This guideline is one of a series of test guidelines that have been developed by the Office of Prevention, Pesticides and Toxic Substances, United States Environmental Protection Agency for use in the testing of pesticides and toxic substances, and the development of test data that must be submitted to the Agency for review under Federal regulations. This guideline is available from the U.S. Government Printing Office, Washington, DC 20402 on The Federal Bulletin Board. Inhalation developmental toxicity study. The inhalation developmental toxicity study is designed to provide information on the potential hazard to the unborn which may arise from exposure of the mother during pregnancy. The following definitions also apply to this test guideline.
Aerodynamic diameter applies to the behavioral size of particles of aerosols.
It is the diameter of a sphere of unit density which behaves aerodynamically like the particles of the test substance. It is used to compare particles of different sizes, shapes, and densities and to predict where in the respiratory tract such particles may be deposited. Concentration refers to an exposure level. Developmental toxicity is the property of a chemical that causes in utero death, structural or functional abnormalities or growth retardation during the period of development. Geometric mean diameter or median diameter is the calculated aerodynamic diameter which divides the particles of an aerosol in half based on the weight of the particles.