While we hear a lot about ozone pollution peaks or the ozone layer protecting the planet from UV rays, there is one aspect of this gas that is little known: ozone cleaning . This disinfection and cleaning technique is increasingly applied by professionals, especially since the beginning of the Covid-19 crisis. Ozone cleaning technique, dangers of exposure to this gas and for exposed employees. Let's review the available protection tools.

What is ozone cleaning?

Ozone cleaning technique

Ozone (O3) cleaning It is a simple technique: it consists of applying the gas to a room, a closed place or a vehicle via an ozone generator (or ozonator) and allowing it to act until it turns into oxygen (O2). Thanks to its oxidizing power, O3 disinfects by destroying viruses, bacteria, parasites and fungi found on all surfaces of a room and suspended in the air.

To be effective, ozone cleaning must be carried out in the relevant indoor environment. It needs an ozone concentration of 10 to 20 ppm in ambient air. This level of concentration is for everyone in that room. a mortal danger creates . Therefore, this procedure should be performed in an area where there are no occupants for the duration of the treatment. After this process, space ventilation or air recycling must be carried out to ensure the safety of future occupants.

Despite these requirements, spray ozone or ozonated water cleaning technique It was developed in hospitals and is now used in various areas (vehicle cleaning, office cleaning, hotel rooms, etc.). This practice is gaining popularity because it avoids the use of toxic and polluting products, is easy to apply, and quickly eliminates odors. Nowadays it is even possible to use this technique at home with a home ozone generator.

Ozone cleaning against coronavirus

The coronavirus health crisis has enhanced the practice of ozone cleaning. This technique is suitable for complex places that need to be disinfected, such as offices, public reception areas or even public transport. complete decontamination It is particularly popular because it makes it possible to perform it easily.

Although there are many alternatives (virulides, dry steam, UV rays, cold plasma, aerosol cans) for disinfection of places potentially affected by COVID-19, ozone cleaning has some advantages:

O3 destroys all kinds of microorganisms (bacteria, viruses, spores) and disinfects all surfaces and ambient air infected with coronavirus.
Ozonators are available to all businesses and public organizations at affordable prices.
Ozone cleaning can be done by one person.
It is a non-polluting technique.

Ozone cleaning dangers

ozone gas

Ozone or trioxygen (CAS number 10028-15-6) is a chemical composed of 3 oxygen atoms that rapidly breaks down into oxygen (dioxygen, O2) in ambient air. Ozone, in gaseous, liquid or diluted water form, is a toxic, corrosive and potentially oxidizing substance. in gaseous form O3 is a colorless or slightly bluish (when pure) gas and It emits an odor similar to bleach or chlorine and can be detected by human scent at levels as low as 0.01 ppm.

Ozone is one of the chemicals with the greatest oxidizing power (52% more effective than chlorine (Cl2), for example, and has a much faster cleaning effect). Trioxygenine oxidizing power , making it a particularly effective microbial agent with a very broad spectrum of action. Known for its oxidizing and disinfectant properties, this substance is used in drinking water disinfection, wastewater treatment, treatment of medical wounds (antiseptic and bactericidal properties), swimming pool water treatment (disinfectant), laundry cleaning, paper industry (bleaching agent), food industry (equipment and food processing). products) or in agriculture (pest control action on grain stocks).

Dangers of ozone exposure

The oxidizing power used by the ozone cleaning process Represents a real health hazard . In fact, exposure to certain concentrations of ozone can have health effects on workers performing the cleaning or on people in the treated area that is inadequately ventilated after the process.

ozone exposure It passes mainly through the respiratory tract, but can also affect the skin, mucous membranes and eyes, causing eye irritation, pulmonary edema, as well as damage to the respiratory organs. Depending on the concentration of the gas in the ambient air, those present may be prone to difficulty breathing, cough, dyspnea, chest pain, bronchial hypersecretion, or shortness of breath for up to 48 hours after exposure. When the concentration of trioxygen in ambient air reaches 5 ppm, it poses an immediate danger to life or health.

Also used in cleaning processes chronic exposure to ozone It can cause harmful pulmonary respiratory effects (atrophy of alveolar walls, fibrosis, bronchopia, dyspnea) and affect the neurological system (headache, memory problems, neuromuscular disorders).

Depends on ozone cleaning To avoid these hazards, in France, the INRS sets occupational exposure limit values (OEL) for trioxygen as follows: 0.1 ppm for TWA (Time-Weighted Average threshold limit value for an 8-hour working day) and 0.2 ppm for STEL (Short Term Exposure limit value for a period of 15 minutes).

Protective equipment for ozone cleaning

Operators performing ozone removal may be exposed chronically and/or excessively to particularly dangerous ozone concentrations. Therefore, these people must have adequate protective equipment: respiratory protection And ozone detector .

Ozone respiratory protection

When contaminated ambient air is encountered during or after the ozone cleaning process, respiratory protection mask Wearing it helps ensure the safety of workers performing the task.

The use of a full face respirator (full face covering) is recommended to help with eye irritation. This air purification protection must be used with ABEK2 Hg CO P3 or ABEK2 NO P3 filter cartridges . These combined filters for gas masks protect against organic, inorganic and acid gases and vapors, ammonia and organic derivatives, vapors, compounds and mercury derivatives, carbon monoxide (CO), solid particles, liquids, radioactive, toxic and microorganisms.

It is common practice to equip workers performing ozone cleaning with air-purifying respiratory protection (gas masks) that provide a certain level of protection. However, it is worth noting that ozone, due to its oxidizing and corrosive properties, reacts with activated carbon and hopkalite, which form the filtering medium in gas mask cartridges. Contact with ozone and these components causes their oxidation and therefore the filter capacity decreases faster than under normal use conditions. Therefore, a filter cartridge used for respiratory protection during ozone cleaning will have a faster degradation time and will need to be replaced more frequently.

In case of very high ozone concentrations in an enclosed space, wearing a self-contained respirator is also recommended. For example, an emergency response would require the use of a full SCBA, which allows the responder to be completely isolated from the atmosphere in which he or she is working (breathing air from a compressed air cylinder).

Additionally, regardless of the respiratory protective equipment used, an inspection of the respirator or SCBA should be performed after each use in such a situation. In fact, ozone exposure in some materials can degrade them through oxidation. For example, at high concentrations, rubber, neoprene, polyamide, and polypropylene are not resistant to O3 in gaseous or diluted form. Inspection and maintenance of respiratory protective equipment will monitor potential degradation of certain elements due to ozone exposure and ensure user safety.

ozone gas detector

We recommend a simple portable single gas detector for the detection of ozone remaining after cleaning. A single gas detector located next to the person doing the cleaning alerts them when the gas concentration reaches a dangerous level. Portable single gas detectors such as the Dräger PAC 8000 ozone detector are compact, easy to use and maximize team safety thanks to visual, vibration and audible alarms triggered at 0.1 and 0.2 ppm. The SI-H100 gas detector with integrated sampling pump can measure the substance up to 30 meters away, providing the operator with additional safety.

The smell of ozone can be detected by human smell, but the perception of ozone is limited to that in a room or a closed environment. clear measurement of gas concentration does not hold its place. Because, at all stages of ozone cleaning To protect the health of employees, it is necessary to have equipment that can precisely measure the presence of trioxygen in the air.