Dust concentrations and particle size distribution in an enclosed swine nursery

Dust levels in a mechanically ventilated swine nursery were measured for 13 sampling days over a six-week period during warm weather conditions. Mean daily room air temperature and relative humidity ranged from 25 to 34°C and from 54 to 88%, respectively. Mean total dust mass concentration (TDC) for all locations was 0.72 mg/m³, ranging from 0.12 to 2.14 mg/m³. The respirable fraction ranged from 2 to 30%, with an overall mean of 11%. The dust mass distribution followed a log-normal distribution with an overall mass median diameter of 13 μm and geometric standard deviation of 3. TDC was significantly higher over the pens than over the service alley, whereas the respirable dust concentration did not show any significant spatial variability. Dust levels, particle size distribution and carbon dioxide concentration exhibited significant variability over time. Air quality sampling in animal buildings should consider these space and time variations. Future research should investigate dust generation rates and dust concentration distributions as affected by various environmental and management factors.