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Questions and Answers

This Q&A clarifies some of the questions we often hear about ozone, Ventafresh and PhytO3.

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Oxygen and ozone

Ozone (O₃) is a molecule which consists of three atoms of oxygen (O). The atom carries the same name as the gas oxygen (O₂). The environment air consists of 21% of O₂. O₂ is one of the gases which is absolutely essential for the functioning of the organism of humans and animals - it delivers, for example, the energy which make muscles perform their work. However, O₂ also is responsible for many degrading processes, e.g. the burning of a fire or the rusting of steel (a chemical process called oxidization).

O atoms are escharotic – they attach to whatever they can. What happens in oxidization processes is that the O₂ molecule of the environment air splits itself into two atoms of O. These atoms will then try to attach themselves to other substances in the environment. Unless these substances are extremely stable (like the metal gold), the O atom will actually break these substances apart – they oxidize. This process happens relatively slowly in environment air and much faster in pure O₂ environment. If there are enough O atoms available, the process is repeated until all materials are completely oxidized - converted into molecules which are very stable. In many cases, these molecules can't even be broken up by the human digestion mechanisms.

Ozone is a variant of oxygen which is extremely unstable. By exposing oxygen to very high energy - for example, certain types of ultraviolet light -, the O₂ molecules are split up and the O atoms attach themselves to the remaining un-split O₂ molecules thus forming O₃. This process happens continuously in the upper atmosphere with the effect that a constantly renewed layer of ozone absorbs the high-energy ultraviolet light.

Under normal circumstances, O₃ is extremely unstable and will break up into O₂ plus an individual O atom within minutes. The remaining O atom will attach itself to whatever substance is available in the environment. Two individual O atoms that happen to meet will again create an O₂ molecule. Ozone therefore cannot be stocked. There is no gas producer in the world who could supply O₃ in bottles: If someone would fill ozone into a pressure bottles and sell it, the buyer would take oxygen (O₂) from the bottle since after transport, the ozone would have be decomposed into oxygen. UV light of a specific wavelength accelerates the decomposition of ozone into oxygen - a mechanism which can be used to destroy ozone.

Therefore, ozone can be considered a transport medium for individual O atoms which will react with other substances as soon as they can.

With the PhytO3 and Ventafresh methods, ozone is created on the spot and is mixed into water. If this process is engineered correctly, the third O atom is split off and converted into a so-called hydroxyl radical (*OH). When an item is washed with this water, the hydroxyl radicals will immediately leave the water and attach themselves to the item. When this happens to viruses, spores or microbes, these pests are destroyed - the cell membranes and amino acids are oxidized into harmless molecules. The O atoms are used up during this process. In order to avoid any remaining ozone creating damage, it's destruction is enforced by applying UV light of a specific wavelength.

Ozone in water

Ventafresh and PhytO3 do not apply ozone, but the ozone is first mixed with water. By applying more energy to this process, the ozone molecules are split and so-called hydroxyl radicals *OH are formed. These have an even higher oxidation effect than ozone and react extremely fast with their environment - usually, within millionths of a second after contact with a foreign substance (ozone reacts "only" within split seconds). This is also called "Advanced Oxidation Process" (AOP).

The advantage of this process is that the hydroxyl radicals are extremely instable - it's not possible that any hydroxyl radical remains unused. Waste products are water, oxygen and small amounts of hydrogen (H₂).

How dangerous is ozone?

In publications, the terms "ppm" (part per million) and mg/m³ (milligrams per cubic meter of air) are both in use. 1 ppm corresponds to approximately 2 mg/m³ = 2000 µg/m³ (micrograms per cubic meter) at room temperature. One part per billion (ppb) corresponds to approximately 2 µg/m³.

In an ideal environment, the ozone concentration in air is 10 to 20 µg/m³. Ozone becomes noticeable at concentrations higher than 10 to 50 µg/m³. 100µg/m³ or more for a short period of time can lead to inflammations of the eyes, coughing or headaches. According to current state of knowledge, there are no long-term consequences to health because the body regenerates very quickly. Exposure to ozone concentrations of 10'000 to 20'000 µg/m³ or more for an hour or more can lead to severe damage of the respiratory organs and even to death due to failure of the respiratory organs.

10% to 15% of the population are very sensitive to ozone exposure and react strongly to higher concentrations. Affected people should get away from the ozone source as quickly as possible in order to minimize the effects on their body.

According to recent studies, ozone does not cause cancer or mutations of cells. Some German studies suggest that ozone may cause cancer, however, there's no evidence yet to support this.

European regulations dictate that ozone concentration at the working place for 42 hours per week should not exceed 200 µg/m³. The permanent concentration (24 hours per day) should not exceed 20 µg/m³. In the USA, the limits are 200 µg/m³ for eight hours per day. A limit of 400 µg/m³ for a maximum of two hours is suggested.

