Air ionization is known for decades, as is the correlation between negative ions and air quality: the more negative ions in the air, the less polluting particles. In urban environment, and especially inside buildings, negative ions are missing. To assess the nocivity of this lack of negative ions, scientists have studied the influence of air ionization on our physiology. Here are some picks from their research results.
"Negative ions can promote the formation of epithelial cells of the nasal mucosa, accelerate mucosa cilia movement of the bronchus, improve alveolar ventilation, increased percentage of oxygen saturation in the blood. Clinical results show, after inhalation of negative ions concentrate in high doses during 30 minutes, a 20% increase of the oxygen absorption, and an increase of carbon dioxide of 14 5% emission. This normalize-ation of lung function may help asthmatic patients." http://www.baike.com/wiki/%E8%B4%9F%E7%A6%BB%E5%AD%90%E7%A9%BA%E6%B0%94%E5%87%80%E5%8C%96%E5%99%A8
"Russian research conducted at the Institute of Theoretical and Experimental Biophysics of the Russian Academy of Sciences, in Pushchino, Russia, found that exposure to negative ions increased levels of the protective antioxidant enzyme superoxide dismutase (SOD) in mammalian erythrocytes. The researchers concluded that the primary physiochemical mechanism of beneficial biological action of negative air ions is suggested to be related to the stimulation of superoxide dismutase activity by micromolar concentrations of H2O2 (hydrogen peroxide)." (Jim English) http://www.ncbi.nlm.nih.gov/pubmed/9237652
"British researchers at the Centre for Sport and Exercise Sciences in Liverpool exposed male subjects to negative ions and measured physiological responses, including body temperature, heart rate and respiration, while at rest and during exercise. Negative ions were found to significantly improve all physiological states, particularly during rest." (Jim English) http://www.ncbi.nlm.nih.gov/pubmed/8064146
No risk exposing oneself to high quantities of negative air ions
A.P. Krueger, University of California Berkeley: "No one as yet has found that the negative air ions concentrations produced by any properly constructed commercial generator may be harmful."
Many scientific studies experiment exposure to high level of negative ions density (10K/cm3 and beyond), without reporting any side-effect.
Do you want to know more?
If you want to dive deeper into the air ionization topic, we advise you the following readings which are as many attempts to provide an overview of research findings regarding negative air ions and the way they benefit human physiology: