Effects and fate of inhaled ultrafine particles

IEC 22

Günter Oberdörster, Department of Environmental Medicine, Department of Environmental Medicine, University of Rochester, 575 Elmwood Avenue, Box 850, Rochester, NY 14642
Airborne particles <100 nm in diameter occur at very high number concentrations in outside air, specifically urban air, and at certain workplaces. More recently, nanotechnology has created new and even smaller sized spherical particles (<10 nm) as well as nanotubes for applications ranging from electronics to biomedical fields. Their use in these areas raises concerns regarding potential exposures of humans and subsequent effects should they become airborne. Toxicological studies involving different types of nano- or ultrafine particles have revealed a wide range of adverse effects, ranging from very high to mild acute pulmonary inflammatory responses to effects on extrapulmonary organs such as the cardiovascular system. The large surface area per given mass of ultrafine particles is toxicologically of importance, it correlates well with their potential to cause inflammation and oxidative stress. Furthermore, ultrafine particles below 50 nm have a high probability to be deposited throughout the respiratory tract upon inhalation. Translocation of 10-50 nm sized particles from the respiratory tract to interstitial sites and to other organs, including the CNS, has also been demonstrated, yet many unanswered questions remain regarding their potency to cause health effects at these sites. Examples of anthropogenic ultrafine particles at the workplace and in the ambient air will illustrate human exposure scenarios; results from toxicological investigations will be presented to demonstrate their potential for causing adverse effects.