|In higher concentrations, ozone may cause health effects after inhalation. Symptons, such as mucous membrane irritation and headaches, often follow. These symptoms can also occur during episodes of photochemical smog. Higher concentrations (> 50 ppm) and long-term exposure (> 30 min) may be fatal . However, remaining in a room with these kinds of concentrations is nearly impossible. |
Long-term effects of ozone exposure are not fully known, but we are warned to consider a decrease in lung capacity and lung diseases. This information is based on experiments with test animals [7,12].
To prevent the above-mentioned health risks, a maximum amount of ozone has been established for areas where one uses ozone. This is the so-called Maximum Admitted Concentration, or MAC-value. This value describes the maximum concentration of a substance that a human can be exposed to for a given period of time. For a normal working week of five days, eight hours per day, ozone has a MAC-value of 0,06 ppm (parts per million, or mg/L). For 15 minutes, the MAC-value is 0,3 ppm .
Ozone can be measured in ppm or ppb (parts per billion, or μg/L), according to various principles. With these measurements, the desired ozone concentration in a system can be monitored. When MAC-values are crossed near the ozone generator, an alarm will sound.
Ozone has a very distinctive smell, causing MAC-value violation to be noticed quickly. The scent threshold of ozone is about 0,02 ppm .