400 Series – TunnelTech 404

The CODEL TunnelTech 404 NO2 and Visibility Air Quality Monitor is a compact extractive analyser configured for the continuous measurement of two key parameters in road tunnels. This extremely stable and reliable monitor incorporates an LED to utilise the capacity of Nitrogen Dioxide to absorb UV and blue light to provide accurate readings in parts per billion.
It also uses the same sampling system to monitor Visibility using a unique double sensor design. NO2 and particulate are produced naturally by the combustion processes within the internal combustion engine and are emitted from the exhausts of all types of vehicles.