Emissions Inventory - Stage 2

Emissions Inventory – Curated Guidance for Stage 2

Assess where you are in developing an emissions inventory to determine which stage you are in and identify the key activities you need to undertake as an air quality manager to go to the next stage. 

The guidance below is for Stage 2. Stage 1 and Stage 3 are also available.

Additional guidance for Stages 4 and 5 is being developed for future iterations of AQMx.

StageCapacityObjectivesActivitiesData sourcesSustainability plan
01.
  • At least 3 full time staff

  • Secured access to laptops

     

  • Develop a Tier 1 / Approach 1 emissions inventory
  • Include greenhouse gases (GHG) from major activity sectors
  • Use Emission Inventory (EI) for UNFCCC reporting
  • Gather air pollutant Emission Factors (EFs) for air pollutants simultaneously
  • Ad hoc updates
  • Emission factors taken from literature (including EMEP/EEA)
  • Activity data taken from publicly available reports, ministries and agencies
  • Guidance from IPCC

  • Donor / project-funded emissions inventory

     

02.

  • Same as Stage 1

     

  • Same as Stage 1
  • Include GHG, and priority air pollutants (PM, SOx, NOx, NH3, VOC and CO)
  • Use EI for UNFCCC reporting and CLRTAP (if party to convention)
  • Use EI for source identification
  • No regular update
  • Emission factors taken from EMEP/EEA Guidebook or alternative national/international methodologies that provide more accurate country- specific estimates
  • Activity data taken from stakeholders and/or MRV (measurement, reporting and verification) framework

  • Donor / project funded emissions inventory

     

03.
  • 3-6 full time staff (depending on quality and completeness of data provision)
  • Secured access to a dedicated database / computer system
  • Develop a Tier 2 / Approach 1 emissions inventory
  • Include GHG, gaseous pollutants and PM
  • Use EI for UNFCCC reporting and CLRTAP (if party to convention)
  • Use EI to generate first emission maps using GIS
  • Use EI for coarse air quality modelling
  • Use EI for policy tracking
  • Update every 2 years
  • Some emission factors measured, other taken from EMEP/EEA Guidebook or alternative national/international methodologies that provide more accurate country-specific estimates
  • Activity data taken from stakeholders and/or MRV framework
  • Some central funding
  • Major donor funding
04.
  • At least 6 full time staff
  • Secured access to in- house data server with secure backup

  • Develop a Tier 2 / Approach 2 emissions inventory


     

  • Include GHG, gaseous pollutants, PM and Short-Lived Climate Pollutants (SLCPs)
  • Use EI for UNFCCC/CLRTAP reporting (if applicable)
  • Develop accuracy and resolution of emission maps
  • Use emission maps for refined air quality modelling
  • Use EI for policy tracking and accountability
  • Generate first emission projections (with measures scenario)
  • Update every 1 or 2 years
  • Development of country-specific emission factors, use of some measured emission factors, and other taken from literature
  • Activity data taken from stakeholders and/or MRV framework
  • Major central funding
  • Some donor funding
05.
  • At least 9 full time staff
  • Secured access to in-house data server with secure backup
  • Develop a Tier 2-3 / Approach 2 emissions inventory
  • Include GHG, gaseous pollutants, PM, SLCPs, VOC speciation and PM size fraction
  • Use EI for UNFCCC reporting
  • Use EI for refined air quality modelling
  • Use EI for policy tracking and accountability
  • Refine emission projections for policy formation
  • Update every year
  • Use of local and measured emission factors
  • Activity data taken from stakeholders and/or MRV framework
  • Centrally funded emissions inventory
  • In-house research

01 Update your plan

As you advance from Stage 1 efforts that focused on developing a Tier 1 GHG inventory to Stage 2, where you will focus more on adding in criteria pollutant emission factors and adding activity categories that are relevant to air pollution while also solidifying institutional relationships and data reporting protocols, update your plan to ensure you have staff resources and clearly designated roles for data collection, inventory compilation as well as quality assurance steps. At Stage 2, your inventory should be aligned with a GHG Monitoring, Reporting and Verification (MRV) framework and housed in a secure and redundant database that enables IPCC reporting and easy conversion to emissions inputs for Source Attribution work (See Source Attribution Stage 2, Step 4) and Decision Support (See Decision Support Stage 2, Step 3).  

02 Review ambient air pollution inventory guidelines

nlike Stage 1 work which focused on the IPCC guidance for GHG inventory development, Stage 2 will focus on integrating criteria pollutant emission factors and sectors into an integrated inventory.  Here you should ensure you are familiar with guidance and methods for air pollution inventory development before you dive in to the development process. Begin by familiarizing yourself with existing guidance and methodologies, such as the EMEP/EEA guidelines and methodologies for PM, SO2, NOx, VOC, and CO which are aligned with the IPCC guidelines. Other examples are also referenced below. Understand the specific requirements outlined in the IPCC guidelines related to GHG inventory development, then identify additional steps needed to include air pollution aspects and sectors in your assessment. Pay special attention to high-emission sources, such as  so-called "high emitter" diesel engines and municipal waste burning, as these can significantly impact overall emissions. As you review the guidelines, critically compare objectives for data collection and compilation tasks, considering how they differ for GHG and air pollution inventories. This comprehensive understanding will enable you to establish a robust inventory that meets both national and international reporting requirements while addressing air quality management goals effectively.  

