Airborne Bacteria “IN” Indoor Environments

Allergies and Mold

Airborne Bacteria “IN” Indoor Environments

Indoor Bacteria have not received as much publicity as the mold, but is indoor bacteria a health concern?


When conducting indoor air quality test, most companies not only test for mold species and colony forming units (cfu) they also test for bacteria.

The most publicized form of indoor bacteria problems is Legionellosis and is an infectious disease caused by bacteria most commonly taking two forms known as:

  • Legionnaires’ disease – the more severe form of the infection and produces pneumonia.
  • Pontiac fever – caused by the same bacterium, but produces a milder respiratory illness without pneumonia which resembles acute influenza.

While bacteria do not receive as much publicity as mold when it comes to indoor air quality, they are a health hazard. Some are serious human pathogens and others especially the gram negative bacteria produce toxic compounds (endotoxins) from the outer membrane of their cell wall. Endotoxins may have a role in “sick building syndrome” and bacteria is the direct cause of “dirty sock syndrome”.

Indoor airborne bacteria can loosely be categorized into bacterial pathogens and environmental bacteria associated with water-damaged building materials. Bacterial pathogens are capable of causing severe diseases in humans if inhaled, ingested or if they come into contact with the skin. The most important airborne bacterial infections in indoor environments are tuberculosis, nosocomial pneumonia, and legionellosis. These infections are primarily acquired through inhalation of the water droplets circulated by the air conditioning system.

Similar to mold, indoor bacteria are present in the air and on surfaces. High levels of bacteria concentration indoors is an indication of high occupancy rate, poor ventilation, or poor building maintenance and poor HVAC system cleanliness maintenance.

We want to hear from you! Call or email to tell us about your indoor air quality problems.  We’ll help you find the right solution.