Ozone gas detectors measure the concentration of ozone in the air. These analyzers can measure ozone in the air to provide a parts per million (ppm) concentration. As an unstable gas, ozone has a unique nature that must be considered during detection. Ozone gas decays to form oxygen as a function of temperature, humidity, time, and air agitation. Therefore, it can be tricky to measure ozone in a consistent fashion. In this guide, we present essential information about ozone detectors and tips to ensure accurate measurements. 

What Is Ozone Gas?

Ozone is a simple gas made up of three oxygen molecules with the chemical formula O3. It has unique behavioral characteristics. It is an unstable gas and decays to oxygen, meaning that it is tricky to handle and measure.

Ozone is a strong oxidizing agent and offers interesting disinfectant properties to effectively kill fungi, bacteria, and viruses. It is often used in "cleaning" situations. For example, ozone is used in transportation applications to clean police vehicles, transit buses, and commercial passenger aircraft.

Why Is Ozone a Special Gas?

Ozone is a special gas because it is unstable and decays to oxygen over time. It cannot be stored in a gas bottle. This unique characteristic makes it tricky to obtain repeatable ozone measurements. Ozone gas also has oxidization properties, making it a useful disinfectant for cleaning and abatement companies. Thanks to ozone's unique therapeutic properties, it is also used throughout medical therapies and applications.

How Is Ozone Gas Measured?

Ozone is measured in the air using low cost gas meters and ozone detectors. These devices cost between $300 and $5000. Typically, low cost detectors employ electrochemical sensors. These are galvanic cells that output voltages proportional to the ozone concentration. These cells are useful in the ppm ozone concentration range.

More expensive ozone detectors employ ultraviolet (UV) absorption technology. Ozone molecules in the air absorb UV radiation. When the change in light absorption is measured by photodetectors, the detector outputs a proportional electronic signal. UV absorption is the best way to detect low levels of ozone in the parts per billion (ppb) range. 

How Do Ozone Sensors Work?

Ozone detectors, meters, and analyzers employ sensor elements to detect O3 gas molecules. These sensors come in three varieties: (1) electrochemical cells, (2) semiconducting metal oxide sensors, and (3) ultraviolet absorption sensors.

What Level of Ozone Is Safe? Acceptable?

Various government agencies have recommended ozone gas exposure limits and emission levels. Some examples are shown in the table below.

 

Is Ozone Safe to Breath?

No, it is not. If you inhale ozone, a cough response is immediately triggered. The National Institute for Occupational Safety and Health (NIOSH) has established the Immediately Dangerous To Life or Health ozone concentration as 5 ppm. 

When working with ozone, make sure you are in a well-ventilated area and have a personal ozone meter to warn you of high levels. 

More on the health effects of ozone can be found here.

What Does Ozone Smell Like?

Ozone has a familiar photocopier room smell. You may not have noticed it, but the ultraviolet light emits ozone in photocopier rooms or when you print a lot of pages at home.

The ozone odor is sometimes described as a "clean," electric smell. 

Can I Determine Ozone Concentration Using My Nose?

No, you cannot. Although your nose can detect very low levels of ozone < 0.02 ppm, the nose quickly adapts and experiences olfactory fatigue.

Olfactory fatigue is used to describe losing sensitivity to specific odors after exposure. When continuously smelling the same scent, your nose and brain will adapt and lose sensitivity to that smell over time. Eventually, you will not recognize the odor, hence the term olfactory fatigue.

Olfactory fatigue will dissipate when the smell is removed, so your sensitivity will return to normal after some time. Each person has different sensitivities to different smells, which also varies with age.

All in all, don't bother trying to correlate the potency of ozone scent to a particular amount of ozone. It simply is not a reliable method of detection.

Can Ozone Be Used as a Cleaning Disinfectant?

Yes, it can. Ozone is a strong oxidizing agent that can kill bacteria, molds, fungi, and viruses. 

When ozone generators or electrostatic air purifiers create ozone, the gas can reach every corner in the room, making it a very effective and residue-free approach compared to spray or chemical methods.

The efficacy in killing microorganisms like bacteria, fungi, and viruses depends on the ozone concentration, exposure time, temperature, humidity, and air agitation. 

All in all, ozone is comparable to other disinfectant methods, such as UV light and chemical disinfectants.

What Level of Ozone Is Needed to Kill Pathogens?

When using ozone to kill pathogens, there are two components that must be determined: (1) concentration and (2) exposure time. Many resources have developed efficient protocols for a variety of pathogens, but each has its intricacies. We recommend referencing the latest literature in the field using Google Scholar. As a guide, here are some examples:

 

What Is an Ozone Gas Detector Used For? 

There are many uses of ozone gas detectors. Some examples include:

Personal Protection Equipment

Portable ozone detectors are clipped onto workers to provide personal protection, ensuring safe exposure levels. For example, ozone is used to disinfect aircraft. When workers are cleaning, portable ozone detectors provide protection from elevated levels of ozone exposure.

Sanitization / Disinfectant / Cleaning

Portable ozone detectors are used to verify ozone concentrations in crop grow rooms. This ensures high yield and destroys pathogens such as fungi, microbes, bacteria, and viruses. High range ozone detectors are occasionally required for this purpose.

Occupation Space Safety

Many water treatment facilities employ ozone to disinfect storage containers. On a production line of small units, wall-mounted ozone monitors are placed to protect employees from equipment malfunctions and large ozone emissions.

Ozone Therapy & Medical

Ozone has many medicinal benefits, as it is used to disinfect and treat disease. It inactivates bacteria, viruses, fungi, yeast, and protozoa. Ozone has also been used to treat diseases such as infected wounds, circulatory disorders, geriatric conditions, macular degeneration, viral diseases, rheumatism/arthritis, cancer, SARS, and AIDS. Therefore, portable low-level ozone gas detectors are required by medical workers to ensure they are working within safe ozone exposure limits.

What Are the Best Ozone Detector Brands?

There are many ozone detectors on the market. The reputable brands include the following:

• Forensics Detectors Ozone Detectors
• Aeroqual Ozone Detectors
• Analytical Technology ATI Ozone Detector
• Ecosensors Ozone Detectors
• Thermo Fisher Ozone Analyzers
• Teledyne Ozone Instruments
• 2B Technologies Ozone Analyzers
• BMT Ozone Analyzers

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