- Orifice = small hole that separates particles by size.
- Larger particles stop in early stages, smaller particles go to later stages.
- Used in air particle samplers and aerosol monitoring.
✅ In one line:
OT-3 particle orifice table shows orifice hole size and the particle size captured at each stage.
If you want, I can also give 2-line exam answer or a simple diagram.