There is an opinion that positive ions are unhealthy. This mistake has a long history. First of all, when was discovered the advantage of ionized air, researches decided that only negative ions are useful. That's why the academician A.F.Chizhevsky began to make his lamps, and his followers - their devices - unipolar, i.e. they generated the ions of one polarity. It is easier to produce such ionizers, there is no need to think that ions can recombine.
Above all the imperfection of generators caused this mistake, but the absence of necessary control equipment was the other very important reason.One more disadvantage of the generator was that it produced not only positive ions but also a great amount of ozone, that's why it was even dangerous to stay for long time in the room with such generator. Ozone is a great oxidant, in small proportions it accelerates aging and in big ones it is poisonous. Also it was cleared out that due to its big chemical activity ozone facilitated the formation of poisonous nitrogen compounds.
All these above listed technical imperfections prevented from the development of air ionization researches for quite long time. But with the beginning of space flights epoch the ionization problem became actual again. Researches were kept on.Now it was important to determine what kinds of ions exist, which of them were useful and which of them were harmful.
First of all, while creation and testing of air ions counter it was determined that positive ions existing in the natural conditions, in spited of the formed views of that time, didn't influence badly on people. Harmful was the lack of both polarity ions, especially negative ones, which were very beneficial for people. By the way the overbalance of ions was also harmful.
Chizhevsky and his contemporaries couldn't know for sure what concentration of ions was beneficial and what proportion was dangerous.Nowadays we have modern gauge length and that's why we can measure the concentration of ions of both polarities with high accuracy.
Thus, even at the beginning of 70-th the experimental researches of air ionization in natural conditions, which were carried out with the help of our equipment, enabled to determine the natural concentrations of air ions of both polarity, and the relation of negative and positive air ions in natural conditions: in the forest, seaside, mountains, on the resorts.
On the basis of these measurements there were made some recommendations on aironization and requirements to air ion composition of air in rooms. And as the result, experimental facts were reflected in norms of SanPid of the Russia Ministry of Health.
The author of the article - Aydar Tuktagulov (Sapphire Company www.ionization.ru)