Oliver F. Bischof- Doctor of Engineering
- Senior Director EMEA at TSI Inc.
Oliver F. Bischof
- Doctor of Engineering
- Senior Director EMEA at TSI Inc.
About
71
Publications
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Introduction
I’m a director at TSI and as such involved in several research projects as (ass.) partner. After completing my PhD at FZ Jülich and RWTH Aachen, I’m still an external researcher at the ICE-3 institute in Jülich.
I was a member of the supervisory board and the External Advisory Committee during three CLOUD projects at CERN. I served four times on the Board of "Gesellschaft für Aerosolforschung" (GAeF), most recently from 2016 to 2018. My biggest honor was the NOSA Aerosologist Award in 2009.
Current institution
Additional affiliations
Education
January 2017 - December 2021
September 2010 - August 2012
February 1993 - December 1993
Publications
Publications (71)
This study provides insights into the performance of a new nano-water-based condensation particle counter (N-WCPC, TSI 3788) and presents a comparison to the well-established butanolbased ultrafine CPC (UCPC, TSI 3776). The suitability of the N-WCPC to measure ambient airborne nanoparticles of various compositions has been assessed with an urban ba...
An increasing number of studies are focusing on the detection and investigation of nanometer-sized particles. One important tool is the Scanning Mobility Particle Sizer (SMPS). In the case of dynamic processes like nucleation events, the lower detection threshold as well as the measurement time are important system parameters. High accuracy of the...
The combination of modern engine technologies, efficient aftertreatment and tighter emission standards resulted in drastically lower particulate emission levels in Europe today. The conventional methods defined to test particulate emissions fail at such low levels as they are aimed at determining the mass of the particles collected on a filter (PM)...
Aerodynamic particle size spectrometers are a well-established method to measure number size distributions of coarse mode particles in the atmosphere. Quality assurance is essential for atmospheric observational aerosol networks to obtain comparable results with known uncertainties. In a laboratory study within the framework of ACTRIS (Aerosols, Cl...
Abstract: Condensation Particle Counters (CPC) are research instruments that are commonly used to measure fine, airborne particles. They are able to determine the particle number concentration of both, the smallest nanoparticles and also larger particles in the accumulation mode, which cannot be measured with optical methods at all or with sufficie...
Characterization of five Differential Mobility Analyzers to Optimize the Yield for Nanoparticle Production
We present an experimental study that compares the transfer function of five different DMAs with the aim to provide a decision matrix that helps to choose the right DMA and the right settings to get the optimal yield for a requested set of ae...
Aerosol particle number concentration measurements are a crucial part of aerosol research. Vertical profile measurements and high-altitude/low-pressure performance of the respective instruments become more important for remote sensing validation and a vital tool for the observation of climate variables. This study tests the new, commercially availa...
The working fluid of a condensation particle counter (CPC) is one of its essential characteristics. Butanol is commonly used as the working fluid in alcohol-based CPCs due to its proven performance for various applications and for a wide range of working conditions over the past almost 5 decades. At the same time, butanol has several disadvantages,...
The working fluid of a condensation particle counter (CPC) is one of its essential characteristics. Butanol is commonly used as the working fluid in alcohol-based CPCs due to its proven performance in various applications and a wide range of working conditions over the past almost five decades. At the same time, butanol has several disadvantages in...
Aerosol particle number concentration measurements are a crucial part of aerosol research. Vertical profile measurements and high-altitude/low pressure performance of the respective instruments become more and more important for remote sensing validation and as a key tool for the observation of climate variables. This study tests the new, commercia...
Aerosol intensive optical properties, including Ångström exponents for aerosol light extinction (EAEs), scattering (SAEs) and absorption (AAEs) as well as and the single-scattering albedo (SSA), are indicators for aerosol size, chemical composition, radiative behaviour and particle sources. Derivation of these parameters requires the measurement of...
Aerosol intensive optical properties like the Ångström exponents for aerosol light extinction, scattering and absorption, or the single-scattering albedo are indicators for aerosol size distributions, chemical composition and radiative behaviour and contain also source information. The observation of these parameters requires the measurement of aer...
