CHAPTER 4
PHYSICAL MEASUREMENTS
The aerosol and fallout sampling devices discussed in this chapter
were placed in the field primarily to obtain representative samples of
active airborne material for measurements of particle size and concen-
tration, activities, and the physical and chemical nature of individual
perticles, These objectives were only partially fulfilled.
In this chapter, aerosols are taken as dispersions of solid or
liquid particles in air which are so small that they readily follow the
streamlines of air set in motion by air-suction devices of verious types,
Fallout is that material which happens to deposit in or on various
containers and surfaces. It is clear that the distinction is purely
for instrumentel convenience and that no actual dividing line exists.
4ol
PROPERTIES OF AEROSOLS
Efforts were made to determine the properties of the ambient
aerosols sampled at three island stations, William, Yoke, and Zebra,
and on the Project 5A YAG's.
belel
Operatio
Reco
Many wmanticipated difficulties were experienced in the field.
The wmexpected size of Shot 1 and the fire on Tare destroyed all but two
of the air filter heads, greatly curtailing the filter eampling effort
subsequent to Shot 1. The millipore filters from Shot 1, though torn
or punctured, collected a considerable amount of activity and were useful for some purposes, After exposing electrostatic precipitators on
4sland stations for Shots 1, 2, and 3, with virtually no airborne activ-
ity arriving within the preset 6~hr sampling period, the island stations
were abandoned and one ESP was installed on each-of the Project 6.4 test
ships, YAG 39 and YAG 40. The two salvaged air filter heads (DMT) were
mounted on the flying bridge of YAG 40.
Suecessful collections were
obtained with these instruments from Shota 4 and 5, with the exception
of the ESP on YAG 39, Shot 4.
In this instance the plug to the aerosol
inlet was inadvertently left in place during the sampling run.
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