Comparison of ammonia measurement methods inside and outside tunnel-ventilated broiler houses

Abstract

SUMMARY Accurately measuring NH3 produced from poultry litter and emitted from mechanically ventilated broiler houses continues to be a challenge. Many technologies and methods are available to measure NH3, with costs ranging from inexpensive (but rather inaccurate, such as colorimetric tubes) to expensive (for precision analytical equipment such as laser spectrometers). This study investigated the variability among selected low, midrange, and high-cost instruments. Inter-instrument and intra-instrument comparisons were made using colorimetric pull tubes and dosimeter tubes, electrochemical sensors, and tunable-diode open-path laser spectrometers (OPL). This study consisted of inside and outside broiler house studies to evaluate instrument performance under different environmental conditions and NH3 concentrations. The OPL showed the least variation during the in-house and outside comparisons. The electrochemical sensors and colorimetric tubes performed well at NH3 levels typically found in a properly ventilated broiler house. With no ventilation, variation among instruments increased as NH3 concentrations increased. With the exception of the OPL, concentrations on the outside were too low and environmental elements were too harsh for these instruments to perform well.