Most faucet aerators mix air and water to produce an aerated stream. A laminar device produces a crystal clear stream of water - no mixing of air and water.
While drawing air from the room around the faucet is no problem in residential and commercial applications, it can be a concern in healthcare institutions such as hospitals, senior care facilities, and medical labs. The room air can then contain harmful bacteria that are best kept out of the drinking water.
An increasing number of hospitals, including the Veterans Health Administration, now recommend using non-aerated devices referred to as "laminar". The VHA Directive 2002-073 requires to "remove aerators in plumbing fixtures" and "replace with laminar flow devices" as part of an effort to limit the risk of Legionella contamination in VA hospitals. For more details, visit
www.va.gov.