Improvements and additions to the Multiple Path Particle Dosimetry model

Abstract

A little over a decade ago, the first UC Irvine dosimetry conference was held entitled “Frontiers in Aerosol Dosimetry Research”. At that time, mechanistic dosimetry models, such as the multiple path particle dosimetry (MPPD) model, primarily focused on humans, with a model for the Long Evans rat also being available. In the intervening years, advances have occurred on a number of fronts that have led to improvements and additions to the user-friendly MPPD software program that is available free to the public. Here, we review a number of the expanded capabilities of the MPPD model. These include:•Calculating deposition and clearance simultaneously for up to 4 lognormal distributions having different mass median aerodynamic diameters and geometric standard deviations. This feature is useful whenever the exposure atmosphere is multimodal as is often the case with workplace exposure atmospheres and can occur in inhalation toxicology studies if the particulate aerosol is difficult to generate stably.•The ability to adjust the total aerosol deposition for the amount of particle “X” when “X” is a subset of the total aerosol. This is particularly important for workplace exposures where the particles of interest (e.g., copper containing particles) are part of the total dust aerosol that was measured.•The ability to specify clearance rates and mucous velocities for both animals and humans so any type of particle can be modeled as well as various lung disease states.•The addition of dose metrics for the upper respiratory tract and enhancements to dose metrics for the lower respiratory tract.•Addition of a lung geometry/morphometry model and physiologic input variables for mice (Balb/c and B6C3F1), Sprague-Dawley rats, male rhesus monkeys, sheep, and pigs. The deposition and clearance of particles in these species can now be examined.