Andreas Mayer's research while affiliated with Universität Bern and other places
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Publications (73)
div class="section abstract"> Ultrafine particles, in particular solid sub-100 nm particles pose high risks to human health due to their high lung deposition efficiency, translocation to all organs including the brain and their harmful chemical composition; due to dense traffic, the population in urban environments is exposed to high concentrations...
The knowledge about nanoaerosols, their potential health effects, their measurement, limitation and administrative-legal treatment has been developed in the last 3 decades in connection with the exhaust gas cleaning of the combustion engines. Nanofiltration, which has thus become known, almost completely eliminates nanoparticles with filters of hig...
A substantial amount of traffic-related particle emissions is released by gasoline cars, since most diesel cars are now equipped with particle filters that reduce particle emissions. Little is known about adverse health effects of gasoline particles, and particularly, whether a gasoline particle filter (GPF) influences the toxicity of gasoline exha...
In the present paper, some results of investigations of nanoparticles from four MPI gasoline cars are represented. The measurements were performed at vehicle tailpipe and in CVS-tunnel. Moreover, two variants of GPF were investigated on a high-emitting modern vehicle, including analytics of PAH. The modern MPI vehicles can emit a considerable amoun...
Adverse effect studies of gasoline exhaust are scarce, even though gasoline direct injection (GDI) vehicles can emit a high number of particles.
The aim of this study was to conduct an in vitro hazard assessment of different GDI exhausts using two different cell culture models mimicking the human airway. In addition to gasoline particle filters (GP...
Retrofitting older vehicles with diesel particulate filter (DPF) is a cost-effective measure to quickly and efficiently reduce particulate matter emissions. This study experimentally analyzes real-world performance of buses retrofitted with CRT DPFs. 18 in-use Euro III technology urban and intercity buses were investigated for a period of 12. month...
Air pollution exposure, including passenger car emissions, may cause substantial respiratory health effects and cancer death. In western countries, the majority of passenger cars are driven by gasoline fuel. Recently, new motor technologies and ethanol fuels have been introduced to the market, but potential health effects have not been thoroughly i...
Seit den Vierzigerjahren des 20. Jahrhunderts gibt es in Kalifornien systematische Bestrebungen, die Auswirkungen auf die Luftqualität durch die Massenmotorisierung zu reduzieren. In Europa erregte der Verkehr in den Sechzigerjahren durch die für den Menschen unmittelbar schädliche Kohlenmonoxidemission Aufmerksamkeit. Daraus ergab sich eine Begren...
Ethanol can be produced from biomass and as such is renewable, unlike petroleum-based fuel. Almost all gasoline cars can drive with fuel containing 10% ethanol (E10), flex-fuel cars can even use 85% ethanol (E85). Brazil and the USA already include 10–27% ethanol in their standard fuel by law. Most health effect studies on car emissions are however...
As a result of increased use of catalytic exhaust aftertreatment systems of vehicles and the low-sulfur Diesel fuels there is an increasing share of nitrogen dioxide NO2 in the ambient air of several cities. This is in spite of lowering the summary nitric oxides NOx emissions from vehicles. NO2 is much more toxic than nitrogen monoxide NO and it wi...
Iron-catalyzed diesel particle filters (DPFs) are widely used for particle abatement. Active catalyst particles, so-called fuel-borne catalysts (FBCs), are formed in situ, in the engine, when combusting precursors, which were premixed with the fuel. The obtained iron oxide particles catalyze soot oxidation in filters. Iron-catalyzed DPFs are consid...
Exhaust aerosol from gasoline passenger cars is a complex mixture of a particulate fraction as well as volatile compounds. In contrary to the observed adverse effects of diesel exhaust particles the gasoline exhaust has, however, received little attention so far. The aim of this study was to perform a comparison of exhaust composition and biologica...
The present paper informs about some results obtained with selective catalytic reduction (SCR) and with SDPF (a diesel particle filter (DPF) with SCR coating) on a medium duty research engine Iveco F1C. This work is a first attempt at evaluating the effects of a SDPF on non-legislated gaseous emissions and on secondary nanoparticles. Beside the lim...
The invisible nanoparticles (NP)∗) from combustion processes penetrate easily into the human body through the respiratory and olfactory pathways and carry numerous harmful health effects potentials. NP count concentrations are limited in EU for Diesel passenger cars since 2013 and for gasoline cars with direct injection (GDI) since 2014. The limit...
Diesel exhaust gas aftertreatment systems, which include the selective catalytic reduction (SCR)) for reduction of NOx are necessary to fulfil the latest legal requirements and are extensively used in the heavy duty (HD) sector. The present paper informs about some results obtained with SCR and with SDPF (a DPF with SCR-coating) on a medium duty re...
