30 | gross beta air concentration reported by the USPHS Radiation Surveillance Network and the Canadian Air Surveillance Network prior to August 1967, "were almost identical. : Answer 4C In response to the first question, the answer is yes. In 1961and 1962 the USSR conducted its atmospheric nuclear testing prog. am primarily at Novaya Zemlya (approximately TOON Latitude) above the Artic Circle. As described by Dr. Lester Machta, Director, Air Resources Laboratory, ESSA, before the Joint Committee on Atomic Energy Congressional Hearings in June 1962, the meteorological parameters of the earth's atmosphere lead to the following situation. as A portion of the radioactivity from atmospheric tests is injected into the stratosphere and is dispersed and diffused around the world before it is finally deposited on the earth's surface. Fallout from this source would be "expected to be rather uniformly deposited over a wide range of latitudes and over a period of years. Another portion of this radioactivity is in- jected into the troposphere and will essentially all be deposited on the ‘earth's surface in about 30 days. Since the tropospheric or near surface air travels west to east, it follows that the radioactivity injected into the troposphere at the polar regions will be deposited in the more northern latitudes; hence, during the 1961-1962 USSR atmospheric tests the Canadian air contained more radioactivity than the U. S. air and there vas more deposition of debris from this source in Canada than in the U. S. It would not be expected that there would be any correlation between past deposition