Concentrations and emissions of particulate matters (PM10 and PM2.5) were continuously measured in a mechanically ventilated turkey grow-out house over one-year period. The PM concentrations were measured using tapered element oscillating microbalances (TEOMs), and the building ventilation rate (VR) was measured by monitoring the operation time of calibrated ventilation fans. Bird activities (BA) were monitored with a passive infrared detector (PID). This paper describes the effects of bird age, BA, VR, air temperature, and indoor relative humidity (RH) on the PM emission rate (ER) based on three flocks (bird age of 35-140 d) data collected during the one-year monitoring. Considerable diurnal variations were observed in BA, PM concentration and PM ER of the turkey barn. The PM concentration and ER were positively related to BA but negatively related to indoor RH. VR was negatively related to PM concentration but positively related to ER.