Exposure to fine and ultrafine particles in copy centres has been studied for some years since they represent a health risk when present in high quantities, especially in indoor air. Studies indicate that ultrafine particles can have more harmful consequences, since they can move from the lungs to other parts of the body. Thus, it was relevant to evaluate the exposure of workers of copy centres to particles and other pollutants, as well as thermal comfort and try to notice which factors influence it. The sample consisted in 2 copy centres, and fine particles, carbon monoxide and carbon dioxide and some parameters of thermal comfort/weather variables were measured. Regarding the variation of pollutant concentrations, these were higher in the afternoon, in the interior and next to the printers and were influenced by the number of times the door was opened.