The virus porcine reproductive and respiratory syndrome (PRRS) has recently been proven to be transmitted by aerosols. The reaction of the industry to this problem was to increase biosecurity protocols by placing high efficiency filters that are fine enough to stop particles that carry the virus from entering the barn. This was a successful strategy for preventing the spreading of PRRS, but there has been some concern about broken filters which are unable to prevent contaminated particles from entering a susceptible herd. In reaction to this concern a study was undertaken to evaluate how broken filters play a role in PRRS infections. A one meter tube was used with a fan on one end which had a solution of the PRRS virus sprayed into it. On the other end of the tube was an air collector used to receive samples. Filters with varying degrees of damage were put in the apparatus to test if they were still capable of stopping PRRS positive particles. The degrees of damage were: Mild (finger impressions), Moderate (lacerations), Severe (Deep finger impressions) and Rodent (holes). After each test the air was sampled in the recipient chamber. After repeating the tests 10 times for each level of damage the amount of PRRS positive air samples at each level was: 20% at mild, 40% at moderate, 100% at severe and 80% for the rodent filter. Also test were done on the mild and moderately damaged filter to find if varying intensities of the PRRS virus had implications on the damaged filters. It was found that the mild filter had negative samples at all degrees of PRRS intensity. While the moderate filter had 0% at the first level of severity and then 60% and 70% at the next two levels. Taking good care of filters during installation so not damage them and quick replacement of damaged filters can help prevent area spreading of the PRRS virus.