Capture efficiency of four chamber designs for measuring ammonia emissions

Abstract

Ammonia (NH 3 ) emissions are an economically and environmentally significant loss pathway of fertilizer and soil-derived N. Chambers are a commonly used method to quantify NH 3 emissions in plot-scale agricultural research. Although this method is widely used, its accuracy may be influenced by the overall design of the chamber, its components, and its interaction with the environment. Four NH 3 chamber designs, including open, open + polytetrafluoroethylene (PTFE), semi-open, and closed, were deployed over a dilute NH 3 solution for 6 h on four dates to determine the effect of chamber design on NH 3 capture efficiency. The solution volume and concentration were measured before and after acid trap deployment, and total volatile NH 3 emission was assumed to be equal to the mass N loss. The NH 3 capture efficiency relative to the estimated total emissions was greatest for the open design (12.9%), whereas the semi-open chamber was the least efficient (3.5%). The closed chamber reduced NH 3 emissions relative to the open and semi-open designs by inhibiting convective gas transport beneath the chamber footprint.

Assessing Ammonia and Greenhouse Gas Emissions from Livestock Manure Storage: Comparison of Measurements with Dynamic and Static Chambers

“…When comparing emission factors from different hoods, the SH always gives an ER one order of magnitude less than when using a DH, in any given situation, with or without a buffer. These results are similar to those observed by Alexander et al [24] and Yang et al at laboratory experiments with synthetic ammonia source solutions [14]; emission factors obtained in a steady-state chamber are 50% lower. Also, when comparing the static chamber with other methods, such as the periodic integrated horizontal flux (IHF) technique [32,33] or boundary layer equation [27], the emission of gases measured was much lower.…”

“…When estimating emissions, direct methods present limitations linked to the spatial variability of the emission source and possible disturbances induced by the chamber size, air velocity, etc. This can alter the natural gradient between the emission source and the atmosphere [21,24]. Nevertheless, the errors presented by the use of chambers can be reduced with correct chamber designs, proper data analyses, and spatial and temporal sampling regimes [13].…”

Towards efficient N cycling in intensive maize: role of cover crops and application methods of digestate liquid fraction

“…Since static chambers have been pointed as unreliable to derive conclusions about absolute NH 3 ‐N losses, calibration is required (Alexander et al, 2021). Starting from NH 3 data derived by chambers, we calculated NH 3 emissions by multiplying values from chamber measurements to specific correction indices accounting for underestimation: those were determined according to “NH 3 source solution methodology” (Alexander et al, 2021; Yang et al, 2019), and subsequently fine‐tuned against data coming from wind‐tunnels (three were present at DLF application time).…”

Environmental Effects of Using Ammonium Sulfate from Animal Manure Scrubbing Technology as Fertilizer

“…Since the experiment was conducted with closed chambers, the effect of wind was missing from the experiment. Several examples in the literature show that ammonia emissions are consistently underestimated when no wind is allowed to blow over the measuring area [26,27]. To make more reliable ammonia emissions, an additional sheltered flux chamber experiment was conducted (Section 3.4).…”