Study of the combined effect of ultra violet and ionizing radiation on gas to particle conversion

In the light of the increasing Kr-85 pollution of the atmosphere due to the reprocessing of the nuclear fuel, we started a research project to investigate whether an increase in atmospheric radioactivity can enhance the transformation of precursors like SO2 into aerosols. This problem drew the attention in the seventies through the work of Vohra who claimed that a synergism between u.v. and ionizing radiation at background dose rates enhances the transformation of SO2. At the GAeF conference in Fredeburg, Metayer presented experimental results that seemed to contradict the assertions of Vohra. In discussing these experiments it is important to notice that both investigators measured only total particle concentration and that not this parameter but rather the aerosol volume should be measured to obtain an answer to our question. Taking this into account, we set up two types of experiments to examine the effect of combined u.v. and ionizing radiation upon aerosol formation relative to the case of u.v. radiation alone: we first looked at the effect on aerosol volume and then also looked at the effect on total number concentration. (author)