The following limits are widely accepted (USA, UK and other parts of Europe):
- 8 hour per day/5 days per week (occupational exposure limit) - 0.1 ppm
- 15 minutes (short term exposure limit) - 0.3 ppm
The acute and chronic effects of excessive exposure to ozone have been well investigated. There has never been a single recorded fatality attributed to ozone exposure in more than 100 years of commercial use. Exposure to concentrations of ozone in excess of 0.3 ppm sometimes causes reports of discomfort in a small susceptible portion of the population. This can be in the form of headaches of dryness of the throat and mucous membranes of the eyes and nose following exposures of short duration. Ozone has been shown to be more injurious at concentrations exceeding 2.0ppm over several hours. When the proper concentration of ozone isn't in excess of 0.3 ppm, ozone will have a sweet freshening smell like the air after a big thunderstorm. Extreme ozone levels at concentrations exceeding 2.0ppm are readily noticeable and are similar to a strong whiff of chlorine that is immediately evident in the sinuses. Ozone is not generally regarded or suspected of being a human carcinogen.
Toxicology of ozone
In the event of an ozone leak:
- Immediately switch the ozone appliance OFF.
- Where high levels of ozone are experienced all should vacate the affected area until it has been thoroughly ventilated.
- Breathing - If a person breathes in large amounts of ozone, move the person into warm uncontaminated air at once. Keep the affected person at rest. Seek medical attention as soon as possible. We are not responsible for any loss or damage to any nature arising from misuse or mishandling of ozone.