CHARACTERISTICS OF RELATIVE 299sr
CONCENTRATIONS IN SURFACE AIR
HERBERT L. VOLCHOK
Health and Safety Laboratory, U. S. Atomic Energy Commission,
”
New York, New York
ABSTRACT
Since taking over the 80th Meridian (West) Air Sampling Program at
the beginning of 1963, the Health and Safety Laboratory has slightly enlarged the scope of the program by the addition of a numberofsites
and has effected some minor operational changes, The 1963 data of air
concentration of Sr at ground level along the 80th Meridian are pre-
sented along with the Naval Research Laboratory data covering the
period 1957 and 1962. Almost all sites in 1963 exhibited higher concen-
trations in 1963 than at any previous time. The “sr/*Sr ratio indicated
that the nuclear debris in the northern hemisphere wasrelatively well
mixed compared to that in the southern hemisphere which showed older
debris, When the 1962 and 1963 data are normalized and averaged, very
systematic seasonal changes, largely unaffected by the testing program,
are observed. Symmetry between the hemispheresisvery clearly shown
when a four-month offset in time is assumed; thus peak values in the
north occur in March and April and in the south, in November and December. A qualitative relation between concentration of "Sr in air and
concentration of Sr in precipitation is described,
INTRODUCTION
At the end of 1962, the Health and Safety Laboratory (HASL) assumed responsibility for the 80th Meridian (West) Air Sampling Pro-
gram, which was formerly conducted by the Naval Research Labora616