Product

Model 405 nm NO2/NO/NOx Monitor

The Model 405 nm NOx Monitor ("nm" for "nanometer" and for "NOx Monitor") is designed for the direct measurement of atmospheric nitrogen dioxide (NO2), nitric oxide (NO) and total reactive oxides of nitrogen (NOx = NO + NO2) in the concentration range 0-10,000 ppb (0-10 ppm) for NO2 and 0-2,000 ppb (0-2 ppm) for NO with high precision and accuracy. In this instrument NO2 is measured directly by absorbance at 405 nm. NO is measured by selective conversion with ~100% efficiency using the highly selective reaction of NO with ozone (O3). Total NOx is obtained by addition of NO and NO2.

Unlike chemiluminescence instruments where NO2 must be converted to NO using either a molybdenum or photolytic converter with highly variable efficiency, in the Model 405 NOx Monitor nitrogen dioxide is measured directly by absorbance, analogous to an ozone monitor. Because NO2 has a much lower absorption cross section than ozone, a folded cell with corner mirrors is used to produce a long absorbance path of ~2m to achieve approximately the same sensitivity for NO2 as we do for ozone in our UV-based-absorbance monitors. The wavelength of 405 nm was chosen because no other species found in ambient air has significant absorbance at that wavelength, making the Model 405 nm extremely selective for NO2.

Although Model 410 Nitric Oxide Monitor can measure NO and NOx when used in combination with Model 401 NO2 Converter, because it is a direct method and requires less power the Model 405 nm is the preferred method for NO2 while providing an accurate measurement of NO as well.

The Model 405 nm NO2/NO/NOx Monitor is designated as a Federal Equivalent Method (FEM) for NO2 compliance monitoring (EQNA-0217-243). SD card data logging is now a standard feature.

Features:
  • Direct measurement of NO2 (absorbance at 405 nm) gives extreme selectivity for NO2
  • Measurement of NO2 over the rang 0-10 ppm, NO over the range 0-2 ppm, and NOX
  • FEM for NO2 over the range 0-500 ppb and 20-30°C operating temperature range
  • Three measurement modes: NO2 only; NO only; NO, NO2 and NOX
  • Power consumption: ~16 watts after warmup
  • Long-life pump (~15,000 hrs)
  • Internal data logger (EEPROM) logs 8,192 lines of data
  • Flash memory (SD card) for virtually unlimited, portable data logging
  • Both serial and user-scalable analog voltage outputs for NO and NO2
  • Convenient user interface to microprocessor, including calibration parameters (gain and zero)
  • Selectable measurement time of 5s or data averaging times of 1min, 5min and 1hr
  • Selectable units for NO2, NO, NOX
  • DewLine™ for elimination of any water vapor interference, a unique feature of 2B Tech instruments


Specifications