

Ozone is expressed as O3 by the chemical symbol. Its oxidization is the strongest next to fluorine among natural elements and it has unique pungent smell. Ozone is very unstable gas, decomposing itself under normal temperature trying to return to the state of oxygen.
Ozone can be generated by discharging electricity in dry air or oxygen, by applying ultraviolet, or by generating oxygen from electrolytes and converting it to ozone.

If the concentration of ozone is high, it is toxic and harmful to people. Therefore, it is important to know the danger of ozone and set up measures for expected accidents.
To prevent the harm of ozone, the Japan Society for Occupational Health has set the permissible concentration of ozone in the work environment as 0.1ppm (in 8 hours).
| Ozone concentration (ppm) | Effect |
|---|---|
| 0.01~0.02 | Odor |
| 0.1 | Strong odor, pungent to the nose or throat |
| 0.2~0.5 | In 3 to 6 hour exposure, the vision lowers. |
| 0.5 | Obviously pungent to the upper bronchial tube. |
| 1.0~2.0 | In 2 hours exposure, there is a headache, pain in the chest, thirst and coughing of the upper bronchial tube. If the exposure is repeated, people get chronic poisoning. |
| 5~10 | Increase of pulse can be noted, causing lung edema. |
| 15~20 | Small animals die in 2 hours. |
| 50 | People’s life is endangered in 1 hour. |
