Artykuły w czasopismach na temat „Particle emissions”
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Kontkanen, Jenni, Chenjuan Deng, Yueyun Fu, Lubna Dada, Ying Zhou, Jing Cai, Kaspar R. Daellenbach i in. "Size-resolved particle number emissions in Beijing determined from measured particle size distributions". Atmospheric Chemistry and Physics 20, nr 19 (5.10.2020): 11329–48. http://dx.doi.org/10.5194/acp-20-11329-2020.
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Abstract. The climate and air quality effects of aerosol particles depend on the number and size of the particles. In urban environments, a large fraction of aerosol particles originates from anthropogenic emissions. To evaluate the effects of different pollution sources on air quality, knowledge of size distributions of particle number emissions is needed. Here we introduce a novel method for determining size-resolved particle number emissions, based on measured particle size distributions. We apply our method to data measured in Beijing, China, to determine the number size distribution of emitted particles in a diameter range from 2 to 1000 nm. The observed particle number emissions are dominated by emissions of particles smaller than 30 nm. Our results suggest that traffic is the major source of particle number emissions with the highest emissions observed for particles around 10 nm during rush hours. At sizes below 6 nm, clustering of atmospheric vapors contributes to calculated emissions. The comparison between our calculated emissions and those estimated with an integrated assessment model GAINS (Greenhouse Gas and Air Pollution Interactions and Synergies) shows that our method yields clearly higher particle emissions at sizes below 60 nm, but at sizes above that the two methods agree well. Overall, our method is proven to be a useful tool for gaining new knowledge of the size distributions of particle number emissions in urban environments and for validating emission inventories and models. In the future, the method will be developed by modeling the transport of particles from different sources to obtain more accurate estimates of particle number emissions.
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Karjalainen, Panu, Hilkka Timonen, Erkka Saukko, Heino Kuuluvainen, Sanna Saarikoski, Päivi Aakko-Saksa, Timo Murtonen i in. "Time-resolved characterization of primary particle emissions and secondary particle formation from a modern gasoline passenger car". Atmospheric Chemistry and Physics 16, nr 13 (14.07.2016): 8559–70. http://dx.doi.org/10.5194/acp-16-8559-2016.
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Abstract. Changes in vehicle emission reduction technologies significantly affect traffic-related emissions in urban areas. In many densely populated areas the amount of traffic is increasing, keeping the emission level high or even increasing. To understand the health effects of traffic-related emissions, both primary (direct) particulate emission and secondary particle formation (from gaseous precursors in the exhaust emissions) need to be characterized. In this study, we used a comprehensive set of measurements to characterize both primary and secondary particulate emissions of a Euro 5 level gasoline passenger car. Our aerosol particle study covers the whole process chain in emission formation, from the tailpipe to the atmosphere, and also takes into account differences in driving patterns. We observed that, in mass terms, the amount of secondary particles was 13 times higher than the amount of primary particles. The formation, composition, number and mass of secondary particles was significantly affected by driving patterns and engine conditions. The highest gaseous and particulate emissions were observed at the beginning of the test cycle when the performance of the engine and the catalyst was below optimal. The key parameter for secondary particle formation was the amount of gaseous hydrocarbons in primary emissions; however, also the primary particle population had an influence.
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Jasiński, Remigiusz. "Analysis of Particle Emissions from a Jet Engine including Conditions of Afterburner Use". Energies 15, nr 20 (18.10.2022): 7696. http://dx.doi.org/10.3390/en15207696.
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Particle emissions from aircraft engines are mainly related to the emission of particles with very small diameters. The phenomena of the formation of particles in various operating conditions of turbine engines are known. However, it is difficult to find the results of research on the use of the afterburner in the literature. Increased aviation activity within military airports and situations such as air shows are associated with a very intense emission of particles, and pose a direct threat to human health. This article presents an analysis of particulate matter emissions from a military aircraft engine, with particular emphasis on operation with an afterburner. The parameters of the emission of particles determined were: PM Number Emissions Index (EIN), Particle Number Emissions Intensity (EN), PM Mass Emission Index (EIM), PM Mass Emission Intensity (EM), Differential Particle Number Emission Index, Differential Particle Volume Emission Index, and Differential Particle Mass Emission Index. The value of EIN for the afterburner use was the lowest among the whole operation range of the engine and was equal to 1.3 × 1015 particles per kilogram. The use of an afterburner resulted in a sharp increase in the EIM coefficient, which reached 670 mg/kg. Despite a very large increase in fuel consumption, the EIM coefficient turned out to be over 60 times greater than in the case of 100% engine thrust.
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Paasonen, Pauli, Kaarle Kupiainen, Zbigniew Klimont, Antoon Visschedijk, Hugo A. C. Denier van der Gon i Markus Amann. "Continental anthropogenic primary particle number emissions". Atmospheric Chemistry and Physics 16, nr 11 (6.06.2016): 6823–40. http://dx.doi.org/10.5194/acp-16-6823-2016.
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Abstract. Atmospheric aerosol particle number concentrations impact our climate and health in ways different from those of aerosol mass concentrations. However, the global, current and future anthropogenic particle number emissions and their size distributions are so far poorly known. In this article, we present the implementation of particle number emission factors and the related size distributions in the GAINS (Greenhouse Gas–Air Pollution Interactions and Synergies) model. This implementation allows for global estimates of particle number emissions under different future scenarios, consistent with emissions of other pollutants and greenhouse gases. In addition to determining the general particulate number emissions, we also describe a method to estimate the number size distributions of the emitted black carbon particles. The first results show that the sources dominating the particle number emissions are different to those dominating the mass emissions. The major global number source is road traffic, followed by residential combustion of biofuels and coal (especially in China, India and Africa), coke production (Russia and China), and industrial combustion and processes. The size distributions of emitted particles differ across the world, depending on the main sources: in regions dominated by traffic and industry, the number size distribution of emissions peaks in diameters range from 20 to 50 nm, whereas in regions with intensive biofuel combustion and/or agricultural waste burning, the emissions of particles with diameters around 100 nm are dominant. In the baseline (current legislation) scenario, the particle number emissions in Europe, Northern and Southern Americas, Australia, and China decrease until 2030, whereas especially for India, a strong increase is estimated. The results of this study provide input for modelling of the future changes in aerosol–cloud interactions as well as particle number related adverse health effects, e.g. in response to tightening emission regulations. However, there are significant uncertainties in these current emission estimates and the key actions for decreasing the uncertainties are pointed out.
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Wang, Dawei, Hai Guo i Congrong He. "An investigation on particle emission from a new laser printer using an environmental chamber". Indoor and Built Environment 26, nr 8 (18.08.2016): 1144–54. http://dx.doi.org/10.1177/1420326x16665160.
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In this study, emissions of ultrafine particles from a new laser printer were evaluated as a function of toner coverage, number of pages printed, fuser temperature and cartridge rotation during different printing orders. Eight combinations of printing jobs were specifically designed to represent eight printing orders. The toner coverage was found to be an important factor affecting particle emissions from the printer. The printing job without toner coverage (0%) acted as a cleaning process, which would tentatively reduce particle emissions in the next job. Particles generated in printing job with toner coverage (5%) could superimpose onto those emitted from the next job, leading to higher particle number emission in the next job than the previous one. Apart from toner coverage, cartridge rotation was an important factor enhancing particle emissions. Cartridge in rotation mode with/without toner coverage could both cause particle emissions and high fuser temperature. The relationship between the particle emission and the temperature of the fuser unit was very strong ( r2 = 0.96). The regression relationship satisfied a positive power law-rise equation. We also found that ventilation for a long period, printing with no cartridge rotation, and/or printing blank pages before toner page printing could reduce particle emissions.
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Feißel, Toni, Florian Büchner, Miles Kunze, Jonas Rost, Valentin Ivanov, Klaus Augsburg, David Hesse i Sebastian Gramstat. "Methodology for Virtual Prediction of Vehicle-Related Particle Emissions and Their Influence on Ambient PM10 in an Urban Environment". Atmosphere 13, nr 11 (18.11.2022): 1924. http://dx.doi.org/10.3390/atmos13111924.
