Characterization of Airborne Dust in Livestock Housing and its Effects on Animal and Environment

摘要

Particulates in the air of animal houses originate to about 85 % from biological sources such as feed, litter, manure and the animals themselves. Therefore these particles are also addressed as bioaerosols Dust concentrations in livestock buildings range from 0.5 to 20 mg. m~(-3) Dust concentrations are higher in pig and poultry houses than in cattle buildings The dust contains high amounts of proteins and carries gases, odours, microorganisms, and endotoxins. The level of airborne microorganisms inlivestock buildings is between 100 and several thousand per litre of air .More than 80% are staphylococci and streptococci The effect of dust and airborne microorganisms on the health of man and animals cannot be strictly separated because both form theparticles that are inhaled. The aerodynamic diameter of the particles determines how deeply they can penetrate into the respiratory tract. Their impact can be described as mechanical, chemical, infectious, immunosuppres-sive, allergic, toxic and pharmacological. Endotoxins which are found in considerable amounts in poultry and pig barns in particular seem to pose a significant health risk for animal and man. Although there is distinct evidence that high dust levels in pig houses reduce production significantly, dust reduction measures are not yet common. It seems necessary to establish scientifically based maximum levels for bioaerosols in livestock buildings. This would benefit both animals, farmers and the residents living in the vicinity of livestock units who are increasingly alarmed that the bioaerosol emissions may pose a health risk for susceptible people such as children. Dispersion models for bioaerosols are needed for planning and development purposes in rural areas.