a, D part

orm ora Some VOCs are toxic (e.g. benzene, 1,3-butadiene) while ously monitored in European Union member states (Larsen, 2004). The introduction of three-way catalyst and evaporative decrease in urban VOC concentrations due to the large share (Dollard et al., 2007). The decrease in traffic emissions tive 2002/69/EC to limit emissions of benzene at national legislations (Larsen, 2004). The datasets obtained from such a routine monitoring may contain large amounts of hidden information that can contribute to the understanding of pro-cesses and trends that govern dispersion and transformatio