New measurement system for PM and ultrafine particles

Transcription

1 Cite abstract as Author(s) (2014), Title, Aerosol Technology 2014, Karlsruhe, Abstract T320A16 PM 0.1 Personal Sampler for Evaluation of Personal Exposure to Aerosol Nanoparticles M. Furuuchi 1, T. Thongyen 1, M. Hata 1, L. Bao 1, A. Toriba 1, T. Ikeda 2, H. Koyama 3 and Y. Otani 1 1 Graduate School of Natural Science and Technology, Kanazawa University, Kanazawa, Japan 2 Nitta Cooperation, Osaka, Japan 3 Shibata Scientific Technology, Tokyo, Japan Keywords: PM 0.1, personal exposure, nanoparticle, inertial filter. A PM 0.1 personal sampler devised by the authors (Furuuchi et al., 2010a) was investigated into its performance for the practical application, or on an improvement for a smaller cut-off size and also the removal of coarse particles using pre-cut impactors. The pressure drop through the inertial filter was discussed along with the separation performance since it is important to use a portable battery pump. An improved PM 0.1 personal sampler was applied to several field measurements to discuss the nanoparticles exposure. The improved PM 0.1 personal sampler is shown in Fig.1, which consists of pre-cut impactors of PM 1.4 /PM 5.6 for the removal of coarse particles of micron order, a webbed SUS inertial filter (pre-filter) to remove of sub-micron particles a layered mesh inertial filter (main filter) to separate particles at 100 nm. The main filter consists of layered square mesh TEM grids sandwiched by spacers with circular hole in a circular nozzle through an aluminium cartridge. A pre-filter consisting of webbed SUS fibers packed in a circular nozzle is located upstream the main inertial filter and a backup filter on a holder located downstream the main filter. The performance of the sampler was evaluated following a previous report (Furuuchi et al., 2010b). In order to validate the measured value by the PM 0.1 personal sampler, concentration and size distribution of ambient aerosol particles were compared between those from the PM 0.1 personal sampler and Nanosampler. The PM 0.1 personal sampler was applied to field measurements in working and living environments: textile factory, printing factory, main road side, smoker s house, breathing zone of a smoker. Cover Aerosol Inlet Outlet Pre-cut Impactor nm Pre-Filter nm Main Filter nm Backup Filter <100nm Figure 1. Schematic of PM 0.1 personal sampler. Fig.2 shows the cutoff size and pressure drop of pre- and main filters which could be adjusted respectively as ~ 450 nm at 0.6 kpa and as ~ 100 nm at 4.6 kpa for 5 L/min of sampling flow rate, where around 5.2 kpa of the total pressure drop through both inertial filters is reasonably lower than the maximum allowable pressure drop (15 kpa) of a used portable battery pump. Size distribution and concentration of particles collected by the PM 0.1 personal sampler with pre-cut impactors were fairly comparable with those by the Nanosampler. Results from field measurements in various living and working environments showed that the exposure to nano-particles is more significant in smoking areas and roadside environments and also in working environment in textile factory. Figure 2. Collection efficiency curve of PM 0.1 personal sampler filters. Pre-cut Filter Pre-Filter Main Filter Total Filter The developed PM 0.1 personal sampler for the evaluation of the nanoparticle exposure was improved for the application to practical purposes. Using the developed sampler, the exposure to nanoparticles in various environments was successfully evaluated, showing an important contribution of nanoparticles in some environments. Furuuchi, M., Choosong, T., Hata, H., Otani, Y., Tekasakul, P., Takizawa, M., Nagura M. (2010a). Development of a Personal Sampler for Evaluating Exposure to Ultrafine Particles, Aerosol and Air Qual. Res., 10, Furuuchi, M., Eryu, K., Nagura, M., Hata, M., Keto, T., Tajima, N., Sekiguchi, K., Ehara, K., Seto, T. and Otani, Y. (2010b). Development and Performance Evaluation of Air Sampler with Inertial Filter for Nanoparticle Sampling, Aerosol and Air Qual. Res., 10,

2 Cite abstract as Author(s) (2014), Title, Aerosol Technology 2014, Karlsruhe, Abstract T310A05 New measurement system for PM and ultrafine particles J. Spielvogel, M. Weiß Palas GmbH, Greschbachstr. 3b, 76229, Karlsruhe, Germany Keywords: aerosol measurement, particle number concentration, particle size distribution, PM fractions According to a recently published report by the European Environment Agency about one third of Europe s population in cities is exposed to excessive concentrations of particulate matter (PM). These people are also exposed to high concentrations of ultrafine particles caused for example by traffic and heating. We will present a new measurement system that can measure the number concentration and size distribution of airborne particles from 8 nm to 18 µm. In addition, it also reports simultaneously different PM-fractions such as PM-1, PM-2.5 and PM-10. With a time resolution of 5 minutes it can further capture dynamic changes in the aerosol distribution caused for example by rush hour traffic in the morning and afternoon. The measurement system combines a scanning mobility particle sizer in which the working fluid to condense the particles can be chosen to be water or butanol with a continuous ambient air quality monitoring system. In the latter a polychromatic light source is used