Nanoparticles from a HD-Diesel engine and their composition were investigated in the present paper. Three variants of fuel additivities were applied to allow the balances of certain tracer-substances after the tests: 2% of additives-free lube oil; 2% of market lube oil with additive package and Fe-based regeneration additive (FBC) with 40 ppm Fe. T...
Nanoparticle emissions of two 2-stroke scooters were investigated along the exhaust- and CVS-system (Constant Volume Sampling) with closed and with open line (cone). Due to their technology, the scooters produce different kind of aerosol (state of oxidation & SOF-content) and in addition to that they were operated with and without oxidation catalys...
The progressing exhaust gas legislation for on- and off-road vehicles includes gradually the nanoparticle count limits. The invisible nanoparticles from different emission sources penetrate like a gas into the living organisms and may cause several health hazards. The present paper shows some results of a modern chain saw with & without oxidation c...
Starting from Euro 6 not only for diesel but also for gasoline vehicles, with direct injection technology (GDI) a solid particle number emissions limit of 6 × 1011 #/km becomes effective. The limit was temporary extended for GDI to 6 x 1012 #/km. Nuclei of metals as well as organics are suspected to significantly contribute especially to the ultraf...
Metal-containing fuel additives catalyzing soot combustion in diesel particle filters are used in a widespread manner, and with the growing popularity of diesel vehicles, their application is expected to increase in the near future. Detailed investigation into how such additives affect exhaust toxicity is therefore necessary and has to be performed...
With the growing number of new exhaust after-treatment systems, fuels and fuel additives for internal combustion engines, efficient and reliable methods for detecting exhaust genotoxicity and mutagenicity are needed in order to avoid the widespread application of technologies with undesirable effects towards public health. In a commonly used approa...
The combined exhaust gas aftertreatment systems (DPF+SCR) are the most efficient way and the best available technology (BAT) to radically reduce the critical Diesel emission components particles (PM&NP) and nitric oxides (NOx). SCR (selective catalytic reduction) is regarded as the most efficient deNOx-system, diesel particle filters are most effic...
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-filter...
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 condit...
Catalytic diesel particle filters (DPFs) have evolved to a powerful environmental technology. Several metal-based, fuel soluble catalysts, so-called fuel-borne catalysts (FBCs), were developed to catalyze soot combustion and support filter regeneration. Mainly iron- and cerium-based FBCs have been commercialized for passenger cars and heavy-duty ve...
The use of alternative fuels and among them the biofuels of 1st generation - fatty acid methyl esters FAME's*) and pure plants oils - for propulsion of IC engines is an important objective in several countries in order to save the fossil fuels and to limit the CO2-production. The properties of bio-fuels and bio-blend-fuels can vary and this has an...
The impact of a combined diesel particle filter-deNO(x) system (DPN) on emissions of reactive nitrogen compounds (RNCs) was studied varying the urea feed factor (α), temperature, and residence time, which are key parameters of the deNO(x) process. The DPN consisted of a platinum-coated cordierite filter and a vanadia-based deNO(x) catalyst supporti...
The aim of this study was to compare the biological response of a sophisticated in vitro 3D co-culture model of the epithelial airway barrier to a co-exposure of CeO(2) NPs and diesel exhaust using a realistic air-liquid exposure system. Independent of the individual effects of either diesel exhaust or CeO(2) NPs investigation observed that a combi...
NO2 is much more toxic than NO. Due to the use of oxidation catalysts and catalytic coatings in the exhaust gas systems in the last decades and due to the use of low sulphur fuels the average NO2-portion in exhaust gases of vehicles increases. Diesel oxidation catalysts (DOC) and Pt-containing DPF-coatings are generally used to support the regenera...
The fatty acid methyl esters (FAME's)-in Europe mostly RME (Rapeseed methyl ester)-are used in several countries as alternative biogene Diesel fuels in various blending ratios with fossil fuels (Bxx). Questions often arise about the influences of these biocomponents on the modern exhaust aftertreatment systems and especially on the regeneration of...
During the first decade of Diesel particle filter development and deployment in cars, trucks, buses and underground sites, DPF regeneration methods were engineered to be compatible with the then prevalent high sulfur content in the fuel > 2000 ppm. The mainly used methods were burners, electrical heaters, replaceable filters and non-precious metal...
The objectives of the present work are to investigate the regulated and unregulated (particle) emissions of a classical and modern 2-stroke and a typical 4-stroke scooter with different ethanol blend fuels. There is also comparison of two different ethanol fuels: pure ethanol (E) and hydrous ethanol (EH) which contains 3.9% water and is denatured w...
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 effici...
