There are three primary technologies used to monitor and measure ozone:
Electrochemical cells, HMOS / GSS, and UV.

Electrochemical ozone sensor uses a porous membrane that allows ozone gas to diffuse into a cell containing electrolyte and electrodes. When ozone comes into contact with the electrolyte, a change in electrochemical potential occurs between the electrodes causing electrons to flow.

In zero air, little or no electron flow occurs. As the presence of ozone increases, the electrical signal increases proportionally. The monitor interprets this signal and displays the ozone concentration in PPM (parts per million).

A heated metal oxide semiconductor (HMOS) sensor works by heating a small substrate to high temperature (around 300-deg F / 149-deg C). At this temperature, the substrate is very sensitive to ozone and exhibits a change in resistance and displays the corresponding ozone level on the display as either PPM or PPB..

UV-based ozone analyzers function on the principle that ozone particles will absorb UV light with a wavelength of 254 nm. When this wavelength of UV light is created and passed through an air chamber, the amount of UV light absorbed is proportional to the amount of ozone present in that airspace. The amount of UV light absorbed in the chamber is interpreted as ozone concentration and displayed or output for our use.

The primary advantage Of This technology are its accuracy and stability over a wide range of ozone concentrations and Since the principle used is very wave length-specific, few other gases interfere. This results in much more accurate readings, even in outdoor environments to provide reliable,stable readings