  The Basset-Boussinesq force is often perfunctory neglected when studying
small inertial particles in turbulence. The force results from the diffusion of
vorticity from the particles, and as it depends on the particles past history,
it complicates the dynamics by turning their equations of motion into
integro-differential equations. However, this force is of the same order as
other viscous forces acting on the particles, and beyond convenience, the
reasons for neglecting it are unclear. We derive strict bounds for the
magnitude of the Basset-Boussinesq force in stably stratified flows, in
contexts of interest for geophysical turbulence. The bounds are validated by
direct numerical simulations. The Basset-Boussinesq force can be neglected when
a buoyancy Stokes number $\textrm{Sb} = N \tau_p$ is small, where $N$ is the
flow Brunt-V\"ais\"al\"a frequency and $\tau_p$ is the particles Stokes time.
For sufficiently strong stratification, or particles with large inertia, this
force must be considered in the dynamics.
