Particle Size and Composition Related to Adverse Health Effects in Aged, Sensitive Rats

Dr. Hahn and colleagues systematically examined lung inflammation in young adult and old rats after inhalation of fine particles (< 2.5 µm in aerodynamic diameter) and ultrafine particles (< 0.1 µm in aerodynamic diameter) of different composition: relatively inert carbon and vanadium pentoxide (V₂O₅), which contains the transition metal vanadium, known to cause toxic effects upon inhalation in humans in occupational settings. In addition, they examined the effect of a short-term increase (spike) in particle exposure concentration on inflammatory response. The investigators hypothesized that a spike in particle concentration would cause a greater inflammatory response than exposure to a steady concentration at equal particle lung burden would.