§ Mr. Eldon Griffithsasked the Minister of Technology if he will state the maximum amounts of strontium 90 and caesium 137 found to exist in the atmosphere ever the United Kingdom at the time of peak atmospheric pollution during the calendar year 1969; and what proportion of these long-lived fission products he attributes to the known fall-out from Chinese nuclear explosions.
§ Dr. Ernest DaviesActivity-concentrations of caesium 137 in the air over the United Kingdom as measured at Chilton, Berkshire, reached 0.0046 picocuries/kilogram of air at the time of the normal seasonal peak in June 1969. The corresponding concentration of strontium 90 was 0.002 picocuries/kilogram.
The Chinese explosion of 27th December, 1968, contributed about 70 per cent. of the long lived activity in the summer of 1969. The remaining 30 per cent. was divided between the Chinese explosion of 17th June, 1967, and older debris.