Positive pressure rooms maintain a higher pressure inside the treated area than that of the surrounding environment. This means air can leave the room without circulating back in, meaning that any airborne particle that originates in the room will be filtered out. Germs, particles and other potential contaminants in the surrounding environment will not enter the room. In medical settings, a positive pressure room allows staff to keep vulnerable patients safe from infections and disease.
In contrast, a negative pressure room uses lower air pressure to allow outside air into the segregated environment, which traps and keeps potentially harmful particles within the negative pressure room by preventing internal air from leaving the space. Negative pressure rooms in medical facilities isolate patients with infectious conditions and protect people outside the room from exposure.