RGD2 Reduction gas detector, Trace Analytical, USA. Used for the monitoring and analysis of atmospheric hydrogen by the Greenhouse Gas Laboratory at Royal Holloway, University of London, Egham from 1995/6 until 2009.

This instrument was one of a suite used at Royal Holloway’s Greenhouse Gas Laboratory for monitoring methane, carbon dioxide and carbon monoxide from 1995/6 until 2009, when they were upgraded. The laboratory’s location on the fringes of London means that depending on the wind direction, both background concentrations from the western Atlantic, and urban levels from London can be measured. As well as contributing to global greenhouse gas records, the lab has used its data to assess the effectiveness of policy measures on air quality and emissions levels in the London area.