DUST CONCENTRATION IN AIR FROM WEANER ROOMS REDUCED BY ADAPTATION OF THE VENTILATION SYSTEM

Abstract

An experiment to study the effect of an adapted ventilation system on dust concentrations in pig confinement buildings production was carried out in rooms for weaned piglets at our research farm in Rosmalen. Two ventilation systems were compared: a traditional one, with air inlet through balance flaps and mechanical air exhaust above the operator walkway, and an adapted one, with air inlet through a horizontal ventilation shaft above the walkway and mechanical air exhaust under the slatted floor. The adapted ventilation system affected both average dust concentration and variation in dust concentration during the 24-hours period. Above the walkway, concentrations of inhalable and respirable dust decreased from 2.7 to 2.2 mg/m 3 (p < 0.01) and from 0.56 to 0.44 mg/m 3 (not significant), respectively. As the amount of endotoxins in inhalable dust (1824 and 1822 EU/g, respectively) was not affected, the aerial endotoxin mass concentration was assumed to be decreased as much as the inhalable dust concentration. The reduced inhalable dust concentration was below the level recommended by Donham and Cumro (1999), but respirable dust concentration was two times higher. Endotoxin concentration was 125 times the level that is recommended by the Dutch Expert Committee on Occupational Standards (1998). Above the pens, the concentration of inhalable dust decreased from 3.5 to 2.6 mg/m 3 (p < 0.01). Performance of the piglets was not affected by the ventilation system. The extra annual costs of the adapted system (about US $ 48 up to US $ 120 per room for 70 weaned piglets) are less than the costs of most other dust reducing systems. It is expected that this ventilation system will contribute to the improvement of labour conditions for stockmen.