TTT
TF 8
4
A GROSS BETA RADIOACTIVITY
© OBSERVED RAGWEED POLLEN
0 COMPUTED RAGWEED POLLEN
—7 108
TTT
{
he
—
Oo
GROSS BETA CONCENTRATION, PC/ML
_
TT
P PT
EDT
—l 104
— 10?
107
—
— 10 2
-—
— 10!
10-4
{|
va
=O
a
+
t
|{
|
3P
1P5P 11P 19P
rey doo
ee Shin
100 FS
|
|
|
{
|
|
10°
25P
fl
|
oH
|
|
573
CONCENTRATION OF RAGWEED POLLEN, GRAINS/100 ML
AIR CLEANSING BY CONVECTIVE STORMS
29P
—_
|
a
a
<=
>
=
80,
—
wl 60
<<
of
=
40-
_
z=
20-b
_
<<
ac
o ke
|
[
|
1030 1040 1050 1100 1110
Le
|
1120 1130 1140
J
1150 1200
TIME, EST
Fig. 3—Results of rainwater analyses and rainfail-rate data for
Sept. 1, 1961. The curve of computed ragweed-pollen concentration ts
explained in the text.
Since the natural pollination seasons ended before September 23, no
pollen analysis was made for this rain.
In each of the three cases and for both classes of contamination,
an early sharp decrease of concentration is observed in the initial
heavy shower. Subsequent increases and decreases also demand in-
terpretation. Although, unfortunately, the complete continuum of sam-
ples was not analyzed for any of these three rains, the results indicate