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Negligible influence of livestock contaminants and sampling system on ammonia measurements with cavity ring-down spectroscopy

Jesper Nørlem Kamp, Albarune Chowdhury, Anders Peter S. Adamsen, Anders Feilberg
2018 Atmospheric Measurement Techniques Discussions  
<p><strong>Abstract.</strong> Pollution from ammonia (NH<sub>3</sub>) is a widespread problem due to the effects on the environment and human health. The agricultural sector accounts for nearly all NH<sub>3</sub> emissions in Europe; thus, focus has especially been on NH<sub>3</sub> emissions from this sector in recent years. We need abatement techniques to reduce NH<sub>3</sub> emissions, and in order to evaluate the techniques, there is a strong need for reliable NH<sub>3</sub> measurement
more » ... sub> measurement methods. Photoacoustic spectroscopy (PAS) is often used to measure NH<sub>3</sub> concentrations, but recent discoveries show interference from compounds typically present in livestock production and during agricultural activities. We tested the performance of the Cavity Ring-Down Spectroscopy (CRDS) from Picarro for filter effects and laboratory and field calibrations with standard gasses. Furthermore, concentrations of ten volatile organic compounds (VOCs) where determined by Proton-Transfer-Reaction Mass Spectrometry (PTR-MS) to test the potential interference of these VOCs. Both laboratory and field calibrations show excellent linearity over a large dynamic range of NH<sub>3</sub> concentrations. The analyzer shows a small humidity effect of up to a few ppb in the extreme case of a nearly water saturated air stream. Besides, from the negligible humidity dependence, there is no interference from the tested VOCs. Overall, the system performs well with only negligible influences from other compounds.</p>
doi:10.5194/amt-2018-377 fatcat:zfbrckoop5hdhgfqxohiicc6vi