NUMBER AND CHARGE OF AIR IONS OUTDOORS AND INDOORS Outdoor air contains both positive and negative ions, with the former generally being somewhat more numerous than the latter. This situation is of no danger to healthy people, because the small predominance (by 10 20%) of the positive air ions is offset by the considerably higher mobility, diffusion, and ionization of the negative air ions. However, in certain localities the negative air ions permanently outnumber the positive ions. Because of this property of the air in some resorts (Sestroretsk, Alma Arasan, Abkhazia, etc.) we call them "electrical resorts." The average number of light air ions (both positive and negative) over the greater part of the globe, is approximately 1000 per fluctuating according to the season, time of day, and geophysical, meteorological, and other conditions.
Ionization of atmospheric air occurs mainly as a result of decay of the radioactive elements, always present in minute quantities in soil and water. Cosmic radiation excites from one to 2.8 pairs of ions per Solar flares usually lead to the abrupt rise in the intensity of cosmic radiation accompanied with a slight, temporary increase in atmospheric ionization.
Research has revealed that the concentration of air ions in summer is considerably higher near green plantations and over meadows than in other places. The difference is most pronounced in cities in the vicinity of factories where the concentration of light air ions drops abruptly, while the increase of charged liquid and solid aerosols is recorded; the latter are generally very damaging to health.
The higher concentration of air ions in the vicinity of green expanses is readily explained by the extensive surfaces giving off radioactive water from the soil through the foliage or herbage. The leaf area of forests and meadows exceeds tens of times the soil area covered by the plants; in the grass meadows which we investigated (temperate latitudes) it is, on the average, 25 times greater, and in the alfalfa fields 85.5 times. This is the rational explanation for the salubrious effect of green expanses in the cities, Our investigations revealed that when air enters closed premises through windows, cracks, and ventilators, it loses almost half its light ions. In the presence of people, the number of light air ions indoors rapidly falls toward zero, owing to the large number of neutral and charged particles exhaled by the human respiratory system. Consequently people spend most of their life in deionized air. In air-conditioned rooms the air is devoid of any light ions. Let us now examine whether the absence from the air of light oxygen ions influences human health and life.