Ventilation air filtration is becoming a popular method to control airborne transmission of diseases on commercial sow farms. For example, air filtration can reduce the frequency of airborne outbreaks of porcine reproductive and respiratory syndrome virus (PRRSV). The capital investment is justified on the basis of diseases losses avoided, but better data on filter lifespan is needed to give producers a more complete understanding of all costs related to air filtration. In Objective 1 a 6-month (May-to-November) intensive study was done on commercial sow farms to determine factors affecting pre-filter lifespan. In Objective 2, a study into methods to prolong pre-filter life span was done under high dust loading conditions (row crop harvest season) on a gilt-development (GDU) farm. The filter brand, correct installation, and three factors related to the filter bank (north or south facing, driveway side, and what the bank faced) were collected along with filter weight and airflow using mobile air filter testing (MAFT) laboratory for random sub-sample from each filter bank on each farm in the study. For Objective 1, the filter brand and correct installation had significant impacts on lifespan. The worst case factors for filter lifespan were facing a barn exhaust, being on the driveway side of the barn and facing north. For Objective 2, the filter prolonging study found that the treatment methods improved filter lifespan and that the extreme loading scenario was significantly worse for filter lifespan than the conditions on the sow farms in this study. The various effects on pre-filter lifespan and improving estimations for filter lifespan is a key step to understanding the operating costs of air filter systems on commercial swine farms.