What is ozone?
Ozone - a term known to everyone. It is mainly associated with the "ozone hole" and the characteristic smell of air after a storm. What is it and what are its properties? What purpose is it made by humans for?
Stratospheric and tropospheric ozone – differences
Ozone, also called tritylene, is an allotropic form of oxygen consisting of triatomic molecules. It is a non-flammable, water-soluble and thermally unstable gas, which under normal conditions is characterized by a blue color and a density higher than air. At a temperature in the range of -193 - 111 C, it takes the form of a violet liquid - in this state it tends to be explosive, e.g. when in contact with trace amounts of organic matter. Ozone is formed through electric discharge or due to solar radiation - depending on the atmosphere layer. The following variations are distinguished:
• stratospheric ozone called the ozone layer - formed in the stratosphere (upper atmosphere) due to the action of solar radiation on oxygen molecules; it is very valuable from the point of view of the Earth and its inhabitants, because it provides protection against harmful ultraviolet (UV) radiation,
• tropospheric ozone (ground level) - formed at the surface of the Earth and is air pollution dangerous to living organisms.
At this point, it should be remembered that ozone is present in all layers of the atmosphere, but it accumulates only in these two mentioned above. The ozone hole mentioned in the introduction is nothing but ozone depletion - the wider it is, the larger amounts of harmful UV radiation reach the Earth's surface. The elevated concentration of tropospheric ozone is also dangerous because it contributes to the development of diseases of the respiratory and circulatory systems -its highest concentration is recorded in the spring and summer.
Properties and application of ozone
In addition to the features discussed so far, ozone has also very strong oxidizing, toxic and aseptic properties. Due to the latter, it is considered one of the most effective disinfectants. It is about 50 times more effective than chlorine and very quickly kills viruses, bacteria, fungi and spores, although due to the relatively short time of decomposition, ozone is unable to completely replace chlorine in the water treatment process. In addition, it is widely used, among others in:
• hospitals, where it is used to sterilize rooms,
• the food industry, e.g. ozone decontamination of the top layer of fruits and vegetables prolongs their freshness and thus the shelf-life date,
• automotive industry - ozonization allows to decontaminate the interior of the car, get rid of unpleasant odors or remove bacteria, mites, pollen and nicotine from the evaporator, etc.,
• cosmetology, e.g. for the production of cosmetics based on the ozonated olive oil.
How to generate ozone on an industrial scale?
On an industrial scale ozone is obtained through ozonators - ozone generators. They are electric-mechanical devices with a very complicated construction. They consist of elements such as housing, fans, high voltage converter, ozonating lamp, ozone regulating rotameters and timers. Ozone can be obtained in a cheapest and easiest way by means of electric discharges - especially quiet, corona and surface ones. In addition, the following methods are used:
• electrochemical method based on the electrolysis of demineralied water,
• radiative-chemical method using X-rays,
• thermal method, in which water is stimulated by UV and IR radiation,
• a wave with a length of 185 nm - it irradiates oxygen, air and drinking water.
Ozone in households
Globally, ozonators are more and more often becoming a part of household equipment - although in Poland, this is not yet a popular solution. Having such a device at home has a number of advantages, noticed not only by people with allergies. Ozone is a proven tool in the fight among others with fungi and mites or rodents and insects, combating of which with traditional methods is costly and time-consuming.
Written by Jakub Hubert Luft
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