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As a result of rising environmental awareness, vehicle-related emissions such as particulate matter are subject to increasing criticism. The air pollution in urban areas is especially linked to health risks. The connection between vehicle-related particle emissions and ambient air quality is highly complex. Therefore, a methodology is presented to evaluate the influence of different vehicle-related sources such as exhaust particles, brake wear and tire and road wear particles (TRWP) on ambient particulate matter (PM). In a first step, particle measurements were conducted based on field trials with an instrumented vehicle to determine the main influence parameters for each emission source. Afterwards, a simplified approach for a qualitative prediction of vehicle-related particle emissions is derived. In a next step, a virtual inner-city scenario is set up. This includes a vehicle simulation environment for predicting the local emission hot spots as well as a computational fluid dynamics model (CFD) to account for particle dispersion in the environment. This methodology allows for the investigation of emissions pathways from the point of generation up to the point of their emission potential.
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Ahlm, L., J. Julin, C. Fountoukis, S. N. Pandis i I. Riipinen. "Particle number concentrations over Europe in 2030: the role of emissions and new particle formation". Atmospheric Chemistry and Physics Discussions 13, nr 4 (3.04.2013): 8769–803. http://dx.doi.org/10.5194/acpd-13-8769-2013.
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Abstract. The aerosol particle number concentration is a key parameter when estimating impacts of aerosol particles on climate and human health. We use a three-dimensional chemical transport model with detailed microphysics, PMCAMx-UF, to simulate particle number concentrations over Europe in the year 2030, by applying emission scenarios for trace gases and primary aerosols. The scenarios are based on expected changes in anthropogenic emissions of sulphur dioxide, ammonia, nitrogen oxides, and primary aerosol particles with a diameter less than 2.5 μm (PM2.5) focusing on a photochemically active period. For the baseline scenario, which represents a best estimate of the evolution of anthropogenic emissions in Europe, PMCAMx-UF predicts that the total particle number concentration (Ntot) will decrease by 30–70% between 2008 and 2030. The number concentration of particles larger than 100 nm (N100), a proxy for cloud condensation nuclei (CCN) concentration, is predicted to decrease by 40–70% during the same period. The predicted decrease in Ntot is mainly a result of reduced new particle formation due to the expected reduction in SO2 emissions, whereas the predicted decrease in N100 is a result of both decreasing condensational growth and reduced primary aerosol emissions. For larger emission reductions, PMCAMx-UF predicts reductions of 60–80% in both Ntot and N100 over Europe. Sensitivity tests reveal that a reduction in SO2 emissions is far more efficient than any other emission reduction investigated, in reducing Ntot. For N100, emission reductions of both SO2 and PM2.5 contribute significantly to the reduced concentration, even though SO2 plays the dominant role once more. The impact of SO2 for both new particle formation and growth over Europe may be expected to be somewhat higher during the simulated period with high photochemical activity than during times of the year with less incoming solar radiation. The predicted reductions in both Ntot and N100 between 2008 and 2030 in this study will likely reduce both the aerosol direct and indirect effects, and limit the damaging effects of aerosol particles on human health in Europe.
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Mathissen, Marcel, Theodoros Grigoratos, Tero Lahde i Rainer Vogt. "Brake Wear Particle Emissions of a Passenger Car Measured on a Chassis Dynamometer". Atmosphere 10, nr 9 (17.09.2019): 556. http://dx.doi.org/10.3390/atmos10090556.
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Brake wear emissions with a special focus on particle number (PN) concentrations were investigated during a chassis dynamometer measurement campaign. A recently developed, well-characterized, measurement approach was applied to measure brake particles in a semi-closed vehicle setup. Implementation of multiple particle measurement devices allowed for simultaneous measurement of volatile and solid particles. Estimated PN emission factors for volatile and solid particles differed by up to three orders of magnitude with an estimated average solid particle emission factor of 3∙109 # km−1 brake−1 over a representative on-road brake cycle. Unrealistic high brake temperatures may occur and need to be ruled out by comparison with on-road temperature measurements. PN emissions are strongly temperature dependent and this may lead to its overestimation. A high variability for PN emissions was found when volatile particles were not removed. Volatiles were observed under high temperature conditions only which are not representative of normal driving conditions. The coefficient of variation for PN emissions was 1.3 without catalytic stripper and 0.11 with catalytic stripper. Investigation of non-braking sections confirmed that particles may be generated at the brake even if no brakes are applied. These “off-brake-event” emissions contribute up to about 30% to the total brake PM10 emission.
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Ahlm, L., J. Julin, C. Fountoukis, S. N. Pandis i I. Riipinen. "Particle number concentrations over Europe in 2030: the role of emissions and new particle formation". Atmospheric Chemistry and Physics 13, nr 20 (22.10.2013): 10271–83. http://dx.doi.org/10.5194/acp-13-10271-2013.
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Abstract. The aerosol particle number concentration is a key parameter when estimating impacts of aerosol particles on climate and human health. We use a three-dimensional chemical transport model with detailed microphysics, PMCAMx-UF, to simulate particle number concentrations over Europe in the year 2030, by applying emission scenarios for trace gases and primary aerosols. The scenarios are based on expected changes in anthropogenic emissions of sulfur dioxide, ammonia, nitrogen oxides, and primary aerosol particles with a diameter less than 2.5 μm (PM2.5) focusing on a photochemically active period, and the implications for other seasons are discussed. For the baseline scenario, which represents a best estimate of the evolution of anthropogenic emissions in Europe, PMCAMx-UF predicts that the total particle number concentration (Ntot) will decrease by 30–70% between 2008 and 2030. The number concentration of particles larger than 100 nm (N100), a proxy for cloud condensation nuclei (CCN) concentration, is predicted to decrease by 40–70% during the same period. The predicted decrease in Ntot is mainly a result of reduced new particle formation due to the expected reduction in SO2 emissions, whereas the predicted decrease in N100 is a result of both decreasing condensational growth and reduced primary aerosol emissions. For larger emission reductions, PMCAMx-UF predicts reductions of 60–80% in both Ntot and N100 over Europe. Sensitivity tests reveal that a reduction in SO2 emissions is far more efficient than any other emission reduction investigated, in reducing Ntot. For N100, emission reductions of both SO2 and PM2.5 contribute significantly to the reduced concentration, even though SO2 plays the dominant role once more. The impact of SO2 for both new particle formation and growth over Europe may be expected to be somewhat higher during the simulated period with high photochemical activity than during times of the year with less incoming solar radiation. The predicted reductions in both Ntot and N100 between 2008 and 2030 in this study will likely reduce both the aerosol direct and indirect effects, and limit the damaging effects of aerosol particles on human health in Europe.
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Gramstat, Sebastian, Thilo Mertens, Robert Waninger i Dmytro Lugovyy. "Impacts on Brake Particle Emission Testing". Atmosphere 11, nr 10 (21.10.2020): 1132. http://dx.doi.org/10.3390/atmos11101132.
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The presented article picks out brake particle emission testing as a central theme. Those emissions are part of the so-called non-exhaust emissions, which play an increasing role for particle emissions from transportation. The authors propose a laboratory test setup by using a brake dynamometer and a constant volume sampling approach to determine the emissions in regard to the particle number concentration. Several impacts were investigated while the same test cycle (novel worldwide harmonized light vehicles test procedure (novel-WLTP)) was applied. In a first item, the importance of the bedding process was investigated and it is shown that friction couples without bedding emit much more particles. Furthermore, the efforts for reaching a bedded friction state are discussed. Additionally, the impact of brake lining compositions is investigated and shows that NAO concepts own crucial advantages in terms of brake particle emissions. Another impact, the vehicle weight and inertia, respectively, shows how important lightweight measures and brake cooling improvements are. Finally, the role of the load profile is discussed, which shows the importance of driving parameters like vehicle speed and reservoir dynamics. The authors show that, under urban driving conditions, extreme low particle emissions are detected. Furthermore, it is explained that off-brake emissions can play a relevant role in regard to brake particle emissions.
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Josephson, Alexander J., Daniel Castaño, Marlin J. Holmes i Rodman R. Linn. "Simulation Comparisons of Particulate Emissions from Fires under Marginal and Critical Conditions". Atmosphere 10, nr 11 (13.11.2019): 704. http://dx.doi.org/10.3390/atmos10110704.
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Using a particulate emissions model developed for FIRETEC, we explore differences in particle emission profiles between high-intensity fires under critical conditions and low-intensity fires under marginal conditions. Simulations were performed in a chaparral shrubland and a coniferous pine forest representative of the southeast United States. In each case, simulations were carried out under marginal and critical fire conditions. Marginal fire conditions include high moisture levels and low winds, often desired for prescribed fires as these conditions produce a low-intensity burn with slower spread rates. Critical fire conditions include low moisture levels and high winds, which easily lead to uncontrollable wildfires which produce a high-intensity burn with faster spread rates. These simulations’ resultant particle emission profiles show critical fire conditions generate larger particle emission factors, higher total mass emissions, and a higher lofting potential of particles into the atmosphere when compared against marginal fire conditions but similar particle size distrubtions. In addition, a sensitivity analysis of the emissions model was performed to evaluate key parameters which govern particle emission factor and particle size.