Indoor particulate matter (PM) emissions generated by two of the main indoor activities which are cooking and heating using electrical devices were investigated. The total number concentration and the size distributions were measured and the impact of the technology design of the electrical appliances on the indoor PM emission was emphasized. The r...
Shadowgraphy, a nonintrusive in-situ approach for imaging, detecting and tracking moving particles in a flow, was combined with sampling techniques for characterizing droplets generated by a hand sprayer in a chamber. The spray was imaged at 4kHz (4000 images per second) allowing a fine and time resolved description of the dynamic of the droplets f...
Air quality inside a residential apartment has been investigated by measuring the PM emission generated from cooking and ironing using electrical devices. The samples were collected in the kitchen, the living room and the bedroom. The total number concentration, the size distributions and mass concentration PM0.1, PM2.5 and PM10 were measured using...
Soot generators are able to produce carbonaceous nanoparticles purposefully and can therefore play a vital role in the calibration of particle instruments with an actual combustion aerosol. Condensation particle counters (CPCs) have become the instrument of choice for legislative measurements of the particle number (PN) concentration. The Euro 5B s...
The paper is devoted the standard CEN/TS 16976 described a standardized measuring method with number concentration of UFP. As well as, described TSI 3750-CEN CPC which meet all of these requirements.
Soot generators are able to produce carbonaceous nanoparticles purposefully and can therefore play a vital role in the calibration of particle instruments with an actual combustion aerosol. Condensation particle counters (CPCs) have become the instrument of choice for legislative measurements of the particle number (PN) concentration. The Euro 5B s...
Exposure to different types of dust and other workplace aerosols can result in adverse health effects including occupational lung diseases, cancer, irritation and inflammatory lung injuries, allergic responses, infection, and effects on the skin (WHO, 1999; Peters et al., 2013). In many cases cascade impactors are used to collect size-fractionated...
Multiple wavelengths measurement of optical properties to characterise aerosol physical and chemical parameters
Experiments designed as optical closure study using purely light scattering aerosols and a set of predominantly light absorbing aerosols
Evaluation of CAPSssa Monitor (Aerodyne Research Inc., USA) to measure extinctions and scattering coe...
The particle size distribution of urban aerosols is typically dominated by ultrafine particles (UFP) originating from local sources such as traffic and industrial emissions. Due to their negligible mass they are clearly underrepresented by legislative PM10 mass measurements. This is one reason why their contribution to urban air quality is better c...
The validity of data obtained with particle counters and sizers depends on their accurate calibration against a known standard that typically is provided by the manufacturer. However, normal use of an instrument may affect the calibration over time, for instance through contamination or drift of sensors controlling the device. The recommended time...
Currently the main pollution comes from the anthropogenic sources related to residential heating and combustion. Most of the emitted particles from this sources are in the mode below 1 μm. Therefore, only by using methods based on the electric mobility separation and size enhancement we can measure the size and concentration of this particles from...
Diurnal variations of vertical profiles for number-size distributions and concentrations of aerosol nanoparticles in planetary boundary layer were measured and evaluated from ground and airborne measurement. One minute integrates of the aerosol distributions by NanoScan spectrometer positioned in an unmanned airship were compared with five minute d...
Nucleation and new particle formation (NPF) events can make a significant contribution to particle number concentrations in remote locations (Kulmala and Kerminen, 2008) as well as urban locations (e.g. Brines et. al., 2015). While the remote NPF events have been subject to observations for years and are quite well understood, urban NPF still needs...
CEN/TS 16976 harmonizes the continuous atmospheric measurements of UFPs by defining requirements for CPC, its sampling system, the measurement procedure and result reporting. This is an important step forward for routine monitoring networks (e.g. GUAN, NABEL, DEFRA) and for evaluation of abatement techniques e.g. low emission zones. TSI released a...
The TSI DustTrak Aerosol Monitor is a portable real-time instrument widely used for particulate matter (PM) mass concentrations monitoring. The aim of this work is to report on issues that have arisen from the use of the latest generation models DustTrak DRX (8533 and 8534) in the BREATHE, UPTECH and IMPROVE projects that can compromise data qualit...
A new real-time, near reference ambient aerosol monitoring instrument using light scattering photometric technology to measure the PM fraction is introduced: Environmental DustTrak (TSI Inc.).
