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Indoor Air Quality

Exposure Levels


  • OSHA
    • 0.1 fibers per cubic centimeter (f/cc) of air
  • Asbestos Hazards Emergency Response Act (AHERA)
    • Testing prior to re-occupancy following abatement in schools
      • 0.01 f/cc by Phase Contrast
      • Average of 70 structures or less by Transmission Electron

Biological Contaminants

  • No regulation or standard has been established due to variations in individual tolerance
  • Guidelines recommend concentrations indoors to be 1/2 to 1/3 less than concurrent outdoor samples with similar species
    • Hundred of species of molds can be toxic in mass quantities
      • Aspergillus/Penicillium
    • Some molds are toxic no matter the quantity
      • Stachybotrys

Chemical Contaminants Indoors and Outdoors

  • Dependent upon chemical (voc) believed to be emitted
    • i.e., Carbon Monoxide 55 mg/m3


  • ASHRAE guidelines specify that 80% of occupants should be comfortable in range of 68-79 degrees F (indoor air temp)


  • ASHRAE guidelines specify that 80% of occupants should be comfortable in range of 30 and 60%


  • OSHA
    • 50 micrograms per cubic meter (ug/m3) of air
    • 50 micrograms per deciliter (ug/dL) of blood
      • Lead and zinc protoporphyrin levels screened
      • Medical removal from work, if limit exceeded

Inadequate Ventilation

  • ASHRAE recommends fresh air intake of 15 cubic feet per minute (cfm) for each occupant
  • Up to 60 cfm depending upon activities in facility


  • 0.05 mg/m3


  • OSHA
    • Vary for area of work
    • Hospitals and offices
      • Minimum illumination intensities of 30 foot-candles
      • Foot-candle is defined as the amount of illumination produced by a standard candle at a distance of one foot.


  • OSHA
    • 85 decibels (dB)




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