Performance of an Infrared Photoacoustic Single Gas Analyzer in Measuring Ammonia from Poultry Houses

Abstract

<p>A single-gas photoacoustic analyzer, Chillgard RT, was evaluated for its performance of measuring ammonia (NH₃) concentrations in poultry production under laboratory and field conditions, using a multi-gas photoacoustic analyzer, INNOVA 1412, as a reference method. Calibration gases were used to evaluate the cross-interferences of carbon dioxide (CO₂), nitrous oxide (N₂O), methane (CH₄), and water vapor on NH₃ measurements by Chillgard RT. The response times of Chillgard RT and INNOVA were measured in the laboratory using four vessels containing broiler litter. Side-by-side field comparisons between the Chillgard RT and INNOVA were conducted on a laying-hen farm and a broiler farm over two five-month periods. A strong linear relationship existed between the Chillgard RT and INNOVA NH₃readings. The NH₃ measurement by the Chillgard RT showed no effect by CO₂, N₂O, CH₄, or water vapor under typical operational conditions in poultry operations. The Chillgard RT demonstrated a faster response to NH₃ than the INNOVA. Following 120-s measurements, the Chillgard RT and INNOVA achieved 99.6% and 96.7% of the expected values, respectively, when the INNOVA was configured at a 30-s sampling interval. The INNOVA response time was positively affected by water vapor level in the air samples. The Chillgard RT overestimated NH₃ concentrations by 3.24%, 10%, and 22.9% for laying-hen houses, stored boiler litter, and broiler houses, respectively, as compared to the INNOVA. Thus, performance of the Chillgard RT should be carefully validated before used in field NH₃measurements.</p>