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Switzerland

Steiner S.,University of Fribourg | Czerwinski J.,Bern University of Applied Sciences | Comte P.,Bern University of Applied Sciences | Popovicheva O.,Moscow State University | And 7 more authors.
Atmospheric Environment | Year: 2013

Alternative fuels are increasingly combusted in diesel- and gasoline engines and the contribution of such exhausts to the overall air pollution is on the rise. Recent findings on the possible adverse effects of biodiesel exhaust are contradictive, at least partly resulting from the various fuel qualities, engine types and different operation conditions that were tested. However, most of the studies are biased by undesired interactions between the exhaust samples and biological culture media. We here report how complete, freshly produced exhausts from fossil diesel (B0), from a blend of 20% rapeseed-methyl ester (RME) and 80% fossil diesel (B20) and from pure rapeseed methyl ester (B100) affect a complex 3D cellular model of the human airway epithelium invitro by exposing the cells at the air-liquid interface. The induction of pro-apoptotic and necrotic cell death, cellular morphology, oxidative stress, and pro-inflammatory responses were assessed. Compared to B0 exhaust, B20 exhaust decreased oxidative stress and pro-inflammatory responses, whereas B100 exhaust, depending on exposure duration, decreased oxidative stress but increased pro-inflammatory responses. The effects are only very weak and given the compared to fossil diesel higher ecological sustainability of biodiesel, it appears that - at least RME - can be considered a valuable alternative to pure fossil diesel. © 2013 The Authors. Source


Czerwinski J.,Nurnberg University of Applied Sciences | Zimmerli Y.,Nurnberg University of Applied Sciences | Mayer A.,TTM | Heeb N.,Empa - Swiss Federal Laboratories for Materials Science and Technology | D'Urbano G.,Swiss Federal Office for the Environment
SAE Technical Papers | Year: 2011

The most efficient way and the best available technology (BAT) to radically reduce the critical Diesel emission components particles (PM&NP) and nitric oxides (NO x) are combined exhaust gas aftertreatment systems (DPF+SCR). SCR (selective catalytic reduction) is regarded as the most efficient deNO x -system, diesel particle filters are most efficient for soot abatement. Today, several suppliers offer combined systems for retrofitting of HD vehicles. The presented results are part of the work in the international network project VERT *) dePN (de-activation, de-contamination, disposal of particles and NO x), which has the objectives to establish test procedures and quality standards and to introduce the SCR-, or combined DPF+SCR-systems in the VERT verification procedure. Examples of results for some of the investigated systems are given and the most important findings are: the average NO x conversion rate at transient operation strongly depends on the operation load profile, on the exhaust gas temperature and the resulting urea dosing control, the particle number filtration efficiency, which is verified at stationary engine operation, is valid also at the transient operation,secondary nanoparticles are produced due to urea injection, they nevertheless do not impact significantly the overall filtration efficiency of the system (here: DPF upstream & SCR downstream, differences of PCFE in the range of 0.1%), the OEM NO x -sensors of the investigated systems are appropriate tools for the in-use control, the system with catalyzed DPF (upstream) attains higher overall deNO x -efficiencies due to NO 2 -production in the DPF, for the investigated systems there are no critical emissions of unregulated components, NH 3 & N 2 O. Copyright © 2011 SAE International. Source


Steiner S.,University of Fribourg | Czerwinski J.,Bern University of Applied Sciences | Comte P.,Bern University of Applied Sciences | Muller L.L.,University of North Carolina at Chapel Hill | And 4 more authors.
Atmospheric Environment | Year: 2013

Increasingly stringent regulation of particulate matter emissions from diesel vehicles has led to the widespread use of diesel particle filters (DPFs), the effect of which on exhaust toxicity is so far poorly understood. We exposed a cellular model of the human respiratory epithelium at the air-liquid interface to non-catalyzed wall-flow DPF-filtered diesel exhaust and compared the resulting biological responses to the ones observed upon exposure to unfiltered exhaust. Filtered diesel exhaust acted highly oxidative, even though to a lesser extent than unfiltered exhaust (quantification of total reduced glutathione), and both exhaust types triggered comparable responses to oxidative stress (measurement of heme-oxygenase 1 (HMOX1) and superoxide-dismutase (SOD1) gene expression). Further, diesel exhaust filtration significantly reduced pro-inflammatory responses (measurement of tumor necrosis factor (TNF) and interleukin-8 (IL-8) gene expression and quantification of the secretion of their gene products TNF-α and IL-8). Because inflammatory processes are central to the onset of adverse respiratory health effects caused by diesel exhaust inhalation, our results imply that DPFs may make a valuable contribution to the detoxification of diesel vehicle emissions. The induction of significant oxidative stress by filtered diesel exhaust however, also implies that the non-particulate exhaust components also need to be considered for lung cell risk assessment. © 2013 The Authors. Source


