STUDYING CUMULATIVE OZONE EXPOSURES IN EUROPE DURING A 7-YEAR PERIOD

Ozone is one of the most harmful pollutants in the troposphere. High o zone concentrations can damage plants, animals and humans. The damagin g effects depend on the magnitude of a critical level of a special par ameter, the cumulative ozone exposure. This is why cumulative ozone ex posures must be carefully studied. It is important to determine the re lationships between relevant emissions (NOx emissions, human-made VOC emissions, and/or a combination of NOx emissions and human-made VOC em issions) and cumulative ozone exposures. All these issues are discusse d in this paper. Meteorological data from seven consecutive years, fro m 1989 to 1995, have been used in the experiments with different scena rios for varying the emissions (the NOx emissions, the human-made VOC emissions, as well as both the NOx emissions and the human-made VOC em issions). The particular air pollution model used in this study is the Danish Eulerian Model. Several hundred runs with different input data (meteorological data and/or emission data) have been performed. Advan ced visualization techniques are used to interpret the large amount of digital data collected in these runs and to show clearly different tr ends and relationships that are normally hidden behind millions and mi llions of numbers. The model results were compared with measurements t aken at more than 80 stations located in different European countries. The experiments indicate that it is sufficient to carry out computati ons over 5 consecutive years in order to eliminate the influence of ex treme meteorological conditions (very warm or very cold summer months) on the cumulative ozone exposures, while this effect is clearly seen if less than 5 years are used in the experiments. It is shown that the relationship between the emissions (NOx and/or human-made VOC emissio ns) and the cumulative ozone exposures is in general nonlinear. Finall y, it is illustrated that the critical values for ozone exposures are exceeded in most of Europe (in many areas by more than 7 times).