Concentrations and emissions of paniculate matter with aerodynamic diameters 〈 10 μm (PM10) were continuously measured in a mechanically ventilated turkey grow-out barn in central Iowa. The PM concentrations were measured with Tapered Element Oscillating Microbalance (TEOM) units; and ventilation rate (VR) of the barn was measured by monitoring the runtime of calibrated ventilation fans. Bird activity (BA) was monitored with passive infrared detectors (PIDs). This paper describes the effects of BA, TO and indoor relative humidity (RH) on the PM concentration and emission rate (ER) based on 18 days of full 24-hr dynamic data collected during 67 days of flock-growing period (bird age of 40 - 107 d) in wintertime. Considerable diurnal variations were observed in BA, PM concentration and PM10 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. The PMIOER during the monitoring period varied from 2.71 to 25.6 mg/ltr-bird or 13.4 to 28.8 g/dAU (AU = 500 kg body mass).