In the present study, we measured the concentrations of fine particulate matter (PM2.5), carbon dioxide (CO2), carbon monoxide (CO) and volatile organic carbon (VOC) in the indoor air of the manufacturing department of a metal factory. The daily average PM2.5 concentration ranged between 86.3 and 404.9 mu g/m(3). The isolation of the manufacturing machines reduced. PM2.5 concentration between 2.5 and 8.8 fold. At the seven measurement points, daily concentrations ranged from 576.7 to 623.4 ppm for CO2, 0.8 to 15.8 ppm for CO, and 0 to 0.58 ppm for VOC, respectively.