Nonwoven fabrics are made from fibers and used across a wide range of applications and products. They are high-tech, innovative and versatile products, indispensable for a lot of application nowadays. Filtration is one of the fastest growing segments in the nonwovens industry, and with the necessity of replacing fiberglass for polymer materials keeping the high filtration efficiency of filter media. The aim of this thesis is to study the effect of different machine settings on filtration efficiency, from polypropylene meltblown webs. The webs were produced by meltblowing in two different processing (A and B), with two different dies configuration, for each one it was varied air flow, air temperature and distance-to-collector (DCD). After collecting samples, they were characterized by basis measures (weight and thickness) and SEM pictures. These information was used for 3D modelling software to obtain the results. Due to problems in processing B, the web samples were obtained with plenty of defects, and it was not possible take clear conclusions about the use of different dies. Conclusions of this project shows highest filtration efficiency results were achieved with higher air flow, higher air temperature and smaller DCD.