Advanced Gas Detection Technology Supports Arctic Greenhouse Gas Research
Dominic Duggan, Quantitech Ltd Unit 3, Old Wolverton Road, Milton Keynes, MK12 5NP, UK Tel: 01908 227722 • Fax: 01908 227733 • Email:
info@quantitech.co.uk • Website:
www.quantitech.co.uk
Enormous quantities of greenhouse gases (GHG) exist within Arctic ice and frozen soils, so with the threat of global warming and increasing frequency of extreme weather phenomena, a
clear understanding of the relationship between GHG in the atmosphere and in the ice/soil is vital because melting of permafrost could cause a dangerous climate tipping point. There can be few more challenging environments for monitoring gases, but PhD researcher Martin Brummell from the University of Saskatchewan has successfully employed a Gasmet DX4015 FTIR analyser to do so in the High Arctic of Canada.
The ability to operate in field conditions creates extra demands for analytical equipment. However, the extreme weather conditions of the High Arctic impose a new level of capability that is rarely available as standard. Field work in such conditions must be simple, flexible and fast, but most importantly, Martin Brummell says, "The equipment must also be extremely reliable because you do not have the luxury of a local Quantitech engineer.
“The Gasmet DX4015 was also the ideal choice because, as an FTIR analyser, it is able to monitor almost any gas, which is normally a feature of mains powered laboratory instruments, but the DX4015 is portable and powered by a small generator, so it is ideal for monitoring in remote locations.”
Sampling and analysis in the Arctic
A set of simple, perforated steel tubes were driven in to the soil, to the point of the permafrost threshold. Inside these tubes gases within the soil were allowed to reach equilibrium via diffusion over 24 hours. This allowed Brummell to analyse gas concentrations to a depth of 1 metre. The procedure was simple and therefore reliably repeatable. Furthermore, measurement of gas concentrations at different depths enabled direct comparison with soil analysis.
Using FTIR in the 'field'
The Gasmet DX4015 is a portable FTIR gas analyser for ambient air analysis. FTIR, an abbreviation for fourier-transform infrared, is an interferometric spectroscopic instrument (interferometer) that uses the infrared component of the electromagnetic spectrum for measurements. A fourier-transform function is applied by the interferometer to obtain the absorption spectrum as a function of frequency or wavelength. Consequently, the DX4015 is able to simultaneously analyse up to 50 gas compounds. The analyser is typically set up to measure a variety of different gases, including VOC´s, acids, aldehydes, and inorganic compounds such as CO, CO2, and N2O.
The DX4015 is operated using a laptop computer running CalcmetTM
software, a program that not only controls
the analyser but also undertakes the analysis. CalcmetTM software is capable of simultaneous detection, identification and quantification of ambient gases, which gives the DX4015 its ability to simultaneously analyse multiple gases in near-real-time.
The FTIR’s many beneficial traits, such as reliability, precision
and flexibility make it a vital piece of analytical equipment in a very wide variety of applications including; industrial emissions monitoring, occupational safety surveys, engine exhaust testing, process monitoring, leak detection, emergency response, chemical spill and fire investigations, and many others.
Brummell’s use of the DX4015 on his most recent research expedition investigating the soils in the polar deserts of the High Arctic, highlights the model’s capabilities in the field. Carried out on Ellesmere Island in the Baffin Region of Nunavut, Canada, the DX4015 had to perform reliably in extreme environmental conditions. The analyser was used to monitor the production, consumption and atmospheric
exchange of the greenhouse gases Carbon Dioxide (CO2), Methane (CH4) and Nitrous Oxide (N2O); all three being
major components of natural biogeochemical cycles. These gases are each released and up-taken by soil microbes in the Arctic.
The DX4015 was used to examine both the flux of gases from the soil surface and the concentration profiles of gases in the soil’s active layer above the permafrost. In doing so the FTIR provides raw data consisting of gas concentrations in parts-per- million (ppm).
Explaining his reasoning behind choosing the Gasmet DX4015, Martin Brummell highlighted some of the analyser's key advantages: “The real-time nature of the Gasmet FTIR, allows me to see results within minutes of setting up in the field. This permits me to make changes to the experimental design and further investigate unexpected results whilst in the field.
IET November / December 2011
www.envirotech-online.com
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