The aim of this study was to determine the aerial contaminants affecting pig activity and evaluate the correlation between pig activity and aerial contaminants in a pig confinement building. This experiment was performed in a confinement growing and finishing room, and the data presented in this article was collected over a period of 50 days, with sampling every 2 days from June to September 2003. Air samples were taken in the middle of empty pens on both sides of the pig confinement building. In this study, we demonstrated statistically significant negative relationships between pig activity and temperature, relative humidity and ammonia, while total dust positively regressed with pig activity. Based on these experimental results, we reasoned that increases in temperature, hydrogen sulfide and ammonia in the pig building suppressed pig activity and that high levels of total dust in the pig building was attributable to increases in pig activity. The exposure limit values of aerial contaminants, such as particulate matter, gaseous compounds and airborne microorganisms related to the pigs’ health should be established in order to promote the performance and welfare of the pigs.