Summary: Ozone Concentrations and dangers to human health (see also: Gabriel, "Gefahr durch Ozonbildung bei Laserdruckern und Kopiergeräten?", tekom nachrichten | Volume 16 | 3 / 1994 | p. 36):

Ozone concentration is regularly used as an indicator for air pollution. In addition, air pollution is correlated to an increased mortality risk. On hot days and with high levels of pollution, the ozone concentration can reach a few hundred µg/m³ - a value which is believed to cause irritation, but not an increased risk of death. Some researchers believe that increased mortality may be related to higher concentrations of other pollutants, e.g. sulfur dioxide, nitrogen oxides, ammonia, formaldehyde, hydrochloric acid, organic substances, etc. Ozone can help in the composition of these substances but can also contribute to their decomposition.

Plants suffer from increased ozone concentrations if they are exposed over a longer period of time.

PhytO3 does not emit ozone gas. Instead, a small amount of ozone is injected into water. This leads to formation of so-called hydroxyl radicals which have an extremely short half life, c.f. ozone in water).

How much ozone does PhytO3 generate?

A PhytO3 machine generates ozone and injects it into water. A part of the dissolved ozone leaves the water and enters the environment air. With PhytO3, about 600 mg ozone are generated per hectare. The dissolved ozone is sprayed on the plants. The ozone and the hydroxyl radicals react with the microbes and the plant surfaces and are destroyed. A unused part of ozone remains in the water and decomposes into oxygen. The rest of the ozone leaves the water and a part of that gets into the environment air.

In order to calculate estimates for the ozone concentration in the environment air, two scenarios need to be considered: The diffusion in closed rooms and the diffusion in an open environment.

Closed Room (Greenhouse)

According to the German author Wagner, "Anorganische Gase/Ozon", Handbuch für Umweltmedizin, Landsberg/Lech 1994, ozone in air has a half-life of a few minutes. After two to six minutes, 50% of the ozone remains; after a maximum of 12 minutes, a quarter. After an hour, the remaining concentration is at most 0.1% of the initial concentration.

A hectare of greenhouses has a volume of about 20'000 m³. If the 600 mg ozone would be directly emitted into the air, the maximum concentration would be 600 mg / 200 m³ = 30 µg/m³ - a concentration slightly above the limit for the permanent concentration.

The actual concentration is much lower, for the following reasons:

• The ozone is solved in water and only a small part of it actually enters the environment air. We assume a maximum of 10% to 20%.
• Spraying needs time; during this time, the already present ozone decomposes. The "new" ozone is mixed with the air which contains decomposed ozone and fresh air.
• The windows of the greenhouses should be open during spraying. This results in a constant mixing and exchange with the outside air.

Improper handling, e.g. inhalation of the ozon water cloud, directing the spraying to other people, etc., can potentially lead to local ozone concentration of several hundred µg/m³. Therefore, precautions should be taken (as necessary with pesticides anyway). These include respiratory masks and goggles. Spraying should be carried out in the morning or evening hours. Workers who sprayed and were not protected should work on something different for at least four times the amount of time required for the spraying to minimize any risk of sickness. The greenhouse should not be entered for an hour after spraying.

Open environment (field)

The layer of active (turbulent) air over a field in summertime has a thickness of 5 to 20 meters. Because of thermal effects, the air is in constant exchange with the upper layers of air. As a very conservative figure, a half-life of 15 minutes for ozone seems to be adequate. Compared to the greenhouse, concentrations are much lower and will be almost zero after a few hours.

Given these assumptions, there is no risk to health if the driving direction of the spraying equipment is against the wind. Ozone concentrations on the field should never exceed a few dozen µg/m³ - a value considered harmless. Respiratory masks and goggles are therefore not necessary. However, subjects who are very sensitive against ozone should wear them anyway. Nobody should walk behind the spraying equipment and as a precaution, the field should not be entered for three hours after spraying.

Why is ozone harmful to microorganisms but not to plants?

Ozone is an oxidation agent - oxidation being another term for burning. When microorganisms are exposed to ozone, the O atoms burn holes in the cell membranes of the microorganisms and destroy their complex chemistry. The last 100 years of research have failed to find a microorganism which is immune against ozone.

Plants, animals and human beings have a skin which consist of several layers of cells which are renewed constantly. When exposed to ozone, the outermost layer of the skin may indeed be affected. However, it will be slowly renewed. Prolonged exposition to ozone (for example, extended bathing of the hands in ozone water) may cause horny skin because of the layers of dead skin.

Some plants have a wax-like coating on their leaves which acts as an additional protection against environment ozone.

