Particle size and morphology drive the kinetic parameters that govern how external exposure translates into internal dose — specifically airway and lung deposition fractions, as well as placental, gut and pulmonary translocation fractions. These fractions are retrieved from a size- and morphology‑based kinetic lookup table derived from published values (see documentation). Clearance kinetics are not currently modelled; the framework currently assumes that once MNPs enter the systemic circulation they are not cleared. Polymer and chemical toxicity scores [Christopher et al. 2024] combine with automatic size/morphology modifiers to produce the final hazard score.
Particle Size
Source: [van Boxel 2025; ICRP 66]Morphology
Source: [Sturm 2012; Zhou 1996]Polymer & Chemical Profile
Source: [Christopher et al. 2024]Defaults are set for a high-concern scenario (PP bottles). Adjust the Polymer Toxicity score if using alternative materials like glass.
Body Weight (BW) [kg]
Source: [WHO Child Growth Standards]Resting Breathing Rate (IR_breath) [m³/hr]
Source: [EPA Exposure Factors - Infant Resting]Normalisation Metric
Source: [Standard RA Practice vs. Particle-Specific]Using Body Weight is standard but may be less relevant for particle toxicology. 'Total Particle Load / day' provides the absolute particle flux.
Bottle MNP Load (Bottle_Load) [particles/day]
Source: [Du et al. 2025 - PP Infant Bottles with Thermal Ageing]This is the total daily particle load, not a concentration. Select the approximate bottle age/usage level to apply the cumulative ageing effect on particle shedding.
IMPORTANT: Ingested vs. Systemic Dose. The Bottle MNP Load shown above is the total daily particle load ingested — the amount that enters the mouth and is swallowed. The systemic dose (the amount reaching internal organs via the bloodstream) is a fraction of this ingested load, determined by the gut translocation fraction, which depends on particle size and morphology (see Section 1). For example, at the default "Fine Nano (50–100 nm)" + "Sphere" setting, gut_translocate ≈ 5%, multiplied by the neonate's elevated gut permeability modifier (2.0×), giving an effective translocation of ~10%. Thus a 24,000 particles/day ingested load yields a systemic contribution of approximately 2,400 particles/day via the bottle pathway. The simulation result reflects this internal dose, not the ingested amount.
Based on Du et al. (2025) exposure estimate of 1,237–2,835 particles/kg-bw/day. The ageing multiplier accounts for cumulative damage from repeated sterilisation cycles (32.5%–264.2% increase over baseline). The recommended dynamic replacement interval is 28–112 days.
Ambient Dust Conc. (C_dust) [p/m³]
Source: [Vianello et al. 2019 - Indoor Air]Exposure Thresholds
Source: [User Defined]Note on Thresholds
Exposure thresholds are currently arbitrary and user-definable. What constitutes Low, Medium and High in terms of daily particle exposures is to be resolved by scientific consensus.