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Karjalainen, P., H. Timonen, E. Saukko, H. Kuuluvainen, S. Saarikoski, P. Aakko-Saksa, T. Murtonen i in. "Time-resolved characterization of primary and secondary particle emissions of a modern gasoline passenger car". Atmospheric Chemistry and Physics Discussions 15, nr 22 (25.11.2015): 33253–82. http://dx.doi.org/10.5194/acpd-15-33253-2015.
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Abstract. Changes in traffic systems and vehicle emission reduction technologies significantly affect traffic-related emissions in urban areas. In many densely populated areas the amount of traffic is increasing, keeping the emission level high or even increasing. To understand the health effects of traffic related emissions, both primary and secondary particles that are formed in the atmosphere from gaseous exhaust emissions need to be characterized. In this study we used a comprehensive set of measurements to characterize both primary and secondary particulate emissions of a modern gasoline passenger car. Our aerosol particle study covers the whole process chain in emission formation, from the engine to the atmosphere, and takes into account also differences in driving patterns. We observed that in mass terms, the amount of secondary particles was 13 times higher than the amount of primary particles. The formation, composition, number, and mass of secondary particles was significantly affected by driving patterns and engine conditions. The highest gaseous and particulate emissions were observed at the beginning of the test cycle when the performance of the engine and the catalyst was below optimal. The key parameter for secondary particle formation was the amount of gaseous hydrocarbons in primary emissions; however, also the primary particle population had an influence. Thus, in order to enhance human health and wellbeing in urban areas, our study strongly indicates that in future legislation, special attention should be directed into the reduction of gaseous hydrocarbons.
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Lou, Diming, Guokang Lou, Bo Wang, Liang Fang i Yunhua Zhang. "Effect of LP-EGR on the Emission Characteristics of GDI Engine". Machines 10, nr 1 (22.12.2021): 7. http://dx.doi.org/10.3390/machines10010007.
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Exhaust gas recirculation (EGR) can improve the fuel economy of gasoline direct-injection (GDI) engines, but at the same time it will have a significant impact on emissions. In this paper, the effects of low-pressure exhaust gas recirculation (LP-EGR) and its rate on the main gaseous and particulate emission characteristic of a GDI engine were investigated. The results showed that the particle size distribution of the GDI engine presented bimodal peaks in nucleation and accumulation mode, and the nucleation mode particles comprised the vast majority of the total particles. The effect of LP-EGR on emissions depended on the engine conditions. At low and medium speed, the particle emissions increased with the increase in the EGR rate, while at high speed, a reduction in the particle emission was observed. When the engine operated in full load condition, an increase in the EGR rate reduced the particle number (PN) concentration significantly, but increased the particle mass (PM) concentration. In terms of the gaseous emission, the EGR could reduce as much as 80% of the NOx emission; however, the total hydrocarbons (THC) emission presented an increased trend, and the maximum increase reached 23.5%. At low and medium loads, the EGR could reduce the CO emission, but at high load, the CO emission worsened with the EGR.
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Giechaskiel, Barouch, Anastasios Melas, Giorgio Martini, Panagiota Dilara i Leonidas Ntziachristos. "Revisiting Total Particle Number Measurements for Vehicle Exhaust Regulations". Atmosphere 13, nr 2 (18.01.2022): 155. http://dx.doi.org/10.3390/atmos13020155.
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Road transport significantly contributes to air pollution in cities. Emission regulations have led to significantly reduced emissions in modern vehicles. Particle emissions are controlled by a particulate matter (PM) mass and a solid particle number (SPN) limit. There are concerns that the SPN limit does not effectively control all relevant particulate species and there are instances of semi-volatile particle emissions that are order of magnitudes higher than the SPN emission levels. This overview discusses whether a new metric (total particles, i.e., solids and volatiles) should be introduced for the effective regulation of vehicle emissions. Initially, it summarizes recent findings on the contribution of road transport to particle number concentration levels in cities. Then, both solid and total particle emission levels from modern vehicles are presented and the adverse health effects of solid and volatile particles are briefly discussed. Finally, the open issues regarding an appropriate methodology (sampling and instrumentation) in order to achieve representative and reproducible results are summarized. The main finding of this overview is that, even though total particle sampling and quantification is feasible, details for its realization in a regulatory context are lacking. It is important to define the methodology details (sampling and dilution, measurement instrumentation, relevant sizes, etc.) and conduct inter-laboratory exercises to determine the reproducibility of a proposed method. It is also necessary to monitor the vehicle emissions according to the new method to understand current and possible future levels. With better understanding of the instances of formation of nucleation mode particles it will be possible to identify its culprits (e.g., fuel, lubricant, combustion, or aftertreatment operation). Then the appropriate solutions can be enforced and the right decisions can be taken on the need for new regulatory initiatives, for example the addition of total particles in the tailpipe, decrease of specific organic precursors, better control of inorganic precursors (e.g., NH3, SOx), or revision of fuel and lubricant specifications.
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Fernández-Camacho, R., S. Rodríguez, J. de la Rosa, A. M. Sánchez de la Campa, M. Viana, A. Alastuey i X. Querol. "Ultrafine particle formation in the inland sea breeze airflow in Southwest Europe". Atmospheric Chemistry and Physics Discussions 10, nr 7 (23.07.2010): 17753–88. http://dx.doi.org/10.5194/acpd-10-17753-2010.
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Abstract. Studies on ultrafine particles and air quality have mostly focused on vehicle exhaust emissions and on new particle formation in "clean" ambient air. Here we present a study of the processes contributing to ultrafine particle concentrations in an urban coastal area (Huelva, SW Spain) where significant anthropogenic emissions of aerosol precursors occur. The overall data analysis shows that two processes predominantly contribute to the number of particles coarser than 2.5 nm: vehicle exhaust emissions and new particle formation due to photo-chemical activity. As typically occurs in urban areas, vehicle exhaust emissions result in high concentrations of black carbon (BC) and particles coarser than 2.5 nm (N) during the morning rush hours. The highest N concentrations were recorded during the 11–17 h period, under the sea breeze regime, when photochemical activity resulted in high O3 levels and new particle formation in the aerosol precursors' rich inland airflow. In this period, it is estimated that about 80% of the number of particles are linked to sulfur dioxide emissions. The contributions to N of "carbonaceous material and those compounds nucleating/condensing immediately after emission" and of the "new particle formation processes in air masses rich gaseous precursors (e.g. SO2)" were estimated by means of a relatively novel method based on simultaneous measurements of BC and N. A comparison with two recent studies suggests that the daily cycles of "new particle formation" during the period when the inland sea breeze is blowing period seem to be a feature of ultrafine particles in coastal areas of South-west Europe.
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Vogt, M., E. D. Nilsson, L. Ahlm, E. M. Mårtensson i C. Johansson. "The relationship between 0.25–2.5 μm aerosol and CO<sub>2</sub> emissions over a city". Atmospheric Chemistry and Physics Discussions 10, nr 9 (9.09.2010): 21521–45. http://dx.doi.org/10.5194/acpd-10-21521-2010.
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Abstract. Unlike exhaust emissions, non-exhaust traffic emissions are completely unregulated and there are large uncertainties in the non-exhaust emission factors required to estimate the emissions of these aerosols. This study provides the first published results of direct measurements of size resolved emission factors for particles in the size range 0.25–2.5 μm using a new approach deriving aerosol emission factors from the CO2 emission fluxes. Because the aerosol and CO2 emissions have a common source and because the CO2 emission per fuel or traffic amount are much less uncertain than the aerosol emissions, this approach has obvious advantages. Therefore aerosol fluxes were measured during one year using the eddy covariance method at the top of a 118 m high communication tower over Stockholm, Sweden. Maximum CO2 and particle fluxes coincides with the wind direction with densest traffic within the footprint area. Negative fluxes (uptake of CO2 and deposition of particles) coincides with an urban forest area. The fluxes of CO2 were used to obtain emission factors for particles by assuming that the CO2 fluxes could converted to amounts of fuel burnt. The estimated emission factors for the fleet mix in the measurement area are, in number 1.4×1011 [particle veh−1 km−1]. Assuming spherical particles of density 1600 kg/m3 this corresponds to 27.5 mg veh−1 km−1. Wind speed influence the emission factor indicating that wind induced turbulence may be important.
