DISCUSSION OF RESULTS
I. Sr90 Surface Air Concentration Data
Large air blower samples, collected over the last several years at the Naval
_ Research Laboratory, Washington, D, C. by I. H. Blifford and associates, were
made available to us for Sr” assay.
Collections were made on Army Chemical
Corps Type V filters of 200 square inches area and of heavy asbestos fiber
composition,
Collection volumes ranged from about 1 to 5 million cubic feet
of air for collection periods of one day to one week.
The large blower samples
which were analyzed from Sr?” were collected from four locations:
Washington,
D. C.3 Kodiak, Alaska; Port lyautey, French Morocco; and Yokosuka, Japan.
A
summary of the Sr90 concentration data, together with the location, collection
period and sample volume for each sample, is presented in the last section of
this report.
.
The Washington, D. C. Sr90 air concentration data are presented in Figure
1.
For these samples, the volumes were computed from recorded flow rate data.
Figure 2 shows the ‘variation in total flow with length of the collection due
to dust loading of filtersat the lashington, D. C, station,
This curve was
obtained from Mr, Blifford at the Naval Research Laboratory, who indicated
quite large variations of individual collection volumes from the average
values shovme
The data for the three foreign stations are presented in Figure 3,
For
these, the collection volumes were not monitored and the volume of each sample
was estimted by assuming the effect of dust loading observed at Washington, D.C.
(Figure 2)
applied equally well at these other locations,
The necessity of
making this assumption imposes a restriction on comparison of relative air
concentrations for the four locations but does allow us to consider the change
in air concentration with time at each location.