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.

AP Series product literature


  • 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.

Manufactured by HORIBA



Non dispersive ultra-violet-absorption method (NDUV)


O3 in ambient air


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.


±1.0% of F.S.


±1.0% of F.S.

Sample gas flow rate

Approx. 0.7 L/min


Measured value, range, alarm, maintenance screen


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.


• 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


100/110/115/120/220/230/240 VAC, 50/60 Hz (to be specified)


430(W) x 550(D) x 221(H) mm


Approx. 20 kg.

** Certified to U.S. EPA Reference Method EQOA-0506-160


AP-370 series Air Pollution Monitor Brochure uploaded on 2013/12/20 (PDF:1.2MB)