EUROTRAC is the EUREKA environmental project studying the transport and chemical transformation of pollutants in the troposphere over Europe. At its inception in 1988 it had three aims: * to increase the basic understanding of atmospheric science; * to promote the technological development of sensitive, specific, fast-response instrumentation for environmental research and monitoring; and * to improve the scientific basis for taking future political decisions on environmental management within Europe. It was clear at an early stage, as the fourteen subprojects were formed and more than two hundred research groups in twenty-four countries were incorporated, that the first aim would readily be achieved. An ample demonstration that the early indications were correct is provided in the other volumes in this series which describe the scientific progress made. Substantial progress was also made towards achieving the second aim although some problems were encountered, mainly due to the high cost of the technological development required.

1 Executive Summary.- 2 Environmental Problems, Policies and EUROTRAC.- 2.1 The Atmosphere as a Recipient and Transport Medium for Pollutants.- 2.2 Environmental Problems.- 2.3 Policies.- 2.4 EUROTRAC and its Application Project.- 2.5 Acknowledgements.- 2.6 References.- 3 Photo-oxidants.- 3.1 Environmental Policy Issues Related to Photo-oxidants.- 3.2 Scientific Findings of Importance for Environmental Policy.- 3.3 Applications and Importance for Environmental Policy, Potential for Applications.- 3.4 References.- 4 Acidification and Deposition of Nutrients.- 4.1 Environmental policy issues related to acidic deposition and deposition of nutrients.- 4.2 Scientific Assessment - Issues and Highlights.- 4.3 Applications and Implications for Policies.- 4.4 Conclusions. Future Potential for Applications.- 4.5 References.- 5 Contribution of EUROTRAC to the Development of Tools for the Study of Environmentally Relevant Trace Constituents.- 5.1 Introduction.- 5.2 Instruments.- 5.3 Laboratory Studies.- 5.4 Models.- 5.5 Other Tools.- 5.6 References.- Appendices.- A. The Application Project Description.- B. The EUROTRAC subprojects with their aims.