Dust concentrations in animal buildings can be reduced by sprinkling a small quantity of canola oil. The sprinkling pressures and oil temperatures have already been defined (PSCI 1994 Annual Research Report). However, we have not yet optimized how much and how often oil was sprinkled at six application rates in three identical swine growing/finishing rooms. For the six oil application rates, dust concentration was reduced between 37% to 89%. Sprinkling more often was more effective than less often in terms of dust reduction. However, sprinkling more often than once a day is difficult when the oil application is less than 10 mL/m2 per day. Sprinkling more oil can reduce more dust, but a daily dosage of more than 10 mL/m2 caused greasy floors. Variable daily dosages for oil sprinkling had a higher efficiency of dust reduction than a constant daily dosage. A recommended variable oil sprinkling dosage is 40 mL/m2 for the first two days, 20 mL/m2 for the second two days and 5 mL/m2 for the rest of the production cycle with a 20 mL/m2 surge every two weeks. For grower/finisher units, this oil sprinkling schedule can reduce dust by 80% using only 0.5 L oil per pig marketed.