Aerosol Transport – Inertia

:: Section 6

Slip Correction Factor

II. Gas Mean Free Path

To quantify the 'slip' effect on the particles, first we need to define the mean free path of gas molecules.

The definition of 'mean free path' of gas molecules is the average distance a gas molecule travels between collisions with other gas molecules. For air, the mean free path is 0.066 μm at STP. If a particle is much smaller than the mean free path, missed collisions are much more likely.