Keeping organic fattening pigs indoors with access to an outdoor concrete pad is common inEU countries. The main environmental impact is related to a risk of high ammonia emissionsfrom excretions on the concrete pad. The objective was to evaluate the effect of frequency ofscraping the pigs’ toilet, on ammonia (NH3) emissions. The  experiment was conducted at anorganic pig farm in southern Sweden over three  consecutive days in August. The experimentincluded four groups of 68 fattening pigs per  group, 24 weeks old. Each group had access toan outdoor concrete area (116,4 m2)  divided into two sections with a wall. One section was atoilet (7.2 x 4.1 m) and the  other was a concrete run (6.9 x 12.7 m). There was no roof over the outdoor area. The whole outdoor concrete area was scraped before the experiment. Each group received a silage bale on the outdoor concrete run. The experimental set-up was tome asure NH3 emissions each day from not scraped vs. daily scraped sub-areas (N= 2  groupsper treatment). In the scraped treatment, only toilet and wet areas with urine  and faeces was scraped. Other sub-areas were dry sub-areas with silage and dry  concrete areas with/without dry faeces. The pigs had access to the whole outdoor area in  between measurements. Wetand dry sub-areas were defined each day before measurements. Measurements of NH3 emissions were conducted with an equilibrium  concentration method, where two chambers and one ambient sampler unit were  randomly placed in each defined sub-area. The results indicated that the toilet sub-area  could have 84 times higher NH3 emissions than the dry sub-area.Scraping toilet sub- areas decreased NH3 emissions, varying from one third lower NH3 emissions down to 17 times lower. This study was part of the CORE Organic Cofund project POWER