Which concentration level is typically higher?

The correct answer is based on the definitions and purposes of the various concentration levels related to workplace safety.

The permissible exposure limit (PEL) is established by regulatory agencies like OSHA (Occupational Safety and Health Administration) and reflects the maximum allowable concentration of a substance in the workplace air over an eight-hour workday. Since these limits are legally enforceable, they tend to be set at levels intended to protect worker safety while also considering industry standards.

In contrast, the threshold limit value (TLV) is recommended by organizations like ACGIH (American Conference of Governmental and Industrial Hygienists) and is often used as a guideline rather than a legal requirement. TLVs can be set slightly lower than PELs, reflecting a more conservative approach to occupational exposure.

Immediately dangerous to life and health (IDLH) levels indicate concentrations that pose an immediate risk to health or life; these are not typical exposure levels and are usually much higher than standard occupational levels since they refer to emergency situations.

Therefore, it is the PEL that is typically established at higher levels, providing a balance between safety and practicality in the workplace, which is reflected in the answer choice.