Based on the book "Ozone Technology Application Collection" compiled by Tsinghua University, relevant ozone application concentrations are classified
and excerpted according to safe concentration air, application concentration, water application concentration, environmental concentration and perceived
concentration for easy search in applications.
[Safe concentration]
1. The ozone concentration that people are allowed to be exposed to is not greater than 0.2mg/m3.
2. Ozone industrial hygiene standards:
International Ozone Association: 0.1 ppm, 10 hours of exposure
United States: 0.1 ppm, 8 hours exposure
Germany, France, Japan: 0.1 ppm
China: 0.15ppm
3. The amount of ozone leakage outside the household ozone disinfection cabinet shall not exceed 0.2mg/m3 (referring to 1.5 meters away), and the
residual concentration after one cycle of disinfection shall not exceed 0.2mg/m3.
4. Animal tests show that the starting concentration of ozone toxicity is 0.3ppm, while the concentration that humans can smell ozone in the air is 0.02
to 0.04ppm. Based on the test results of ozone toxicity to lung function, it is proposed that 1.5 to 2.0ppm is the allowable level of ozone. upper limit of
concentration. The Ministry of Health stipulates that the maximum allowable concentration of ozone is 0.2mg/m3.
[Air application concentration]
★As air deodorization and sterilization, a low ozone concentration is required, such as 0.5ppm (1mg/m3), while surface disinfection of items (killing
microorganisms and removing chemical pollution) requires an ozone concentration that is increased dozens of times.
★The oxygen concentration for air applications is between 1mg/m3 and 10mg/m3.
★ The killing effect is better when the temperature is low and the humidity is high, especially when the relative humidity is less than 45%. Ozone has
almost no killing effect on microorganisms suspended in the air. It gradually increases at 60% and reaches the maximum value at 95%.
★ Use ozone to disinfect food processing workshops, 0.5~1.0ppm can kill 80% of natural bacteria in the air.
★ Cold storage disinfection requires an ozone concentration of 6 to 10 ppm. The bacterial killing rate is about 90% and the mold killing rate is about
80% when the warehouse is closed for more than 24 hours after shutdown.
★During fruit storage, 2 to 3 ppm of ozone can be used to inhibit the growth of mold, and the storage period can be doubled.
[Application concentration in water]
★The solubility of ozone in water applications is between 0.1mg/L and 10mg/L. The low value is used as the minimum concentration required for
water disinfection and purification, and the high value is used as the achievable concentration value of "ozone water disinfectant".
★Ozonation of tap water, the international conventional standard is a solubility value of 0.4mg/L, maintained for 4 minutes, that is, the CT value is 1.6.
★ The residual ozone concentration in the water should be maintained at 0.1~0.5mg/L for 5~10 minutes to achieve disinfection purposes.
★ Ozone water disinfection and sterilization is rapid, and the disinfection effect occurs instantly. Once the ozone concentration in clean water reaches
a certain level, it will kill bacteria within 0.5 to 1 minute. When the concentration reaches 4 mg/L, the hepatitis B virus inactivation rate will be 100%
within 1 minute.
★Herbold reported: At 20°C, when the ozone concentration in water reaches 0.43mg/L, it can kill 100% of E. coli. At 10°C, only 0.36mg/L is needed
to kill them all.
★When the ozone concentration is 0.25~38mg/L, it only takes a few seconds or minutes to completely inactivate hepatitis A virus (HAV)
★When the solubility of ozone in mineral water is 0.4~0.5mg/L, it can meet the sterilization and quality assurance requirements. The reasonable dosage
of ozone is 1.5~2.0mg/L.
★Bottled water treatment should reach an ozone solubility value of 0.3~0.5mg/L, and the ozone added should meet the amount of 2gO3 produced in
1m3 of water. According to practical experience, the ozone concentration is easily reached when the concentration is higher than 8mg/L. 4.1 Bactericidal
characteristics of ozone[12]
The main purpose of ozone treatment of drinking water is to disinfect and reduce biological oxygen demand (BOD) and chemical oxygen demand (COD),
remove nitrite, suspended solids and decolorization, and has reached the level of full production application. When using ozone equipment for drinking
water treatment, the dosage of ozone is generally 1-3 mg/L and the contact time is 10-15 minutes, which can be used as a reference for calculation based
on water consumption when selecting a model. Chemical oxygen consumption (manganese method) (COD-Mn), dissolved organic matter (DOC), UV
extinction value (SAC-254nm). The unit of ozone dosage is PPm=mg/L. The main function of ozone is to oxidize organic matter in microbial cells or
destroy the chain structure of organisms, leading to cell death. Therefore, ozone has strong killing power against tenacious microorganisms such as
viruses and spores. In addition, while killing microorganisms, ozone can also oxidize various organic matter in the water, remove the color, smell,
taste and phenols in the water, inhibit the reproduction of microorganisms and purify the water; extend the CD activated carbon, HD titanium rod core,
The service life of UF membrane and NF membrane.
When the ozone concentration in ozone water reaches the sterilization concentration of 0.3 mg/L, disinfection and sterilization occur instantly. When
the remaining ozone concentration in the water reaches 0.3 mg/L, 100% of bacteria can be killed within 0.5 to 1 minute, and the remaining When the
ozone concentration reaches 0.4 mg/L, the virus inactivation rate reaches 100% within 1 minute [10].
