Ozone analyser
To determine its ozone concentration a sample of ambient air is drawn through a flow cell, which is irradiated with ultraviolet light of wavelength 254nm from a mercury vapour lamp. The intensity of ultraviolet light detected by the instrument is reduced depending on how much ozone is in the sample to absorb it
A second source, that has been scrubbed of ozone using a manganese dioxide (MnO2) scrubber, is then drawn through the absorption chamber, resulting in a higher intensity of light reaching the detector. The difference in the intensity of the two yields the concentration of ozone in the sample.
Last updated: 28 November 2003