Aerosols (liquid mists & droplets) — properties & hazards overview
Physical state
Liquid droplets in a gas
Typical size range
0.5 – 50 µm (submicron possible)
Formation
Condensation, atomisation, entrainment
Water solubility
Depends entirely on the carrier
Toxicity
Carrier-dependent
Flammability
Solvent/oil mists
Chronic risk
Deep lung deposition
Environmental
Plume, deposition, corrosion
| Property | Value / Note |
|---|---|
| Description | Two-phase system: a gas carrying fine liquid droplets. Composition follows the process — acid mist, solvent condensate, salt solution, fragrance oils or scrubber liquor carry-over. |
| Size fractions | Coarse (> 10 µm) drops out by inertia; 1–10 µm needs a demister; < 1 µm needs fibre-bed, wet ESP or condensation growth. |
| Typical sources | Spray drying, quenching, evaporation, hot-gas cooling, atomised additives and demister carry-over in the scrubber itself. |
| Difference with dust | Dust is solid and is captured by impaction; aerosols are liquid, coalesce on a surface and drain. See the separate sheet Particulate Matter for the solid fraction. |
| Best analytical detection | Isokinetic sampling with a heated probe combined with an optical (light-scattering) monitor for continuous trending; the optical reading alone does not distinguish droplets from dust. |
*Indicative values. Classify an aerosol by its carrier: the SDS of the carried substance sets the exposure and disposal limits.