How do I test for black mold?

Testing for Black Mold

For suspected black mold in indoor environments, professional testing is recommended for areas larger than 10 square feet, while visual inspection by a certified environmental hygienist is the primary diagnostic approach since no uniformly accepted environmental sampling methods exist. 1

Testing Methods for Black Mold

Visual Inspection

• A certified environmental hygienist should conduct visual inspection, especially when mold is suspected but not visible 1
• Look for visible signs of mold growth, water damage, or excessive moisture
• Pay special attention to areas prone to dampness: bathrooms, kitchens, basements, and areas with water leaks

Air Sampling

• Air sampling can be performed using specialized equipment that collects air samples for laboratory analysis
• Air samples should collect a total volume between 180-1080 L, depending on the size of the area 2
• For accurate assessment, samples should be:
  • Sealed after collection
  • Incubated for 5 days at temperatures between 28°C-37°C 2
  • Note that lower incubation temperatures may show higher counts, while 37°C will only grow fungi capable of growing at human body temperature 2

Professional Sampling Equipment

• Use sampling methods based on aspiration where air impacts or is filtered through collection media 2
• Equipment should be capable of sampling an appropriate volume of air (2 m³ in 10 minutes) 2
• Collection media may include:
  • Porous filters
  • Agar media
  • Adhesive strips
  • Liquid collection systems

When to Test

• For areas smaller than 10 ft², cleaning can be done using commercial products, soap and water, or a bleach solution (1 cup bleach to 1 gallon water) 1
• For areas larger than 10 ft², professional remediation is recommended 1
• Testing is particularly important:
  • After water damage or flooding
  • When there's a musty odor but no visible mold
  • When occupants experience unexplained allergic symptoms
  • Before occupying a new home with suspected mold issues

Interpreting Results

• Normal Aspergillus counts in non-protected environmental air typically range between 10-25 CFU/m³ 2
• Higher counts may be considered abnormal, especially in areas where immunocompromised individuals may be present 2
• Increases in mold counts often correlate with construction, land movements, or structural work 2

Important Caveats

• There is currently no validated method to test humans for toxigenic mold exposure 1
• No uniformly accepted environmental sampling methods exist for comprehensive mold assessment 1
• The concept of "toxic mold syndrome" lacks scientific evidence 3, 4
• Mold can cause legitimate health issues including allergies, asthma triggers, and hypersensitivity pneumonitis in susceptible individuals 3, 5
• Immunocompromised individuals are at higher risk for fungal infections and require more aggressive monitoring 1

Prevention and Remediation

• Maintain indoor humidity below 50% 1
• Use high-efficiency air filters 1
• Promptly repair water leaks 1
• Improve ventilation in bathrooms and kitchens 1
• For contaminated surfaces, clean thoroughly with sporicidal detergent (bleach 1:10 dilution or hydrogen peroxide ≥6%) with at least 20 minutes contact time 1

Remember that while testing can identify the presence of mold, the most effective approach is addressing moisture sources and proper remediation of affected areas.