How To Take an Air Sample: Fall Plates Instructions

How To Take an Air Sample Using Fall Plates


  1. Select sites that represent the problem or space being investigated.
    Notes: consider an outdoor site to act as a control sample. In an office, a desktop will act as a ‘typical’ location. In a kitchen, a countertop or table works well
  2. Remove the 3 petri dishes from the ziplock baggie.
  3. Place the plates in a central location at the sample site agar side down |________| . The 3 plates need to be within 2 meters of each other.
  4. Open the lid of each plate to expose the agar surface to air.
    Notes: use ALL 3 plates = 1 sample
  5. Leave plates exposed for 15 minutes. Continue to use the room normally while the plates are exposed.
  6. Replace petri-dish lids. Label baggie with location, date & time.
  7. Place dishes back into baggie and ship to laboratory.

General Notes:

Storage: refrigerate, agar-side up. Do not let the plates freeze. Discard plates if there is visible growth of any kind on the agar surface or between the lid and side of dish. Discard plates if the agar has pulled away from the walls of the dish.

Use: remove excess condensation on the lids that can occur in stored plates by holding the plates agar-side up in one hand & removing the lid with the other hand. Using a flicking motion, the excess moisture on the lid can be discarded.

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