Limitations of the APR and PAPR include all of the following EXCEPT:

The correct answer highlights that the limitation regarding weight is not applicable to air-purifying respirators (APRs) and powered air-purifying respirators (PAPRs). In the context of these respiratory protection devices, the focus on their limitations typically addresses issues related to their functional capabilities, such as the need for the cartridge to specifically match the type of contaminant being filtered, the requirement for a minimum oxygen concentration in the surrounding atmosphere, and restrictions regarding their use in Immediately Dangerous to Life or Health (IDLH) environments.

While APRs and PAPRs can vary in weight based on the design and components, the inherent properties of these devices themselves are not categorized as drawbacks directly tied to their usage or effectiveness in respiratory protection. Instead, the lightweight nature of some models can even enhance user comfort and reduce fatigue during prolonged use, making it more advantageous rather than a limitation.

Thus, understanding that the lightweight characteristic does not restrict the functionality or safety of APRs and PAPRs helps clarify why this option does not fit in with the other limitations outlined in the question.