to illuminate aerosol particles as they pass through the optical sensing volume. The scattered light of each individual particle is then detected with a photomultiplier. Figure 1. Particle size distributions from 8 nm to 23 µm. In blue before working hours, in red after people have appeared and started to work. We will show and discuss selected measurements in which the additional information of particle size distribution helps to interpret the PMdata and also facilitates source apportionment. The system is operated through a touchscreen with intuitive graphical user interface and integrated data logger. Data can be easily viewed on the screen or later extensively evaluated through the included software. Figure 1 shows two particle size distributions directly on the touchscreen of the instrument. This example shows a marked difference in small and large size fractions between an empty production building and after people have arrived for work. It also shows how quickly measurements can be compared right on the instrument. The evaluation software allows plotting the data from the U-SMPS and optical spectrometer either separately or combined

3 Cite abstract as Author(s) (2014), Title, Aerosol Technology 2014, Karlsruhe, Abstract T312A05 Follow-up model of the Respicon three fraction aerosol sampler and monitor J. Pelzer 1, C. Möhlmann 1, J. Haus 3, W. Dunkhorst 2, H.Lödding 2 and W. Koch 2 1 Institut für Arbeitsschutz, Alte Heerstraße 111, Sankt Augustin, Germany 2 Fraunhofer Institute for Toxicology and Experimental Medicine, Nikolai-Fuchs-Straße 1, Hannover, Germany 3 Helmut Hund GmbH, Artur-Herzog-Straße 2, Wetzlar, Germany Keywords: photometer, direct reading, inhalable, thoracic, respirable, personal air sampling The Respicon aerosol sampler and monitor is a well-known instrument to determine workplace aerosol concentrations of the inhalable, thoracic and respirable dust fractions. Because of the current decrease of dust limit values, an improvement in personal air monitors was seen necessary in order to be able to determine dust concentrations well below 1 mg/m³. The Respicon was chosen because of its unique characteristics. The improvements of the Respicon were on the one hand realised by doubling the air flow to 6.2 l/min and on the other hand by integrating more sensitive light scattering photometers. With help of a powerful personal air pump (SG 10-2 from GSA, Neuss, Germany) a new set of virtual impactors and critical orifices was developed to allow air flows of 5.32 l/min for the respirable fraction, 0.66 for the middle stage and 0.22 for the third stage collecting the larger particles. Performing weighing of the dust loads on the filters, the limit of detection for the respirable fraction will be 0.47 mg/m³ for 2 h sampling and 0.11 for 8 h, using a minimum weight difference of 0.3 mg. The temperature drift mainly determines the limit of detection of the monitor which is seen well below 10 µg/m³. The sensitivity of the photometer of the old Respicon with 3.1 l/min ranges between 5 and 34 mv/mg/m³ for the respirable fraction, depending on the kind of dust (Koch et al. 1999). The photometers were changed by integrating more powerful laser diodes together with high sensitive photo diodes. They were tested for parallel performance, temperature drift, long term performance and dependency on kind of dust. The sensitivity was increased from about 20 mv/mg/m³ (old version) up to 140 to 430 mv/mg/m³ depending on particle size and refractive index. The improved Respicon shows mean calibration factors between 200 and 350 mv/mg/m³ for the five dusts tested (Fig. 2). A new datalogger will support electrical energy and display and store measurement data (Fig. 1). Further tests are ongoing to reach all desired characteristics and a launch on the market in near future. Figure 1. Respicon with 6.2 l/min and new data logger Figure 2. Photometer calibration factors for different dusts Koch, W., Dunkhorst, W. & Lödding, H. (1999): Design and Performance of a new personal Aerosol Monitor, Aerosol Science and Technology, 31:

4 Cite abstract as Author(s) (2014), Title, Aerosol Technology 2014, Karlsruhe, Abstract T320A18 Long-term performance of personal monitors for ultrafine particles M.Fierz 1,2, D.Meier 2, P.Steigmeier 1 and H. Burtscher 1 1 University of Applied Sciences Northwestern Switzerland, 5210 Windisch, Switzerland 2 naneos particle solutions llc, 5210 Windisch, Switzerland Keywords: instrumentation Presenting author [email protected] In recent years, nanoparticles in workplaces have received a lot of attention. Nevertheless, their measurement still appears to be challenging nanoparticle detectors typically require routine servicing and calibration to work properly, and personnel needs to be trained to use the equipment properly. We have recently introduced a miniature nanoparticle detector (Fierz et al, 2014), the partector, which is very simple to operate it needs no working fluids, contains no radioactive sources, and basically operates with the use of a single button. It uses a pulsed unipolar diffusion charger followed by a non-contact detection of the particle charge; this charge can be interpreted as a lungdeposited surface area (LDSA), a potentially very interesting metric, since toxicologists have shown that health effects correlate best with particle surface area rather than particle number or particle mass (e.g. Waters et al., 2009). Due