Indoor Air Quality (IAQ) refers to the effect, good or bad, of the contents of the air inside a structure, on its occupants.
Good IAQ is the quality of air which has no unwanted gases or particles in it at concentrations which will adversely affect someone. Poor IAQ occurs when gases or particles are present at an excessive concentration so as to affect the satisfaction or health of occupants.
In minor instances, poor IAQ may only be annoying to one person. At the extreme, it could be fatal to all of the occupants of a structure.
It is important to note that the concentration of the contaminant or contaminants is crucial. Potentially infectious, toxic, allergenic, or irritating substances are always present in the air. There is nearly always a threshold level below which no effect occurs.
