The present invention includes a filtered mask enclosure having an exterior portion and interior regions within the exterior portion such that the interior regions have a filtering region and a purging region connected to the filtering region. The present invention further includes a method of removing a first contaminant in a gas phase, a second contaminant in a solid phase, and a third contaminant having an electrical charge from a purge gas and flowing the purge gas through a vicinity of a mask while exposing a wafer with light through the mask.