What is defined as the sterile area of the airport?

The sterile area of the airport is defined as the space where passengers who have cleared security can move freely without undergoing additional security screenings. This area typically includes the gate area for boarding onto and off of aircraft. Being in this area means that passengers are considered to be in a secure zone, as they have already passed through security checks.

The other areas mentioned such as the concessions area, security screening area, and check-in area do not qualify as sterile zones. The concessions area, though it may be located within the terminal, is accessible to anyone, including those who have not passed security. The security screening area is where passengers undergo checks, making it a transitional space rather than a designated sterile area. The check-in area is where passengers check their baggage and obtain boarding passes, and typically, this area is open to all travelers and does not require passing through security. Hence, the gate area is specifically designed as a sterile environment where further screening is not necessary.