Ambient O₃ Monitor

The APOA-370 uses the cross flow modulation type, ultra-violet absorption method in conjunction with the comparative calculation method.
This permits continuous measurement with great stability and high sensitivity (0.1 ppm F.S.)

HORIBA's innovative heated deozonizer provides reference gas by decomposing the O₃ found in the sample gas.
This has the advantages of (1) reducing the influence from interference, (2) making the monitor insensitive to great changes in moisture content, and (3) prolonging the working life of the monitor.

All gas connections are either Teflon or glass.

Non dispersive ultra-violet absorption method (NDUV)
The ultra-violet absorption method works on the pri-nciple that ozone absorbs ultra-violet rays in the area of 254 nm. Measurements are taken from conti-nuous, alternate injections of the sample gas and the reference gas into the measurement cell, controlled by a long-life solenoid valve. The cross flow modu-lation method is characteristically zero-drift free. A comparative calculation circuit automatically compensates for all fluctuations in the mercury vapor light source and in the detector. This means that, in principle, the APOA-370 makes it possible to carry out zero-span drift free, continuous measurements. In addition, HORIBA's unique de-ozonizer for the comparison gas line is unaffected by interference elements or moisture retention, prolonged, stable measurement is possible.