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The VICONOX tunnel monitor is a single sensor solution for measuring NO2, NO, CO, visibility and temperature within a traffic tunnel, rail tunnel or other confined space. These measurements can be used as part of an air quality management system for ventilation control and/or secondary smoke detection.


  • Direct in-situ measurement of NO2, NO, CO, Visibility and Temperature (or combinations thereof)

  • Direct optical measurement of nitrogen dioxide (NO2) using differential absorption

  • Visibility measurement using accepted light transmission opacity technique

  • Proven infrared spectroscopy technique for NO and CO measurement

  • Temperature and humidity compensated measurements to ensure stable readings across all conditions

  • Intelligent analyser with optional TSCU operator interface



  • Rugged design to withstand corrosive atmospheres and regular tunnel washing

  • High quality 316 stainless steel construction ensuring a long service life

  • Pre-aligned quick release TX and RX heads enabling easier installation and maintenance

  • IP65 rated external enclosure with quick release dust protection tubes

  • Plug and socket cable connection enabling simple installation

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