New Hampshire health officials have equipped all 28 acute care hospitals in the state with portable isolation units, which can quickly convert a regular patient room into a room with negative air pressure.

The equipment includes high-efficiency particulate air filters with 99.99% efficiency. The units, which provide 12 air exchanges an hour, can be set to vent air out of the room or to recirculate it in the room.

The $140,000 cost was funded through a federal bioterrorism preparedness grant, but the equipment can be used routinely to control infectious diseases requiring isolation, such as tuberculosis. If necessary, hospitals can share the portable units. According to the New Hampshire Hospital Association, New Hampshire has more than doubled the number of isolation rooms available statewide.