Mayer A.C.,TTM | Ulrich A.,Empa - Swiss Federal Laboratories for Materials Science and Technology | Czerwinski J.,University of Applied Sciences and Arts Western Switzerland | Mooney J.J.,LLC LLC
SAE Technical Papers | Year: 2010

Concern for engine particle emission led to EC-regulations of the number of solid particles emitted by LDV and HDV. However, all conventional piston-driven combustion engines emit metal oxide particles of which only little is known. The main sources are abrasion between piston-ring and cylinder, abrasion of bearing, cams and valves, catalyst coatings, metal-organic lubrication oil additives, and fuel additives. While abrasion usually generates particles in the μm-range, high concentrations of nanosize metal oxide particles are also observed, probably resulting from nucleation processes during combustion. In general, metal oxides, especially from transition metals, have high surface reactivity and can therefore be very toxic, especially nanosize particles, which evidently provide a high specific bioactive surface and are suspected to penetrate into the organism. Hence, these particles must be scrutinized for quantity, size distribution and composition. Published data are summarized and data from investigations of various engines with respect to metal oxide particle emission are reported. These investigations were performed without and with VERT approved particle filters, where VERT is an international verification standard for emission reduction technologies, which, besides of filtration effectiveness, durability and limited pollutants also includes the analysis of secondary emissions, potentially formed by these technologies and of size specific metal emissions. In good agreement with literature, the overall metal mass in the exhaust of IC-engines without particle filter is in the range of 0.1-1 mg/km metal. This combines wear metals and metals from lubrication oil additives. Size specific chemical analysis has shown that a large part of metal oxide particles are to be found in the size classes below 60 nm. However there are more metal oxide particles in the exhaust attached to soot particles of larger size, as chemical analysis also revealed. If there are less soot particles prevalent, like at idle conditions some of them do appear unattached in a separate fraction of much smaller size. SMPS particle size distribution at idle shows peaks of up to 10 8 particles per cc in the size range of 10-30 nm. It must be assumed that these are all metal oxide particles since PMP sampling was applied which means that these particles survived 300 °C and thus can not be volatiles.This high number of solid metal oxide particles implies a potential health risk. Hence, there is a need to further focus on small metal oxide particle emissions. For Diesel engines, industry has demonstrated that particle filters are available which can very efficiently filter those nanoparticles. There is little known about metal oxide emissions of other engines but it must be anticipated that all IC piston engines do emit such particles. Elimination of such metal oxide particles by highly efficient filtration therefore might become an urgent future requirement for all engine categories. Copyright © 2010 SAE International. Source


Mayer A.,TTM | Czerwinski J.,University of Applied science Biel Bienne | Kasper M.,Matter Aerosol AG | Ulrich A.,Empa - Swiss Federal Laboratories for Materials Science and Technology | Mooney J.J.,John J. Mooney LLC
SAE Technical Papers | Year: 2012

All internal combustion piston engines emit solid nanoparticles. Some are soot particles resulting from incomplete combustion of fuels, or lube oil. Some particles are metal compounds, most probably metal oxides. A major source of metal compound particles is engine abrasion. The lube oil transports these abraded particles into the combustion zone. There they are partially vaporized and ultrafine oxide particles formed through nucleation [1]. Other sources are the metallic additives to the lube oil, metallic additives in the fuel, and debris from the catalytic coatings in the exhaust-gas emission control devices. The formation process results in extremely fine particles, typically smaller than 50 nm. Thus they intrude through the alveolar membranes directly into the human organism. The consequent health risk necessitates a careful investigation of these emissions and effective curtailment. Substantial information is available on diesel engine particulate emissions [2, 3, 4] but less for SI engines. Beside an example of metal oxide particles from a diesel engine, the present paper shows preliminary results of nanoparticles emissions of SI engines. Four SI engines were investigated: two older and two newer engines, comprising two car engines and two motorbikes. The tests were done on standard transient driving cycles, and steady-state at constant 50 km/h and idling. Prior investigations observed, especially during idling, high concentrations of metal oxide particles [2]. All tests were done with particle samples collected from the CVS tunnel, during a long operating period, to have sufficient material for analyzing the composition. At the steady-state points, the particle size spectra were measured. The results show that the older SI engines emit high concentrations of soot particles and metal oxide (= ash) particles. The size distribution is decisively bimodal for both soot and ash particles. The newer engines' emission results are less uniform and the concentrations lower, as expected. Altogether, the concentrations of these metal oxide particles are so high, that more detailed investigations are recommended. Copyright © 2012 SAE International. Source

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