[en] s pointed out that while the protective ozone layer in the upper atmosphere is threatened by supersonic air traffic and releases of freon, there is an increase in the concentration of ozone in the biosphere. The biological effect of ozone in forming free radicals is similar to the biological effect of ionising rad radiation, and the normal atmospheric concentration of ozone produces 3600 times the number of free radicals per person per year as does a background radiation of 100 mrem per year. It is also pointed out that the limits for sulphur oxides and nitrogen oxides in the atmosphere are 100 and 5 times the background levels respectively, while the limit for radioactive release is 1/100 th of the background level. The transmission of solar energy from space stations by microwave is also thought to be dubious due to possible biological effects of such radiation. In conclusion a balanced view on the biological and environmental hazards of power generation from all sources, and not only nuclear, is called for. (JIW)