Ammonia Emissions Measured Using Two Different GasFinder Open-Path Lasers

Citation

Baldé, H., Zaag, A.V., Smith, W., Desjardins, R.L. (2019). Ammonia Emissions Measured Using Two Different GasFinder Open-Path Lasers. Atmosphere, [online] 10(5), http://dx.doi.org/10.3390/atmos10050261

Plain language summary

The challenges of accurately measuring ammonia emissions on-site from agricultural systems are well known. One approach to do this is using an open path laser coupled with a backward Lagrangian stochastic dispersion model. This model works well for both point- and area-sources but the open path lasers must be able to detect low ammonia concentrations and small concentration differences. This study compared the new GasFinder3 open path laser (Boreal Laser Inc., Edmonton, Canada) with the previous GasFinder2 sensor. The study was conducted at an outdoor open-air manure compost site and a field of wheat stubble that had been fertilized with urea ammonium nitrate. The two lasers reported similar concentrations at the compost site but differed at the field site, where concentrations were much lower.

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.