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

Emissions of CO2, NH3, N2O, and CH4 from pig units have been continuou sly measured by use of Infrared Photoacoustic Detection (IPD). The emi ssion of all gases varied during the growth of the pigs. For example, the highest value of CH4 emission rate was four times as high as the l owest during the experimental period In addition, all gas emissions ha ve a typical diurnal fluctuation. The gas emission value observed at t he peak hours (1:00-2:00 P.M.) was twice as high as that observed arou nd 6:00 A.M., even though the room temperature was kept at around 17 d egrees C. Those variations may explain why the results presented by ot her authors differed so much. The CO2, NH3, N2O, and CH4 emissions fro m pig units during a full fattening period of 8 weeks were estimated t o 5540, 181, 9.1, and 302 g/pig (reference units) and those were reduc ed slightly at 5440 168, 8.4, and 268 g/pig (experimental units), resp ectively with weekly discharge of slurry. All CH4 and N2O data from IP D should be recalibrated far reference purposes by the GC method, as t he IPD tended to overestimate both the CH4 and N2O values in the sampl es under normal conditions in the pig units.