Dust levels and control methods in poultry houses.

This article summarizes information from the papers and posters presented at the international symposium on "Dust Control in Animal Production Facilities", held in Aarhus (Denmark) on 30 May-2 June 1999. Dust concentrations in poultry houses vary from 0.02 to 81.33 mg/m3 for inhalable dust and from 0.01 to 6.5 mg/m3 for respirable dust. Houses with caged laying hens showed the lowest dust concentrations, i.e., less than 2 mg/m3, while the dust concentrations in the other housing systems, e.g., perchery and aviary systems, were often four to five times higher. Other factors affecting the dust concentrations are animal category, animal activity, bedding materials and season. The most important sources of dust seem to be the animals and their excrements. Further studies on the effects of housing systems on dust sources and their compounds are desired for development of a healthier working environment in poultry production facilities. Adjustment of the relative humidity (RH) of the air in a broiler house to 75% will have an effect on inhalable dust, but not on respirable dust. A slight immediate effect on the respirable dust was observed after fogging with pure water or water with rapeseed oil. In an aviary system, a 50 to 65% reduction of the inhalable dust concentration was found after spraying water with 10% of oil and pure water, respectively. To obtain a higher dust reducing efficiency, improvement of techniques for application of droplets onto dust sources will be desired.