Embodiments of the present invention pertain to reducing the obstruction of air flow through a bypass channel associated with a disk drive. According to one embodiment, disk drive filtering system includes a selective filtering region, an electrostatic pass-by filter, and a filter free region. The selective filtering region is disposed within a bypass channel. The electrostatic pass-by filter is disposed within the selective filtering region and is used for filtering the air that flows through the selective filtering region. The filter free region is disposed proximate to the electrostatic pass-by filter so that a substantial portion of the air is allowed to flow unobstructed through the selective filtering region.