During the first decade of Diesel particle filter development and deployment in cars, trucks, buses and underground sites, DPF regeneration methods were engineered that were compatible with the then prevalent high sulfur content in the fuel > 2000 ppm. The mainly used methods were burners, electrical heaters, replaceable filters and non-precious me...
All conventional piston-driven combustion engines emit metal oxide particles. The main sources are the abrasion between piston-ring and cylinder, abrasion in the bearings, catalyst coating, lube-oil additives, and fuel additives for promoting the exhaust-gas after-treatment. Metal oxides, especially from transition metals, are very toxic when they...
The objectives of the present work are to investigate the regulated and unregulated (particle) emissions of a classical and modern 2-stroke and a typical 4-stroke scooter with different ethanol blend fuels. There is also comparison of two different ethanol fuels: pure ethanol (E) and hydrous ethanol (EH) which contains 3.9% water and is denatured w...
All internal combustion piston engines emit nanoparticles. Part of them are soot particles as a results of incomplete combustion of fuels, or lube oil. Another part are metal particles, most probably oxides, commonly called ash. A major source of metal particles is engine wear and corrosion. The lube oil reentraines these abraded particles into the...
The aim of this study was to compare the cytotoxicity and the (pro-)inflammatory responses of two-stroke (direct injection and carburetor technology) and four-stroke scooter and diesel car exhaust emissions on lung cells in vitro. This was analyzed by exposing a 3D in vitro model of the epithelial airway (consisting of human bronchial epithelial ce...
We would like to comment on the article by Cho et al. (2009), which was published in the November 2009 issue of Environmental Health Perspectives (EHP). We read the paper with great interest because the size-dependent effects of particulate matter are very important but have not yet been definitively clarified. In reporting the size-dependent effec...
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 coatin...
A constantly growing number of scooters produce an increasing amount of potentially harmful emissions. Due to their engine technology, two-stroke scooters emit huge amounts of adverse substances, which can induce adverse pulmonary and cardiovascular health effects. The aim of this study was to develop a system to expose a characterized triple cell...
Diesel exhaust contains several genotoxic compounds that may or may not penetrate diesel particulate filters (DPFs). Furthermore, the DPF-supported combustion of soot and adsorbed compounds may lead to the formation of additional pollutants. Herein, we compare the impact of 14 different DPFs on emissions of known genotoxic compounds. During a four...
The combined Diesel exhaust gas aftertreatment systems (DPF+SCR) *) are today a best available technology (BAT) to radically reduce the critical Diesel emission components particles (PM&NP) and nitric oxides (NOx). SCR (selective catalytic reduction) is regarded as the most efficient deNOx-system. The combined systems are already offered today by s...
Four of these Particulate Reduction Systems (PMS) were tested on a passenger car and one of them on a HDV. Expectation of the research team was that they would reach at least a PM-reduction of 30% under all realistic operating conditions. The standard German filter test procedure for PMS was performed but moreover, the response to various operating...
Zur Prüfung von Partikelfiltern für die Nachrüstung von Dieselmotoren müssen neue Wege beschritten werden. Unter Berücksichtigung der gesundheitlichen Wirkungen der Partikel sowie der physikalischen und chemischen Eigenschaften von Partikelfiltern ergibt sich als optimale Lösung die Prüfung der Komponente selbst, getrennt von der Anwendung. Das gew...
Diesel particulate filters (DPFs) are a promising technology to detoxify diesel exhaust. However, the secondary combustion of diesel soot and associated compounds may also induce the formation of new pollutants. Diesel soot is rated as carcinogenic to humans and also acts as a carrier for a variety of genotoxic compounds such as certain polycyclic...
A filter system is presented which allows the reduction of the concentration of ultrafine particles in vehicle cabins to very low levels. The original ventilation system is switched to the recirculation mode and all cabin intake air is supplied via a retrofitted filter system. Tests with a variety of different vehicles (from passenger cars to coach...
Potential risks of a secondary formation of polychlorinated dibenzodioxins/furans (PCDD/Fs) were assessed for two cordierite-based, wall-through diesel particulate filters (DPFs) for which soot combustion was either catalyzed with an iron- or a copper-based fuel additive. A heavy duty diesel engine was used as test platform, applying the eight-stag...
Limited and nonlimited emissions of scooters were analyzed during several annual research programs of the Swiss Agency of Environment Forests and Landscape (SAEFL, BUWAL). Small scooters, which are very much used in the congested centers of several cities are a remarkable source of air pollution. Therefore every effort to reduce the emissions is an...
In the paper the activities on reduction of Particle Mater emission of city busses in public transportation in City of Biel (Switzerland) were discussed. Following objectives were pursued in the 4 years project: clearing up of the usefulness of water-emulsion fuel, of exhaust gas emissions of busses before and after DPF retrofit, of efficiency of f...
