group began by identifying priority areas for improvement and collecting new emission factors from scientific and technical literature sources.

The establishment of the IPCC TFI expert group on SLCFs and its work on SLCF methodologies (see Action 2.2) is also highly relevant. The synthesis of methods applicable outside of Europe will be essential for enhanced reporting black carbon emissions by countries outside the EMEP domain and the UNECE. Cross-convention collaboration between TFEIP and the IPCC expert group on SLCFs has already been initiated and can be maintained and enhanced. These groups can work in close collaboration to develop a technical consensus on some priority issues (e.g. working definition of BC), and to agree upon the best approach in terms of emission factors (e.g. whether black carbon coefficients should be expressed as fractions of PM2.5 emissions or as explicit emissions factors in units of black carbon mass per unit activity data). In this regard, it may also be beneficial for this cross-convention cooperation to include a link to the ongoing methodological work under the IMO with respect to the monitoring of black carbon emissions from shipping (see Area of action Shipping).


Component 2.4b. Emissions inventory capacity-building

While improvements in methodological guidance are important, the availability of adequate emission factors per se do not guarantee wide-spread and good quality reporting of black carbon emission inventories. National circumstances can restrict the establishment, maintenance, and improvement of national inventory systems for BC. Capacity-building focused on development of national black carbon emission inventories is very relevant here. For more details on current and potential capacity building activities concerning emission inventories see information on Action 2.1.