This study attempts to develop a model to evaluate the aerosol transmission of the PRRS virus. The PRRS virus traveled by aerosol as far as 150m. A portable air sampler was used to collect air samples at 1, 30, 60, 90, 120 and 150m. The process was repeated 5 times at each distance and then the air samples were tested by TaqMan PCR and virus isolation. PRRSV RNA was detected in all five replicate air samples collected at 1, 30, 60 and 90 m, in four of the five collected at 120 m, and in three of the five collected at 150 m. Further testing involved exposing PRRS negative pigs to the aerosolised PRRS virus after it had traveled 150m. Half of the pigs in the experiment became infected with PRRS, and swab samples taken from the interior of the housing chambers were PRRS positive.