Permissible Exposure Limit - Time Weighted Average (PEL-TWA) describes which of the following?

Permissible Exposure Limit - Time Weighted Average (PEL-TWA) describes which of the following?

• A. airborne concentrations of substances and represents conditions under which nearly all workers may be repeatedly exposed day after day without adverse health effects
• B. the vapor concentration in air that can be detected by most individuals through sense of smell
• C. the maximum concentration of vapor in air that is NEVER allowed
• D. concentration of vapor in air that must not be exceeded in the work place (8 hours)

Answer: (D)