03 Clarify mandates and institutional relationships

UNFCCC requires the EI for GHG but also CO, NOx, SO2, and VOC which are also common compounds of interest for AQ alongside other species (PM, NH3, etc.). The same database should be used to promote consistency (see Step 5), but could lead to duplication unless an agreement is established over which staff are responsible for which aspects of data collection and maintenance.  This is especially true where the different methodologies converge. Establish clear mandates for staff of both the climate change and air quality departments on how data is to be collected, managed and quality assured. 

04 Carry out a benchmark analysis

Carry out a benchmark of international, regional, and national literature to identify context-relevant emission factors where they exist and updating Stage 1 estimates where better, local data is identified for all compounds (i.e., GHGs, SLCPs and air pollutants). Systematically review existing studies, reports, and databases that pertain to your specific emissions sources. Focus on sources that align with your region’s economic activities and practices, ensuring data relevance. Document variations in emission factors across different contexts and reconcile discrepancies.  Where region-specific emission factors cannot be identified, continue to use default values from IPCC and EMEP/EEA but note where improvements are needed for your review in Step 9 below.   

05 Establish a common database

In addition to data obtained from ministries and other sources, it is crucial to derive information from the established monitoring, reporting, and verification (MRV) system. Consider expanding this MRV system (database/server) to accommodate spatialized activity data for future gridded emissions assessments. If a greenhouse gas (GHG) MRV system does not already exist, you should establish one that integrates your emission inventory database into a unified structure. Begin by identifying gaps in data collection and storage capabilities related to spatialized activity.  
Incorporate a robust database capable of handling diverse datasets, ensuring it can store high-resolution spatial data. Utilize geospatial tools and geographic information systems (GIS) to effectively manage and analyze location-specific emissions data.  
Engage with stakeholders to identify the necessary types of activity data, such as energy consumption, transportation metrics, waste burning practices, agricultural and forestry operations, and land use patterns. Establish standardized data formats and protocols for consistent input and quality control.  
Finally, consider developing a user-friendly interface for data access that promotes transparency and enables users to visualize and interpret gridded emission inventories effectively, supporting informed policy decisions and efficient resource allocation. 

06 Replicate steps 3-10 from Stage 1 guidance including all pollutants

Decide on a common base year for both GHG and air pollutants and repeat the process used for your Stage 1 inventory ensuring that you include all air pollutant relevant sectors and the full complement of GHG, SLCP and air pollution emission factors. Quality checks from Step 6 can compare your data against global inventories like CEDS, EDGAR, and GEIA. Look for discrepancies in emissions totals, trends, and source contributions. Utilize these benchmarks to identify potential errors or gaps in your inventory and adjust methodologies or data sources to enhance accuracy and reliability. 

07 Data visualization

When developing data visualizations for an air pollution emission inventory, choose clear and effective methods to illustrate findings. Use pie charts to visually represent the proportion of different emission sources relative to total emissions. Bar graphs can help compare emissions across different species or sectors, while histograms can illustrate the distribution of emissions data over time or locations. Waterfall graphs are effective for showing cumulative contributions of various species to overall emissions totals. Incorporate color coding to enhance readability and ensure that each graph has a clear title and legend. Finally, provide contextual information to help viewers interpret the visualizations accurately, aiding in data understanding and decision-making. 

08 Report to UNFCCC, LRTAP or other regional agreements

When reporting emissions data to the UNFCCC or the Convention on the Long-Range Transport of Air Pollution, ensure adherence to specific guidelines and formats outlined by these organizations through the authorized and mandated Ministry. Maintain accuracy and transparency by using standardized methodologies for data collection and calculation. Regularly update your emissions inventory to reflect the latest information and verify data consistency. Engage stakeholders throughout the process to facilitate collaboration and ensure comprehensive reporting, thereby enhancing the credibility and effectiveness of your submissions. The CLRTAP inventory reporting requirements include 25 pollutants including black carbon and ozone (short-lived climate pollutants) according to the EU Directive 2016/2284. 

09 Develop an emissions inventory improvement plan

Begin with your key category analysis (Stage 1, Step 8) to identify sectors contributing significantly to total emissions. Assess the relative uncertainty of existing data through statistical analysis and expert judgment, prioritizing categories with high uncertainty. Based on this analysis, determine which sectors should advance to Tier 2 methodologies, which offer more detailed data and improved emission factors. Document clear objectives and timelines for upgrading methodologies, allocate resources and training for staff, and outline procedures for ongoing data verification and quality control. Engaging stakeholders will enhance the plan's effectiveness and ensure it is aligned with national and international reporting requirements.