「Permissible Exposure Limit-Time Weighted Average」
The personnel worked eight hours a day, repeated exposure to this concentration, than didn't have any adverse reactions.
「PEL-Short Term Exposure Limit」
The personnel continuous exposure to this concentration of any 15 minutes, did not have any intolerable irritation or chronic or irreversible organization disease, and the function of anesthesia, to add accident or to reduce the work efficiency.
「Maximum allowable concentration」
This concentration shall not exposed over this any time, to prevent intolerable impulse or physiological disease.