to the non-contact detection principle, our device should in principle have longer service intervals than comparable filter-based instruments. However, as with any nanoparticle detector, the long-term reliability of our device is questionable: In general, the wires or tips in corona chargers foul, and need to be cleaned regularly; furthermore, the insulators in the electrometer may also become dirty over time, and therefore the electrometer s amplification may change over time. Especially for the use in industry by nanoparticle laymen, it is important that devices remain reliable over time, and that they can detect problems with self-tests. We have therefore performed long-term tests (over 6 months) in the Swiss air pollution monitoring network (NABEL) to assess long-term reliability, and continued to improve our device with internal self-tests to detect issues with the device. We will present an overview of our device, its long-term performance, and the discuss how to make devices based on corona charging and electrometer detection more reliable. M. Fierz, D. Meier, P. Steigmeier, & H. Burtscher (2014) Aerosol Measurement by Induced Currents. Aerosol Sci. Technol., doi: / Waters K.M. et al. (2009) Tox Sci 107:

5 Cite abstract as Author(s) (2014), Title, Aerosol Technology 2014, Karlsruhe, Abstract T320A13 Introducing a nano Condensation Nucleus Counter system for real-time detection of nucleation and recently formed particles in the laboratory and on field K. Lehtipalo 1,2, M. Väkevä 2, J. Mikkilä 2, A. Franchin 1,2, M. Kulmala 1 and J. Vanhanen 2 1 Department of Physics, University of Helsinki, Helsinki, FINLAND 2 Airmodus Oy, Helsinki, FINLAND Keywords: condensation particle counters, nucleation, nano-particles Presenting author [email protected] Nucleation, i.e. formation of new airborne particles from precursor gases, happens frequently in the atmosphere in many different kind of environments (Kulmala et al. 2004), but also in engine exhausts (Rönkkö et al., 2007) and different industrial processes. The new particle formation process is not yet completely understood, mainly because there has been a lack of suitable instruments to detect the recently formed clusters and particles and study their composition. A new generation of condensation particle counters (CPCs) using diethylene glycol as working fluid have emerged in recent years (e.g. Vanhanen et al., 2011, Jiang et al., 2011, Wimmer et al., 2013) and they allow starting particle measurements even from 1 nm and thus realtime detection of nucleation. The Airmodus A11 nano Condensation Nucleus Counter (ncnc) system consists of a Particle Size Magnifier (PSM) and a CPC (Airmodus model A20). The PSM (Vanhanen et al., 2011) is a pre-conditioner, which can be used for lowering the cut-off size of a CPC even down to 1 nm in mobility diameter. It activates and grows the particles in the sample up to about 90 nm by condensing diethylene glycol onto them. Since the supersaturation achieved in the PSM can be changed by changing the mixing ratio of the sample and saturator flow rates, the user can select the cut-off size or use the PSM for resolving the activation spectrum of the particles by continuously changing the supersaturation. The relation between the flow mixing ratio and the cutoff diameter has been determined by calibrations using size-selected ammonium sulphate ions and clusters. The PSM was found to activate ammonium sulphate clusters consisting of just a few molecules, and it was able to detect even single large molecules (Vanhanen et al., 2011, Wimmer et al., 2013, Kangasluoma et al., 2013). Using the information from the calibrations, the activation spectra from the ncnc can be used to get a size distribution of the particles between about 1-3 nm, or since clusters and particles of different composition can activate at slightly different flow rates (Kangasluoma et al., 2013), it can be used to get information about their composition. The ncnc can be used to detect nucleation in various environments and systems both in the laboratory and from outside air. Especially by combining it to the new mass spectrometric methods, like the CI-APi-TOF (Jokinen et al., 2012) it is possible to cover the whole size range from molecules to aerosol particles. Figure 1. Principle of the A11 nano Condensation nucleus Counter system. Green arrows describe the sample flow, and blue arrows the information flow. This research has been funded by the ERC-Advanced "ATMNUCLE'' grant no ), the Academy of Finland (Center of Excellence project no ), and the Eurostars Programme under contract no. E!6911 Jiang, J. et al. (2011) Aerosol Sci. Technol. 45, Jokinen, T. et al. (2012) Atmos. Chem. Phys., 12, Kangasluoma, J. et al., (2013). Aerosol Sci. Technol. 5, Kulmala, M. et al. (2004). J. Aerosol Sci., 35: Rönkkö, T. et al. (2007). Environ. Sci Tech.41, Vanhanen, J. et al. (2011) Aerosol Sci. Tech. 4, Wimmer D. et al. (2013). Atmos. Meas. Tech. 6,

