Nitrogen oxides in ambient are measured indirectly by photometrically measuring the light intensity, resulting from the chemiluminescent reaction of nitric oxide (NO) with ozone (O3 ).
NO2 is first quantitatively reduced to NO by means of a converter. NO, which commonly exists in ambient air together with NO2, passes through the converter unchanged causing a resultant total NOx concentration equal to NO + NO2.
A sample of the input air is also measured without having passed through the converted. This latter NO measurement is subtracted from the former measurement (NO + NO2) to yield the final NO2 measurement.
The optical filter(660nm) attached on PMT provides reliable measurement, and temperature are controlled between 6~8℃ with only 0.1℃ fluctuation by a thermoelectric cooler, ensure the measurement stability.
Permeation dryer are introduced in ozone generation to provide long system durability without any replacement. An catalytic ozone scrubber is standard for maximum safety and pump life before exhaust.
Standard Range | Min: 0~100 ppb F.S. Max: 0~20 ppm F.S. (Selectable) |
Zero Noise | < 0.4 ppb (RMS) |
Span Noise | < 2.5 ppb |
Lower Detectable limit | < 0.8 ppb |
Zero Drift (24 hours) | < 2 ppb |
Span Drift (7 days) | < 5 ppb |
Response Time | < 60s (T90) |
Precision | < 1% |
Linearity | < 1% F.S. |
Sample Flow Rate | 500 cc/min ±10% |
Operating Temperature | 20~30°C range (per US EPA guidelines). Instrument may be safely operated over the range of 5~40°C |
Power Requirement | 100~240 VAC, Converter applicable |
Dimensions and Weight | 178mm(H) x 432mm(W) x 597mm(D), 22kg |