What is the primary characteristic of the air flow in a laminar flow hood?

The primary characteristic of the airflow in a laminar flow hood is that it is drawn through a HEPA filter and blown in parallel flow. This design ensures that the air entering the work area is free from contaminants, as the HEPA filter removes particles that are 0.3 microns and larger with high efficiency. The parallel airflow minimizes turbulence, creating a sterile environment that is crucial for sensitive biological work.

By directing air uniformly and steadily, any contaminants present in the surrounding air are carried away from the work surface, which is essential for maintaining a sterile field necessary for procedures like cell culture or preparing sensitive biological samples. This feature differentiates laminar flow hoods from other types of workspaces that may use turbulent airflow, which could disrupt the sterile environment and introduce contaminants.