FACT SHEET
Factors Affecting Indoor Air Quality


There are three major sources of contaminants affecting indoor air quality:

  1. Indoor
    • Personal Activities (smoking or personal hygiene)
    • Housekeeping (deodorizers, cleaning materials, or dust)
    • Maintenance Activities (remodeling, new furniture/carpet, or pest control)
    • Miscellaneous: Emissions from office equipment (photocopier machines, VDTs)
      • Office supplies (toners, carbonless paper products)
      • Liquid spills or leaks
      • Room occupant load
      • Thermal and/or humidity comfort
  2. Outdoor
    • Contaminated outdoor air (vehicle exhaust, pollen, or industrial pollutants)
    • Nearby source emissions (garbage dumpsters, loading docks, or re-entrained exhaust from buildings)
    • Soil gas (radon, underground storage tanks, or pesticides)
    • Microbial from standing water (molds or mildew)
  3. HVAC System
    • Inadequate distribution of fresh air in ventilation system
    • Dust in ductwork
    • Dirty air filters
    • Microbiological growth in ductworks and/or humidifiers

Adapted from EPA "Building Air Quality, A Guide for Building Owners and Facility Managers", December 1991.


Industrial Hygiene | EH&S Fact Sheets