Technology
| all | Safety Management of Ozone (R7) |
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１．Relation of Ozone Concentration with Safety and Effects
Ozone is a gaseous substance with a strong oxidizing power that gives us good effects. However, as ozone is harmful to living organisms on the other hand, we have to understand well the relation of ozone gas concentration with effect and harm so that we can make the most of its effects in compliance with safety requirements. To this end it is essential for us to make accurate management of the concentration of ozone. Shown in Table 1 is part of the relation between the concentration and beneficial effect or harm. A guideline as to the safety standard of ozone in a work environment is laid down by the Society for Occupational Health and Permissible Concentration Committee.
Table 1. Ozone Concentration and Its Characteristics
| Concentration (ppm) |
Characteristics (Effect and Harm) |
|---|---|
| 0.02－0.05 | No ozone odor is felt below this range although there are great differences among individuals. As the permissible value is 0.1ppm at present, no odor ensures an absolute safety. So, the human sense of odor makes an excellent and most inexpensive monitor. |
| 0.05－0.1 | Permissible value for eight-hour labor (40 hours per week). Ozone odor is felt. |
| 0.3 | Permissible value when exposed for a short time of 15 minutes or less. |
| 0.5 | In case a healthy person does a contingent work for a short time (within one hour), there is no worry with less than this concentration. However, ozone irritates nose and throat. Too much irritation may cause headache, chest pain, respiratory thirst or coughing. You are suggested to wear a mask with activated carbon. |
| 0.5－1.0 | With more concentration than this level and long operation of one week or longer, ozone sterilizes inside of the room, deodorizes and gives a cockroach repelling effect²⁾. |
| 10 | In some dozens of minutes you may become unable to breathe, suffer pulmonary edema and go into a coma. |
| 40 | Sterilizing effect equivalent to formalin gas, used for disinfection of aseptic hospital wards³⁾ |
1) American Conference of Governmental Industrial Hygienist; Ozone, Documentation Review/revised, 453, 1987, CAS; 10028-15-6”
2) Published Unexamined Application № ． 62-215509, Title ： Cockroach Repelling Method applied by Shigeo Ohki
3) Toru Masaoka, “Aseptic patient room in Osaka Medical Center for Cancer and Cardiovascular Diseases” Lifestyle-related diseases, 20(1), 15-21, 1979
They adopted the values from those laid down by the American Conference of Governmental Industrial Hygienists. They regulated the permissible concentration of ozone at 0.05～0.1ppm for eight working hours per day, 40 hours per week, and at 0.3ppm for an exposure of 15 minutes or shorter. ¹⁾
You can measure an ozone concentration within the range related to safety management in use of an inexpensive densitometer of gas detection type which is available at 10,000 yen or a little more in the market.