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Dust Sampling for Mold

Mold in Dust Sampling


  • To determine whether the surface spore population represents a normal population or is skewed, indicating the possibility of mold growth in the area. Marker spores indicative of mold growth may also be noted.

Note: A dust sample can be analyzed by direct microscopic examination or by culture. Both have their own advantages and disadvantages. It is usually recommended that both culture and direct examination be performed on the sample since either one alone may result in an inaccurate characterization of the dust sampled. If only one method of analysis is to be used, usually a culturable analysis is the best choice.

Advantages and Disadvantages

  • Advantages
    • Dust samples are considered by some to relate to the history of what has been in the air.
    • Dust samples for a direct examination may be analyzed immediately.
  • Disadvantages
    • The results are dependent upon many factors that are difficult to control and may be difficult to interpret.


  • Dust filter cassette.
  • Vacuum pump.

Sampling Protocols

  • Control as many sampling variables as possible including the time of vacuuming, the amount of pressure applied, the size of the area sampled, the direction of sampling, and the equipment used.
  • Sample from areas that are unlikely to be affected by foot traffic or other sources of fungi that are not from the air. Corners of rooms, tops of ceiling fans, and other infrequently disturbed areas are often good.
  • Try to get at least a teaspoon of dust and record the area vacuumed if possible.


  • There are no special shipping requirements for fungal analysis (Note: dust samples for dust mite allergen analysis should be sent with a cold pack via an overnight courier).