The PRPH filter system is a depressor, pressurizer, air recirculator: three tools in one. It is a stand alone product on wheels built in 304 stainless steel. It can be sanitized, complete with rigid pocket pre-filter and HEPA filter. The instrument can therefore be used to create negative pressure areas in the presence of harmful pathogens, to create clean areas in overpressure or it can be used as a recirculator to keep the air clean from bacteria, particulates, viruses and fungi.