Emissions Monitoring

The Opsis monitoring solution in aluminium smelters is based on either DOAS or laser diode technique. The on-line, open-path systems are used for monitoring HF and sulphur dioxide in potrooms, in fence-line applications and in continuous emissions monitoring. Opsis has long experience of monitoring in aluminium smelters.

Gaseous Compounds

  • Hydrogen fluoride (HF)
  • Sulphur dioxide (SO2)
  • Nitrogen dioxide (NO2)
  • Water vapour (H2O)
  • Other compounds


Opsis offers two different open-path methods. One is based on the DOAS technique that has the benefit of being able to monitor multiple gases such as HF, sulphur dioxide (SO2), nitrogen dioxide (NO2) and water vapour (H2O). The other method is based on tuneable diode laser (TDL). Both types of systems can monitor several pot rooms or stack/ducts using one analyser. Additional compounds can be monitored.
Why Opsis?

  • Automatic alignment
  • Multi-gas and multi-path system
  • Withstands the aggressive environment
  • Monitoring along the entire potroom with one system
  • Combines the benefits of UV, IR and TDL technology
  • No sample required
  • The working environment can be controlled
  • The multi-path capability offers cost-effective solutions for monitoring several pot rooms and/or sections in the smelter
  • No sensitive electronic equipment, that might be exposed to high electro-magnetic fields
  • Operates with a minimum of maintenance
  • Easily calibrated
  • Comprehensive after-sales support


Opsis offers complete software packages for data handling, including data acquisition, validation and reporting. The software meets the EC regulation for reporting. Please refer to EnviMan Data Management System.

Close to 100 systems have been installed worldwide. For more information regarding information material and references, please contact Opsis.