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Kouam, Jules, Victor Songmene, Ali Bahloul i Agnes M. Samuel. "Characterization of Si and SiO2 in Dust Emitted during Granite Polishing as a Function of Cutting Conditions". Materials 15, nr 11 (2.06.2022): 3965. http://dx.doi.org/10.3390/ma15113965.
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Particles emitted during manufacturing processes such as polishing can represent a serious danger for the environment and for occupational safety. The formation mechanisms responsible for these dust emissions include chip formation, friction at the tool/workpiece and chip/tool interfaces, shearing and cutting. These mechanisms thus depend on workpiece and tool properties, as well as the polishing conditions. In the case of granite polishing, particle emissions during polishing can contain chemical compounds such as silica, which represent harmful health risks for the worker. It is therefore important to characterize the particles emitted and to search for possible interactions between the particles (size and composition) and the machining conditions in order to find ways of reducing emissions at the source. In this study, an investigation was undertaken to characterize the particles emitted during granite polishing as a function of polishing conditions, type of granite, and abrasive grit sizes used. Scanning electron microscopy (SEM) was employed for particle morphology characterization and particle grain size and chemical composition were evaluated using X-ray diffraction (XRD) and energy dispersive X-ray (EDX) techniques, respectively. Results show that the influence of polishing speed and feed rate on particle emission depends mainly on the granite type used, providing useful information for controlling the polishing procedure, and thereby dust emission.
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Wang, Xinning, Yin Shen, Yanfen Lin, Jun Pan, Yan Zhang, Peter K. K. Louie, Mei Li i Qingyan Fu. "Atmospheric pollution from ships and its impact on local air quality at a port site in Shanghai". Atmospheric Chemistry and Physics 19, nr 9 (14.05.2019): 6315–30. http://dx.doi.org/10.5194/acp-19-6315-2019.
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Abstract. Growing shipping activities in port areas have generated negative impacts on climate, air quality and human health. To better evaluate the environmental impact of ship emissions, an experimental characterization of air pollution from ships was conducted in Shanghai Port in the summer of 2016. The ambient concentrations of gaseous NO, NO2, SO2 and O3 in addition to fine particulate matter concentrations (PM2.5), particle size distributions and the chemical composition of individual particles from ship emission were continuously monitored for 3 months. Ship emission plumes were visible at the port site in terms of clear peaks in the gaseous species and particulate matter concentrations. The SO2 and vanadium particle numbers were found to correlate best with ship emissions in Shanghai Port. Single-particle data showed that ship emission particles at the port site mainly concentrated in a smaller size range (<0.4 µm), where their number contributions were more important than their mass contributions to ambient particulate matter. The composition of ship emission particles at the port site suggested that they were mostly freshly emitted particles: their mass spectra were dominated by peaks of sulfate, elemental carbon (EC), and trace metals such as V, Ni, Fe and Ca, in addition to displaying very low nitrate signals. The gaseous NOx composition in some cases of plumes showed evidence of atmospheric transformation by ambient O3, which subsequently resulted in O3 depletion in the area. Quantitative estimations in this study showed that ship emissions contributed 36.4 % to SO2, 0.7 % to NO, 5.1 % to NO2, −0.9 % to O3, 5.9 % to PM2.5 and 49.5 % to vanadium particles in the port region if land-based emissions were included, and 57.2 % to SO2, 71.9 % to NO, 30.4 % to NO2, −16.6 % to O3, 27.6 % to PM2.5 and 77.0 % to vanadium particles if land-based emissions were excluded.
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Fernández-Camacho, R., S. Rodríguez, J. de la Rosa, A. M. Sánchez de la Campa, M. Viana, A. Alastuey i X. Querol. "Ultrafine particle formation in the inland sea breeze airflow in Southwest Europe". Atmospheric Chemistry and Physics 10, nr 19 (11.10.2010): 9615–30. http://dx.doi.org/10.5194/acp-10-9615-2010.
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Abstract. Studies on ultrafine particles (diameter < 100nm) and air quality have mostly focused on vehicle exhaust emissions and on new particle formation in "clean" ambient air. Here we present a study focused on the processes contributing to ultrafine particle concentrations in a city (Huelva, SW Spain) placed close to a coastal area where significant anthropogenic emissions of aerosol precursors occur. The overall data analysis shows that two processes predominantly contribute to the number of particles coarser than 2.5 nm: vehicle exhaust emissions and new particle formation due to photo-chemical activity. As typically occurs in urban areas, vehicle exhaust emissions result in high concentrations of black carbon (BC) and particles coarser than 2.5 nm (N) during the morning rush hours. The highest N concentrations were recorded during the 11:00–17:00 h period, under the sea breeze regime, when low BC concentrations were registered and photochemical activity resulted in high O3 levels and in new particle formation in the aerosol precursors' rich inland airflow. In this period, it is estimated that about 80% of the number of particles are linked to sulfur dioxide emissions. The contributions to N of "carbonaceous material and those compounds nucleating/condensing immediately after emission" and of the "new particle formation processes in air masses rich gaseous precursors (e.g. SO2)" were estimated by means of a relatively novel method based on simultaneous measurements of BC and N. A comparison with two recent studies suggests that the daily cycles of "new particle formation" during the inland sea breeze is blowing period seem to be a feature of ultrafine particles in coastal areas of South-west Europe.
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Gomes Nogueira, Ana Paula, Davide Carlevaris, Cinzia Menapace i Giovanni Straffelini. "Tribological and Emission Behavior of Novel Friction Materials". Atmosphere 11, nr 10 (30.09.2020): 1050. http://dx.doi.org/10.3390/atmos11101050.
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The tribological behavior and the related airborne particles emission of three copper-free automotive friction materials are investigated. The tests were conducted using a pin-on-disc tribometer equipped with a specifically designed clean-enclosure chamber for the emission measurement. Particle number concentration from particle size 0.3 µm up to 10 µm and the mass of emitted particles between 1 µm to 10 µm were measured. Particular emphasis was given to the chemical composition of the bulk materials, the friction layers and the emissions, in order to explain the acting wear mechanisms, and the recorded emission of airborne particles. The results indicate that the recorded emissions do not correlate with the friction coefficient and the wear rates, since the wear mechanisms exert a different influence on the tribological and emission behavior of the materials under study.
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Peters, K., P. Stier, J. Quaas i H. Graßl. "Aerosol indirect effects from shipping emissions: sensitivity studies with the global aerosol-climate model ECHAM-HAM". Atmospheric Chemistry and Physics Discussions 12, nr 3 (8.03.2012): 7073–123. http://dx.doi.org/10.5194/acpd-12-7073-2012.
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Abstract. In this study, we employ the global aerosol-climate model ECHAM-HAM to globally assess aerosol indirect effects (AIEs) resulting from shipping emissions of aerosols and aerosol precursor gases. We implement shipping emissions of sulphur dioxide (SO2), black carbon (BC) and particulate organic matter (POM) for the year 2000 into the model and quantify the model's sensitivity towards uncertainties associated with the emission parameterisation as well as with the shipping emissions themselves. Sensitivity experiments are designed to investigate (i) the uncertainty in the size distribution of emitted particles, (ii) the uncertainty associated with the total amount of emissions, and (iii) the impact of reducing carbonaceous emissions from ships. We use the results from one sensitivity experiment for a detailed discussion of shipping-induced changes in the global aerosol system as well as the resulting impact on cloud properties. From all sensitivity experiments, we find AIEs from shipping emissions to range from −0.07 ± 0.01 W m−2 to −0.32 ± 0.01 W m−2 (global mean value and inter-annual variability as a standard deviation). The magnitude of the AIEs depends much more on the assumed emission size distribution and subsequent aerosol microphysical interactions than on the magnitude of the emissions themselves. It is important to note that although the strongest estimate of AIEs from shipping emissions in this study is relatively large, still much larger estimates have been reported in the literature before on the basis of modelling studies. We find that omitting just carbonaceous particle emissions from ships favours new particle formation in the boundary layer. These newly formed particles contribute just about as much to the CCN budget as the carbonaceous particles would, leaving the globally averaged AIEs nearly unaltered compared to a simulation including carbonaceous particle emissions from ships.
