  This work explores characteristics of the negative polarization branch (NPB),
which occurs in scattered light from rough surfaces, with particular focus on
the effects of fine particles. Factors such as albedo, compression, roughness,
and the refractive index are considered to determine their influence on the
NPB. This study compiles experimental data and lunar observations to derive
insights from a wide array of literature. Employing our proposed methodology,
we estimate the representative grain sizes on the lunar surface to be $D \sim 1
\mathrm{-} 2 \mathrm{\mu m}$, with $D \lesssim 2 \mathrm{-} 4 \mathrm{\mu m}$,
consistent with observed grain size frequency distributions in laboratory
settings for lunar fines. Considering Mars, we propose that the finest
particles are likely lacking ($D\gg 10 \mathrm{\mu m}$), which matches previous
estimations. This study highlights the potential of multiwavelength,
particularly near-infrared, polarimetry for precisely gauging small particles
on airless celestial bodies. The conclusions provided here extend to
cross-validation with grain sizes derived from thermal modeling, asteroid
taxonomic classification, and regolith evolution studies.
