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