Sensitivity Analysis of the EUROS Model for the 2003 Summer Smog Episode in Belgium

Like in other Western European countries, the summer of 2003 was characterized by exceptional warm weather conditions and two strong ozone episodes from 14-20 July and in the first half of August. The August episode counted 12 consecutive days of ozone exceedances, which never happened before. The total number of days of ozone exceedances in 2003 was 65, which is the highest number ever registered. At the European level, long-term objectives for the reduction of ozone concentrations have been defined in the Framework Directive 96/62/EC. According to the ozone daughter directive (2002/3/EC), the target values should be attained by the member states by the year 2010. In order to reach these objectives, most of the member states will have to reduce drastically the emission of pollutants responsible for ozone formation, i.e. nitrogen oxides (NOx) and non-methane volatile organic compounds (VOC). The emission reductions are prescribed for each of the EU member states, by means of national emission ceilings under the Gothenburg Protocol (1999) and the EU directive on National Emission Ceilings (2001/81/EC).