Ammonia Emissions Measured Using Two Different GasFinder Open-Path Lasers

Hambaliou Baldé,Ward Smith,Andrew Vanderzaag,Raymond L Desjardins

doi:10.3390/atmos10050261

Abstract

The challenges of accurately measuring in situ ammonia (NH3) losses from agricultural systems are well known. Using an open path laser coupled with a backward Lagrangian stochastic dispersion model is a promising approach for quantifying both point- and area-sources; however, this approach requires the open path laser to detect low NH3 concentrations and small concentration differences. In this study, we compared the new GasFinder3 open path laser (Boreal laser Inc., Edmonton, Canada) with the GasFinder2 sensor, the previous version. The study took place at two locations: an outdoor open-air manure compost site, and a field of wheat stubble which was fertilized with urea ammonium nitrate. Results showed the two lasers reported similar concentrations during three days of measurements at the compost site, but differed at the field site, where concentrations were close to the minimum detection limit. The GasFinder3 had a lower standard deviation under all conditions, especially with low wind speed and high relative humidity.

Highlights

The agriculture sector contributes up to 80% of global NH3 emissions [1], which are emitted mainly from the field application of nitrogen from inorganic fertilizer and organic material
During measurements at the compost site, average air temperatures ranged from 19.3 ◦ C on day 2 (D2) to 25.5 ◦ C on D3 (Table 1)
Averaged solar radiation were similar on D2 and D3 (2.9 MJ m−2 h−1 ), and lower on D1 (1.9 MJ m−2 h−1 )

Summary

Introduction

The agriculture sector contributes up to 80% of global NH3 emissions [1], which are emitted mainly from the field application of nitrogen from inorganic fertilizer and organic material (e.g., livestock manure, compost). Horizontal Flux method, which is non-disruptive but requires a circular plot, which limits its flexibility for studying farm-scale practices. Micrometeorological methods, such as the backward Lagrangian dispersion method (bLS) [4], enable the measurement of NH3 losses from point sources and area sources, with little constraint to either shape or size

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Conclusion