IAQ Contaminant Sources

Indoor air contaminants can originate within the building or be drawn in from outdoors. If contaminant sources are not controlled, IAQ problems can arise, even if the HVAC system is properly designed and well maintained. It may be helpful to think of indoor air pollutant sources as fitting into one of the following categories. The examples given for each category are not intended to be a complete list.

Air Quality Sources Outside the Building

Contaminated Outside Air

Emissions From Nearby Sources

Soil Gas

Moisture or Standing Water Promoting Excess Microbial Growth


HVAC System

Non-HVAC Equipment

Human Activities

Personal Activities

Housekeeping Activities

Maintenance Activities

Building Components and Furnishings

Locations That Produce or Collect Dust or Fibers

Chemicals Released from Building Components or Furnishings

Other Sources

Accidental Events

Special Use Areas and Mixed Use Buildings

Redecorating or Remodeling and Repair Activities