Fig. 1.

Schematic overview on ambient fine and ultrafine particle deposition and interaction with organs and the circulation contributing to the development and progression of dementia and neurodegeneration. Orange lines and arrows: Particle paths through the upper airways into the lung. Dark red lines: Particle paths through the esophagus into the gastrointestinal tract. Gray lines and arrows: Paths of ultrafine particles and constituents from the barrier organs to the brain.