mobility (general) in aerosol physics

https://dx.doi.org/10.1351/goldbook.MT06760
Mass transport is described by a mobilityb, defined by:
b i = ν i F i
where ν i is the average drift velocity and F i is the force on particle i.
Source:
PAC, 1999, 71, 1307 (Definitions of Terms for Diffusion in the Solid State) on page 1319