Emissions have been analysed by end user rather than emission source. Emissions from power stations and refineries have been reallocated to end users on an approximate basis according to their use of the fuel. Analysis by end user is a recent addition to the United Kingdom emission inventory and is subject to more uncertainty than the analysis by emission source. The statistics presented should be interpreted as giving a broad indication of emissions by end user. Civil aircraft emissions include only those associated with ground movement and take off and landing cycles up to 1km from the airport.
Exports are emissions arising from the production of secondary fuel which is then exported.
As there is no UK end user of this secondary fuel, these emissions are allocated to exports. Although its global warming potential is much less per tonne than the other greenhouse gases it is present in the atmosphere in vastly greater quantities. Previous editions have included projected emissions of CO 2 as published by the DTI in 1995. At the time of writing, these projections are being reviewed by the DTI in the light of new data that have become available. A number of nitrogen compounds including nitrogen dioxide and nitric oxide are formed in the combustion of fossil fuel.