500 Series – TunnelTech 503

The TunnelTech 503 NO2 sensor, is an essential part of any road or rail tunnel safety system. Firstly, it monitors the atmosphere within the tunnel and ensures that the tunnel ventilation system provides sufficient clean air to protect tunnel users health.
NO2 is produced naturally by the combustion processes within the internal combustion engine and is emitted from the tail pipes of all types of vehicles. NO2 is also particularly toxic and prolonged exposure to levels as low as a few hundred parts per billion will have a detrimental effect on human health.