The Swiss 1998 Ordinance on Air Pollution Control (OAPC) mandates curtailment of carcinogenic Diesel particle emissions at construction sites (4). In addition particle traps are compulsory at underground workplaces (3). In compliance, more than 6,000 Diesel engines were retrofitted with different particle trap systems. Many traps surpassed 99% filt...
A filter system is presented which allows the reduction of the concentration of ultrafine particles in vehicle cabins to very low levels. The original ventilation system is switched to the recirculation mode and all cabin intake air is supplied via a retrofitted filter system. Tests with a variety of different vehicles (from passenger cars to coach...
Citations
... In order to address these questions, and cover this gap in the literature, in this study we compare two identical CPCs in both single and photometric counting modes with different materials (graphite, silver) and different sizes. The results of this study are not useful only for vehicle exhaust emission measurements [17][18][19], but any other aerosol measurement field (e.g. nanomaterials, ambient air, work exposure) [20,21]. ...
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... This is mostly combined with legal requirements which currently specify the obligatory to control the level of particles emitted of diameter (23 nm -10 µm). Nowadays, due to the minute size of NPs, research on automotive generated particles is focused on the development of methods enabling the characterization of NPs in terms of their physical and chemical properties [10,11]. Nanoparticles which are the part of the nucleation mode are the subject a great attention of scientists and engine designers, mainly due to their strong impact on human health [12]. ...
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... The following figures show the wind tunnel-like test facility (Fig. 5, 6), sample collection through gelatine filters (Fig. 7), and sample counting the plaques before and after filters (Fig. 8). The equipment and the procedure are described in detail in [28]. Example of result is given in Fig. 9, which illustrates a calculated filtration of > 99.99%. ...
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... The detailed measurement of metallic nanoparticle emission is difficult and expensive. For example, according to [75], online particle analysis can be performed with the Scanning Mobility Particle Sizer (SMPS). Size fractionated chemical analysis of nanoparticles in vehicle emissions were carried out by sampling with an electrical low-pressure multistage impactor ELPI with subsequent acid digestion in a microwave system and chemical analysis with plasma mass spectrometry ICPMS. ...
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... Although the principle of operation of these components is similar, due to the development of manufacturing technology and the use of different construction materials, they may have been responsible for different levels of emission of toxic compounds. As is well known, many construction materials are responsible for the emission of volatile organic compounds [18,43]; whereas, the use of precious metal catalytic layers is responsible for the emission of harmful by-products, including nitrogen dioxide, sulphates or ammonia [21,[44][45][46][47][48]. In the study, the probability of cell death due to external factors (stress, physical, mechanical) was minimised. ...
... Although the principle of operation of these components is similar, due to the development of manufacturing technology and the use of different construction materials, they may have been responsible for different levels of emission of toxic compounds. As is well known, many construction materials are responsible for the emission of volatile organic compounds [18,43]; whereas, the use of precious metal catalytic layers is responsible for the emission of harmful by-products, including nitrogen dioxide, sulphates or ammonia [21,[44][45][46][47][48]. In the study, the probability of cell death due to external factors (stress, physical, mechanical) was minimised. ...
... Efficiency is referred as the ability to reduce the number of particles. The backpressure increase usually leads to fuel consumption elevation, poor engine performance, and even causes serious damages of the engine (Czerwinski et al., 2017); (Van Nieuwstadt and Ulrey, 2017). The GPF should be strong enough to withstand external forces and high temperature influence on the distance above 160 000 kilometres (European Commission, 2018;Tanaka et al., 2018). ...
... Concluding the results of this study showed a limited potential of the fuel line retrofit devices. Urea (ammonia) based systems, which seem the only promising technologies [14] need case by case assessment [15]. The durability of such systems should also be assessed [16] ...
... Another study [19] proposed the 'Q NOx ratio' method that consists of evaluating the ratio between CO 2 and NOx emissions (g CO2 /g NOx )-normalized emission-at the tailpipe based on NOx data On-Board Diagnostic (OBD) vehicle systems. In [20], the authors proposed a 'load jump' method to properly evaluate the SCR system efficiency at PTI tests and presents the results on three Diesel Euro 6b passenger cars. The procedure requires warming-up the vehicle and performing a cool-down in idling (negative load jump), with simultaneous NOx measurements at the vehicle tailpipe. ...
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... It's crucial to ensure the initial GPF's status when conducting GPFrelated tests, but to our knowledge, no standard method is available to pre-condition the GPF before the tests and to check the filter status. Heeb et al. (2018) weighed the GPF periodically to check the GPF status, but this method might suffer large uncertainty and the reason is similar to that reported in Ref. (Giechaskiel et al., 2014b). Besides, during the reassembling of the GPF, it might suffer some wear, which will also increase the weighing uncertainty. ...
