On behalf of the Federal Environment Agency, the IZT systematically estimated the future emissions of four air pollutants for the first time. Sulphur dioxide, nitrogen oxides, ammonia and volatile hydrocarbons (NMVOC) are responsible for summer smog and for the acidification and over-fertilisation of soils and water bodies. The IZT prepared both an emissions estimate for the year 2000 and emissions forecasts for the years 2005, 2010, 2015 and 2020. For this purpose, the latest data and assumptions available to the Federal Environment Agency on emission-causing activities and emission factors were collected and documented in a standardised manner - for five relevant polluter and source groups: for transport, for solvents and for water. source groups: for transport, for solvent use in households, commerce and industry, for stationary combustion plants (from natural gas heating to coal-fired power plants), for agriculture (fertilisers and animal excrement) and for industrial process emissions (e.g. in the chemical industry).

The thematic background to the project is the international efforts to combat acidification, eutrophication and ground-level ozone, which are reflected in the Gothenburg Protocol to the UN/ECE's Geneva Convention on Air Pollution and in EC Directive 2001/81/EC on national emission ceilings for certain atmospheric pollutants (NEC Directive). In these legal acts, the signatory states of the protocol and the EU member states are obliged, among other things, to comply with national emission ceilings for the pollutants sulphur dioxide (SO2), nitrogen oxides (NOx), ammonia (NH3) and volatile organic hydrocarbons (VOC) and to submit action plans to reduce these emissions.
The aim of the project was to support the Federal Environment Agency (UBA) in fulfilling its reporting obligations and in planning measures to reduce emissions of the aforementioned pollutants. The subject of the study was therefore the systematic and transparent presentation and further development of estimates of German emissions of SO2, NOx, NH3 and VOC for the years 2000, 2010, 2015 and 2020 as well as the analysis of emission reduction potentials and associated reduction measures and instruments for their implementation.
The starting point of the work was the analysis and documentation of the previous activities carried out at the Federal Environment Agency (UBA) to estimate emissions for 2000 and 2010. On this basis, emission scenarios were developed with the close involvement of the UBA's expertise, taking into account the legal situation already adopted and potential additional measures. Finally, together with the UBA, measures and instruments were identified with which the emission ceilings from the Gothenburg Protocol and the NEC Directive could be complied with.