6 Cite abstract as Author(s) (2014), Title, Aerosol Technology 2014, Karlsruhe, Abstract T320A11 ELPI+ calibration over a wide particle size range A. Järvinen 1, M. Aitomaa 1, A. Rostedt 1, J. Keskinen 1 and J. Yli-Ojanperä 1 1 Department of Physics, Tampere University of Technology, Korkeakoulunkatu 3, 33720, Tampere, Finland Keywords: ELPI+, impactor, charger, calibration. The ELPI+ is an aerosol instrument based on the Electrical Low Pressure Impactor (Keskinen et al., 1992). The measurement principle of the instrument includes unipolar diffusion charging of particles, size classification of the particles in an impactor, and electrical detection of the current carried by the particles. The electrical current measurement from the impactor stages allows real time detection of particles and size distribution measurement. The ELPI+ size range from 6 nm up to 10 m is a challenge for calibration because different references are needed for different size ranges and both the charger and the impactor require calibration. Challenges are related to the accuracy of the particle size in case of the impactor calibration and the accuracy of the particle number concentration in case of the charging efficiency measurements. The particle size uncertainty is related to electrostatic classification and multiple charging. The number concentration of micrometre sized particles is a challenging quantity because equal concentration between the instrument and the reference is needed. Also the lack of reliable number concentration references is an issue in micrometre size range. The calibration of the ELPI+ is presented thoroughly in Järvinen et al. (2014). Diethylhexyl sebacate (DEHS) was used as particle material for all the methods. For the smallest particle sizes an Evaporation Condensation Generator (ECG) followed by a Differential Mobility Analyser (DMA) was used. The largest particles were generated by a Vibrating Orifice Aerosol Generator (VOAG) which produces inherently known particle size. Typically the most challenging size range, from 30 nm to 2 m, was covered by using the recently introduced Singly Charged Aerosol Reference (SCAR) (Yli-Ojanperä et al. 2010) followed by a DMA. The electrical cascade impactor calibration procedure used in this study has been introduced by Keskinen et al. (1999). The advantage of this method is that particle concentration information is not needed as the measurement relies solely on the electric currents of the impactor stages. Only the particle size needs to be known. The charger calibration is based on the determination of the charger outlet current as a function of inlet particle concentration for different particle sizes. The concentration measurements were based on particle number measurement by a calibrated Condensation Particle Counter (CPC) and by Aerodynamic Particle Sizer (APS). The ELPI+ charger provides higher charging efficiency (Figure 1) compared to the previous ELPI classic model. This effect is noticeable in the small particle sizes below 50 nm. The impactor collection efficiency curves (Figure 2) are similar to the classic model, except minor differences in case of the stages with the largest cut diameters Charging efficiency Pn Collection efficiency Mobility diameter ( m) Figure 1. Charging efficiency Pn of the ELPI+ diffusion charger Aerodynamic diameter ( m) Figure 2. Collection efficiencies of the ELPI+ cascade impactor stages. This work was supported by the CLEEN Ltd. through the MMEA research program. Järvinen, A., Aitomaa, M., Rostedt, A., Keskinen, J., & Yli-Ojanperä, J. (2014). J. Aerosol Science, in press. Keskinen, J., Pietarinen, K., & Lehtimäki, M. (1992). J. Aerosol Science, 23, Keskinen, J., Marjamäki, M., Virtanen, A., Mäkelä, T., & Hillamo, R. (1999). J. Aerosol Science, 30, Yli-Ojanperä, J., Mäkelä, M., Marjamäki, M., Rostedt, A., & Keskinen, J. (2010). J. Aerosol Science, 41,

7 Cite abstract as Author(s) (2014), Title, Aerosol Technology 2014, Karlsruhe, Abstract T312A04 On-line characterization of aerosols from NP-doped products in the construction industry: the challenge of dynamic background identification. J. Lopez de Ipiña 1, C. Vaquero 1, N. Galarza 1, G. Aragon 2, I. Mugica 2, I. Larraza 3 and C. G.-Canas 2 1 TECNALIA, Leonardo da Vinci 11, 01500, Miñano, Spain 2 Department of Chemical and Environmental Engineering, University of the Basque Country, Alameda de Urquijo s/n, 48013, Bilbao, Spain 3 ACCIONA Concrete Group Materials Area, Technological Innovation Division, Valportillo II, Alcobendas, Spain Keywords: workplace aerosol, characterization, direct reading instruments, background, construction sector. In the recent years the construction sector is incorporating new materials based on nanotechnology to both product and processes. This requires an assessment of workplace aerosol quality and raise issues about occupational exposure. The present work focuses on the on-line analysis of the released aerosol during the manufacturing of depollutant mortar. Is has been done in the frame of SCAFFOLD project, which aims to the management of potential risks arising from the use of manufactured nanomaterials in the construction sector. The experimental strategy, procedure and data interpretation follow the tiered approach established in Asbach et al. (2012). The measurement and sampling devices combine size resolved and size integrated with time resolved and time integrated techniques, as classified by Kuhlbusch et al. (2011). Size segregated samples were simultaneously obtained by means of co-located impactors. The selected industrial scenario is the manufacturing of the mortar within a workshop of 1250 m 2. Two new formulations are considered: adding nano-tio 2 (Material C) and nano-tio 2 (Material B) supported onto sepiolite. Batch size was 1 Ton. Operation consists of the consecutive tasks: weighing, adding to the mixer and mortar bagging. A detailed description