Photoacoustic infrared spectroscopy (PAS) is increasingly used for measurement of N2O and CO2 fluxes at the soil surface. However, PAS calibration is complex. Water vapor, CO2, and temperature interfere with accurate N2O measurement. To accurately measure N2O, PAS calibrations must compensate for these interferences. Our article, ‘Evaluation of photoacoustic infrared spectroscopy for the simultaneous measurement of N2O and CO2 gas concentrations and fluxes at the soil surface’ (Iqbal et al., 2013), compared PAS and gas chromatography (GC) analytical procedures. Results demonstrated that PAS can measure N2O concentrations (ca. 0.5–3.0 ppm) and fluxes (ca. 0.5–5.0 ppm min−1) with accuracy and precision similar to GC without interferences from H2O vapor or CO2 concentrations typically encountered in static flux chambers at the soil surface.
Available at: http://works.bepress.com/castellano-michael/17/
This article is published as Iqbal J, Castellano MJ, Parkin TB. 2014. Accuracy and precision of no instrument is guaranteed. Global Change Biology doi: 10.1111/gcb.12446. Posted with permission.