Suspended particulate matter (SPM) significantly impacts water clarity, degrading underwater electro-optical detection systems. It is also comprised of the living, detrital, and minerogenic particles that contribute to oceanic biogeochemical cycling. Models designed to derive SPM from optical properties such as particulate backscattering and attenuation have been largely empirical in nature, i.e., simple linear relationships, and therefore fluctuate with varying particle composition. Consequently, such models perform well regionally and/or temporally, but their applicability is constrained. An analytical inversion model has been developed to quantitatively interpret scattering measurements in terms of SPM. The algorithm requires measurements of backscattering and spectral attenuation. These measurements can be made with commercial-off-the-shelf technology suitable for deployment on compact autonomous platforms, thus having the potential to dramatically increase spatial and temporal resolving capabilities for SPM. Recent work evaluates the role of particle size ranges in greater detail and assesses performance for multiple data sets including the GlobCOAST data set, a large, diverse data set of high quality SPM and optical property measurements.