round-level ozone is a typical example of a "modern polluting agent". Its precursors are produced by incineration and under the influence of sunlight the highly reactive irritant gas O3 is formed. This is responsible for the fact that there is hardly any ozone in the polluting urban areas, whereas in recreational areas and places with clean air, the effects are felt strongly. The "Ozone and Clover" project is intended to make students aware of ozone-related problems. About 430 classes participate in the experiment. Using the very sensitive white clover variety, California, the effects of ground-level ozone were made visible. The students sowed the clover in the last days of March. The clover variety forms stains when coming into contact with ozone. The students entered the results on work sheets and mailed them for evaluation before their summer holidays. The eco-office evaluated the data of the clover at 161 different locations. It is amazing the extent to which this bio-indicator network of the young researchers correlates with the scientific measurements of the ozone stress. The results were presented to the public at a press conference. Teachers who had participated in the "Ozone and Clover" project said that the educational value of the experiment was very positive. It was an excellent way of showing the young people the effects of increased ozone levels in a very dramatic way. In the meantime the idea of ozone detection has been taken up by the 1st German Broadcasting Corporation (ARD). Since summer 1995 the weather forecast has been illustrating ozone damage by means of tobacco plants which act as bioindicators.

Topic: environmental education Target group: schools Method: bio-indication Duration: 2 years Contact: Thomas Lang, WWF Schweiz, Lehrer/innen-Service, Postfach, CH-8010 Zürich; Tel.: ++41 1 2972280