APNA-370 – Ambient NOx Monitor

The APNA-370 continuously monitors atmospheric NO, NO2 and NOx concentrations

using a cross-flow modulated semi decompression chemiluminescence method. The APNA-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 continuous monitoring and instantaneous analysis of gas in its unaltered state, has been a preferred method for monitoring the atmospheric pollution.


  • Continuous NOX, NO, NOmeasurements using a dual cross-flow single chemiluminescence detector and referential calculation.
  • HORIBA original detector (Silicon photodiode sensor) respond to gas concentration quickly .
  • Stable, repeatable measurements; Low range: 0-0.1 ppm F.S.
  • Includes auto-recycle internal drier to make dry air for generating ozone gas
  • Base configuration includes: O3 drier unit, O3 decomposer, reference gas generator and sample pump.


PrincipleCross flow modulation type, reduced pressure chemiluminescence (CLD)
ApplicationNO2, NO and NOX in ambient air
RangeStandard 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 rateApprox. 0.8L/min
IndicationMeasured value, range, alarm, maintenance screen
AlarmsDuring AIC, zero calibration error, span calibration error, temperature error in converter, etc.
On-screen messages are available in four languagesEnglish, 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
Power100/110/115/120/220/230/240 VAC, 50/60 Hz (to be specified)
Dimensions430(W) x 550(D) x 221(H) mm
MassApprox. 20 kg,

** U.S. EPA designation RFNA-0506-157




Environmental Protection


NO – Nitric oxide, NO2 – Nitrogen dioxide, NOx – Nitrogen oxides


Environmental & water treatment