Odour in ambient air of pig housing systems with exercise yards and natural ventilation

Whereas closed housing with forced ventilation predominated in the past, nowadays, most new pig housing facilities are designed as multi-surface systems with bedding and exercise yards. New pig housing systems have to observe minimum separation distances from inhabited areas. However, these distances are not sufficient for new housing systems with natural ventilation or for exercise yards, particularly in pig farming. The aim of this research project was to compare the ambient odour from open and closed housing systems and from housing systems with and without an exercise yard for pigs.Odour plume inspections were carried out in ten housing systems with fully slatted floor and forced ventilation without an exercise yard; ten multi-surface systems with forced ventilation and an exercise yard and 13 multi-surface systems with natural ventilation and an exercise yard. A comparison was also made of odour concentrations in exercise yards for cattle and pigs at different degrees of dirtiness. Multi-surface systems in combination with solid flooring or perforated surfaces produced a greater odour impact than fully slatted systems. The ambient odour from housing with natural ventilation and exercise yards was greater than that from closed housing with forced ventilation. Pig exercise yards had a higher odour concentration than cattle exercise yards. Besides this, particular care is required in the case of ground-level odour sources at production sites subject to cold airflow.