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Peters, K., P. Stier, J. Quaas i H. Graßl. "Aerosol indirect effects from shipping emissions: sensitivity studies with the global aerosol-climate model ECHAM-HAM". Atmospheric Chemistry and Physics 12, nr 13 (13.07.2012): 5985–6007. http://dx.doi.org/10.5194/acp-12-5985-2012.
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Abstract. In this study, we employ the global aerosol-climate model ECHAM-HAM to globally assess aerosol indirect effects (AIEs) resulting from shipping emissions of aerosols and aerosol precursor gases. We implement shipping emissions of sulphur dioxide (SO2), black carbon (BC) and particulate organic matter (POM) for the year 2000 into the model and quantify the model's sensitivity towards uncertainties associated with the emission parameterisation as well as with the shipping emissions themselves. Sensitivity experiments are designed to investigate (i) the uncertainty in the size distribution of emitted particles, (ii) the uncertainty associated with the total amount of emissions, and (iii) the impact of reducing carbonaceous emissions from ships. We use the results from one sensitivity experiment for a detailed discussion of shipping-induced changes in the global aerosol system as well as the resulting impact on cloud properties. From all sensitivity experiments, we find AIEs from shipping emissions to range from −0.32 ± 0.01 W m−2 to −0.07 ± 0.01 W m−2 (global mean value and inter-annual variability as a standard deviation). The magnitude of the AIEs depends much more on the assumed emission size distribution and subsequent aerosol microphysical interactions than on the magnitude of the emissions themselves. It is important to note that although the strongest estimate of AIEs from shipping emissions in this study is relatively large, still much larger estimates have been reported in the literature before on the basis of modelling studies. We find that omitting just carbonaceous particle emissions from ships favours new particle formation in the boundary layer. These newly formed particles contribute just about as much to the CCN budget as the carbonaceous particles would, leaving the globally averaged AIEs nearly unaltered compared to a simulation including carbonaceous particle emissions from ships.
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Olin, Miska, David Patoulias, Heino Kuuluvainen, Jarkko V. Niemi, Topi Rönkkö, Spyros N. Pandis, Ilona Riipinen i Miikka Dal Maso. "Contribution of traffic-originated nanoparticle emissions to regional and local aerosol levels". Atmospheric Chemistry and Physics 22, nr 2 (24.01.2022): 1131–48. http://dx.doi.org/10.5194/acp-22-1131-2022.
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Abstract. Sub-50 nm particles originating from traffic emissions pose risks to human health due to their high lung deposition efficiency and potentially harmful chemical composition. We present a modeling study using an updated European Aerosol Cloud Climate and Air Quality Interactions (EUCAARI) number emission inventory, incorporating a more realistic, empirically justified particle size distribution (PSD) for sub-50 nm particles from road traffic as compared with the previous version. We present experimental PSDs and CO2 concentrations, measured in a highly trafficked street canyon in Helsinki, Finland, as an emission factor particle size distribution (EFPSD), which was then used in updating the EUCAARI inventory. We applied the updated inventory in a simulation using the regional chemical transport model PMCAMx-UF over Europe for May 2008. This was done to test the effect of updated emissions at regional and local scales, particularly in comparison with atmospheric new particle formation (NPF). Updating the inventory increased the simulated average total particle number concentrations by only 1 %, although the total particle number emissions were increased to a 3-fold level. The concentrations increased up to 11 % when only 1.3–3 nm sized particles (nanocluster aerosol, NCA) were considered. These values indicate that the effect of updating overall is insignificant at a regional scale during this photochemically active period. During this period, the fraction of the total particle number originating from atmospheric NPF processes was 91 %; thus, these simulations give a lower limit for the contribution of traffic to the aerosol levels. Nevertheless, the situation is different when examining the effect of the update closer spatially or temporally or when focusing on the chemical composition or the origin of the particles. For example, the daily average NCA concentrations increased by a factor of several hundred or thousand in some locations on certain days. Overall, the most significant effects – reaching several orders of magnitude – from updating the inventory are observed when examining specific particle sizes (especially 7–20 nm), particle components, and specific urban areas. While the model still has a tendency to predict more sub-50 nm particles compared to the observations, the most notable underestimations in the concentrations of sub-10 nm particles are now overcome. Additionally, the simulated distributions now agree better with the data observed at locations with high traffic densities. The findings of this study highlight the need to consider emissions, PSDs, and composition of sub-50 nm particles from road traffic in studies focusing on urban air quality. Updating this emission source brings the simulated aerosol levels, particularly in urban locations, closer to observations, which highlights its importance for calculations of human exposure to nanoparticles.
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Xausa, Filippo, Pauli Paasonen, Risto Makkonen, Mikhail Arshinov, Aijun Ding, Hugo Denier Van Der Gon, Veli-Matti Kerminen i Markku Kulmala. "Advancing global aerosol simulations with size-segregated anthropogenic particle number emissions". Atmospheric Chemistry and Physics 18, nr 13 (16.07.2018): 10039–54. http://dx.doi.org/10.5194/acp-18-10039-2018.
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Abstract. Climate models are important tools that are used for generating climate change projections, in which aerosol–climate interactions are one of the main sources of uncertainties. In order to quantify aerosol–radiation and aerosol–cloud interactions, detailed input of anthropogenic aerosol number emissions is necessary. However, the anthropogenic aerosol number emissions are usually converted from the corresponding mass emissions in pre-compiled emission inventories through a very simplistic method depending uniquely on chemical composition, particle size and density, which are defined for a few, very wide main source sectors. In this work, the anthropogenic particle number emissions converted from the AeroCom mass in the ECHAM-HAM climate model were replaced with the recently formulated number emissions from the Greenhouse Gas and Air Pollution Interactions and Synergies (GAINS) model. In the GAINS model the emission number size distributions vary, for example, with respect to the fuel and technology. Special attention was paid to accumulation mode particles (particle diameter dp > 100 nm) because of (i) their capability of acting as cloud condensation nuclei (CCN), thus forming cloud droplets and affecting Earth's radiation budget, and (ii) their dominant role in forming the coagulation sink and thus limiting the concentration of sub-100 nm particles. In addition, the estimates of anthropogenic CCN formation, and thus the forcing from aerosol–climate interactions, are expected to be affected. Analysis of global particle number concentrations and size distributions reveals that GAINS implementation increases CCN concentration compared with AeroCom, with regional enhancement factors reaching values as high as 10. A comparison between modeled and observed concentrations shows that the increase in number concentration for accumulation mode particles agrees well with measurements, but it leads to a consistent underestimation of both nucleation mode and Aitken mode (dp < 100 nm) particle number concentrations. This suggests that revisions are needed in the new particle formation and growth schemes currently applied in global modeling frameworks.
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Zhao, Yujiao, Mengyao Wang, Pengfei Tao, Guozhi Qiu i Xueying Lu. "Emission Characteristics of Particulate Matter from Boiling Food". Atmosphere 14, nr 1 (12.01.2023): 167. http://dx.doi.org/10.3390/atmos14010167.
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Cooking food in water or soup, such as hot pot, is a widely used cooking method in China. This type of cooking requires no oil and cooks at a lower temperature, but that does not mean it produces fewer pollutants or is less harmful. There are few research studies on the emission characteristics and mechanisms of particulate matter emissions when eating hot pot (the boiling process), which leads to the unreasonable design of ventilation systems for this kind of catering. In this paper, the effects of boiling different ingredients (including noodles, potatoes, fish, tofu, meatballs, and pork) on particle number concentration emissions were studied. The particle number concentration and particle size distribution of PM with diameters of 0.3 μm and less, 0.3–0.5 μm and 0.5–1.0 μm (PM0.3, PM0.3–0.5 and PM0.5–1.0, respectively) were measured in an experimental chamber. The food type and shape showed very little change in the PM emission characteristics of boiling. When the boiling state was reached, the number concentration, particle size distribution, and arithmetic mean diameter of particles all fluctuated within 60 s. The emission characteristics of particles produced by boiling water and heating oil were compared. Heating oil produced more small particles, and boiling water released more large particles. Transient and steady methods were used to calculate the emission rate of particles, and the steady-state calculation has a high estimation of the emission rate.
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Reyes, Felipe, Yeanice Vasquez, Ernesto Gramsch, Pedro Oyola, Bernhard Rappenglück i María A. Rubio. "Photooxidation of Emissions from Firewood and Pellet Combustion Using a Photochemical Chamber". Atmosphere 10, nr 10 (24.09.2019): 575. http://dx.doi.org/10.3390/atmos10100575.
