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Quick Answer
Air sampling measures airborne spores and fragments at a moment in time. Surface sampling confirms what is growing on a material or what has settled on a surface.
If the goal is to locate a moisture source or confirm visible growth, a good inspection often matters more than testing. Sampling is most useful for documentation or verification.
What Air Sampling Measures
Air sampling pulls a measured volume of air through a spore trap cassette and reports spores per cubic meter. It is useful for comparing indoor air to an outdoor control sample.
Learn more about how air sampling works and its limitations.
- Best for: comparing indoor and outdoor levels
- Common use: post remediation verification
- Key requirement: outdoor control sample
- Major limitation: highly variable snapshot
What Surface Sampling Measures
Surface sampling uses swabs, tape lifts, or bulk samples to identify what is on a surface or inside a material. It helps confirm visible growth and can be used to document conditions.
See our guide to surface sampling methods and when they help.
- Best for: confirming visible growth
- Common use: documentation for disputes
- Key requirement: a defined sampling target
- Major limitation: does not reflect air levels
Side by Side Comparison
Air Sampling
- Measures airborne spores and fragments
- Requires outdoor control sample
- Good for clearance testing
- Sensitive to weather and HVAC changes
Surface Sampling
- Measures what is on a surface or material
- Good for confirming visible growth
- Useful for documentation and species ID
- Does not show airborne exposure level
Best Use Cases
Choose Air Sampling When
- You need clearance testing after remediation
- Symptoms persist and the source is unclear
- You want indoor and outdoor comparison data
- You need documentation for insurance or legal use
Choose Surface Sampling When
- You need to confirm visible growth
- You want documentation of contamination
- You are collecting a material sample for analysis
- You need species identification on a surface
When to Use Both
Using both methods can be appropriate when there is visible growth and you also need to understand airborne risk. For example, after remediation you might confirm surfaces are clean and verify that air levels match outdoor conditions.
Pair testing with a strong inspection and a clear sampling plan. The goal is to answer a specific question, not to collect data for its own sake.