Since the first international conference on urban air quality, held at the University ofHertfordshire in 1996, significant advances have taken place in the field of urban air pollution. In addition to the scientific advances in the measurement, modelling and management of urban air quality, significant progress has been achieved in relation to the establishment of major frameworks to ensure a more effective mechanism for international collaboration. Two such frameworks are SATURN (Studying Atmospheric Pollution in Urban Areas) and TRAPOS (Optimisation of Modelling Methods for Traffic Pollution in Streets). In response to such advances, the second international conference was held at the Technical University of Madrid in March 1999 with active participation of SATURN and TRAPOS investigators. The organisation of the conference was headed by the Institute of Physics in collaboration with the Technical University of Madrid and the University of Hertfordshire. The support of IUAPPA and AWMA ensured a truly worldwide promotion and participation. The meeting attracted 140 scientists from 26 different countries establishing it as a major forum for exchanging and discussing the latest research fmdings in this field.

Urban areas are major sources of air pollution. Pollutant emissions affecting air quality in cities are considered to have adverse consequences for human health. Public and government concern about environmental issues arising from urban air pollution has increased over the last decades. The urban air pollution problem is widespread throughout the world and it is important to find ways of eliminating or at least reducing the risks for human health. The fundamentals of the physical and chemical processes occurring during air pollutant transport in the atmosphere are nowadays understood to a large extent. In particular, modelling of such processes has experienced a remarkable growth in the last decades. Monitoring capabilities have also improved markedly in the most urban areas around the world. However, neither modelling nor monitoring can solve urban air pollution problems, as they are only a first step in improving useful information for future regulations. The defining of efficient control strategies can not be achieved without a clear knowledge of the complete pollution process, i.e. emission, atmospheric transport and transformation, and deposition at the receptor. Improving our ability to establish valid urban scale source-receptor relation ships has been the objective of SA TURN, one of the 14 subprojects of EURO TRAC-2. Similar to the other subprojects of this co-ordinated environmental pro ject within the EUREKA initiative, SA TURN brought together international groups of scientists to work on problems directly related to atmospheric chemistry and physics. The present volume summarises the scientific results of SATURN."

Understanding urban air pollution is a prerequisite to finding effective solutions to air quality problems and for a sustainable development in the urban environment. In this book the current state of the art in urban air pollution research is presented. A major focus is on suitable air pollution modelling concepts, covering also street canyon geometries. Such models may be applied to establish source-receptor relationships in support of urban air quality management. Procedures for evaluating the performance of air pollution models are proposed, and results from field experiments and laboratory studies are shown to provide better insight into the characteristics of air pollution at the urban and local scales. The contents of this book are of a high policy relevance, given their direct connection to the formulation of improved tools for urban air quality assessments.

Since the first international conference on urban air quality, held at the University ofHertfordshire in 1996, significant advances have taken place in the field of urban air pollution. In addition to the scientific advances in the measurement, modelling and management of urban air quality, significant progress has been achieved in relation to the establishment of major frameworks to ensure a more effective mechanism for international collaboration. Two such frameworks are SATURN (Studying Atmospheric Pollution in Urban Areas) and TRAPOS (Optimisation of Modelling Methods for Traffic Pollution in Streets). In response to such advances, the second international conference was held at the Technical University of Madrid in March 1999 with active participation of SATURN and TRAPOS investigators. The organisation of the conference was headed by the Institute of Physics in collaboration with the Technical University of Madrid and the University of Hertfordshire. The support of IUAPPA and AWMA ensured a truly worldwide promotion and participation. The meeting attracted 140 scientists from 26 different countries establishing it as a major forum for exchanging and discussing the latest research fmdings in this field.

Hohe bodennahe Ozonkonzentrationen sind ein Hinweis auf den sogenannten photochemischen Smog, der bei h-herer Emission von Stickstoffoxiden, Kohlenmonoxid und Kohlenwasserstoffen und starker Sonneneinstrahlung auftritt. Diese Art der Luft- verschmutzung kommt auch in unseren Breiten vor, in erster Linie im Sommerhalbjahr. Zu den Folgen z{hlen Waldsch{den, gesundheitliche Belastungen f}r Mensch und Tier und die Zer- st-rung historischer Kunstwerke. Durch Emittierung aller an der Smogbildung beteiligten Schadstoffe tragen Kraftfahrzeu- ge erheblich zur Entstehung photochemischen Smogs bei. Das Buch beschreibt den Zusammenhang zwischen den Emissionen des Kraftfahrzeugverkehrs und der Ozonbildung. Nach der Schilderung der gegenw{rtigen Emissionssituation werden Me- thoden zur Emissionsminderung vorgestellt. Anschlie end wird der zur Ozonbildung f}hrende photochemische Reaktionsmecha- nismus erl{utert und Methoden zur mathematischen Beschrei- bung der Ozonbildung kurz skizziert. Schlie lich werden Er- gebnisse ausgew{hlter Modellrechnungen vorgestellt, die den Einflu einzelner, mit dem Kraftfahrzeugverkehr verkn}pfter Faktorenauf die Ozonbildung beleuchten und zu einer Reihe wichtiger Folgerungen f}hren. Die Besonderheit dieses Bucches besteht in der zusammenfas- senden Darstellung des Komplexes "Emission - Ausbreitung und Umwandlung in der Atmosph{re - Immission" f}r einen der haupts{chlichen Schadstoffemittenten, den Kraftfahrzeugver- kehr. Sobietet es dem Leser umfangreiche Informationen zu einem wichtigen und zugleich aktuellen Thema auf dem Gebiet des Umweltschutzes.