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The main emission source in Central and Southern Chilean cities is biomass combustion from residential heating and cooking due to old combustion technologies that are still widely utilized. In order to improve our understanding of biomass burning pollution and how it ages in the atmosphere, emissions from a pellet and wood stoves were studied with the aid of a photochemical chamber. Firewood combustion is an inefficient process that produces higher chamber loading of primary emission (gases and particles) compared to pellets. When these emissions are exposed to UV irradiation secondary particles are formed. However, with both fuels the secondary particle concentration was negligible with regards to the primary initial particle concentration. Observations show that when the initial mass is the same, firewood combustion emissions are more rapidly oxidized compared to emissions from pellet combustion. Particle aging evolution inside the chamber was evaluated using fragment tracer signals, via the mass fractions f44 vs f43 and f44 vs f60 triangles plots. For the same UV irradiation time, it was found that primary particles emitted form from firewood combustion show a slower aging rate compared to those emitted from pellet combustion, but this is due to high primary loading from wood combustion. Particle aging observed inside the chamber was similar to that found it in ambient urban air of Santiago de Chile in spring of 2011, indicating that chamber measurements can be a good indicator for some atmospheric processes. Levoglucosan, a well-known tracer for biomass combustion was also studied. It was found that wood stoves yielded higher levels than pellet stoves. This is due to the higher fuel combustion efficiency in pellet stoves, which yield low levoglucosan levels, making it difficult to use it for evaluation of the impact of pellet emissions on pollution.
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Cheung, H. C., L. Morawska i Z. D. Ristovski. "Observation of new particle formation in subtropical urban environment". Atmospheric Chemistry and Physics 11, nr 8 (27.04.2011): 3823–33. http://dx.doi.org/10.5194/acp-11-3823-2011.
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Abstract. The aim of this study was to characterise the new particle formation events in a subtropical urban environment in the Southern Hemisphere. The study measured the number concentration of particles and its size distribution in Brisbane, Australia during 2009. The variation of particle number concentration and nucleation burst events were characterised as well as the particle growth rate which was first reported in urban environment of Australia. The annual average NUFP, NAitken and NNuc were 9.3×103, 3.7×103 and 5.6×103 cm−3, respectively. Weak seasonal variation in number concentration was observed. Local traffic exhaust emissions were a major contributor of the pollution (NUFP) observed in morning which was dominated by the Aitken mode particles, while particles formed by secondary formation processes contributed to the particle number concentration during afternoon. Overall, 65 nucleation burst events were identified during the study period. Nucleation burst events were classified into two groups, with and without particles growth after the burst of nucleation mode particles observed. The average particle growth rate of the nucleation events was 4.6 nm h−1 (ranged from 1.79–7.78 nm h−1). Case studies of the nucleation burst events were characterised including (i) the nucleation burst with particle growth which is associated with the particle precursor emitted from local traffic exhaust emission, (ii) the nucleation burst without particle growth which is due to the transport of industrial emissions from the coast to Brisbane city or other possible sources with unfavourable conditions which suppressed particle growth and (iii) interplay between the above two cases which demonstrated the impact of the vehicle and industrial emissions on the variation of particle number concentration and its size distribution during the same day.
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Vogt, M., E. D. Nilsson, L. Ahlm, E. M. Mårtensson i C. Johansson. "The relationship between 0.25–2.5 μm aerosol and CO<sub>2</sub> emissions over a city". Atmospheric Chemistry and Physics 11, nr 10 (24.05.2011): 4851–59. http://dx.doi.org/10.5194/acp-11-4851-2011.
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Abstract. Unlike exhaust emissions, non-exhaust traffic emissions are completely unregulated and in addition, there are large uncertainties in the non-exhaust emission factors required to estimate the emissions of these aerosols. This study provides the first published results of direct measurements of size resolved emission factors for particles in the size range 0.25–2.5 μm using a new approach to derive aerosol emission factors based on carbon dioxide (CO2) emission fluxes. Aerosol fluxes were measured over one year using the eddy covariance method at the top of a 105 m high communication tower in Stockholm, Sweden. Maximum CO2 and particle fluxes were found when the wind direction coincided with the area of densest traffic within the footprint area. Negative fluxes (uptake of CO2 and deposition of particles) coincided with periods of sampling from an urban forest area. The fluxes of CO2 were used to obtain emission factors for particles by assuming that the CO2 fluxes could be directly related to the amount of fuel burnt by vehicles in the footprint area. The estimated emission factor for the fleet mix in the measurement area was, in number 1.8 × 1011 particle veh−1 km−1 (for 0.25–2.5 μm size range). Assuming spherical particles of density 1600 kg m−3 this corresponds to 27.5 mg veh−1 km−1. For particles (0.8–2.5 μm) the emission factors were 5.1 × 109 veh−1 km−1 for number and 11.5 mg veh−1 km−1 for mass. But a wind speed dependence was noted for high wind speeds. Thus, for wind speeds larger than 9 m s−1, as measured in the tower at 105 m (U105), the emission factor for particle number and mass was parameterised as: Ef (Number, 0.8–2.5 μm) = (6.1 ± 1.7)109 U105 −50 ± 188 and Ef (Mass, 0.8–2.5 μm) = (20 ± 12) U105 − 171 ±122.
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Giechaskiel, Barouch, Anastasios Melas i Tero Lähde. "Detailed Characterization of Solid and Volatile Particle Emissions of Two Euro 6 Diesel Vehicles". Applied Sciences 12, nr 7 (24.03.2022): 3321. http://dx.doi.org/10.3390/app12073321.
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The solid particle number emissions of Diesel vehicles are very low due to the particulate filters as exhaust aftertreatment devices. However, periodically, the trapped particles are oxidized (i.e., active regeneration) in order to keep the backpressure at low levels. The solid particle number emissions during regenerations are only partly covered by the regulations. Many studies have examined the emissions during regenerations, but their contribution to the overall emissions has not been addressed adequately. Furthermore, the number concentration of volatile particles, which is not included in the regulations, can be many of orders of magnitude higher. In this study, the particulate emissions of two light-duty Euro 6 vehicles were measured simultaneously at the tailpipe and the dilution tunnel. The results showed that the weighted (i.e., considering the emissions during regeneration) solid particle number emissions remained well below the applicable limit of 6 × 1011 #/km (solid particles > 23 nm). This was true even when considering solid sub-23 nm particles. However, the weighted volatile particle number emissions were many orders of magnitude higher, reaching up to 3 × 1013 #/km. The results also confirmed the equivalency of the solid particle number results between tailpipe and dilution tunnel locations. This was not the case for the volatile particles which were strongly affected by desorption phenomena. The high number of volatiles during regenerations even interfered with the 10 nm solid particle number measurements at the dilution tunnel, even though a catalytic stripper equipped instrument was also used in the dilution tunnel.
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Cai, Jing, Biwu Chu, Lei Yao, Chao Yan, Liine M. Heikkinen, Feixue Zheng, Chang Li i in. "Size-segregated particle number and mass concentrations from different emission sources in urban Beijing". Atmospheric Chemistry and Physics 20, nr 21 (4.11.2020): 12721–40. http://dx.doi.org/10.5194/acp-20-12721-2020.
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Abstract. Although secondary particulate matter is reported to be the main contributor of PM2.5 during haze in Chinese megacities, primary particle emissions also affect particle concentrations. In order to improve estimates of the contribution of primary sources to the particle number and mass concentrations, we performed source apportionment analyses using both chemical fingerprints and particle size distributions measured at the same site in urban Beijing from April to July 2018. Both methods resolved factors related to primary emissions, including vehicular emissions and cooking emissions, which together make up 76 % and 24 % of total particle number and organic aerosol (OA) mass, respectively. Similar source types, including particles related to vehicular emissions (1.6±1.1 µg m−3; 2.4±1.8×103 cm−3 and 5.5±2.8×103 cm−3 for two traffic-related components), cooking emissions (2.6±1.9 µg m−3 and 5.5±3.3×103 cm−3) and secondary aerosols (51±41 µg m−3 and 4.2±3.0×103 cm−3), were resolved by both methods. Converted mass concentrations from particle size distributions components were comparable with those from chemical fingerprints. Size distribution source apportionment separated vehicular emissions into a component with a mode diameter of 20 nm (“traffic-ultrafine”) and a component with a mode diameter of 100 nm (“traffic-fine”). Consistent with similar day- and nighttime diesel vehicle PM2.5 emissions estimated for the Beijing area, traffic-fine particles, hydrocarbon-like OA (HOA, traffic-related factor resulting from source apportionment using chemical fingerprints) and black carbon (BC) showed similar diurnal patterns, with higher concentrations during the night and morning than during the afternoon when the boundary layer is higher. Traffic-ultrafine particles showed the highest concentrations during the rush-hour period, suggesting a prominent role of local gasoline vehicle emissions. In the absence of new particle formation, our results show that vehicular-related emissions (14 % and 30 % for ultrafine and fine particles, respectively) and cooking-activity-related emissions (32 %) dominate the particle number concentration, while secondary particulate matter (over 80 %) governs PM2.5 mass during the non-heating season in Beijing.
