Dust particle counts, airborne dust mass concentrations, and amounts of settled dust were monitored during a 12 weeks study in a pig feeder barn. Particle counts were converted to particle production rates per kilogram of pig mass to account for changes in ventilation rate and number of animals. The effects of adding rapeseed oil to the feed and 2 flooring types (partially slatted and fully slatted floor) were investigated. Dust production rates indicated a high degree of variation over time. When rapeseed oil was added to the feed there was no significant decrease in airborne respirable particle production rates, but a significant decrease in the dust mass concentration and in the amount of settled dust. There was no significant difference in dust levels for the 2 types of flooring.