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Ever been up in the mountains, at the beach, or in a thunderstorm and suddenly felt a huge change in your mood? That’s not just a feeling of awe. It might be negative ions.

Negative ions are molecules floating in the air or atmosphere that have been charged with electricity.

Negative ions exist in nature in tons of places, including:

  • ultraviolet (UV) rays from the sun
  • discharges of electricity in the air after a thunderclap or lightning strike
  • wherever water collides with itself like a waterfall or the ocean shore (creating the Lenard effect)
  • produced as part of the normal growth process for many plants

Many researchers of “negative ionization” have posited that being exposed to negative ions can have positive effects. Part of this is due to the chemical reactions that ions have with your bodily tissues and DNA.

But is there any real evidence for these claims?

Let’s dive into the research behind the benefits (if any) of negative ionization, what risks and side effects may be possible from exposure, and finding negative ions.

Proponents of negative ionization make a lot of seemingly lofty claims about its mental health benefits in particular. Here is what years of research have and haven’t found.

Research supports exposure to negative ions:

  • reducing symptoms of depression for some people
  • having an activating influence on some body systems and cognitive performance
  • promoting antimicrobial activity

Not enough evidence for:

  • reducing serotonin to help manage anxiety
  • lowering blood pressure
  • improving your breathing

A 2013 review of scientific literature on negative ionization published between 1957 and 2012 found that ionization had no impact on people’s general mental health but did find a notable effect on people with depression.

  • Hours of negative ion exposure may reduce symptoms of depression. High levels of exposure (like several hours or more) to negative ions caused people with chronic depression and seasonal affective disorder (SAD) to record lower scores on surveys of their depression symptoms.
  • Shorter duration of negative ion exposure may positively affect seasonal depression. Lower levels of exposure (just 30 minutes or so) were only enough to help people affected by SAD.

A very small 2015 study didn’t find any major effects on mood or mental health from negative ions. But this study did find a small improvement on cognitive performance after short-term exposure to increased negative ions.

A 2018 review of ionization literature also found an effect of negative ionization on many facets of human health. Researchers looked at 100 years of studies and found evidence that negative ions could:

  • help regulate sleep patterns and mood
  • reduce stress
  • boost immune system function
  • increase metabolism of carbs and fats
  • kill or inhibit the growth of harmful bacteria, viruses, and mold species, such as E. coli, Staphylococcus aureus, and the bacterium that causes tuberculosis

But researchers also noted that there was no evidence that negative ions could:

  • reduce serotonin to help manage anxiety
  • lower blood pressure
  • improve breathing

And this same study looked at how negative ions affected indoor air pollution. Many negative ion generators or “ionizers” can help reduce pollution particles that are up to 5 feet off the ground by as much as 97 percent.

But keep in mind that this effect has mainly been studied in controlled environments that don’t have major sources of new pollutants constantly entering the air.

The greatest risks of negative ions come from ion generators used in small spaces like bedrooms.

Ionizers create negative ions by discharging electrical currents into the air (like the corona discharge effect of a lightning storm).

Ozone particles

But negative ionizers can release ground-level (tropospheric) ozone into the air. Some researchers claim this can make symptoms of conditions like asthma worse (though a 2013 review of studies found no reliable, significant evidence of an effect — beneficial or detrimental — on asthma or pulmonary functions).

Static electricity buildup

The extra electrical charges released into the air by an ionizer can also lead to dangerous levels of electrical charge in your home.

Respiratory irritation

Negatively charged particles also stick to surfaces after they’re knocked out of the air by electrical charges. This can include your airways (the windpipe and the inside of your lungs). This can cause a build-up of particles in your respiratory system. This can worsen asthma symptoms or increase your risk of lung disease.

The atoms that make up molecules have a certain number of electrons floating around a central core, the nucleus. Some electrons are positively charged. Others are negatively charged. This electron balance can be disturbed when enough energy is applied to the atom. The atom then becomes an air ion.

The atom becomes a positive ion if electrons are displaced from the atom. But it becomes a negative ion if an extra electron is pushed into the atom so that it has an excessive number of electrons.

Positive ions are known as cations. They’re often created simultaneously with negative ions, or anions. The other half of the Lenard effect is the creation of positively charged water molecules at the same time that negatively charged air molecules are created.

Positive ions are created by much different processes. During particularly cloudy days, electrical charges in the air are conducted more quickly by increased amounts of humidity. Any negative ions also quickly become attached to any particulate matter in the moist air. This leaves a high concentration of positive ions in the air. That can make you feel lethargic.

Positive ions may also make you feel worse off. The 2013 literature review mentioned earlier found that many people who were exposed to increased levels of positive ions reported more:

  • unpleasantness
  • acute respiratory irritation
  • joint symptoms

Get outdoors

The best way to get negative ions is to go to where they exist naturally. There’s little anyone can say against spending a little time outdoors.

  • Step outside in the rain.
  • Visit a waterfall, creek, riverbank, or beach.
  • Sit beside a decorative water fountain, often found at parks, shopping areas, and the lobbies of office buildings and hotels.

Skip ionizer devices

Although some research supports some positive effects of exposure to negative ions, there is no evidence-based medicine that supports negative ion therapy.

So don’t bother getting any home negative ionizers. They can produce dangerous indoor ozone and just waste space and electricity.

You may have also heard that Himalayan salt lamps produce negative ions. But the amount they produce, if any, hasn’t been shown to be significant.

Negative ions are everywhere in nature. And they have some demonstrated benefits.

But they’re not a miracle cure-all for all the conditions that you might read about on websites and in marketing buzz.

Don’t count on negative ions to make any major medical changes to your life. But enjoy the next thunderstorm or a trip to a cascading waterfall for your negative ion fix.