of the spatial layout will be given. Figure 1 shows the temporal evolution of total particle concentrations as measured simultaneously in two locations: industrial site background and operator position, during the addition to the mortar. It is observed a significant release during the addition to the mixer hopper. The released particles are far larger than 100 nm. However, data obtained by direct-reading instruments do not allow allocating the differential contribution of Materials B and C respective to the Control Material A. Statistical analysis of the temporal series is currently ongoing. #/cm3' 1,00E+07' 1,00E+06' 1,00E+05' 1,00E+04' 1,00E+03' Material'A' Conven&onal)addi&ves)) Material'B' Conven&onal)addi&ves)+) TiO2)sepiolite) Material'C' Conven&onal)addi&ves)+) nanotio2)) Figure 1. Total particle concentration along the addition for the different materials. Green line: background. Blue line: ELPI+. Red line: CPC3775 This opens the discussion to several aspects, including: a) The suitability of portable devices to identify potential releases from these kind of operations. b) The challenge of discriminating the signal from a complex background. c) The complementary off-line techniques, for an allocation of the effect of new additives. d) The implications for occupational exposure and potential risk management in the construction sector. The European Commission under grant SCAFFOLD supported this work. Asbach C. et al. Nanogem. Standard Operation Procedures for assessing exposure to nanomaterials, following a tiered approach, (2012), Kuhlbusch T., Asbach C., Fissan H., Goehler D. and Stinz M., (2011). Particle Fiber Toxicology, 8:22

8 Cite abstract as Author(s) (2014), Title, Aerosol Technology 2014, Karlsruhe, Abstract T320A23 PM 0.1 High Volume Air Sampler for Ambient Nanoparticles T. Zhang 1, T.Thongyen 1, A. Toriba 2, M. Hata 1, L. Bao 1, Y. Otani 1, T. Ikeda 3, H. Koyama 4, M. Furuuchi 1 1 Graduate School of Natural Science and Technology, Kanazawa University, Kanazawa, Japan 2 Graduate School of Medical Science, Kanazawa University, Kanazawa, Japan 3 Business Development Center, Nitta Corporation, Yamatokohriyama, Japan 4Shibata Scientific Technology, Soka, Japan Keywords: PM 0.1, air sampler, nanoparticle, inertial filter, high volume. In order to conduct various quantitative chemical analyses of atmospheric particles, a relatively large mass of particles, possibly on the order of a mg, must be collected from atmospheric air through filtration. Although particles smaller than 0.1 µm, i.e., nanoparticles, account for a large proportion of the total population, their mass is very small. Therefore, a long sampling time is required to collect a sufficient mass of atmospheric nanoparticles. The authors (Otani, 2007; Furuuchi, 2010) developed an inertial filter to overcome these difficulties. This filter has advantages, such as a nanometer-size cutoff (d p50 ) diameter at a moderate pressure drop (< 20 kpa), as well as a sufficiently high sampling flow rate that permits the rapid collection of particles. In the present study, a new type of the inertial filter for high-volume air sampling was developed and applied to ambient air sampling. A filter using wire mesh screens using alternate layers of spaced sheets with circular holes aligned to provide multi-circular nozzles was devised and its separation performance was investigated experimentally. A supplemental inlet for the nanoparticle collection applied to an existing portable high volume air sampler was devised and the consistency with other types of existing samplers was discussed based on ambient particle sampling. Fig. 1 shows the concept on the structure of an inertial filter, which consists of circular screen meshes sandwiched by thin spacing sheets perforated with equivalent circular holes. These holes are aligned with one another to form circular nozzles with wire meshes. In the devised sampler, wire mesh screen (SHS-380/114, calendared, Asada Mesh, thickness ~14 µm) and circular spacing sheet (SUS- Circular hole Spacing sheet Wire mesh screen Fig.1 Schematic of the new structure of a multinozzle inertial filter using layered-mesh screens with spacing sheets with circular holes. 304) with circular holes (φ 5 mm) (thickness 0.1 mm) were used. A single nozzle inertial filter of φ 5 mm diameter was tested for the separation performance of at 20 L/min following a previous report (Furuuchi et al., 2010). A multi-nozzle (19 of φ 5 mm nozzles, 380~650 L/min) inertial filter with pre-cut impactors of PM 4 /PM 2.5 /PM 0.5 (380 L/min) was also devised as a practical instrument for the field measurement and its separation performance was also examined based on the number concentration using ambient particles as test particles using SMPS. A webbed stainlesssteel fiber mat was used between PM 0.5 impactor and the inertial filter to decrease the influence of bouncing of particles. Fig. 2 shows the separation performance of a single nozzle inertial filter at along with those for the multi-nozzle inertial filter with pre-cut impactors. The cut-off size is adjustable in the range of 100~200 nm within 12.1 kpa of pressure drop through the inertial filter, which is reasonably small to supress the evaporation loss of semi-volatiles. The good consistency with data from an existing sampler was also confirmed. Otani, Otani, Y., Eryu, K., Furuuchi, M., Tajima, N., Tekasakul, P. (2007). Inertial Classification of Nanoparticles with Fibrous Filters, Aerosol and Air Qual. Res.,7, Furuuchi, M., Eryu, K., Nagura, M., Hata, M., Keto, T., Tajima, N., Sekiguchi, K., Ehara, K., Seto, T. and Otani, Y. (2010). Development and Performance Evaluation of Air Sampler with Inertial Filter for Nanoparticle Sampling, Aerosol and Air Qual. Res., 10, Collection efficiency E (%) Mesh + SUS fiber mat 20L/min (ambient) Mesh + SUS fiber mat 29L/min (ambient) Multi nozzle inertial filter 380L/min (ambient) Multi nozzle inertial filter 650L/min (ambient) Aerodynamic diameter (µm) Fig.2 Separation performance of layered mesh inertial filters

