Calibration aerosol
Prioritizes a reference size population, controlled concentration and metrology system appropriate to the instrument.
Generation chain
The aerosol is not identical to the bottle
A liquid suspension becomes an aerosol through atomization, droplet drying, transport and dilution. Each stage can shift the delivered size distribution or concentration.
| Stage | Primary risk | Control question |
|---|---|---|
| Stock preparation | Agglomeration or concentration error | Was the suspension mixed and diluted under a validated method? |
| Atomization | Droplet-size and generator dependence | Does the generator produce a stable, suitable aerosol? |
| Drying / conditioning | Residual water or nonvolatile residue | What remains after droplets evaporate? |
| Transport | Diffusion, sedimentation and wall loss | How much material reaches the test section? |
| Dilution | Coincidence or unstable concentration | Is the delivered count within the instrument or test range? |
Material selection
Calibration aerosol and challenge aerosol serve different purposes
Filter challenge aerosol
Prioritizes test-method compatibility, sufficient challenge concentration and stable delivered distribution.
Research aerosol
May prioritize material property, surface chemistry or experimental flexibility rather than a commercial calibration claim.
Residue control
Water evaporates; dissolved and suspended material does not
Surfactants, salts, contaminants and agglomerates can create residues or secondary particles. Do not assume the dry aerosol diameter equals the liquid droplet diameter or the certified PSL diameter without understanding the generation method.
Method boundary: never dry or aerosolize a product outside its intended-use documentation without validating the delivered population and safety controls.
Documentation
Record the delivered system
- PSL lot, bottle concentration, dilution and diluent.
- Generator model, settings and operating time.
- Drying or conditioning path.
- Transport tubing, flow rates and test geometry.
- Reference instrument and sampling locations.
- Delivered size and concentration stability.
- Cleaning, waste and cross-contamination controls.
Applied Physics technical pathway
Match the standard to the measurement—not the other way around.
Send the instrument, medium, target size, concentration, certificate and packaging requirements to Applied Physics for a technical recommendation.