The respirable dust levels found by researchers at the Stephen F. Austin State University were below the permissible exposure limit (set at 5mg per cubic metre) set by the Occupational Safety and Health Administration (OSHA). They were, however, beyond the limit for animal buildings suggested by other researchers.

Poultry houses are known for generating excessive dust, which originates from bedding materials, fibreglass insulations, feed, dried faecal materials and feather particles, S.B. Jerez and colleagues report in their paper in the current issue of Journal of Applied Poultry Research.

They explain that dust may contain microorganisms, including endotoxins, fungi and bacteria, that may affect living things when inhaled.

Dust that contains living organisms is referred to as bioaerosol, and its particle size may range from 0.5 to 100µm. Respirable dust, which has an aerodynamic diameter of less than or equal to 4µm, can travel to and be deposited in the gas-exchange region of the human respiratory system. This is of particular concern because of the greater health hazard that it poses.

The Nacogdoches-based group found concentrations of respirable dust and bioaerosol measured with samplers attached to the workers (worker-exposure concentrations) to be more than three times (0.82 versus 0.26mg per cubic metre) and one-and-a-half times (58.46 versus 33.79cfu per cubic metre) higher, respectively, than the concentrations measured with stationary samplers indoors.

Reference

Jerez S.B., Y. Cheng and J. Bray. 2014. Exposure of workers to dust and bioaerosol on a poultry farm. J. Appl. Poult. Res. 23(1):7-14. doi: 10.3382/japr.2012-00710