Gas emissions (NH 3 GHG) from four pig fattening rooms on slatted flooring with flat scraping and under-floor air evac uation were measured in three consecutive batches between May 2009 and June 2010 i n the experimental station of Crecom (France). Gas concentrations and ventilation rates were measured and recorded during 3 periods of 14 days during the bre eding period (day 7 to 21, 35 to 49 and 63 to 77). Gas concentrations were measured with a n infrared photoacoustic monitor (INNOVA 1412) in the room area. Manure was scrap ed once a day and stored in the breeding rooms for two weeks. Measured carbon emissions (C-CH 4 and C-CO 2 ) were validated by comparison with the C mass balanc e deficit, whereas measured nitrogen emissions (N- NH 3 and N-N 2 O) were not validated by comparison with the N mass balance deficit. Observed differences between measurement and mass balance deficits were explained by the samplin g point site for concentration measurements that was not representative of the exha ust air. With additional experiments, we demonstrated that ammonia concentrat ions measured in the exhausted air were 51 % higher than those measured in the room. Under-floor air evacuation combined with a flat scraper system enabl ed the reduction of ammonia concentrations in the room and improved air quality and the working environment. However, compared to a slurry storage system, a flat scraper system with manure stored in the room after scraping, reduces GHG emiss ions (N 2 O and CH 4 ) in the exhaust air, but can increase NH 3 emissions