9 Cite abstract as Author(s) (2014), Title, Aerosol Technology 2014, Karlsruhe, Abstract T320A14 Measurement of solid particle concentration is aided by catalytic stripper technology J. J. Swanson, H.-J. Schulz, and A.M. Boies Catalytic Instruments GmbH, Lug ins Land 53, Rosenheim Keywords: semi-volatile, organic carbon, new instrumentation, exhaust measurement Diesel, locomotive, and gas turbine exhaust contains a complex mixture of solid particles and semi-volatile material that is found in both the particle and the vapor phase. Physical and chemical characterization of these exhaust aerosols in the environment enables a better understanding of potential health effects, effectiveness of alternative combustion technologies and emission control devices, and also the impact of new fuel and lubricant formulations on emissions. To reflect the growing consensus that solid, elemental carbon is a relevant metric and to force the use of diesel particulate filters, Euro 5b regulations introduced a protocol for measuring the solid particle number concentration for particles larger than 23 nm. Similarly, the aerospace SAE E-31 program aims to develop a methodology to measure solid particle mass and number concentration in gas turbine exhaust. While the aforementioned efforts are generally successful, issues remain with regards to the standard heated tube approach ( evaporation tube or thermal denuder ) for separating solid and semi-volatile material due to the formation of artifacts that manifest as incomplete evaporation and/or vapor renucleation. An alternative to this is the catalytic stripper (CS) 1, which has the potential to allow reliable extension of solid particle methods to a lower size range in the absence of artifacts. The objectives of this paper are two-fold. First, recent advances in CS technology that have been presented in successful demonstration studies are discussed. These include 1) design of a miniature CS, 2) laboratory validation of a CS when challenged with very high concentrations of semi-volatile hydrocarbon and sulfuric acid aerosols 2, and 3) performance of the CS compared to other methods 2. While demonstration studies have validated the technology, standardizing the approach is the next step to move forward. Thus, the second objective is to describe current efforts to improve both the design of the catalytic element and choice of components as well as methods used for evaluation. The CS geometry is fixed though the choice of cell density and physical dimensions. For a fixed geometry, the operating temperature and flowrate dictate performance, although performance needs may vary depending on application. Fig. 1 shows typical solid particle loss curves for a CS operating at 1.5 L/min and 350 C. Design parameters for the CS reflect a balance between solid particle loss, flowrate, residence time, operating temperature, and vapor removal. Fig. 1 shows how the removal of tetracontane vapor increases at the expense of decreased penetration of solid material this effect is magnified for the smallest particles. Penetration Penetration calculated for CS wall tempeature of 350 C Tetracontane removal = 95% Tetracontane removal = 99.9% Dp, nm Figure 1 Typical solid particle loss curves (including diffusion and thermophoresis) for CS designed to remove 95% and 99.9% of tetracontane (C 40 H 82 ). Fig. 2 shows a cross-sectional view of a typical catalytic element including heating, insulation, and the catalytic material. Figure 2 Schematic of catalytic element. Aerosol flow is from left to right. Overall, results show CS technology is a robust means to separate solid and semi-volatile material. The combination of CS technology and any traditional particle instrument can then be used to provide a realtime measure of solid particle number, size, surface area, or mass concentration. Further to this, the standardization of catalytic element design and performance evaluation techniques provides a basic platform for the design for new aerosol instrumentation. 1 Abdul-Khalek, I.S.; Kittelson, D.B. (1995). Real time measurement of volatile and solid exhaust particles using a catalytic stripper. Society of Automotive Engineers, Swanson, J.; Kittelson, D. (2010). Evaluation of Thermal Denuder and Catalytic Stripper Methods for Solid Particle Measurements. J. Aerosol Science, 41:12,

