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

Abstract

Abstract. Emission of ammonia (NH3) is a ubiquitous problem due to the adverse effects of NH3 on the environment and human health. The agricultural sector accounts for nearly all NH3 emissions in Europe. Hence, technologies for the abatement of NH3 emissions from this sector have been in strong demand in recent years. In order to document emissions and evaluate abatement technologies, there is a strong need for reliable NH3 measurement methods. Photoacoustic spectroscopy (PAS) is often used to measure NH3 concentrations, but recent research shows interference from compounds typically present in livestock production and during agricultural activities. In this work, the performance of cavity ring-down spectroscopy (CRDS) from Picarro, as an alternative to PAS, has been tested with respect to method validation under laboratory and field conditions. Potential interferences of 10 volatile organic compounds (VOCs) on CRDS NH3 measurement were tested with simultaneous VOC analysis performed by proton-transfer-reaction mass spectrometry (PTR-MS). Both laboratory and field calibrations show excellent linearity over a large dynamic range of NH3 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. Apart from the negligible humidity dependency, no interferences of the tested VOCs were observed. Overall, the CRDS system performs satisfactory and is well suited for measurements of NH3 emissions from livestock production.

Methanogenic pathways and δ13C values from swine manure with a cavity ring‐down spectrometer: Ammonia cross‐interference and carbon isotope labeling

“…In addition to influencing the CH 4 isotopologues, NH 3 had a significant effect on the measured H 2 O concentration, corresponding to 0.41% H 2 O per ppm NH 3 (Figure S1, supporting information). This interference is also apparent in Figure A at the H 2 O absorption lines that are located around 6028.78 cm −1 and is consistent with studies reporting closely related absorption features of NH 3 and H 2 O …”

Photoacoustic measurement with infrared band-pass filters significantly overestimates NH<sub>3</sub> emissions from cattle houses due to volatile organic compound (VOC) interferences

“…This observation is possibly related to the relatively rapid vibrational energy transfer between the VOC and oxygen (Harren et al, 2000). While nitrogen has a vibrational frequency around 2360 cm −1 , oxygen has a vibrational frequency of 1554 cm −1 , with only 170 collisions needed to transfer energy to the vibrational mode of O 2 (Lambert, 1977).…”

Low-Cost Fluorescence Sensor for Ammonia Measurement in Livestock Houses

“…Measurements of NH 3 with a CRDS analyzer from Picarro model G2103 (Picarro Inc., Santa Clara, CA, USA) was compared to NH 3 measured with the fluorescence sensor presented here. This specific CRDS-instrument has been proven reliable in an agricultural environment [17].…”

“…Several measurement techniques for measuring NH 3 are available [16], and measurements in an agricultural environments are routinely performed with e.g., cavity ring-down spectroscopy (CRDS) [17], AMANDA [18], PAS [19], miniDOAS [20], PTR-MS [21], ALPHA samplers [22], Leuning tubes [23] and impingers [24]. Most of these techniques are expensive (e.g., PTR-MS and CRDS) and/or labor intensive (e.g., impingers, ALPHA samplers, and Leuning tubes) while others are prone to systematic errors [19].…”