Definitions for "Reference concentration"
An estimate (with uncertainty spanning perhaps an order of magnitude) of a continuous inhalation exposure to the human population that is likely to be without risk of deleterious effects during a lifetime. It can be derived from a no-observed- adverse-effect-level (NOAEL), lowest-observed-adverse-effect-level (LOAEL), or benchmark concentration, with uncertainty factors generally applied to reflect limitations of the data used. Reference concentrations are generally used in the U.S. Environmental Protection Agency's noncancer health assessments and expressed in milligrams per cubic meter (mg/m3).
A concentration specified by EPA to limit human inhalation exposure to potentially hazardous levels of chemicals in air.
An estimate of the daily inhalation dose, expressed in terms of an ambient concentration, that can be taken daily over a lifetime without appreciable risk. more