Ionized air is caused by numerous practices, both by anthropogenic and natural means. Not all of it is bad, as negative ions can be beneficial to health; however some ionized air can affect the ozone layer. The next few sections examines this relationship, beginning with an overview of the earth’s atmosphere.
Earth’s Atmosphere - an Overview
The earth’s atmosphere consists of four layers;
- The Troposphere: extends 6-19 Km from earth and contains our weather systems; commercial aircraft fly in this sector.
- The Stratosphere: extends to 45 Km and contains the main part of the ozone layer protecting earth from high frequency UV rays. The ozone layer extends into the Mesosphere; commercial aircraft fly in this zone as well.
- Mesosphere: extends to 85km and contains part of the ozone layer.
- Ionosphere: extends beyond 85km further into outer space.
The location of these layers is shown below.
Causes of the Hole in the Ozone layer
As we have seen, the ozone layer is located in the stratosphere, extending somewhat into the Mesosphere.
Over time, anthropogenic activities such as the use of Chlorofluorocarbons (CFC’s) a chemical component contained in refrigerant used in air conditioning, refrigeration, foam insulation and aerosols eventually caused the degradation of the ozone layer. This thinning of the ozone layer over time led to a hole being discovered in the layer; appearing in it above the Antarctic zone. This in turn led to the banning of all CFC’s in industry through the Montreal Protocol of 1987.
However the ozone layer is also under attack through natural occurring stratospheric clouds. These are produced over the Antarctic and contain chlorine icicles that react with UV rays in the -80°C conditions in the stratosphere, seriously depleting the ozone layer. For eight weeks every year this adds to the actions of other activities that create the hole in the ozone.
The damage to the ozone layer is also caused by ionized air, produced for example by lightning.
The largest hole in the ozone layer ever observed was recorded in 2006; its area being over 10.6 million square miles; this is shown in the image below from Wikipedia by NASA.
In the image, the blue and purple colors are where there is the least ozone, and the greens, yellows, and reds are where there is more ozone.
Ionization of Air – The Causes
Natural Causes of Ionization
Basically, lightning is caused by the electric field around a cloud breaking down; separating of the surrounding air into positive ions and electrons, thus ionizing the air.
Wind can produce ionized air through the movement of weather masses against each other or against the earth.
- Falling Water
Falling water such as in a waterfall; causes the water droplets to become negatively charged, ionizing the surrounding air.
Causes of Ionization in the Domestic and Industrial Sectors
- Static Electricity
Most of us will have experienced this phenomenon when changing bed linen; a static charge being set up and earthed by our body. However this is only one example of production of static electricity. (See reference section for further details)
- Ionization Machines
People with bronchial problems such as asthma and other allergies or illness, can benefit from the use of an air ionizing appliance. It should be noted that only negative ions are beneficial to health; positive ions are detrimental. (See reference section for further details)
The largest causes of ionization in industry are through an electrical discharge known as arcing; the production of a spark in high/low voltage equipment.
This has the same effect as lightning, where some of the surrounding air is separated into positive ions and electrons.
The electrical discharge can occur in switchgear, electric motors, electrical power stations, and sub-stations.
Switchgear and substations that regulate the voltage to our houses from the national grid will produce electrical discharges. Motors used in industry, power generators, as well as the motors in our domestic appliances will also produce a discharge of electricity through the contact of the brushes and the motor rotor.
- Nuclear Energy
As part of the production of nuclear energy, an ionization chamber is used; the ions being produced using an anode and cathode in an enclosed gas filled chamber.
The Effects that Ionized Air has on the Ozone Layer
Chlorofluorocarbons were the major component destroying the ozone layer, being over 90% responsible for creating the hole. Other detrimental effects are ionized air, produced by anthropogenic industrial activities such electrical discharge from power generation, switchboards, and electric motors.
Natural activities that are adding directly to the ozone layer destruction include stratified clouds over Antarctica region as discussed previously.
Natural activities responsible for depletion through air ionization: the earth’s magnetic field, lightning, and waterfalls make up the bulk of the remaining activities. Ionizing devices producing negative ions, being especially beneficial to the ill, add little to the destruction of the ozone layer.
- jamesgoulding: The Effects of Positive and Negative Ionized Air on Health
- buzzle: Ozone Layer Depletion
- freescohealth: Air Ionization Produced from Lightning
- mech: Causes and Cures of Static Electricity