Studies have shown that some people become very depressed when negative ion counts are
very low (seasonal depression).
A high negative ion exposure appeared associated with feeling better about self, less
sensitive, and more responsive or innervated (energized). -From August, 1982 issue
of Aviation, Space, and Environmental Medicine.
"Results indicated that subjects had faster reaction times and reported feeling
significantly more energetic under negative Air Ion conditions then under normal air
conditions." -From Influence of Negative Air Ions on Human performance and
"... The introduction of negative ion generation increased the subjective rating
of alertness, atmospheric freshness, and environmental and personal warmth.