Final answer:
Lydia is likely entering Zone 2, which requires a high level of cleanliness, including scrubs, hand sanitization, and hair coverage, but not a surgical mask.
Step-by-step explanation:
The scenario described suggests that Lydia is entering an environment that requires a high level of sanitation but does not require the highest level of asepsis, as a surgical mask is not mandated. In surgical asepsis zones, Zone 1 is generally considered to be the least restrictive, where standard precautions against infection are taken, but full surgical asepsis is not required. Zone 3, on the other hand, requires more stringent asepsis practices, typically including the use of a surgical mask to protect open surgical fields. Given the information provided and the fact that Lydia is not required to wear a surgical mask but must still change into scrubs, sanitize hands, and cover hair, it would suggest that she is entering Zone 2. This zone would require a higher level of cleanliness than general areas but less than operating rooms or similar environments where invasive procedures occur requiring a mask.