A 2013 comprehensive review of 80 years of research into air ions and respiratory function outcomes found that there was no clear support for any beneficial role in respiratory function, nor evidence for significant detrimental effect. In conclusion, "exposure to negative or positive air ions does not appear to play an appreciable role in respiratory function." There is weak evidence that negative air ionization is associated with lower depression scores, particularly at the highest exposure level. No consistent influence of positive or negative air ionization on anxiety, mood, relaxation, sleep, and personal comfort measures was observed. Adverse health effects of ozone byproduct Studies have been carried out on negative ion generators. One study shows that the ozone generated can exceed guidelines in small, non ventilated areas. Another study showed that ozone can react with other constituents, namely cleaning agents to increase pollutants such as formaldehyde (this study had as its objective the testing of the use of cleaning products and air fresheners indoors and associated health risks as opposed to adverse health effects of<unk> s).
Air ioniser
Respirometer
Crusaid
Hug machine
Sweat diagnostics
Haidinger's brush
Mind machine
Air purifier