EDGAR-HTAP : a harmonized gridded air pollution emission dataset based on national inventories

On the global scale the harmonization and improvement of emission inventories is imperative to get consolidated estimates on formation of global air pollution, and it's influence on human health and climate, and so on the benefit of future policies combating these air pollution aspects. The EDGAR-HTAP project compiled a global emission dataset with annual inventories for CH4, NMVOC, CO, SO2, NOx, NH3, PM10, PM2.5, BC and OC and covering the period 2000-2005 using, to the extent possible, official or scientific inventories at the national or regional scale that are likely to be acceptable for policy makers in each region of the world. This compilation of different official inventories from EMEP, UNFCCC, EPA for USA, GAINS for China and REAS was first gap-filled with global emission data of EDGARv4.1. The IPCC code or UNFCCC's Common Reporting Format, is used as key for harmonizing the data at sector level. Next, the resulting emissions by country and sector were allocated to a 0.1º × 0.1º grid consistently using the EDGARv4.1 proxy data. The emissions of EDGAR-HTAP were compared with the emission inventory used for the Representative Concentration Pathways for the next IPCC Assessment Report Differences between the national inventories and other bottom-up estimates shows the impact of using higher tier methods and/or country-specific emission factors for compiling a national inventory. Weaknesses in the official emission reports in the EMEP domain were in particular found for diffusive sources. A paradigm of high quality emission inventories consists in scoring high for IPCC's 'T-A-C-CC- A' (Transparency -Accuracy- Consistency - Comparability -Completeness) principles. Weaknesses remain in the coherency across borders between different national inventories, in particular when using different datasets applying different inventorying techniques. Therefore the EDGAR-HTAP_V1 can not be considered as a consistent global time series dataset, but can be recommended as a summary with indicative national totals subject to emission reduction policies.