Ions in Nature
In nature, ions are generated in abundance wherever energy is transferred into the air. For example by ultra-violet light from the sun, by lightning and thunderstorms, by friction within wind and rain, the splitting of water into droplets by waterfalls and surf - and by natural radiation in rocks and soil.
Negative ions - refreshing
Places we find refreshing, such as in the mountains, near waterfalls and seashores have high concentrations of negative ions. It is no coincidence that this is where health resorts are traditionally situated.
But areas with high levels of positive ions often leave us feeling uncomfortable and irritable.
Positive ions - oppressive
Many people find the atmosphere just before a storm is 'heavy' and oppressive. This has been attributed to the high levels of positive ions that build up in the air, which are also believed to be the trigger of "storm-sensitivity" in asthmatics and many others.
Certainly, in laboratory conditions, similar symptoms could be triggered in subjects when they were exposed to abnormally high levels of positive ions.
This photograph was taken during some unusually fierce storms which swept across the south east of the UK in 1994. In the hours before the storms arrived, hundreds of people had reported to hospital with severe asthma attacks. Was it due to positive ions?
Many studies suggest it could be!
Immediately after the storm
the air feels clean and refreshed with negative ions.
In the upper atmosphere the action of the Sun's ultra violet rays forms a thick band of ions called the ionosphere, starting at 60 km and finishing around 100km above the Earth. It is the ionosphere that reflects radio waves back to earth, allowing us to broadcast over long distances. The reason distant stations fade after dark is because the ions diminish as the sunlight disappears.
The Sun is constantly ejecting streams of charged particles into space. (This is known as the solar wind). As these particles approach the Earth they are caught in its magnetic field and swept round to the North and South poles. Pouring into the atmosphere, they ionize its component gases in a spectacular display of glowing colours, called the Aurora.
As you can see
Our atmosphere is absolutely teeming with ions. Nature was making them even before life began. Indeed scientists believe that ionization, in the form of lightning, was probably instrumental in the formation of ammino acids - the essential components for the beginnings of life!