HORIBA Europe GmbH

- Model APOA-370 - Ambient Ozone Monitor



The APOA-370 continuously monitors atmospheric ozone concentrations using a cross flow modulated ultraviolet absorption method. The APOA-370 employs an independent, internal dry-method sampling device to achieve the highest levels of sensitivity and accuracy. The dry method, due to its minimal maintenance requirements and capability of continuously monitoring and instantaneously analyzing gases in their unaltered state, has been a preferred method for monitoring the atmospheric pollution.

  • 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 PTFE or glass.

Cross flow modulation type, Non dispersive ultra-violet absorption method  NDUV)

The ultra-violet absorption method works on the principle that ozone absorbs ultra-violet rays in the area of 254 nm. Measurements are taken from continuous, alternate injections of the sample gas and the reference gas into the measurement cell, controlled by a long-life solenoid valve. The cross flow modulation 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.

  • Principle: Non dispersive ultra-violet-absorption method (NDUV)
  • Application: O3 in ambient air
  • Range: Standard ranges: 0-0.1/0.2/0.5/1.0 ppm; auto range ~ manual range selectable;
    can be operated by remote switching.
    Optional (measurable) ranges: 4 ranges selectable from 0-10 ppm, within 10 times range ratio;
    auto range ~ manual range selectable; can be operated by remote switching.
  • Repeatability: ±1.0% of F.S.
  • Linearity: ±1.0% of F.S.
  • Sample gas flow rate: Approx. 0.7 L/min
  • Indication: Measured value, range, alarm, maintenance screen
  • Alarms: During AIC, zero calibration error, span calibration error, temperature error in ozone separator, light intensity error, etc.
  • On-screen messages are available in four languages: English, German, French, and Japanese.
  • Input/output:
    • 0-1 V/0-10 V/4-20 mA, to be specified (2 systems: either (1) momentary value and integrated or (2) moving average value)
    • Contact input/output
    • RS-232C
  • Power: 100/110/115/120/220/230/240 VAC, 50/60 Hz (to be specified)
  • Dimensions: 430(W) x 550(D) x 221(H) mm
  • Mass: Approx. 20 kg.

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