The physiological process by which toxicants pass body membranes and enter the bloodstream or other body components from the site of exposure.

American Conference of Governmental Industrial Hygienists.

Air changes per hour. One ACH means a volume of outdoor air equal to the volume of the space being ventilated has entered that space in one hour.

Those that occur immediately on exposure.

Americans with Disabilities Act of 1990.

A biological response to exposure to multiple chemicals which is equal to the sum of the effects of the individual agents.

Inability to perceive objects through otherwise normally functioning sensory channels.

Asbestos Hazard Emergency Response Act.

Air handling unit refers to ventilation equipment in HVAC systems.

An IAQ control strategy to remove various airborne particles and/or gases before the air enters the occupied space. The three types of air cleaning most commonly used are particulate filtration, electrostatic precipitation, and gas sorption.