PRRSV costs the US swine industry 560 million dollars each year in lost productivity. We can now successfully eliminate PRRSV from individual farms, but we cannot keep herds from becoming re-infected. With the NPB-stated goal of national PRRSV elimination, an improved understanding in these areas is critical to its success. The primary routes of PRRSV transmission between farms are infected pigs and contaminated semen, but transmission of PRRSV has also been reported via non-porcine vectors and fomites, including contaminated needles, coveralls, boots, insects, and migratory waterfowl. Mechanical transmission of PRRSV can occur in warm and cold weather by contaminated transport vehicles and cargo. Aerosol transmission within and between herds has been postulated and aerosol transmission of PRRSV has been reported over short distances under experimental conditions. Aerosol transmission of PRRSV is known to occur, but the frequency of aerosol transmission within and between herds is unknown. Thus, the objective in the acquisition of this equipment was to obtain the resources needed to determine the parameters of PRRSV aerosol transmission under experimental conditions at the individual pig level. Our long-term goal is to quantify the contribution of aerosol transmission to circulation of PRRSV within and between farms. Ultimately, we will develop models capable of predicting the circumstances and distances of PRRSV aerosol transmission.