American Niagara Falls at sunset

What is negative air ionization?

A springtime thunderstorm hits, and as soon as it passes you are eager to go out for a walk. The feeling can be exhilarating. The same thing happens visiting Niagara Falls or by the seaside. If you were to make physical measurements, you would find that oxygen (O2) in the air has taken on a tiny negative electrical charge, becoming O2. These particles are enveloped by microdroplets of moisture, H20, which help maintain the charge until the O2 is attracted to a neutralizing surface. The arrangement of O2 molecules enveloped by moisture is called “superoxide”, but you might also call it fresh air.

By contrast, if you live and work indoors for extended periods, with heating or air conditioning, or are close to computer screens and TV displays, the superoxide is depleted: positive ions compete with negative ions, removing their benefit.

What does an electrical ionizer do?

Fortunately, we don’t have to wait for trips to the beach to gain this natural benefit from the air.  An electrical device indoors can suffuse the air with negative ions. Old air purification technology produces an O2 stream attracted to positively charged pollutants in the circulating air, such as household dust, cigarette smoke, and pet and skin dander.  When the unit is left on all day, the stream of negative ions continuously seeks out these pollutants; they become heavier, and tend to fall to the floor.

This subtle air purification effect is fine for cleaning, but insufficient to replicate your subjective experience at the beach. That requires far more powerful ionization from a specially designed device.

How has CET contributed to the development of this field?

For many years, there were claims that negative air ionization could improve blue mood, poor work concentration, and exhaustion. However, these studies used very low concentrations of negative ions from home air purifiers — and showed inconsistent results. The positive effect could be rightly questioned as wishful thinking. Then, with new more powerful devices in the 1990s, CET scientists working at Columbia University performed the first randomized, placebo-controlled clinical trial of high-density negative air ionization in subjects with winter depression (seasonal affective disorder, SAD).  The control group received a low dose of ions, similar to the level of standard home air purifiers. The subjects took treatment at home every morning for 30 minutes a day. After three weeks, about 60% of the high-density group responded with major mood improvement, while only 15% responded to low-density ionization — a highly significant difference.  Importantly, the subjects could not tell which group they had been assigned to, since humans cannot perceive the level of negative air ions in the circulation.

Following this promising demonstration of positive effect on mood, additional trials showed similar benefit when tested in the bedroom during sleep, and with patients who were depressed all year round (not only in the winter). The ion effect was similar to that found for bright light therapy in patients with SAD. Brief exposures to high-density ions also improved mood and alertness in college students tested at a workstation, whether or not they were depressed.

How to decide between light therapy and negative air ionization

The two treatments have been compared in separate groups of subjects with SAD. While the overall results were positive, there were individual cases with little or no improvement. That’s no surprise: If you were seeing a doctor for an antidepressant, you might test 3 or 4 pills before finding the one that suits you best. Or you might find that none works for you.  In our case, you might start with a light box, since it has been intensively investigated. On the other hand, you might choose a high-density negative ionizer, which allows you to move around, and even administer the treatment at night, eliminating the need to sit attentively by the device as is the case with a light box.

Can I use high-density negative air ionization along with bright light therapy to maximize the effect?

First, you should see whether you respond fully to either treatment by itself. If there is still room for mood improvement, the two methods can be used together, but not at the same time of day.  Both the ionizer and the light box need to be placed close to your sitting position. The light box is electrically grounded. If you use the two devices at the same time, negative air ions will flow preferentially to the light box, rather than to you! So, you need to find separate times of day if you want to combine the treatments. One solution is to set up the ionizer in your bedroom and turn it on automatically with a 24-hour appliance timer 90 minutes before you expect to wake up. Once out of bed, take the light therapy session seated at your desk or table.

If you are taking treatment with a clinician’s supervision, possibly including an antidepressant, be sure to discuss any treatment combination. Monitoring and dose adjustments — for example, session duration at the light box, or drug tapering — require expert advice and attention.

What leads us to recommend a particular model to best suit our visitors’ needs?

Having monitored the market over two decades of gradual growth and innovation, CET has sought out the best constructed high-density negative air ionizer, with reliable operation over long-term use.  Importantly, our supplier is well-informed in the science and technology behind the device, and responsive to consumer inquiries.