Final answer:
The average airborne exposure in any 8-hour shift or 40-hour work week that cannot be exceeded is known as the Permissible Exposure Limit (PEL), a regulatory limit set by OSHA.
Step-by-step explanation:
The term that describes the average airborne exposure in any 8-hour shift or 40-hour work week which cannot be exceeded is the Permissible Exposure Limit (PEL). PELs are regulatory limits on the amount or concentration of a substance in the air, set by the Occupational Safety and Health Administration (OSHA). These limits are intended to protect workers against the health effects of exposure to hazardous substances. The Permissible Exposure Limit is considered a legal limit in the United States for exposure of an employee to a chemical substance or physical agent. For example, government guidelines recommend that 85 dB not be exceeded for 8-hour daily exposures in the absence of hearing protection. This recommendation aligns with the concept of PELs, in terms of maintaining levels of exposure that are deemed safe for workers.