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Tissari, Jarkko, Sampsa Väätäinen, Jani Leskinen, Mikko Savolahti, Heikki Lamberg, Miika Kortelainen, Niko Karvosenoja i Olli Sippula. "Fine Particle Emissions from Sauna Stoves: Effects of Combustion Appliance and Fuel, and Implications for the Finnish Emission Inventory". Atmosphere 10, nr 12 (4.12.2019): 775. http://dx.doi.org/10.3390/atmos10120775.
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Sauna Stoves (SS) are simple wood combustion appliances used mainly in Nordic countries. They generate emissions that have an impact on air quality and climate. In this study, a new measurement concept for comparing the operation, thermal efficiency, and real-life fine particle and gaseous emissions of SS was utilized. In addition, a novel, simple, and universal emission calculation procedure for the determination of nominal emission factors was developed for which the equations are presented for the first time. Fine particle and gaseous concentrations from 10 different types of SS were investigated. It was found that each SS model was an individual in relation to stove performance: stove heating time, air-to-fuel ratio, thermal efficiency, and emissions. Nine-fold differences in fine particle mass (PM1) concentrations, and about 90-fold differences in concentrations of polycyclic aromatic hydrocarbons (PAH) were found between the SS, when dry (11% moisture content) birch wood was used. By using moist (18%) wood, particle number and carbon monoxide concentrations increased, but interestingly, PM1, PAH, and black carbon (BC) concentrations clearly decreased, when comparing to dry wood. E.g., PAH concentrations were 5.5–9.6 times higher with dry wood than with moist wood. Between wood species, 2–3-fold maximum differences in the emissions were found, whereas about 1.5-fold differences were observed between bark-containing and debarked wood logs. On average, the emissions measured in this study were considerably lower than in previous studies and emission inventories. This suggests that overall the designs of sauna stoves available on the market have improved during the 2010s. The findings of this study were used to update the calculation scheme behind the inventories, causing the estimates for total PM emissions from SS in Finland to decrease. However, wood-fired sauna stoves are still estimated to be the highest individual emission source of fine particles and black carbon in Finland.
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Mamakos, Athanasios, Michael Arndt, David Hesse i Klaus Augsburg. "Physical Characterization of Brake-Wear Particles in a PM10 Dilution Tunnel". Atmosphere 10, nr 11 (23.10.2019): 639. http://dx.doi.org/10.3390/atmos10110639.
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A dilution tunnel was designed for the characterization of brake-wear particle emissions up to 10 μm on a brake dyno. The particulate matter emission levels from a single front brake were found to be 4.5 mg/km (1.5 mg/km being smaller than 2.5 μm) over a novel real-world brake cycle, for a commercial Economic Commission for Europe (ECE) pad. Particle Number (PN) emissions as defined in exhaust regulations were in the order of 1.5 to 6 × 109 particles per km per brake (#/km/brake). Concentration levels could exceed the linearity range of full-flow Condensation Particle Counters (CPCs) over specific braking events, but remained at background levels for 60% of the cycle. Similar concentrations measured with condensation and optical counters suggesting that the majority of emitted particles were larger the 300 nm. Application of higher braking pressures resulted in elevated PN emissions and the systematic formation of nano-sized particles that were thermally stable at 350 °C. Volatile particles were observed only during successive harsh braking events leading to elevated temperatures. The onset depended on the type of brakes and their prehistory, but always at relatively high disc temperatures (280 to 490 °C).
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Wang, Xiaowei, Lin Zhang, Mingda Wang, Xiaojun Jing i Xuejing Gu. "Sub-23 nm Solid Particle Number Emission Characteristics for a Heavy-duty Engine Fuelled with Compression Natural Gas". E3S Web of Conferences 329 (2021): 01012. http://dx.doi.org/10.1051/e3sconf/202132901012.
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Cold and hot WHTC (World harmonized Transient-State Cycle) were separately run on the engine test bed for a heavy-duty natural gas engine fuelled with high calorific value natural gas and low calorific value natural gas. The particle emissions including PN10 (number of particles above 10nm) and PN23 (number of particles above 23nm) were measured. The results show that the transient emission of PN10 and PN23 have basically the same trends. The weighted specific emission of PN10 is 21.6 times of PN23. Cold start PN emissions account for a relatively large proportion. Fuel property has a great influence on the PN emissions of natural gas engines. The increase of carbon-containing fuels such as methane and ethane in the fuel gas will lead to a rapid increase in PN emissions especially in the cold start process. It is extremely important to strengthen the control of sub-23nm particulate emissions for heavy-duty natural gas engines.
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Lou, Di Ming, Ze Wei Zhu, Pi Qiang Tan i Zhi Yuan Hu. "Characterization of the Particle Emissions from Diesel Transit Bus Equipping Diesel Particulate Filter with Fuel Burner". Advanced Materials Research 864-867 (grudzień 2013): 1386–93. http://dx.doi.org/10.4028/www.scientific.net/amr.864-867.1386.
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On-road particle emissions were tested in urban areas of Shanghai from a diesel bus equipping diesel particulate filter with fuel burner. EEPS 3090 particle analyzer was used for analyzing concentrations of particles in different diameters. In this paper, characterization of particles in soot loading and regeneration processes were identified, and particle reduction ability of DPF bus was analyzed. Result shows that, the averaged particle emission rate from DPF bus was degraded by 1 to 2 orders of magnitude during soot loading. Particle concentration distribution was transformed from nuclei-accumulated bi-modal pattern to uniformly multi-peaks patterns. In DPF regeneration process, particles of accumulated mode sized between 60.4nm and 107.5nm were decomposed and oxidized into fine nuclei particles of 29.4nm to 60.4nm, which increases total particle concentration. Reduction percentage of particle number per kilometer of DPF bus for soot loading and regeneration process reaches respectively 97% and 83.2% compared with normal diesel bus.
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Guo, Dongdong, Yunshan Ge, Xin Wang, Haixu Liu, Sheng Su, Chunbo Li i Tinghong Tao. "Sub-23 nm Particle Emissions from China-6 GDI Vehicle: Impacts of Drive Cycle and Ambient Temperature". Atmosphere 13, nr 8 (1.08.2022): 1216. http://dx.doi.org/10.3390/atmos13081216.
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Both the EU and China are evaluating the feasibility of lowering the detection limit of particle number (PN) measurement to 10 nm in future legislations, making it necessary to better understand the sub-23 nm particle emission characteristics from state-of-the-art vehicles. In this study, solid PN emissions with a diameter larger than 10 nm and 23 nm (known as SPN10 and SPN23) were compared over the WLTC, RTS95, and a so-called “worst-case” real driving emission (RDE) cycle (highly dynamic/0 °C) using two certification-level particle number counters (PNCs) employing evaporation tube (ET) and catalytic stripper (CS) as volatile particle remover (VPR). The results show that SPN10 emissions were 31.7%, 27.8%, and 15.2% higher than SPN23 over the WLTC, RTS95, and laboratory RDE cycles. Sub-23 nm particles were almost not identified within the engine cold-start phase and tended to be a hot-running pollutant favored by aggressive driving styles (frequent accelerations and high engine loads), fuel-cut during decelerations, and long idles. Lower testing temperature delayed the light-off of catalyst and, therefore, significantly reduced the formation of sub-23 nm particles within the engine warm-up stage. Lowering the detection limit to 10 nm is deemed to provide more public health protection since it will guide manufacturers to pay more attention to vehicle hot-running emissions.
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Manktelow, P. T., K. S. Carslaw, G. W. Mann i D. V. Spracklen. "Variable CCN formation potential of regional sulfur emissions". Atmospheric Chemistry and Physics Discussions 9, nr 1 (29.01.2009): 3095–112. http://dx.doi.org/10.5194/acpd-9-3095-2009.
