airborne contaminant, a material in the atmosphere that can affect the health of persons in the same or nearby environments. Particularly vulnerable are the tissues of the upper respiratory tract and lungs, including the terminal bronchioles and alveoli. The effects depend in part on the solubility of the inhaled matter. Inhaled contaminants may cause tissue damage, tissue reaction, disease, or physical obstruction. Some airborne contaminants, such as carbon monoxide, may have little or no direct effect on the lungs but can be absorbed into the bloodstream and carried to other organs or damage the blood itself. Biologically inert gases may dilute the atmospheric oxygen below the normal blood saturation value, thereby disturbing cellular respiration.
