CMA CMA Sampling & Testing Methods 2 — Questions and Answers
Question 1: A spore trap analysis report shows predominantly Cladosporium at low levels both indoors and outdoors. What does this finding most likely indicate?
- Significant indoor mold amplification
- Normal background fungal ecology with no indoor source (Correct answer)
- Hidden water damage behind walls
- Inadequate HVAC filtration
Correct answer: Normal background fungal ecology with no indoor source
Cladosporium at low concentrations matching outdoor levels is normal background; it is ubiquitous outdoors and its indoor presence often reflects normal air exchange.
Question 2: Which mold genus is considered a strong indicator of water-damaged building materials when found in elevated concentrations indoors?
- Cladosporium
- Alternaria
- Stachybotrys chartarum (Correct answer)
- Basidiospores
Correct answer: Stachybotrys chartarum
Stachybotrys chartarum requires chronically wet cellulosic materials to grow and is rarely found in outdoor air, making its indoor presence a reliable indicator of water damage.
Question 3: What does the ERMI (Environmental Relative Moldiness Index) score measure?
- The total mass of mold in a building in grams
- A DNA-based index comparing water-damage indicator molds to common outdoor molds in dust (Correct answer)
- The percentage of wall area affected by visible mold
- The viable spore count per cubic meter of indoor air
Correct answer: A DNA-based index comparing water-damage indicator molds to common outdoor molds in dust
ERMI uses qPCR to quantify 36 mold species in settled dust, calculating a score that compares Group 1 (water-damage associated) species against Group 2 (common outdoor/background) species.
Question 4: When collecting a tape lift sample from a surface, which laboratory analysis method is typically used?
- Culture on MEA agar
- Direct microscopy (Correct answer)
- qPCR amplification
- Gas chromatography
Correct answer: Direct microscopy
Tape lifts are examined directly under a microscope, allowing identification of fungal structures (spores, hyphae) by morphology without requiring culture growth.
Question 5: What minimum air volume is typically recommended when collecting an Air-O-Cell spore trap sample?
- 5 liters
- 15 liters
- 75 liters (Correct answer)
- 150 liters
Correct answer: 75 liters
Standard Air-O-Cell protocol recommends collecting 75 liters of air (typically at 15 L/min for 5 minutes) to obtain a representative sample for analysis.
Question 6: What is the primary limitation of non-viable (spore trap) air sampling compared to viable (culture) sampling?
- Spore trap sampling cannot detect Aspergillus species
- Spore trap sampling cannot distinguish between live and dead spores (Correct answer)
- Spore trap sampling requires more expensive laboratory equipment
- Spore trap sampling is only valid outdoors
Correct answer: Spore trap sampling cannot distinguish between live and dead spores
Non-viable spore trap analysis identifies and counts spores morphologically but cannot determine whether they are alive (viable) or dead, which matters for exposure and remediation assessment.
CMA CMA Sampling & Testing Methods 2
A spore trap analysis report shows predominantly Cladosporium at low levels both indoors and outdoors.
What does this finding most likely indicate?