Leonidas Ntziachristos

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Although the mechanisms of airborne particulate matter (PM) related health effects remain incompletely understood, one emerging hypothesis is that these adverse effects derive from oxidative stress, initiated by the formation of reactive oxygen species (ROS) within affected cells. Typically, ROS are formed in cells through the reduction of oxygen by(More)
This study presents the number, surface and volume concentrations, and size distribution of particles next to the 1-710 freeway during February through April 2006. 1-710 has the highest ratio (up to 25%) of heavy-duty diesel vehicles in the Los Angeles highway network. Particle concentration measurements were accompanied by measurements of black carbon,(More)
UNLABELLED Road transport emissions are a major contributor to ambient particulate matter concentrations and have been associated with adverse health effects. Therefore, these emissions are targeted through increasingly stringent European emission standards. These policies succeed in reducing exhaust emissions, but do not address "nonexhaust" emissions from(More)
Three light-duty vehicles in five different configurations [a Honda Accord operating with diesel with a closed-coupled oxidation catalyst and an underfloor catalyst replaced in some tests with a diesel particle filter (DPF), a Toyota Corolla operating with gasoline, and a VW Golf alternatively operating with petrodiesel or biodiesel] were tested in a(More)
The Dekati mass monitor (OMM) is an instrument which measures the mass concentration of airborne particles in real time by combining aerodynamic and mobility size particle classification. In this study, we evaluate the performance of the DMM by sampling exhaust from five engines and vehicles of different technologies in both steady-state and transient(More)
The link between emissions of vehicular particulate matter (PM) and adverse health effects is well established. However, the influence of new emission control technologies and fuel types on both PM emissions and health effects has been less well investigated. We examined the health impact of PM emissions from two vehicles equipped with or without a diesel(More)
Today in most European member states diesel contains up to 5% vol biodiesel. Since blending is expected to increase to 10% vol, the question arises, how this higher mixing ratio will affect tailpipe emissions particularly those linked to adverse health effects. This paper focuses on the impact of biodiesel on carbonyl compound emissions, attempting also to(More)
Particulate matter (PM) emitted from three light-duty vehicles was studied in terms of its physicochemical and ecotoxicological character using Microtox bioassay tests. A diesel vehicle equipped with an oxidation catalyst emitted PM which consisted of carbon species at over 97%. PM from a diesel vehicle with a particle filter (DPF) consisted of almost equal(More)