Assessment of a Low-Cost Portable Device for Gas Concentration Monitoring in Livestock Housing

The increasing regulatory pressure to monitor and reduce GHG emissions and air pollutants requires cost-effective methods for their surveillance. The most common techniques used for scientific investigations into gas concentration monitoring in barns are accurate but expensive and require complex maintenance. This research study analyzed the potential use of low-cost portable measurement devices for the measurement of ammonia (NH3) and carbon dioxide (CO2) concentrations in an open dairy barn. A comparison between the gas concentrations acquired at different heights from the floor by using portable devices and those acquired by a photoacoustic infrared multigas spectroscope (i.e., reference measurement) in the same sampling locations was carried out to determine the precision of the low-cost portable devices. The performances of the low-cost portable devices were statistically analyzed by application of the one-way analysis of variance, correlation analysis, and regression analysis. The results showed a significant difference between the gas concentration values at various heights from the floor for both NH3 and CO2. The correlations between the concentrations acquired by the low-cost portable devices and the INNOVA were statistically significant (r = 0.83; p < 0.001) for gas concentrations monitored at 0.4 m from the floor. Compared with the reference measurement device, the low-cost devices were effective at the monitoring of NH3 concentrations at 0.40 m from the floor; however, they underestimated the concentrations in the barn at increasing heights from the floor, and the device was not adequate for CO2 concentrations. In detail, the relative measurement error of the low-cost devices compared to the INNOVA was reduced close to the floor during NH3 concentration measurements. Within these limitations, this device may be useful for monitoring the NH3 concentration in the barn and assessing variations in the NH3 concentrations mainly related to the animal occupied zone. Further efforts are needed in this field of research to identify a low-cost device that can simplify emission estimation from open dairy barns.