The reason why ozone is deadly to microorganisms but does not affect plants lies therefore in the duration of exposure and concentration of the gas in the water. These factors need to be adjusted carefully in order to minimize damage to plants and maximize damage to microorganisms. When concentrations are too high or exposure is too long, the ozone will very effectively kill every microorganism but will also effect the plant. When concentrations are too low or exposure is too short, the ozone will not affect the plant, but will not kill all microorganisms either.

In the Ventafresh method, the food-processing machines are carefully adjusted in order to maximize the impact on microorganisms and minimize impact on the food. In the PhytO3 method, the ozonized water sprayers and the UV lamps are carefully arranged for optimum efficiency. Also, the driving speed of the farming machine to some degree controls the kill efficiency and impact on plants.

How do you make sure that no traces of ozone remain in the food?

Ozone cannot be created and put on stock - it degenerates very quickly into harmless oxygen. Only continuous regeneration can cause a certain constant concentration of the gas (as it happens in the upper atmosphere and in certain smog conditions on the earth surface). Under normal conditions, ozone decomposes within minutes (sometimes, within seconds). Even if somebody wanted to, there's no way how the ozone can be transported to the consumer. With the Ventafresh and PhytO3 methods, the decomposition of ozone into oxygen is accelerated by applying UV light of a certain wavelength.

Why are Ventafresh and PhytO3 "risk-free"?

PhytO3 and Ventafresh apply a variety of methods to decontaminate and sterilize food. These methods have in common that they will not leave any residues on the produce. Therefore, the consumer gets a products which does not contain traces of chemical or biological substances. This, of course, requires that no chemical substances were used in production which penetrate the product - Ventafresh and PhytO3 sterilize the food surface. If animals are fed antibiotics, these substances cannot be removed from the meat with Ventafresh. Chemicals which have been used on plants and which affect the metabolism of the plant cannot be removed by PhytO3.

Ventafresh and PhytO3 therefore cannot substitute careful and chemistry-free food production, but they can make sure that only a very small amount of microorganisms survive on the surface of the food.

They reduce the risk of consumers to digest pesticides and biological contaminations and they reduce the risks of workers being affected by harmful chemicals.

On the processed food, there are no traces of ozone. All tests have shown that both methods are very effective in removing chemical and microbiological residues.

Ozone warnings

Under certain circumstances, ozone is created from NO₂ - which is a by-product of burning oil and gasoline - and O₂. This reaction requires a lot of ultraviolet light, so ozone concentrations are typically highest near places with high traffic on clear days in summertime. Normally, ozone concentration will reach its peak in the early afternoon. The ozone concentrations generated by the traffic are actually not very high; the health is probably affected by other by-products of these chemical reactions.

Ozone migrates from the traffic centers to the countryside. Because of the higher pollution of the air in the cities, it decomposes faster in the cities. It's therefore possible that ozone concentration in a forest in the mountains is higher than in the heart of a metropolis.

The ozone layer

In the stratosphere, 10 to 50 km above the Earth's surface, ozone fulfills the important task to filter out harmful UV-B and UV-C radiation. UV-B and UV-C are known to have very negative effects to human health. This radiation on its way to the surface meets O₂ molecules which are split into ozone; this process absorbs a tiny bit of the radiation. Because there's so much stratosphere, the reaction happens many times until almost all of the UV radiation is consumed by O₂ molecules. The overall effect is that all UV-C and most of UV-B is filtered out.

Certain chemicals which are now prohibited in many countries as well as exhausts from airliners affect the ozone layer negatively. They cause the so-called ozone hole.

Other applications of ozone

Ozone is in use for over 100 years for water disinfection and for about 50 years to disinfect whirlpools, swimming pools and public paths. In many cases, it has replaced chlorine as a disinfectant: Since ozone is much stronger, it can be used in lower concentrations. To avoid the swimmers being affected, the ozone is often (and should be) destroyed using UV light which also adds a sterilizing effect.

There's a growing number of applications in the food processing industry where ozone is used to sterilize equipment or processed items.

In dentistry, ozone is now sometimes used to remove caries from teeth.

In some countries, devices are available to be put into the refrigerator in order to remove odors and increase life span of the food. Care must be taken, however, that concentrations are low enough not to affect consumers.

What's the "systemic acquired resistance"?

"Systemic Acquired Resistance" (SAR) is an effect where plants under certain circumstances develop defense mechanisms against certain microorganisms and insects. There are chemical products available which induce SAR; it's also known that UV light and/or ozone increase SAR.

PhytO3 uses ozone and UV light in order to increase SAR in plants. The plants thus become less susceptible to microbiological attacks.

Note: Ventafresh and PhytO3 are patented technologies. If you're interested in testing the products or working with them, please contact SwissFood Tech Management, Inc.

© 2006-2008 SwissFood Tech Management, Inc. · [conturia]