Many aerosol sources of interest, like combustion, cigarette smoke, emission form nanoparticle production, cabin air in vehicles consist of particles in the size range from 10 nm to well above 1 μm. Mass limits of PM 2.5 and PM 10 demand measurement of particle size up to 2.5 μm or 10 μm, respectively. A key parameter for the source characterizatio...
Drastically lower particle emissions from the tailpipe due to modern engine technologies and efficient aftertreatment (e.g. DPFs) have led to monitoring particle number (PN) in addition to monitoring the mass of particles collected on a filter (PM). The Particulate Measurement Programme (PMP) introduced PN measurements with a condensation particle...
The Engine Exhaust Particle Sizer™ spectrometer (EEPS, Model 3090, TSI Inc.) is widely used to measure the size distribution of fast changing exhaust particles at ambient pressure in engine research and development. It can provide particle size, number and mass at different locations in the combustion process. The EEPS records particle size distrib...
The assessment of workplaces regarding emissions and human exposure to aerosols is challenging and ideally requires field-portable and suitably sensitive instruments. Particle mass measurements are often used for reference but in the nanometer range the comprehensive characterization of aerosols by their number concentration and size distribution h...
Particle size distribution measurements with Scanning Mobility Particle Sizers (SMPS) starting from 1 nm in diameter are highly demanded in science and industry for applications like gas to particle conversion, engineered nanoparticle synthesis, particle nucleation and growth, and combustion emissions research. By use of diethylene glycol (DEG) as...
Aerodynamic particle size spectrometers are a well-established
method to measure number size distributions of coarse mode particles
in the atmosphere. Quality assurance is essential for atmospheric
observational aerosol networks to obtain comparable results with
known uncertainties. In a laboratory study within the framework of
ACTRIS (Aerosols, Cl...
REDMAAS (Red Española de DMAs Ambientales), the Spanish network of environmental Differential Mobility Analyzers (DMAs), currently consists of six research groups involved in the measurement of atmospheric aerosol size distributions by means of DMAs. The aim of this network is to guarantee the good quality and comparability of the routine measureme...
The Nanoparticle Emission Tester (NPET) is well suited for in-use conformity and maintenance testing of diesel-powered, non-road mobile machinery (NRMM) as well as vehicle inspection and maintenance programs. It can reliably determine if the installed DPF is working properly or if it is damaged and needs to be replaced. This can be used as a quick...
Electrical mobility classification (EC) followed by Condensation Particle Counter (CPC) detection is the technique combined in Scanning Mobility Particle Sizers (SMPS) to retrieve nanoparticle size distributions in the range from 2.5 nm to 1 µm. The detectable size range of SMPS systems can be extended by the addition of an Optical Particle Sizer (...
The generation of aerosols containing sufficient concentrations of well-defined nanoparticles from salts, polymers, core-shell and virus like materials, vaccines or proteins is needed in various fields of in-vivo and in-vitro toxicology. We present a new Electrospray Aerosol Generator (EAG, TSI model 3482) that was designed for ease of use and stab...
Electrical mobility classification (EC) followed by Condensation Particle Counter (CPC) detection is the technique combined in Scanning Mobility Particle Sizers (SMPS) to retrieve nanoparticle size distributions in the range from 2.5 nm to 1 µm. The detectable size range of SMPS systems can be extended by the addition of an Optical Particle Sizer (...
The combination of modern engine technologies, efficient aftertreatment and tighter emission standards has led to drastically lower particle emission levels in Europe today. For example, the current Euro 6 standard for heavy duty engines resulted in a 90% reduction of particulates compared to earlier standards. Yet conventional test methods aimed a...
The Measurement of particle number and size distributions based on the Scanning Mobility Particle Sizer (SMPS) technique (Knutson & Whitby, 1975; Wang & Flagan 1990) are widely used and the method of choice in the size range from about 1 nm to 1 μm. In the SMPS, particles are first conditioned, charged and subsequently selected in a Differential Mo...
