Once negative ions from ionized air reach the bloodstream, they produce biochemical reactions that increase levels of the chemical serotonin, which is key in the treatment of depression, and increase the flow of oxygen to the brain, boosting mental energy. Negative ions can also protect against airborne germs, says WebMD.
Negative air ions help to prevent infection by colliding with suspended air particles that contain disease. The air particles are given a charge that causes them to aggregate together and fall out of the air, resulting in disinfected air. The clean air produced by negative ions stops the transmission of infection, according to New Scientist. The process that stops disease transmission also stops particles that cause throat irritation, coughing and sneezing.
Negative ions are created in nature as air molecules break apart due to sunlight, radiation, moving air and water. The amount of negative ions in nature as compared to indoors might be part of the reason for people's increased well-being when outdoors. Scientists have observed improved moods in individuals immediately after thunderstorms, when negative ions are abundant in the air. Individuals who experience seasonal affective disorder and chronic depression show the same levels of relief as traditional antidepressant medication when exposed to negative air ions.