Ozone alert, don't gamble with your health or that of others!!!!

In the wake of the pandemic, we are once again seeing a significant number of ozone generators, "ozonators" and other technologies that release ozone into indoor air. The argument here is ozone's ability to deodorize and purify indoor air.

Ozone and its undesirable effects

Ozone is extremely harmful to the lungs, kidneys, brain and eyes. For example, a concentration of 9 ppm of ozone in the air will cause pulmonary oedema. Between this value and the average threshold of olfactory perception (0.1 ppm on average), we find dry mouth, coughing, bronchial hypersecretion, dyspnea, retrosternal pain and respiratory system abnormalities. A mere 0.2 to 0.5 ppm of ozone in the air can already cause vision disorders such as reduced night vision and poor adaptability to light, increased peripheral vision and altered ocular motricity. Added to this are kidney disorders (acute nephritis) and neurological problems (dizziness, asthenia, altered taste, slurred speech, poor coordination of movement, etc.).

What do the regulations say?

French regulations and European directives set a quality objective of 120 µg/m3 (i.e. 0.06 ppm) as the maximum daily exposure average over 8 hours, and an alert threshold of 240 µg/m3 (i.e. 0.12 ppm).

As soon as the olfactory threshold is reached, the concentration observed corresponds roughly to the health alert threshold.

The half-life of ozone in air is 3 days at 20°C. Half-life is the median of a product's lifetime, i.e. the time below which more than 50% of the product remains, and above which less than 50% remains. Ozone can therefore remain in the air for several days in high concentrations.

The equipment on the market dispenses ozone into the air at a fixed rate. For the most sophisticated products, programming or remote control can be used to control the ozone generator's operating time.

Sensors capable of monitoring and limiting the concentration of ozone in indoor air are expensive technologies requiring frequent calibration, and are therefore not offered as part of the products sold.

There's nothing you can do to estimate the concentration of ozone in indoor air during use, except your sense of smell!!! and as soon as you smell ozone, you're already on health alert, and at twice the maximum permissible dose.

It's virtually impossible to use such equipment safely in occupied premises without endangering your health.

Similarly, it is virtually impossible to use this equipment on occupied public premises in compliance with French and European regulations.

Only equipment fitted with reliable ozone controllers to enable automatic regulation of the ozone level in the atmosphere below the regulatory level should be used in the presence of a human operator. In this case, a maintenance contract is mandatory.

The maximum permissible concentration of 0.06 ppm /m3 of air, or even the alert threshold concentration, is far too low to claim any exploitable virucidal effect.