Deedee Cheriel

Does being near water make you feel relaxed? Therapeutic landscape designers Marco Mencagli and Marco Nieri explain how negative ions—abundant near bodies of water—have a profound, if poorly understood, role in health and happiness.

Among the chemophysical properties of the biosphere that humanity has altered in recent times, the air’s level of ionization is not debated enough. The expression “ionization” refers to the quantity and the quality of electrically charged particles in the atmosphere. It has been observed that in natural environments characterized by well-developed plant life, in particular trees and shrubs, negative ions predominate over positive ions.

Environments with a predominance of negative ions are shown to be effective in reducing states of stress and depression and psychophysical maladies connected to stressful events. Various studies and experiments have noted the antidepressant effects of high concentrations of negative ions, called anions, in the air.

A review published in the United States in 2013 presents a meta-analysis of five different clinical studies that all confirmed a direct correlation between high negative ionization of environments and improvement in depressive states. Studies conducted in Japan and Romania showed that a high concentration of negative ions in the environment enables quicker recovery from intense physical exertion, with a normalization of blood pressure in less time. Studies also show that cognitive performance, especially memory, is improved in both children and adults.

Wherever there are bodies of moving water there is always negative ionization, created by what is called the Lenard effect: the greater the kinetic energy with which a body of water crashes into a solid object or disperses into the air, the more notable and effective the production of ions. The separation of electrons from water molecules, which are electrically neutral, produces as many positive ions as negative. But while the majority of negative ions remain suspended in the air until their neutralization, positively charged water particles rapidly fall to the ground (or the body of water) after impact, and are in turn absorbed and deactivated. For this reason, the atmosphere near bodies of colliding water can contain as many as tens of thousands of small negative ions per cubic centimeter, these ions being much more active from a biological perspective as well.

The spectacular waterfalls formed by rivers large and small are an important source of negative ionization, with a high therapeutic quality. A shore of the sea or ocean can likewise be an effective source, with its power correlated to the water’s degree of agitation: it is clear that a wave colliding forcefully against a cliff can produce more negative ions than a placid lake lapping a sandy shore.

Of course you don’t have to take a cruise to Niagara Falls or watch the waves crash at Thunder Hole in New England’s Acadia National Park to get an effective ion shower. If well planned, even small waterfalls or fountains with a flow of water comparable to a stream can fill the air in their immediate vicinity with several thousand negative ions per cubic centimeter. The important thing is that the water’s movement is sufficiently high and forceful to produce a significant Lenard effect.

The body of water’s beneficial activities can be further strengthened by lush greenery, with trees and shrubbery capable of holding the aerosols in the area benefiting from negative ionization. Even decorative elements such as fountains that reproduce the effect of small waterfalls can help in creating effective green spaces aimed at psychophysiological well-being. For several years the study of air ionization has also been extended to hydrothermal areas. Hot springs have biological and therapeutic properties due especially to their chemical composition and in part to their temperature. A thermal or hyperthermal complex in which waters circulate and bubble so as to release a high amount of aerosols into the air is definitely a significant source of anions.

If you aren’t near an active body of water, other sources of negative ions accessible to anyone are natural environments characterized by sufficiently dense, lush vegetation and a prevalent, well-developed tree cover. It isn’t difficult to find this model: many deciduous and coniferous forests can have these characteristics, as long as there is enough water to guarantee good levels of relative humidity in the air. A good amount of natural light is favorable, thanks to the generation of negative ions during photosynthesis. We can also infer that many forest environments suitable for the practice of forest bathing also have a sufficient level of air ionization, often with a predominance of negative ions over positive ones. If the forests are located in a mountain environment, it is likely that the amount of anions is even more significant.

Waterfalls, seashores, large bodies of moving water, hot springs, forests, woods, mountains: nature gives us a wide array of therapeutic opportunities. The ion shower is an example of the purifying, regenerative power of natural environments.

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Reprinted from The Secret Therapy of Trees: Harness the Healing Energy of Forest Bathing and Natural Landscapes © 2016 by Sperling & Kupfer Editori S.p.A, © 2018 by Mondadori Libri S.p.A for the imprint Sperling & Kupfer. Published in English in 2019 by Rodale Books, an imprint of Penguin Random House.