the study was conducted in a facility for pigs during the nursery and finishing in the town of 'montadas', in the semiarid of the state of paraiba, brazil, in the rainy and dry season, aiming to evaluate the concentration of oxygen, methane, carbon monoxide and ammonia, and the bioclimatic indexes: ambient temperature (at), relative humidity (rh) and the index of black globe temperature and humidity (ibgth). these indexes differed significantly (p>0.05) between the periods and times. the at in the rainy season was in the thermal comfort zone(tcz) in most of the times in the nursery; for the finishing phase, thermal discomfort occurred; during the dry season, there was thermal comfort in the nursery phase; in the finishing phase the thermal discomfort occurred at all times. in the rainy season, the ibgth was in tcz; in the dry season, it was above the tcz. the rh in the rainy period was in the tcz; in the dry season, in most of the times, below the range of the tcz. the concentration of gases showed no differences (p > 0.05) between periods and between the times, and the carbon monoxide, hydrogen sulfide and methane were below 1.0 ppm, and the ammonia showed a mean of 5.2 ppm. none of the analyzed gases exceeded the limits established by brazilian and international standards for animals and workers.