Pollution monitoring systems based on resonance absorption measurements of ozone with a "tunable" CO(2) laser: some criteria.

Measurements have been made with a line tunable CO(2) laser on ozone in order to establish some useful criteria for pollution monitoring via the direct absorption scheme. The absorption coefficient a and the pressure dependence of the extinction coefficient k(nu)(P) at frequencies nu corresponding to the P(8) to P(36) vibration-rotation lines of the CO(2) laser have been measured. Good agreement has been found with theory (within the framework of Lorentz and Doppler broadenings) for these experimental observations. It has been found that foreign gas species lines within +/-0.1 cm(-1) of the laser line can contribute significantly to the absorption process if their absorption intensities are not more than an order of magnitude below the intensity of the gas species being monitored.