Minus ion

Minus ion (マイナスイオン) is a Japanese marketing term that became trendy around from 1999 to 2003, referring to something in the atmosphere that is allegedly good for health. The wasei-eigo is sometimes translated in English as negative ion in articles about Japanese products and services. However, the term "negative ion" has also been used in physics-related topics unrelated to personal well-being and marketing. Minus ions are considered as pseudoscience. Products and services that claim to emit minus ion include air conditioners, humidifiers, wrist watches, and public baths (sentō) ; in the advertisements, scientific explanation as to what "minus ion" is, what its benefits are, and how it works are often not forthcoming.