Indoor Environmental Quality

Banner image: mold, vent, construction workers, hands cleaning a counter top


Indoor environmental quality (IEQ) refers to indoor conditions in a building related to the health of those who occupy it. IEQ includes factors such as lighting, air quality, and damp conditions. Workers sometimes express concern about symptoms or illnesses caused by exposures from the buildings they work in. One reason for this is because their symptoms get better when they are not in the building.

Research has shown that some respiratory symptoms and illnesses can be related to damp buildings. However, the levels of indoor exposures that indicate a risk for disease is not clear. Results of environmental and medical tests are often not sufficient. Therefore, determining which exposures are responsible for building-related conditions can be challenging.

Indoor environments are complex. Exposures can include a variety of contaminants in the form of gases and particles such as:

  • Office machines
  • Cleaning products
  • Water-damaged building material
  • Microbial growth (fungal, mold, and bacterial)
  • Insects
  • Carpets and furnishings
  • Perfumes

Additional contaminants include cigarette smoke, construction activities, and outdoor pollutants. Indoor temperatures, relative humidity, and ventilation can also affect how individuals respond to the indoor environment.

Understanding the sources of indoor environmental contaminants and controlling them can help prevent or resolve building-related symptoms in workers. Those with persistent or worsening symptoms should seek a medical evaluation for diagnosis and treatment.