MAC values

The MAC (Maximum Allowable Concentration) value of a substance is the highest concentration in which a substance may be present in the laboratory atmosphere in gaseous, vapour or suspended form and which, according to latest findings, will generally not have any health effects on, nor be unduly burdensome to, staff working in the laboratory even after repeated or prolonged (8-hour working day) exposure, assuming a mean working week of 40 hours.

MAC values are set to ensure health and safety at the workplace.

They are not physical constants but rather values which are set, usually by national bodies (e.g. in Germany: by a Senate Commission of the German Research Council (Deutsche Forschungsgemeinschaft, (DFG)).

They are defined and revised based on reliable toxicological and medical evidence.

The DFG issues a complete list annually showing any changes that have been made.

A looseleaf collection explaining the rationale behind definition of MAC values is also updated annually.


Source : The MERCK Co.