Ambient Ozone Monitors

Ambient ozone monitors serve an important purpose. If ozone leaks around an industrial ozone generator or the associated equipment, it can create a safety hazard for operators of the equipment. While ozone can be detected at concentrations well below those that are considered dangerous, it is a good idea to have at least one ambient ozone monitor.

These units will have the option for alerting the operator to low level leaks with an indicator light or audible alarm and at higher levels will shut down the ozone generator. There are several types:

• UV photometers
• Electrochemical sensors, and
• Solid state sensors that use semiconductor technology

UV Photometers

The UV photometer type draws a sample of the ambient air into the unit where UV light is passed through the gas sample. UV at the wavelength used does not “see” air or oxygen, but does measure ozone. While such monitors can measure a range of concentration, measurements in the 0-1 ppm range would be the most common with a resolution of 0.001 ppm.

Electrochemical Sensors

The other technology employs an electrochemical sensor that measure the reaction of ozone that passes through a membrane and contacts a special electrode. The electrochemical sensors are available in ranges similar to the UV monitors, but are moderately less expensive. Additionally, they are somewhat less accurate (+/- 5%). In the case of an ambient monitor, such accuracy is probably not important. Both sensor types are widely deployed in industrial ozone water treatment applications.

Solid State Sensors

Solid state sensors are technology that employs HMOS (heated metal oxide semiconductor) sensor. The range is .02-.30 ppm. Accuracy is not as high as the other technologies with results of +/- 20%. This requires setting the sensor alarm lower than for the other instruments. However, the cost is considerably less, perhaps one third the cost of the electrochemical sensor.

Important Notes

It is important to note that ozone is heavier than air, so ozone will tend to collect in low-lying areas. Sensors should be placed closer to the floor or in basement areas below the industrial ozone generators or associated equipment. Handheld versions of ambient ozone monitors can be used as personal warning systems or for locating leaks in an ozone water treatment system.

Contact Spartan Environmental if you have questions.