Common Sources Of Indoor Environment Pollution

The US EPA recognizes that indoor air pollution can be 10 to 100 times as polluted as outdoor air, even when compared to a smoggy Los Angeles day.

Where does this pollution come from? From many sources including, but not exclusive to:

Outdoor air:

  • pollen
  • dust
  • fungal spores
  • industrial emissions
  • vehicle emissions (busses, loading docks, exhausts near outdoor air intakes, furnace stack emissions)
  • pesticides
  • roofing tars
  • sewer gas

hazardous materials:

  • lead
  • asbestos
  • pcbs
  • ozone


  • chemical emissions from new furniture
  • particle board, plastics, room dividers, curtains, ceiling tiles…
  • Microbial growth on furnishings and carpets

ventilation system:

  • dust, mould, or debris in ductwork, coils, humidifiers, drip pans, etc.
  • Improper venting of combustion products
  • low air delivery rates
  • no hvac present
  • turning off hvacs after hours

underground sources:

  • radon
  • underground fuel tank leaks

chemical off-gassing:

  • building materials: insulation, caulking, paints, varnishes, glues
  • art and science labs, technical/vocational areas, cooking labs.
  • Office supplies; felt markers, whiteout, inks, laminators, photocopiers, printers
  • fire retardants
  • scented personal products
  • smoking lounges
  • cleaning agents, waxes and floor strippers
  • air fresheners
  • perfumes
  • aerosol sprays
  • combustion gasses from furnaces, stoves, etc.
  • Flooring: carpets, soft vinyl tile and glues


  • lighting
  • thermal comfort
  • humidity
  • acoustics: noise pollution
  • electromagnetic fields
  • infrequent or inadequate cleaning