N2O Emissions Levels Are No Laughing Matter

Following increasing demand for measurement of N2O in source emissions, Signal have dramatically improved their Model 7000FM NDIR Analyser to provide more stable readings with a greater accuracy.

Nitrous Oxide, N2O, also known as laughing gas, is a significant greenhouse gas with a global warming potential 296 times that of CO2. Increasing incidence of the reduction of NOx using selective non-catalytic reduction (SNCR), for example in vehicles and power generation, plus other industrial combustion processes are resulting in observations of rising emissions of N2O in the atmosphere. In fact a recent National Oceanic and Atmospheric Administration (NOAA) study has also concluded that N2O is now the top ozone-depleting substance emitted through human activites. As a result there is increasing interest in accurately determining global levels of N2O emissions.

The measurement of N2O poses various technical difficulties. Although it absorbs infra-red light it is a relatively weak absorber and has many cross-interferents, most significantly CO. Whilst in ambient air concentrations of CO are negligible, when attempting to measure N2O from combustions processes it becomes difficult to eliminate the effects of this cross sensitivity. The traditional method has been to use a blocking cell containing CO, however this approach has the downside of reducing the light transmission, CO is a much stronger absorber than N2O, which drastically limits both the lowest detectable limit and resolution of the analyser. Signal has come up with an alternative solution whereby a catalytic scrubber is used instead to remove CO from the sample without affecting the concentration of N2O. Using this method means that Signal can now offer an analyser with a lowest range of an incredible 0-10ppm with as little as 0.01ppm noise, specifications previously unheard of for a source N2O analyser.