What is Ozone?

Ozone molecule contains 3 oxygen atoms. It is a very reactive and unstable gas with a short half-life before it reverts back to oxygen. Ozone is the second most powerful oxidant in the world and its function is to destroy bacteria, viruses and odours in the environment. It occurs readily in nature, most often as a result of lightning effect that occurs during thunderstorm. In fact that “fresh, clean, spring rain” smells that we notice after a storm most often results from nature’s creation of ozone. However, we are probably most familiar with ozone from reading about the “ozone layer” that circles the planet above the earth atmosphere. Ozone is also created by the sun’s ultra-violet ray which serves to protect us from its ultra-violet radiation.

“Residual” ozone created will return to oxygen usually within 30 minutes, in amounts equal to half its level. What this means is that after each subsequent 30 minute period there would be half as much residual ozone left at the end of the period as was present at the beginning of the period. This is similar to a geometric progression of 16;8;4;2;1. In practice the half life is usually less than 30 minutes due to temperature, dust, and other contaminants in the air. Therefore, ozone, while very powerful, doesn’t last long. It does its job and then disappears back into safe oxygen.

HOW DOES OZONE WORK?

While ozone is very powerful, it has a very short life cycle. When it comes in contact with odours, bacteria or viruses, the extra atom of oxygen destroys them completely by oxidation. In so doing, that extra atom of oxygen is destroyed and there is nothing left – no odour, no bacteria, no extra atom, only oxygen. In addition to the effectiveness of ozone, we also know that it is safe to use because we able to notice its unpleasant odour at residual levels. By residual, we mean, the amount of ozone that is produced in excess of the required amount to eliminate whatever contamination that may be present in the room. You can either reduce the ozone output or turn-off the system that generates ozone.

HOW IS OZONE PRODUCED?

There are basically two methods of producing ozone – Ultra-Violet and Corona Discharge. Most equipments utilize the corona discharge method, simulating in essence, Lightning. Equipment utilizing UV method is now becoming popular with new technology that allows higher amounts of ozone to be produced using special quartz tubes and new adjustable ballasts which allow variable outputs with UV ozone.

HOW DOES OZONE HANDLE TOBACCO SMOKE?

It eliminates the irritation caused by phenol gas, by oxidizing them. Phenol gas is the invisible part of tobacco smoke that causes discomfort to one’s eyes and creates the offensive odours. Ozone removes the environment of these effects of smoke, rather than merely filtering out some of the visible particles like an “electronic air cleaner”.

IS OZONE HARMFUL AND WHAT ARE THE LONG TERM EFFECTS?

Ozone has been known for almost a century now, so quite a lot is known about it. Several regulatory agencies, including OSHA – Occupational safety and health agency-have stipulated that the safe allowable level of residual is 0.1 ppm (parts per million) based upon the historical safety of ozone.

Note that this permissible level is for continuous exposure throughout an entire 8 hour day for 5 days a week. If anyone is exposed to that concentration of ozone, it is usually as the by-product of an industrial process like arc-welding. The temporary affects of such a low exposure would range from headaches, to sore throats, irritation in the eyes, nose and the like, similar again to what we would experience in a traffic jam.

WHAT ARE THE APPLICABLE REGULATIONS REGARDING OZONE?

The Singapore Ministry of the Environment and the Workplace Safety and Health Act follow the OSHA Guideline which stipulates that continuous exposure for 8 hours a day for 5 days per week in an environment containing 0.1 ppm of ozone is safe.

WHAT ARE THE COMMON USES OF OZONE?

Ozone is commonly used for disinfection and adour elimination in a wide industry. In the commercial sector, they are well adopted by hotels, food industry, private clubs, hospitals, clinics, supermarkets etc. It is also effective for the removal of tobacco smell and tearing eyes as a result of cigarette smoke exposure. Homes and offices are also favourable places for the use ozone generating system. However, for optimum performance, the ozone system should be operated in an enclosed area below 30˚C as ozone breaks down fast in hot environment.

WHAT ARE THE COMMON USES OF OZONE WATER?

Ozone is extremely soluble in water at 25˚C (solubility is 109 mg/l). It is 13 times more soluble than oxygen. It is difficult to get highly dissolved ozone concentrations in water because ozone is very reactive and instantly reacts with contaminants or itself in water. Nevertheless, its presence in the water has many applications. Ozone water can be used to eliminate germs and bacteria present on vegetables, fruits, raw meat and fishes that cause food contamination and decay. Washing clothes, bottles, cups, kitchen tools, basin and floor with ozone water provides good sterilization and deodorization. It can also be used to wash hands, body and face to prevent the spread of infection. Ozone is environmental-friendly as it does not leave behind harmful residual like chlorine – it turns back to oxygen after reaction or oxidation.