158 
diurnal curves are much less pronounced and apparently 
decisively influenced by austausch phenomena [47], 
inasmuch as for mountain stations well-developed regu- 
lar diurnal variations appear only when there is a strong 
convective exchange of air with lower layers. 
The seasonal variation seems to run parallel to the 
temperature curve, as is shown by the increase of the 
Taste TV. MEASUREMENTS OF THE RADON CONTENT 
OF THE ATMOSPHERE 
Place and time of meas- Avelies Noo Mean Mae Mins 
urement tests (C cm=3 & 10718) 
Montreal 1907-8 Eve [20] 41 | 60 127 ~=«18 
Cambridge 1908-10 | Satterly [50] 87 | 108 350 35 
Chicago 1908 Ashman [3] 6 | 95 200 45 
Manila 1912-14 Wright and 50 | 71 154 14 
Smith [60] 
Mount Pauai 1913 | Wright and 10; 19 34 8 
(2460 m msl) Smith [60] 
Freiburg, Switzer- | Olujic [45] 36 | 131 305 8654 
land 1917 
Tnnsbruck 1912-20 
Seeham-Salzburg 
1914-18 
Schweidler [53]| 339 | 340 1220 0 
Schweidler [53]| 207 | 114 405 0 
Innsbruck 1919 Zlatarovic [62] | 49 | 483 1140 40 
Halle 1923-24 Wigand and — — 500 300 
Wenk [59] 
Halle 1923-24 (Q- | Wigand and 5 | 170 => = 
1000 m msl) Wenk [59] 
(1000-2000 m msl)| Wigand and 3| 85 a i 
Wenk [59] 
(> 2000 m msl) Wigand and 3 8 = = 
Wenk [59] 
Novaya Zemlya 1927) Béhounek [10] | — 1? —- — 
Graz 1928 Kosmath [34] 63 | 142 270 = 48 
Halle 1931 Ee 704 | 300 900 140 
43 
Turin 1932 Aliverti [1] 26 | 414 _—_-_ = 
Innsbruck 1933 Klling [26] 201 | 436 2580 25 
Patscherkofel near | Israél [89] 9 | 108 610 30 
Innsbruck 1933 
(1980 m msl) 
Leiden, Holland 
Land breeze Israél [80] —_ 85 = = 
Sea breeze Israél [30] _ 21 - — 
Frankfurt am Main | Becker [9] 80 | 154 526 28 
1933-34 
Taunus Observa- Becker [9] 48 | 125 477 «14 
tory 1933 
Innsbruck 1934 Maéek [88] 29 | 432 1780 472 
Bad Nauheim 1985 | Schwalb [52] 90 | 585 9200 0 
Innsbruck 1935 Priebsch, Rad-| 225 | 312 1560 10 
inger and 
Dymek [47] 
Hafelekar near Priebsch, Rad-| 128 | 100 275 7 
Innsbruck 1935-86] inger and 
(2300 m ms!) Dymek [47] 
New York 1941-42 | Hess [24] a || Sel 481 10 
Oceans: 
Pacific Ocean Bauer and — 33 == = 
i Swann [4] 
Subarctic Bauer and — Ope 
Swann [4] 
All oceans, far | Mauchly [41] — ee 
from continents 
* Approximate. 
monthly mean from spring to summer [89, 42, 43, 47]; 
however, in the valley at Innsbruck, the cold season 
(January) shows the highest Rn values. This apparent 
contradiction can probably be explained by the fact 
that the temperature influence upon the exhalation is 
opposed by the effect of the temperature lapse rate on 
the vertical transport of Rn. In other words, during 
ATMOSPHERIC ELECTRICITY 
the cold season the Rn content of the valley air may 
mcrease in spite of reduced exhalation because of very 
little vertical transport, whereas in summer the effect 
of the austausch exceeds that of strong exhalation. 
Annual variations on mountaintops have not been 
measured as yet. 
There is a close relationship with meteorological 
influences: Falling pressure increases the Rn content, 
rising pressure decreases it [85, 39, 47], as is to be 
expected from the atmospheric influence upon the ex- 
halation. The influence of the wind is twofold: With 
increasing wind velocity there appears first an increase 
in Fn content (because of increased exhalation), then 
a decrease (because of predominance of upward trans- 
port over increased exhalation). The direction of the 
wind is also important inasmuch as air masses of mari- 
time origin show a smaller An content than those of 
continental origin [9]. Precipitation, particularly that 
of long duration, decreases the Rn content; this can 
easily be explained by a decrease of exhalation due 
to the clogging of the ground capillaries (e.g., [389]). 
Precipitation particles themselves show a measurable 
content of radioactive inductions [23] which they ap- 
parently acquire while fallmg; on the high seas they 
are practically inactive, as is to be expected [48]. 
Taste V. RADON EXHALATION OF THE GROUND 
Exhalation 
Place Author (C cm=2 sec? & 
0738) 
Dublin Smyth [55] 74 
Manila Wright and Smith [60] 21 
Liebenau/Graz Kosmath [35] 40 
Innsbruck Zupancic [63] 23 
Innsbruck Zeilinger [61] 50 
Mean: 40 
The fact that temperature inversion layers with a 
high aerosol content appear to be especially rich in Rn 
[9] would seem to indicate an austausch effect. On the 
other hand, this fact may also point to a causal rela- 
tionship such that, because of selective adsorption by 
the aerosol particles, the vertical distribution of Rn 
is essentially caused by the distribution of the aerosol 
[27]. 
Radon Balance of the Atmosphere. As has been men- 
tioned in the beginning, the gaseous emanations are 
the connecting links between the primary radioactivity 
of the ground and that of the atmosphere. By diffusion 
and the suction effect of the wind upon the ground 
capillaries, these emanations are brought into the at- 
mosphere where they are distributed to greater heights 
under the influence of vertical convection. Since, to- 
gether with their disintegration products, they have 
only a limited life-span, a height distribution, char- 
acteristic for each of the radioactive substances, must 
develop. 
The measurements undertaken so far (see Table IV) 
show the expected decrease with height, but are not 
sufficient for the quantitative examination of this rela- 
tionship. However, there is another possibility of de- 
i 