La technique utilisée pour la mesure du nombre de particules et de la distribution en taille avec le granulomètre (SMPS) de mobilité électrique séquentiel (Knutson and Whitby 1975; Wang and Flagan 1990) est très largement répandue et est devenue le choix principal dans la gamme de taille de 1nm à 1µm. Après une étape de conditionnement, les particu...
Nanoparticles are ubiquitous in both outdoor and indoor environments due to a large variety of natural and anthropogenic sources. Key parameters for characterizing nanoparticles include their size distribution and number concentration. A novel, portable and compact nanoparticle sizing instrument, the NanoScan SMPS, has been designed for application...
A novel instrument, the NanoScan SMPS (TSI 3910), is introduced here that provides the capability of employing well-established Scanning Mobility Particle Sizing (SMPS) technology in a format that can be easily utilized in the field. The use of a non-radioactive unipolar charger, radial Differential Mobility Analyzer (rDMA) and
isopropanol-based Co...
Aerosol Science and Technology: History and Reviews captures an exciting slice of history in the evolution of aerosol science. It presents in-depth biographies of four leading international aerosol researchers and highlights pivotal research institutions in New York, Minnesota, and Austria. One collection of chapters reflects on the legacy of the P...
Optical Particle Counters are in widespread use for measuring various aerosols including environmental monitoring. Since almost all optical particle counters and spectrometers are factory-calibrated with polystyrene latex (PSL) particles, sizing errors could be significant if the refractive indices of the aerosol are significantly different from th...
Real-time measurement of the size distribution of particles in engine exhaust emissions is used by engine manufacturers to optimize engines with regard to emissions, by automotive suppliers to develop efficient exhaust aftertreatment systems, and by scientists and legislators to assess the effect of engine exhaust on air quality and possible advers...
In order for the growing significance of nanotechnology to be addressed by occupational safety and health as well as from other aspects, workplace exposure to nanoparticles must be determined and examined. The quantity of measurement most frequently employed for nanoparticles is the particle number concentration. Seven contributions by six manufact...
Growing interest in the effects of ultrafine particles (UFP) on air quality, climate change, and human health has driven the need for reliable and accurate ultrafine particle quantification. A significant portion of the particles in ambient air is in the ultrafine size range, originating from vehicle emissions or formed from gas phase organic compo...
In order for the growing significance of nanotechnology to be addressed by occupational safety and health as well as from other aspects, workplace exposure to nanoparticles must be determined and
examined. The quantity of measurement most frequently employed for nanoparticles is the particle number concentration. Seven contributions by six manufact...
The UNECE GRPE Particle Measurement Programme (PMP) recommended that a Particle Number Counter (PNC) shall be used to measure the particle number (PN) concentration of diesel exhaust emissions to complement mass-based measurements (GRPE-PMP-17-1). Following this recommendation, the European Commission proposed to add a PN limit value to its Euro 5...
Continuous-flow, thermally diffusive condensation particle counters (CPC’s) that use n-butyl alcohol (butanol) as their working fluid have been used to measure aerosol particles for more than 30 years. A new, completely redesigned general-purpose butanol CPC was developed at the end of 2005. Just one year prior to that a continuous, laminar-flow wa...
In this study calibration measurements of new TSI condensation particle counter models, using either butanol or water as working fluid, are described. Experiments were carried our at ambient, laboratory conditions for two particle materials, silver and sodium chloride. The obtained counting efficiency curves are presented.
The benefits of sizing aerosolized submicrometer particles using an electrical mobility sizing technique have been well documented. This type of analytical tool has been found to be able to measure particle diameter with an uncertainty of only 0.1% [1]. The National Institute of Standards and Technology (NIST) have been using electrical mobility to...
Condensation particle counters (CPCs) are well suited to measure the number concentration of small airborne particles. Continuous-flow, thermally diffusive CPCs that utilize n-butyl alcohol (butanol) as the condensing vapour have been developed in the late 1970s (Bricard et al., 1976). The first commercial model of this type, the CNC 3020 (TSI Inc....
Several nucleation events were observed during the latest Cloud and Aerosol Characterization Experiment (CLACE 4) in winter 2005, conducted on the Jungfraujoch high Alpine site (3580 metres a.s.l.). The ambient aerosol size distribution was measured both indoors under dry conditions (due to heating) and outdoors under ambient conditions (temperatur...
