Appendix 1
The Methodology of the National Atmospheric Emissions Inventory
1. Introduction
The NAEI reports estimates of the UK emissions of a number of gaseous pollutants. Estimates are calculated for each source category based on its fuel consumption or other activity statistics. These are then summed to obtain a total emission for the UK. This Appendix describes the methodology used to estimate the emissions and is laid out according to source category. The inventory is revised on an annual basis and the methodology described here is that of the 1996 Inventory. All revisions are applied to the full time series back to the earliest year, 1970. The pollutants discussed here are:- carbon dioxide as expressed as carbon
- NOx as nitrogen dioxide
- SO
1.1 The Emission Source Classification
The NAEI reports emissions from the combustion of fuels and non-combustion emissions from a range of sectors. The fuels data are taken from the Digest of UK Energy Statistics (DUKES), (DTI, 1997). Hence the fuel definitions and the choice of base sector categories used in the NAEI reflect those in DTI (1997). The choice of non-combustion sources generally reflects the availability of data on these emissions.The 1996 NAEI is reported according to the UNECE/CORINAIR SNAP 94 Version 1.0 eleven sector classification which is less detailed than the NAEI base categories. A listing of the NAEI base categories and their mapping onto the UNECE/CORINAIR SNAP 94 categories is shown in Table A1.
This format represents a change over previous inventories where the UNECE/CORINAIR SNAP 90 system was used. The main changes in the classification are discussed in Appendix 2.Table A1 Mapping of NAEI Base Categories to CORINAIR SNAP 94
