A pressure control system for a sealed enclosure may include opposing one-way valves to limit the differential pressure between the atmospheres internal and external to the sealed enclosure. The pressure control system may allow the internal atmosphere to vent out of a first one-way valve if the internal pressure exceeds the external pressure by a first predetermined pressure. The pressure control system may allow the external atmosphere to be drawn in through a second one-way valve if the external pressure exceeds the internal pressure by a second predetermined pressure. By allowing the exchange of gasses only when the differential pressure falls outside of a predetermined range, overall contamination may be reduced. By reducing the ingress of contaminants, such as dust, water, smog, and outgassed substances, performance may be improved and service life of components housed within the sealed enclosure may be extended.