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