10 Cite abstract as Author(s) (2014), Title, Aerosol Technology 2014, Karlsruhe, Abstract T313A09 Simple on-line instrument for quality control in aerosol processing of nanomaterial Anssi Arffman, Juha Harra, Paxton Juuti, Antti Rostedt, Jyrki M. Mäkelä, Jaakko Yli-Ojanperä and Jorma Keskinen Aerosol Physics Laboratory, Department of Physics, Tampere University of Technology, Tampere, Finland Keywords: mobility size, low pressure impactor, effective density. Several aerosol methods, such as flames and furnaces, are widely used in the processing of nanomaterial. Depending on the application, the quality of the produced material depends, for example, on the particle size and morphology. The latter is usually quantized with fractal dimension or effective density. Traditionally, these parameters are monitored with off-line methods, such as microscopy, or with parallel on-line measurements requiring several aerosol instruments (see e.g. Ristimäki et al. 2002). In this study, we introduce a simple on-line instrument capable of measuring simultaneously particle size, effective density and number concentration. The developed instrument is a simplified version of the instrument presented in Rostedt et al. (2009). It consists of a unipolar charger followed by three electrical measurements. Electrometers are connected to a mobility analyser, a low pressure slit impactor (Arffman et al. 2012) and a filter. A schematic illustration of the operating principle is shown in Figure 1. The mobility analyser classifies particles according to their electrical mobility, which can be used to determine the mean mobility diameter d m. On the other hand, the impactor classifies particles according to their aerodynamic diameter d am. Thus, by combining the mean mobility diameter and the mean aerodynamic diameter, the effective mean density ρ eff of the monitored particles can be resolved. particles (GMD ~30 nm) generated with an evaporation condensation technique (see e.g. Harra et al. 2012). The effective density of the particles was varied by changing the sintering temperature. Figure 2 shows the effective density of the silver particles as well as the temperature of sintering furnace as a function of time. As the temperature increases from the room temperature to 450 C, the effective density increases from approximately 3500 to 8000 kg/m 3. This is expected due to the compaction of the particles from agglomerates to more spherical. Figure 2. The effective density of the silver particles and the temperature of the sintering furnace as a function of time. All in all, the introduced simple on-line aerosol instrument requires only three electrical measurements which can be combined in order to monitor particle size, effective density, and number concentration. We expect that the newly developed instrument is useful for on-line quality control in aerosol processing of nanomaterial. The research leading to these results has received funding from the European Union s Seventh Framework Programme under Grant Agreement n (BUONAPART E). Figure 1. A schematic illustration of the instrument. The total current I tot is a sum of three currents measured from the mobility analyser I ma, the impactor I i and the filter. A prototype of the instrument was first calibrated with monodisperse dioctyl sebacate particles and then tested using polydisperse silver Arffman, A., Yli-Ojanperä, J., Keskinen, J. (2012). J. Aerosol Sci., 53, Harra, J., Mäkitalo, J., Siikanen, R., Virkki, M., Genty, G., Kobayashi, T., Kauranen, M., Mäkelä, J.M. (2012). J. Nanopart. Res., 14, 870. Ristimäki, J., Virtanen, A., Marjamäki, M., Rostedt, A., Keskinen, J. (2002). J. Aerosol Sci., 33, Rostedt, A., Marjamäki, M., Keskinen, J. (2009). J. Aerosol Sci., 40,

11 Cite abstract as Author(s) (2014), Title, Aerosol Technology 2014, Karlsruhe, Abstract T220A09 Mathematical model of aerosol sampler for an unmanned aerial vehicle S.A. Solov ev 1, S.K. Zaripov 1, O.V. Solov eva 2 1 Kazan Federal University, Kremlevskaya st. 18, , Kazan, Russia 2 Kazan State Power Engineering University, Krasnoselskaya st. 51, , Kazan, Russia Keywords: aerosol sampler, panel method, porous screen. The safe radioactive aerosols monitoring can be provided by use the unmanned aerial vehicles (UAV) (Parajarvi et al., 2008). In the mentioned work the aerosol sampler of conical shape without pump is developed for a UAV. The sampler operates in the range of air velocity km/h. Dangerous airborne substances are collected on the filter inside the sampler (fig.1). The air flow rate through collection zone is controlled by changing permeability of interior filter. The conical expansion of inner air flow leads to decrease of air velocity before filter. The inner flow rate as a function of a UAV velocity at various filters has been found theoretically and experimentally. The radioactive aerosols with sizes µm were studied by Parajarvi et al. (2008). In this submicron range of particle diameters the deviation of their trajectories from air flow streamlines will be too small to change the particle concentration inside the sampler. The mentioned passive conical sampler with interior filter can be used for sampling of coarse aerosols. In this case the concentration of particles in undisturbed air and in the collection zone can be different due to their inertial behavior. To predict the performance of the sampler the aspiration efficiency calculation is needed. Figure 1. Scheme of sampler with porous screen In this work the mathematical model of aerosol sampling into conical sampler that is facing the direction of movement of UAV is developed. The boundary value problem for air flow velocity potential φ is numerically solved by panel (source) method (Fletcher, 1990) within an inviscid model of incompressible fluid flow. The filter is considered as a porous screen. It is assumed that fluid flow through the filter can be described