A brief account of work, carried out within the framework of the Effects Programme of the Dutch National Coal Research Programme is given. Each chapter deals with a particular project or cluster of related projects. The information is based on summaries of a large number of research reports written by participating institutes. The titles of the chapters are, apart from the title of this record: Toxic properties in vitro of fly ash and stack ash from various coal-burning installations; Effects of respirable fly ash in `in vitro` and in inhalation studies; Long-term effects on soil and vegetation caused by emissions of trace elements; and Effects of flue gas from a coal-fired boiler on plants. It can be stated that there is now a clearly improved understanding of the nature and, to a lesser extent, the magnitude of biological effects as a result of the burning of coal. Definite pointers have been provided concerning the way in which the combustion of coal should take place. However, since coal flue gas contains a wide variety of organic and inorganic components, it is not possible to establish air quality criteria for its specific components. 1 fig., 7 ills., 4 tabs., 35 refs.