Diagnosed Infection or Clusters of Serious Health Problems
May be Legionnaire's disease or histoplasmosis related to bacteria or mold found in the building or near outdoor air intakes. Contact your local or state health department for guidance.

Air Handling Unit
  • Is the system turned on?
  • Is the airflow from vents sufficient?1
  • Are the fans turned on?
  • Are the filters clean and properly installed?
  • Are dampers operating correctly?
  • Is there moisture, debris or mold in or near the unit?
  • Are drain pans clean and sloped toward the drain?
  • Do coils need to be cleaned?
  • Is combustion equipment properly vented without flue leaks or backdrafting?

Biological Sources

Excess moisture can cause mold, dust mites and bacteria to flourish. Moist or wet materials should be dried within 24-48 hours to avoid mold growth or replaced if mold already exists.

  • Do you see or smell mold?
  • Are there signs of rodents or pests?
  • Are there animals or pets in classrooms?
  • Is condensation often present on windows or cold surfaces?
  • Do you see wet or frequently damp areas?
  • Is indoor relative humidity above 60 percent?

1 Airflow: To detect airflow, use special chemical smoke or a piece of tissue. Release puffs of smoke near openings between the complaint area and adjacent areas (openings include cracks, ducts, wiring and plumbing passageways, and leaky or open doors and windows). Release smoke near vents and grilles to determine airflow direction, if any. Do not breathe on or move quickly near puffs of smoke.