How dangerous the UV and ozone technology for air purification in kitchen ventilation is and how this risk is being downplayed by many manufacturers is shown by a comparison of known air pollutants and their indoor and outdoor limits:
Nitrogen dioxide NO2
For nitrogen dioxide, the limit values for indoor workplaces in Europe are between approximately 1 and 6 milligrams per cubic meter of room air, which corresponds to 1,000 to 6,000 micrograms per cubic meter of indoor air! Driving bans are issued when cities exceed the EU limit of 40 micrograms of nitrogen dioxide per cubic meter of city air.
A very large gap between indoor and outdoor limits for nitrogen dioxide, but you will see, it is even more extreme for ozone! What is the situation with ozone in comparison? Are the thresholds similar or are they different, and if so to what extent?
Ozone is a colorless and poisonous gas. The Commission of the German Research Foundation assesses ozone as a substance suspected of causing cancer in humans. For ozone, the limit values for indoor workplaces in Europe are between approximately 0 and 0.2 milligrams per cubic meter of room air, which corresponds to 0 to 200 micrograms per cubic meter of room air!
In cities, for example, alarm limits are set by the German Environment Agency as follows: For the ozone concentration there is an information threshold of 180 micrograms per cubic meter and an alarm threshold of 240 micrograms per cubic meter. From an ozone value of 180 micrograms per cubic meter, behavioral recommendations are given to the public via the media.
If these limit values and alarm thresholds are observed, systems and statements from the kitchen ventilation industry, such as the following, must be critically evaluated:
“Complaints due to excessive ozone concentrations in the exhaust air may occur, even if the ozone concentrations released are well below the permissible limit of 20 mg/m³ according to European kitchen ventilation standard EN 16282-8.”
A limit of 20 milligrams of ozone per cubic meter of exhaust air, as previously stated, corresponds to 20,000 micrograms per cubic meter of air! 20,000!!!!!! Please compare this with the data of the German Environment Agency, which have set an alarm threshold of already 240 micrograms per cubic meter for ozone, here in the original read: https://www.umweltbundesamt.de/themen/luft/luftschadstoffe/ozon
This shows very clearly how grossly negligent many manufacturers of ventilation systems for commercial kitchens deal with these UV and ozone technologies and how little the users are really informed. The whole issue is reinforced by the fact that many manufacturers, probably distribute UV and ozone systems that emit such high ozone concentrations and then manufacturers do not even have the measurement technology to determine the ozone concentrations.
In this sense, it would be advisable for some manufacturers to behave like the three wise monkeys and their proverb derived from the Japanese:
“What does not conform to the law of an appropriate behavior, do not look! What does not conform to the law of appropriate behavior, do not listen! What does not conform to the law of appropriate behavior, do not talk about it! What does not conform to the law of appropriate behavior, do not do that! “