“Several experimental human studies on air ion exposure and mood ratings have been published throughout the years. While their evidence is inconsistent, the findings have increased awareness of mood alterations possibly associated with such exposure. Ions are ubiquitous, whereby any molecule with an unbalanced electron to proton ratio results in a net positive or negative electrical charge. Air ions are produced from alterations in the atmosphere and weather phenomena, by natural radioactivity, and by combustion processes. They are also generated by air ionizers sold commercially and by corona activity on the surface of high voltage conductors of transmission lines.”
Source BMC Psychiatry. 2013; 13: 29.
The 2013 study quoted above found no evidence that ionised air affects anxiety, mood, relaxation/sleep, or personal comfort. It did conclude however that ionisation has a significant association with severity levels ofand Seasonal Affective Disorder.
The response to high-density ionization was observed in patients with seasonal or chronic depression, but an effect of low-density ionization was observed only in patients with seasonal depression.
There is as yet no explanation for the effect.