Origin of data

This data is usually collected at the country level, except for three biogenic sources, where we used gridded data as basic activity data (e.g. in soil types). Emission factors are either defined uniformly for all countries, such as for CO2, or evaluated for individual countries, or groups of countries (regions). In the latter case we often distinguished between OECD countries, Eastern Europe and the former USSR, and other non-OECD countries. In some cases, such as for road traffic, we used emission estimates for individual countries and independently defined activity levels to derive country-specific emission factors. In Version 2.0 major point sources are included, when available, as distribution parameters by combining them per source category in so-called thematic maps. Thematic maps on a 1ox1o grid were used as a spatial allocation function to convert - per source or per process - country emissions to gridded emissions. For fuel combustion in industry and electric power generation, we used point- source information and area-source data from the TNO-MEP database ('LOTOS') and from US-EPA to distribute country totals for Europe and the USA, respectively, combined with population density for other regions. 

The same approach was used for some industrial sources. A population density map was used a default when no source-specific map was available. Also, for sources where point-source data was available for only a limited number of countries, we used this map to distribute the emissions for other countries. Below more information is given per major source category. 

Fossil fuel use

Energy data for 112 countries are from IEA energy statistics (period 1971-1992). This basic dataset has been extended with 71 smaller countries based on regional totals from IEA and split according to country totals per major fuel type provided by UN statistics. Furthermore, data on road transport were added for another 6 countries and for 37 IEA/UN countries, which had no sector data from IEA/UN. Emission factors for CO₂, N₂O and NMVOC comply with GEIA data. CO2 factors also essentially comply with factors recommended in the IPCC Guidelines for Greenhouse Gas Inventories. Fuel combustion factors for CH₄, CO, NO_x and NMVOC are generally country specific for Europe and North America, whereas for other world regions global average values were applied, derived from the country specific data. For SO₂, the factors are based on an analysis of data published on sulphur contents of fuel use per country. Emission factors for CH₄ from coal production are based on country specific factors and a division in surface and underground mining. CH₄ and NMVOC factors for oil production and gas production and transmission are based on Arthur D. Little and Ebert et al., respectively.

Industrial processes

Activity data are generally taken from UN statistics (1990 or period 1970-1990). Exceptions are solvent use, for which a number of specific activity levels for 1990 were taken from published industrial data and estimates for per country use of solvents based on economic characterics, and halocarbons, for which data from AFEAS were used, supplemented with published data, e.g. from McCulloch (halons) and Midgley and McCulloch (MCF), as well as own estimates for non-reporting countries. Emission factors for CO₂, N₂O and NMVOC comply with GEIA data. The emission factor for CO₂  from cement also complies with IPCC recommendations. Effective emission factors for N2O are based on Reimer et al. and Castellan et al. Factors for CH₄, CO, NO_x  and NMVOC are generally country specific for Europe and North America, whereas for other world regions global average values were applied, derived from the country specific data. The factors for SO₂ from primary metal smelting are based on simple stoichiometric relationships and corrected for data on sulphur recovery per country.

Biofuel use

Most country total activity levels were taken from BUN (Hall et al.), except for a number of OECD countries and countries in the Middle East which were based on IEA data and Leach, respectively. The division in specific fuel types and sectors has been based on country specific data and assumed similarities between countries. Emission factors are based on Hall et al. (CO₂), Veldt and Berdowski (CH₄, CO, NMVOC), Smith et al. (for N₂O), LOTOS-TNO (NO_x), and Berdowski (SO₂). 

Land-use and waste treatment

Activity data per country are generally from FAO. Exceptions are deforestation and savannah burning, for which gridded data from Hao et al. were used (also based on FAO statistics), agricultural waste burning (Andreae), landfills (Subak et al.) and uncontrolled waste burning (own assumption on amounts per capita). Emission factors for N₂O and NMVOC comply with GEIA. For CH4, emission factors are from Kreileman and Bouwman (rice), Subak et al. (landfills), Gibbs and Leng (animals). The N₂O factors are from Crutzen and Andreae (as in Bouwman et al.). Biomass burning factors for CH₄, CO and NMVOC are from Veldt and Berdowski and for NO_x and SO₂ from Andreae.

Natural sources

For most natural sources we used data available from the GEIA data centre.