How does a laminar flow hood work and when is it used?

A laminar flow hood provides a sterile work environment by delivering filtered air in a uniform parallel flow pattern. HEPA filters (99.97% efficient for 0.3 um particles) remove airborne particles and microorganisms. Horizontal flow hoods direct air toward the operator (product protection), while vertical flow biological safety cabinets direct air downward with exhaust filtration (operator and product protection). Applications include: aseptic transfers, culture manipulation, sterility testing, and media preparation. Proper use requires: allowing stabilization time before work, avoiding disruption of airflow patterns, regular certification and filter replacement, and appropriate decontamination procedures.