Atmospheric nucleation is a process of environmental importance. It has both a direct and an indirect effect on the climate influencing the albedo and leading to optical extinction. The direct effect is due to the presence of newly formed particles and their interaction with sun light while the indirect effect is caused by the particles acting as c...
Stolzenburg and McMurry (1991) developed the first ultrafine condensation particle counter (UCPC). TSI
subsequently commercialized the UCPC (model 3025) leading to wide use of the instrument. It was the
first CPC specifically developed for detecting ultrafine aerosol particles with particle diameters smaller
than 20 nanometers. Recently a new butan...
Urban aerosol is typically dominated by ultrafine particles which often originate from local sources such as traffic and industrial emissions. Ultrafine particles are not well represented by PM10 or PM2.5 measurements. We investigated the physical properties of the urban aerosol in a light industrial area near a freeway and in close
proximity to a...
Ausgehend von den Grundlagen der Partikelmessmethoden für Durchmesser, Anzahl und Masse und einer Darstellung der physikalischen Wirkprinzipien werden die wichtigsten Messgeräte zur Bestimmung dieser Partikelemissionen vorgestellt. Im Einzelnen sind dies für die Anzahlverteilungsbestimmung das SMPS, EEPS und das ELPI. Für die Massenbestimmung werde...
Condensation particle counters (CPCs) have been used extensively during the past decade to measure the particle number concentration and, as part of a scanning mobility particle sizer (SMPS™) spectrometer, the size distribution of ultrafine and fine particle emissions from a wide range of spark ignition and diesel engines. This paper illustrates a...
For nearly 25 years, TSI condensation particle counters (CPCs) have been extensively used by researchers, including automobile and truck manufacturers, to measure the number concentration and, as part of a scanning mobility particle sizer (SMPS™) system, the size distribution of particle emissions from diesel and spark ignition engines. As proposed...
Angesichts der deutlich reduzierten Partikelemission durch Verbrennungsabgase haben Blow-by-Gaspartikel heutzutage einen wachsenden Anteil an der Gesamtpartikelemission. Sie belasten jedoch nicht allein die Umwelt, sondern verschmutzen auch den Motorraum und erhöhen die Wartungskosten, da sich an kritischen Komponenten Rückstände ansammeln. Dieser...
As particulate matter (PM) emissions from engine exhaust are reduced significantly, blow-by gas particles have become a large contributor to the total PM emission. Yet, blow-by gas emissions not only contribute to air pollution, they also soil the engine compartment and lead to increased maintenance costs as residue builds up on critical components...
Partikel im Abgas von Verbrennungsmotoren sind in jüngster Zeit ein Gegenstand kontroverser Diskussion geworden. Insbesondere Dieselmotoren mit ihrem hohen Anteil ultrafeiner Partikel sind dabei mit schädlichen Umwelteinflüssen und negativen Auswirkungen auf die menschliche Gesundheit in Verbindung gebracht worden. Da die bislang für Motorabgase ge...
Recently, particulate emissions from vehicles and other combustion engines have become a topic of controversial discussion and great public concern throughout the world. Diesel engines, specially, have been implicated in causing air pollution and having adverse health effects because they emit a large number of ultrafine particles. Many epidemiolog...
Particulate materials play an important role in our daily life. Some are of natural origin, like starch and yeast, others are industrially produced, like pigments, ceramic powders or emulsions. The particle size distribution (PSD) has – besides chemical composition – an essential influence on many aspects of their product quality such as dispersion...
Questions
Questions (4)
In recent years several fine dust monitors that are based on single-particle light-scattering have achieved equivalency certifications for the measurement of PM2.5 in ambient air. Some of them show a lower particle size limit of 0.3 µm, others even claim 0.12 µm (without showing an independant validation). I'm wondering how these devices perform in heavily traffic dominated environments, where SMPS and related submicrometer sizing instruments typically show particle size distributions that peak between 50 and 150 nm. I obvioulsy understand the diameter to the power of 3 relationship between particle number and mass, but wouldn't they miss most of the PM2.5 anyway? Has anyone done a detailed comparison of these comparatively affordable PM monitors against reference methods?
