A passive sampling method for radiocarbon analysis of atmospheric CO2 using molecular sieve

作者：Garnett Mark H^*; Hartley Iain P

来源：Atmospheric Environment, 2010, 44(7): 877-883.

DOI：10.1016/j.atmosenv.2009.12.005

• Atmospheric CO2
• Radiocarbon
• Passive sampling
• Molecular sieve

Radiocarbon (C-14) analysis of atmospheric CO2 can provide information on CO2 sources and is potentially valuable for validating inventories of fossil fuel-derived CO2 emissions to the atmosphere. We tested zeolite molecular sieve cartridges, in both field and laboratory experiments, for passively collecting atmospheric CO2. Cartridges were exposed to the free atmosphere in two configurations which controlled CO2 trapping rate, allowing collection of sufficient CO2 in between 1.5 and 10 months at current levels. C-14 results for passive samples were within measurement uncertainty of samples collected using a pump-based system, showing that the method collected samples with C-14 contents representative of the atmosphere. delta C-13 analysis confirmed that the cartridges collected representative CO2 samples, however, fractionation during passive trapping means that delta C-13 values need to be adjusted by an amount which we have quantified. Trapping rate was proportional to atmospheric CO2 concentration, and was not affected by exposure time unless this exceeded a threshold. Passive sampling using molecular sieve cartridges provides an easy and reliable method to collect atmospheric CO2 for C-14 analysis.

• 出版日期2010-3