SOME PROBLEMS OF ATMOSPHERIC CHEMISTRY 
normally ranges up to 0.05 ng m~“, but during the in- 
trusion of air masses from districts where the smoldering 
of seaweed is practiced it is 0.6 ug m“* (von Fellen- 
berg’s mean [25]). In eastern central Europe (Szepes, 
Slovakia) the normal is 0.08 pg m™“, but the intrusion 
of air from seaweed-burning regions raises this value to 
0.13 we m-~. If air from the interior of the continent 
(Russia) reaches central Hurope, the mean there drops 
to only 0.1 ug m-*. If the natural mean, that is, that 
quantity of iodine which directly and solely originates 
from the sea, is calculated, the value found for central 
Europe is 0.0025 weg m-. The higher values actually 
found reveal the effects of industrial processes, of coal 
combustion, and of decomposition processes on the 
earth’s surface. 
Under the influence of light, and to a lesser extent 
of O3, or by autocatalytic processes, there exists an 
iodine cycle between the gaseous phase and a state 
wherein the iodine is dissolved in droplets. If the iodine 
is dissolved as iodide ion, it is easily oxidized to molec- 
ular iodine, escapes as gas from its solution, and when 
further oxidized forms iodine pentoxide (which is in- 
tensely hygroscopic and nucleogenic). However, by re- 
duction of the free iodine to hydrogen iodide and sub- 
sequent formation of condensation nuclei, the iodine 
can again return to the dissolved state. 
Ozone of Air Strata near the Ground. Repeated 
measurements [8, 9, 13, 14, 50, 54] show that the con- 
centration of QO 3 in the air near the ground is, on the 
average, independent of the height of the sampling point 
above sea level. Means and deviations shown in Table 
I support this conclusion. Only a mean of individual 
measurements made by Ehmert [23] during flights at 
altitudes from 1000 to 8000 m above the ground is 
essentially higher than the other means. The peak 
values were found by Ehmert at the level of the cumulus 
and stratus cloud cover. By using optical methods, E. 
Regener [48] also found a few high values at greater 
heights in the troposphere during thunderstorm condi- 
tions, that is, at a time when air was not only being 
transported downward from above, but also upward 
out of the thunderstorm region where electrical equali- 
zation processes between clouds were taking place. For 
this reason, O’Brien, Mohler, and Stewart [42, 43] were 
unable to confirm these findings for stable anticyclonic 
conditions. These authors found smaller concentrations 
of O; im the lower stratosphere than at the ground. In 
such eases, Regener visualizes a damming effect of the 
O; flow at the ground, a phenomenon that, however, 
would be possible only if the reducing substances in 
the air were present in far smaller quantities, and if the 
oxidation power of O3; were small enough to resemble 
that of O2. In the ‘“‘pure” mountain air of Ober Schrei- 
berhau, Cauer [12] found reduced substances to be in 
excess by a factor of 160, that is, there was an active 
oxygen deficiency. Laboratory experiments have shown 
that the O; from a limited O; source does not decom- 
pose rapidly, but reacts almost instantaneously with the 
reducing substances of the air so that after a brief time 
nothing further can be detected save the odor, which 
evidently characterizes the reaction products rather 
1129 
than the O3. Since the reducing substances originate 
principally from anaerobic decomposition processes of 
organic material in soils and waters whence they rise 
upward almost continuously, the O3, assuming its ex- 
clusively stratospheric origin, could appear at ground 
level only at intervals and for short periods during 
conditions of subsidence from greater altitudes. Like- 
wise, an accumulation of 03, whatever its source, can 
occur only where the reducing substances in the air or 
the decomposing organic substances in the soil are 
lacking. This would probably be the case in extended 
desert regions, such as the Atacama Desert. 
Taste I. Surrach Ozonr CoNCENTRATIONS IN EUROPE 
nee Num- 
Location Aire | Men) fous, [bret 
ses 
Friedrichshafen, Lake of 
Constanceseseeee reer 1000-8000) 38* |23.8— 77.8*| 14 
Jungfrau, Switzerland..... 3450 11.9 | 4.0- 30.0 | 20 
Weszterheim, Tatra, Slo- 
Vialkuan naaeanruen yee caer 1010 30.0 | 5.0-102.0 | 412 
Ober Schreiberhau, Ries- 
engebirge............. 750 16.8 | 0.3- 36.0 | 351 
Glatzer Bergland, Silesia. .| 400-800 | 14.5 | 0.0- 40.0 | 448 
Koenigstein, Taunus:.....| 400 
More than 20 m from 
lightning rod 
Generale oan seeceee 15.9 | 0.0— 99.9 | 472 
Cloudy weather....... 18.3 | 1.38- 99.9 | 339 
Fair weather.......... 10.6 | 0.0— 35.0 | 133 
Not more than 0.02 m 
from lightning rod 
Generales ese. ee. 31.7 | 1.9-189.1 | 128 
Cloudy weather....... 46.9 | 5.2-189.1 | 77 
Fair weather.......... 11.4 | 1.9- 87.5 | 51 
Island of Norderney, 
NOHO SEE worccayoooer 20 
Generali.4 eres 24.8 | 5.5- 73.4 | 181 
Near a grounded con- 
ductor tip (~0.02m) ... 35.5 | 3.1-126.1 |} 48 
Berlin, radio antenna mast.| 175 6.0 | 0.0- 20.0 | 50 
* Approximate values. 
Therefore, it is hard for a chemist to conceive of the 
generally assumed presence of an “‘ozone flow” from 
the stratosphere, whose richest O;-bearing strata at 
22-26 km altitude contain no more than about 200-300 
pe m-*, especially because the short-wave insolation 
causes, in addition to O; formation, an almost equally 
intense dissociation at high altitudes. Hence, the chem- 
ist is compelled to seek other continuously active and 
especially more copious O; sources than that which the 
stratosphere can offer, even under optimum conditions 
(except in the case of foehn). Moreover, the results of 
a series of measurements made in the Riesengebirge 
[50, 54] and in the Taunus [13] agree with these con- 
siderations. According to these results, strong fluctua- 
tions are usual even for stable weather conditions with- 
out high-reaching turbulence; unusually low or even 
zero values were found for air that had subsided from a 
considerable altitude (above 3000 m) during foehn 
conditions or as a consequence of subsidence in an anti- 
cyclone over the plains. In other words, the zero values 
occur in air with few large nuclei, but with relatively 
considerable quantities of motile small nuclei, that is, 
