Despite numerous experimental and analytical differences across studies, the literature does not clearly support a beneficial role in exposure to negative air ions and respiratory function or asthmatic symptom alleviation. Further, collectively, the human experimental studies do not indicate a significant detrimental effect of exposure to positive air ions on respiratory measures. Exposure to negative or positive air ions does not appear to play an appreciable role in respiratory function.

A few isolated studies have shown modest and equivocal effects from negative ionization. For instance, in 1981, researchers at the University of Surrey in England looked at the incidence of stuffiness, nausea, dizziness and headaches in people in an office environment. They found office air had fewer negative ions than is typical outside. So the team conducted a double-blind study and found that the reintroduction of ions reduced the incidence of these symptoms over a 12-week period. The findings were published in the Journal of Environmental Psychology. A 1993 study published in the Journal of Human Ergonomics found that negative ions could slightly affect people's circadian rhythms, although they had no impact on anxiety or exercise levels.
What's more, the amount of air in the room is so huge relative to the size of the rock crystals that few of the pollutants circulating in the room could stick to the surface of the rock salt. Even if the lamps did manage to attract pollutants, the surface of the rock salt would quickly become coated with pollutants and no more could stick. Meanwhile, the air supply is always being replenished, either through ventilation systems or open doors or windows, bringing ever-more air pollutants into the room, he said.

No consistent influence of positive or negative air ionization on anxiety, mood, relaxation, sleep, and personal comfort measures was observed. Negative air ionization was associated with lower depression scores particularly at the highest exposure level. Future research is needed to evaluate the biological plausibility of this association. Source: Air ions and mood outcomes: a review and meta-analysis.  
At any rate, we plugged the unit into an electrical outlet, dimmed the light to a very pleasing dim orange color and placed the lamp on a table. The lamp has been turned on 24/7 for a couple of weeks now. The dimmer is cold to the touch and we have experienced no issues whatsoever with the product. We are very pleased with the lamp, its appearance, and the nice pinking-orange dimmable warm glow it casts.