[Nature and amount of aerial pollutants from livestock buildings]

The air in animal housing contains gases, odours, dust particles and microorganisms which are discharged by way of the ventilation system into the environment. There is increasing concern within parts of the population that these compounds may affect the respiratory health of people living close to livestock enterprises. A brief survey is presented on airborne emissions from livestock buildings. About 136 gaseous compounds are analysed in animal house air of which only 22 are quantified. The most environment-related compounds are ammonia and methane. It is assumed that German animal husbandry emits up to 750,000 Mg ammonia per year. The concentrations of airborne microorganisms in livestock buildings are between some 100 and several 1000 per liter. Staphylococcae, streptococcae, colilike bacteria, fungi, moulds and yeasts are regularly found. The 24 h average concentrations of dust in animal barns vary considerably. In poultry houses the highest inhalable resp. respirable dust concentrations (up to 10 mg/m3 resp. 1.2 mg/m3) were found, followed by pig houses (5.5 mg/m3) and cattle barns (1.22 mg/m3 resp. 0.17 mg/m3). The concentrations of endotoxins in the airborne dust can range from 0.6 ng/m3 (cattle, respirable dust) to 860 ng/m3 (laying hens, inhalable dust). The presently discussed occupational health threshold at the workplace is around 5 ng/m3 (50 EU/m3). The emission rate for respirable dust from piggeries is at about 60 mg/h, from poultry houses nearly 300 mg/h and from cattle barns at 20 mg/h, related to 500 kg liveweight of the animals. Little is known about the distances these particles are transported through the air outside the animal buildings.