An air quality management system as a tool for establishing a SO2- and NOx-policy

Abstract A description is given of the development and use of an Air Quality Management System (AQMS) directed to the support of policy decisions made with respect to the conservation and improvement of clean air in the Netherlands. The AQMS consists of three separate modules oriented to economy, transmission and impact assessment. Application of the AQMS to SO 2 has led to the construction of an environmental decision scheme, in which maximum acceptable emission levels are given as a function of the primary and secondary SO 2 -air quality standard, the S import-export balance and acidification. Together with information on the socio-economic impacts and the energy options this formed the basis for the political decision to limit future SO 2 -emissions in the Netherlands to a value not higher than 500 × 10 6 kg y −1 , in fact to establish a ceiling value for the emissions of SO 2 . For NO x the AQMS is still under development, so at the moment it is not possible to formulate a complete NO x -environmental decision scheme. Up till now the emphasis has been on the development of the transmission module of the AQMS for NO x , i.e. the impact of domestic and foreign emissions. The results of this module are presented in the paper. The (partly preliminary) results of the AQMS-calculations point out the importance of long-range transport of NO x and photochemical precursors and products for the countrywide NO 2 -pattern. The results emphasize the need for the abatement of NO x [and especially hydrocarbons (HC)] on a European scale. Also abatement of automobile exhaust is needed in order to prevent violation of the NO 2 -standard at sites with high circulation of traffic.