Abstract
There are real difficulties in designing sampling procedures that assure compliance with the present hygienic standards for air contaminants. A reasoned and consistent system of sampling is developed, based on the assurance that a critical body burden is not exceeded. It is shown that the duration of the sampling should be proportional to the biological half-time of the substance. A large safety margin is obtained by making the duration one-tenth of the half-time. The sampling results are then summarized in the formula, Average + Range/(n-1)½. When the resulting figure is less than the ACGIH threshold limit value, a favorable report can be given.
