N95 masks are not required when?

N95 masks are not required specifically in scenarios where there is a lower risk of aerosol transmission, such as when personnel are inside the apparatus. In this context, the apparatus serves as a controlled environment that limits exposure to airborne pathogens, making the use of N95 masks unnecessary.

When providing aerosol-generating procedures or treating patients suspected or confirmed to have Covid-19, the use of N95 masks is critical due to the high risk of airborne transmission associated with these activities. Therefore, the correct answer focuses on the context where the risk is minimized, thus not requiring the additional protective measure of wearing N95 masks while in the apparatus.

This understanding helps ensure that personnel use appropriate protective equipment based on the specific risks of their environment and interactions.