Bioaerosols : Tiny particles, big effect


10.000-fach vergrößerte Bioaerosolpartikel aus einem Legehennenstall: Deutlich zu erkennen sind Federfragmente (gelb), Einstreu- und Kotreste (braun) und Bakterien (rosa).
10,000 times magnified bioaerosol particles from a layer house: clearly visible are feather fragments (orange), litter and faeces matter (brown) and bacteria (pink). (© Thünen-Institut)

While we only inhale a few bacteria with one breath of fresh air, there may be millions of bacteria in a breath full of air in large livestock barns. Airborne bacteria are only a small part of the so-called bioaerosols. These consist of a complex mixture of various biological components, ranging from simple organic molecules with dimensions in the nanometer range of viruses, bacteria and fungal spores to pollen of 0.1 millimeters in diameter, as well as animal and plant residues of different sizes.

This "biological dust" usually forms larger aggregates, to which also odorants or ammonia can be bound. Therefore, we always look at the emissions of bioaerosols "holistically", along with dust, ammonia and odors.

Bioaerosols are found in the vicinity of the stables and in the surrounding environment  as they exit via the stable exhaust. Especially in systems with tens of thousands of animals, these emissions into the immediate vicinity of the stables could lead to health problems. However, there is currently no sufficient evidence that residents are at risk, but many questions are still open, to which the Institute of Agricultural Technology will dedicate itself in the future.