Dosimetry and toxicology of inhaled ultrafine particles

Abstract

Both epidemiological and toxicological studies indicate that inhalation and subsequent deposition of airborne particles into the lungs have adverse health effects. Recently, the ultrafine particle (UfP) fraction (diameter < 100 nm) has received particular attention, as their small size may lead to more toxic properties. In this study we summarize the current knowledge on the dosimetry of inhaled particles (including UfPs) with a focus on recent data on translocation of UfPs into secondary target organs (such as brain and heart) suggesting that the lifetime dose of ambient UfPs in secondary target organs is about 10(11) particles. Furthermore, we highlight the main pathways of particle induced toxicity and the reasons for the potentially higher toxicity of UfPs. Finally, we discuss recent evidence indicating that (BET) surface area is the single most relevant dose metric for the toxicity of UfPs, which has important implications for regulatory measures on the toxicity of ambient and engineered particles.

Nano-objects emitted during maintenance of common particle generators: direct chemical characterization with aerosol mass spectrometry and implications for risk assessments

“…The alveolar region of the lung has been pointed out as a target region in nanotoxicology, partly due to the rather poor defense mechanisms in this part of the lung towards deposited particles (Schmid et al 2009). Since the dimensions of the large super-agglomerates are in the range of thousands of nanometer (GMD =1.8 µm), they contain a very large number of primary particles.…”

“…The particle surface area that is available to interact with bio molecules and cells is considered to be an important particle property describing the toxicity of particles (Schmid et al 2009). For visualization the total surface area for each specific particle size interval during the 4 selected emission events were estimated, and given in Fig.…”

Comparative Testing of a Miniature Diffusion Size Classifier to Assess Airborne Ultrafine Particles Under Field Conditions

“…Traffic emissions are an important source of PM and traffic exposure has been directly linked to adverse health outcomes (Peters et al 2004;Riediker et al 2004). Recent publications suggest that ultrafine particles (UFP) play a critical role in triggering oxidative stress and inflammatory processes that provoke atherogenic and thrombotic effects and influence the autonomous nervous system (Schmid et al 2009;Schneider et al 2010;Peters et al 2011). Detection and quantification of these particles is important and a first step to characterizing potential health hazards.…”

Outdoor air pollution and risk for kidney parenchyma cancer in 14 European cohorts

“…Although the amount of particles accumulating in secondary target organs, such as the kidney, is many times lower than the lung tissue dose, it may be relevant for carcinogenic processes 34,35 . Experimental evidence supports that diesel particles induce cancer-relevant processes in the kidneys: diesel exhaust particles induced oxidative stress in cultured human kidney cells 14 and exacerbated renal oxidative stress, inflammation and DNA damage in mice 15 .…”