CONTINUOUS MEASUREMENT OF NITROUS OXIDE AND METHANE EMISSION IN PIG UNITS BY INFRARED PHOTOACOUSTIC DETECTION

Abstract

Emissions of CO2, NH3, N2O, and CH4 from pig units have been continuously measured by use of InfraredPhotoacoustic Detection (IPD). The emission of all gases varied during the growth of the pigs. For example, the highestvalue of CH4 emission rate was four times as high as the lowest during the experimental period. In addition, all gasemissions have a typical diurnal fluctuation. The gas emission value observed at the peak hours (1:00-2:00 P.M.) was twiceas high as that observed around 6:00 A.M., even though the room temperature was kept at around 17C. Those variationsmay explain why the results presented by other authors differed so much. The CO2, NH3, N2O, and CH4 emissions from pigunits during a full fattening period of 8 weeks were estimated to 5540, 181, 9.1, and 302 g/pig (reference units) and thosewere reduced slightly at 5440, 168, 8.4, and 268 g/pig (experimental units), respectively with weekly discharge of slurry. AllCH4 and N2O data from IPD should be recalibrated for reference purposes by the GC method, as the IPD tended tooverestimate both the CH4 and N2O values in the samples under normal conditions in the pig units.