Installed, fan-powered HEPA and carbon units that supply filtered outside air and can lightly pressurize a space. What that is designed to do.
Pure Air Systems builds fan-powered HEPA-and-carbon units that can supply filtered makeup air rather than only recirculating room air, holding a space at slightly higher pressure than its surroundings. The company states it has built these systems since 1985.
Positive pressure is designed for a different exposure than a room purifier: air that seeps in from outside — a neighbor’s dryer vent, traffic exhaust, drifting smoke, spray — rather than what is already inside. A pressurized space forces incoming air through the filter instead of through gaps and shared walls. This is installed equipment with ductwork or a dedicated intake, not a plug-in box.
The Institute sells nothing and rates nothing; this page reports what the unit is, how it is built, and what it is designed to do.
This page profiles one brand in reporting voice: what the unit is, how it is built, and what it is designed to do. It does not rank units or name one to buy. How reactive you are, your dominant triggers and your room size all change what fits; the Air Filters & Purifiers guide walks the general decision before naming any product.
Fan-powered true HEPA plus carbon, capable of makeup air and light pressurization. A recirculating purifier filters what has already leaked in; a pressurized supply filters it on the way in. In apartments and smoky regions that infiltration is the exposure a room purifier does not address.
The base 600HS carbon stage is a coconut-carbon pad of roughly five pounds — a gas stage, not a deep VOC bed. An upgraded CPZ triple-blend (permanganate and zeolite) is offered; it is impregnated media, and the material fact stated on other impregnated-media units applies. Installation involves ductwork or a dedicated intake. Other outside-air units in the same category include the AirScape scrubber (aluminum, MERV-11 plus H13 HEPA, about 1,200 CFM).
Whole-home healthy-air construction — sealing, ventilation, and material selection — is the broader context for any single unit. See the Air Filters & Purifiers guide and the Indoor Air Quality guide.