by the Darcy s law. The pressure drop across the filter is proportional to the flux through filter (O Neill, 2006), (1) where is the free-stream velocity, is the normal component of air filtration velocity, is the parameter that describes the porous screen properties including its permeability. The case and correspond to the absolutely permeable screen (sampler without filter) and impermeable screen (solid wall). Using Bernoully s theorem for the steady motion of inviscid fluid and the relation (1) the formula for can be written (2) The air flow velocity components obtained from numerical solution are used to calculate the trajectories from the particle motion equations. The values of initial ordinates of limiting trajectories are used to calculate the aspiration coefficient The ratio of velocities in free flow and in the sampling inlet cross-section is usually used as a parameter for aerosol sampling into thin-walled samplers in moving air. In the case of passive sampler with filter the aspiration coefficient was estimated using the parameters and ( ), are radii of the sampler inlet and the porous screen). Using the equation of mass conservation, (3) and (2) we can write the relation between and in the form ( ) (4) By varying the parameter and we can find the values that will provide needed ratio including isokinetic sampling. The comparison of limiting streamlines at and various with the numerical results from Gilfanov & Zaripov (2012) is given in fig.2 (1 - present work). The results of numerical calculation of the aspiration coefficient will be presented on the conference. r 1,0 0,8 0,6 0,4 0,2 1 2 R a =2, =0.75 R a =10, =4.95 R a =50, = Figure 2. Limiting streamlines This work was supported by RFBR (grants , ). Fletcher, C.A.J. (1990) Computational Techniques for Fluid Dynamics. Berlin, Germany: Springer-Verlag. Gilfanov, A.K., Zaripov, S.K. (2012) Mathematical models of aerosol sampling into thinwalled samplers. Kazan, Russia: Kazan University (in Russian). O Neill, F.G. (2006). Ocean Engineering, 33, Perajarvi, K., Lihtinen, J., Pollanen, R and Toivonen, H. (2008). Radiation Protection Dosimetry, 3 (132), N x

12 Cite abstract as Author(s) (2014), Title, Aerosol Technology 2014, Karlsruhe, Abstract T311A01 Design and evaluation of a variable head PM 1 /PM 2.5 sampler Anand Kumar 1 and Tarun Gupta 1,2 1 Environmental Engineering and Management Program, Indian Institute of Technology Kanpur, , Kanpur, India 2 APTL at Center for Environmental Science and Engineering, Indian Institute of Technology Kanpur, , Kanpur, India Keywords: Particulate Matter, Impactor, Sampler. This study presents the design and lab evaluation of a compact, mobile medium flow inertial impactor that operates at a flow rate of 175 l/min and consists of two different circular acceleration nozzles designed for PM 2.5 (particle aerodynamic diameter < 2.5 µm) and PM 1 (particle aerodynamic diameter < 1µm). Any of the two could be used at a time as per the requirement. Various impactor nozzles were designed for PM 1 /PM 2.5 using the design equations based on the empirical solution of Navier-Stokes equations for varying conditions of air flow around a flat or round impaction substrate. The impactor nozzles along with impaction substrate unit were tested individually using a laboratory testing rig setup with flow rates ranging between 100 to 200 lpm using the dry aerosol generation system for different S/W (ratio of distance between nozzle exit to substrate surface and nozzle width) ratios. A dry aerosol generator was employed using dolomite powder (sieved through a 45 m size mesh) to produce a stable flow of polydisperse aerosol. A portable aerosol spectrometer (PAS 1.108, Grimm GmbH) was used to test the performance of the impactor. High vacuum grade silicone grease of depth 0.40 cm was used as an impaction substrate which allows particles to penetrate into it and soon their surface is wetted with silicone oil hence eliminating particle bounce off (Turner & Hering, 1987; Demokritou et al., 2001b; Hill et al., 2002). a Jet velocity at nozzle exit, b Reynolds number of jet at nozzle exit, c Pressure drop across the impactor assembly The average particle losses for the impactor nozzle and sampler body were well below 15% and the pressure drop for this PM 1 /PM 2.5 sampler was 1.07 kpa and 0.35 kpa, respectively. Its operating air flow rate of 175 l/min allows shorter sampling time as compared to any other traditional low flow rate sampler. Being compact and handy, it could be a very effective setup to selectively monitor PM 1 /PM 2.5 in a short span of time on a routine basis, especially in a developing country like India where some of the major cities are in adverse situation in terms of ambient air quality. Also, when co-located with a real-time monitor (like a typical optical particle counter), it can provide a useful comparison due to the advantage of its higher operating air flow rate. Demokritou, P., Kavouras, I. G., Ferguson, S. T., Koutrakis, P. (2001b). Aerosol Science Technology, 35, Hill, J. S., Patel, P. D., Turner, J. R. (1999). 92nd meeting of Air and Waste Management Association, paper # Turner, J. R., Hering, S. V. (1987). J Aerosol Science, 18, Table 1. Design parameters and experimentally calculated characteristics of the impactor PM 2.5 Configuration PM 1 Configuration Number of Nozzles 4 8 Nozzle Diameter (mm) S/W U a (cm/s) Re b d 50 (µm) Stk ΔP c (kpa) σ g