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Abstract. Aerosols are short lived so their geographical distribution and impact on climate depends on where they are emitted. Previous model studies have shown that the mass of sulfate aerosol produced per unit sulfur emission (the sulfate burden potential) and the associated direct radiative forcing vary regionally because of differences in meteorology and photochemistry. Using a global model of aerosol microphysics, we show that the total number of aerosol particles produced per unit sulfur emission (the aerosol number potential) has a different regional variation to that of sulfate mass. The aerosol number potential of N. American and Asian emissions is calculated to be a factor of 3 to 4 times greater than that of European emissions, even though Europe has a higher sulfate burden potential. Pollution from North America and Asia tends to reach higher altitudes than European pollution so forms more new particles through nucleation. These regional differences in particle production mean that sulfur emissions from N. America and E. Asia produce cloud condensation nuclei up to 70% more efficiently than Europe. Taking account of the higher sulfate burden potential of Europe in these simulations shows that E. Asian sulfate produces CCN twice as effectively as European sulfate. The impact of regional sulfur emissions on particle concentrations is also much more widely spread than the impact on sulfate mass, due to efficient particle production in the free troposphere during long range transport. These results imply that regional sulfur emissions will have different climate forcing potentials through changes in cloud drop number.
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Manktelow, P. T., K. S. Carslaw, G. W. Mann i D. V. Spracklen. "Variable CCN formation potential of regional sulfur emissions". Atmospheric Chemistry and Physics 9, nr 10 (20.05.2009): 3253–59. http://dx.doi.org/10.5194/acp-9-3253-2009.
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Abstract. Aerosols are short lived so their geographical distribution and impact on climate depends on where they are emitted. Previous model studies have shown that the mass of sulfate aerosol produced per unit sulfur emission (the sulfate burden potential) and the associated direct radiative forcing vary regionally because of differences in meteorology and photochemistry. Using a global model of aerosol microphysics, we show that the total number of aerosol particles produced per unit sulfur emission (the aerosol number potential) has a different regional variation to that of sulfate mass. The aerosol number potential of N. American and Asian emissions is calculated to be a factor of 3 to 4 times greater than that of European emissions, even though Europe has a higher sulfate burden potential. Pollution from N. America and Asia tends to reach higher altitudes than European pollution so forms more new particles through nucleation. Regional differences in particle production and growth mean that sulfur emissions from N. America and E. Asia produce 50 nm diameter cloud condensation nuclei up to 70% more efficiently than Europe. For 80 nm diameter CCN, N. America and Europe produce CCN 2.5 times more efficiently than E. Asia. The impact of regional sulfur emissions on particle concentrations is also much more widely spread than the impact on sulfate mass, due to efficient particle production in the free troposphere during long range transport. These results imply that regional sulfur emissions will have different climate forcing potentials through changes in cloud drop number.
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Mylläri, Fanni, Eija Asmi, Tatu Anttila, Erkka Saukko, Ville Vakkari, Liisa Pirjola, Risto Hillamo i in. "New particle formation in the fresh flue-gas plume from a coal-fired power plant: effect of flue-gas cleaning". Atmospheric Chemistry and Physics 16, nr 11 (15.06.2016): 7485–96. http://dx.doi.org/10.5194/acp-16-7485-2016.
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Abstract. Atmospheric emissions, including particle number and size distribution, from a 726 MWth coal-fired power plant were studied experimentally from a power plant stack and flue-gas plume dispersing in the atmosphere. Experiments were conducted under two different flue-gas cleaning conditions. The results were utilized in a plume dispersion and dilution model taking into account particle formation precursor (H2SO4 resulted from the oxidation of emitted SO2) and assessment related to nucleation rates. The experiments showed that the primary emissions of particles and SO2 were effectively reduced by flue-gas desulfurization and fabric filters, especially the emissions of particles smaller than 200 nm in diameter. Primary pollutant concentrations reached background levels in 200–300 s. However, the atmospheric measurements indicated that new particles larger than 2.5 nm are formed in the flue-gas plume, even in the very early phases of atmospheric ageing. The effective number emission of nucleated particles were several orders of magnitude higher than the primary particle emission. Modelling studies indicate that regardless of continuing dilution of the flue gas, nucleation precursor (H2SO4 from SO2 oxidation) concentrations remain relatively constant. In addition, results indicate that flue-gas nucleation is more efficient than predicted by atmospheric aerosol modelling. In particular, the observation of the new particle formation with rather low flue-gas SO2 concentrations changes the current understanding of the air quality effects of coal combustion. The results can be used to evaluate optimal ways to achieve better air quality, particularly in polluted areas like India and China.
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Heintzenberg, Jost, Wolfram Birmili, Bryan Hellack, Gerald Spindler, Thomas Tuch i Alfred Wiedensohler. "Aerosol pollution maps and trends over Germany with hourly data at four rural background stations from 2009 to 2018". Atmospheric Chemistry and Physics 20, nr 18 (24.09.2020): 10967–84. http://dx.doi.org/10.5194/acp-20-10967-2020.
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Abstract. A total of 10 years of hourly aerosol and gas data at four rural German stations have been combined with hourly back trajectories to the stations and inventories of the European Emissions Database for Global Atmospheric Research (EDGAR), yielding pollution maps over Germany of PM10, particle number concentrations, and equivalent black carbon (eBC). The maps reflect aerosol emissions modified with atmospheric processes during transport between sources and receptor sites. Compared to emission maps, strong western European emission centers do not dominate the downwind concentrations because their emissions are reduced by atmospheric processes on the way to the receptor area. PM10, eBC, and to some extent also particle number concentrations are rather controlled by emissions from southeastern Europe from which pollution transport often occurs under drier conditions. Newly formed particles are found in air masses from a broad sector reaching from southern Germany to western Europe, which we explain with gaseous particle precursors coming with little wet scavenging from this region. Annual emissions for 2009 of PM10, BC, SO2, and NOx were accumulated along each trajectory and compared with the corresponding measured time series. The agreement of each pair of time series was optimized by varying monthly factors and annual factors on the 2009 emissions. This approach yielded broader summer emission minima than published values that were partly displaced from the midsummer positions. The validity of connecting the ambient concentration and emission of particulate pollution was tested by calculating temporal changes in eBC for subsets of back trajectories passing over two separate prominent emission regions, region A to the northwest and B to the southeast of the measuring stations. Consistent with reported emission data the calculated emission decreases over region A are significantly stronger than over region B.
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Chýlek, Radomír, Libor Kudela, Jiří Pospíšil i Ladislav Šnajdárek. "Parameters Influencing the Emission of Ultrafine Particles during 3D Printing". International Journal of Environmental Research and Public Health 18, nr 21 (6.11.2021): 11670. http://dx.doi.org/10.3390/ijerph182111670.
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This paper presents a complex and extensive experimental evaluation of fine particle emissions released by an FDM 3D printer for four of the most common printing materials (ABS, PLA, PET-G, and TPU). These thermoplastic filaments were examined at three printing temperatures within their recommended range. In addition, these measurements were extended using various types of printing nozzles, which influenced the emissions considerably. This research is based on more than a hundred individual measurements for which a standardized printing method was developed. The study presents information about differences between particular printing conditions in terms of the amount of fine particles emitted as well as the particle size distributions during printing periods. This expands existing knowledge about the emission of ultrafine particles during 3D printing, and it can help reduce the emissions of these devices to achieve cleaner and safer 3D printer operations.
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Rönkkö, Topi, Heino Kuuluvainen, Panu Karjalainen, Jorma Keskinen, Risto Hillamo, Jarkko V. Niemi, Liisa Pirjola i in. "Traffic is a major source of atmospheric nanocluster aerosol". Proceedings of the National Academy of Sciences 114, nr 29 (3.07.2017): 7549–54. http://dx.doi.org/10.1073/pnas.1700830114.
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In densely populated areas, traffic is a significant source of atmospheric aerosol particles. Owing to their small size and complicated chemical and physical characteristics, atmospheric particles resulting from traffic emissions pose a significant risk to human health and also contribute to anthropogenic forcing of climate. Previous research has established that vehicles directly emit primary aerosol particles and also contribute to secondary aerosol particle formation by emitting aerosol precursors. Here, we extend the urban atmospheric aerosol characterization to cover nanocluster aerosol (NCA) particles and show that a major fraction of particles emitted by road transportation are in a previously unmeasured size range of 1.3–3.0 nm. For instance, in a semiurban roadside environment, the NCA represented 20–54% of the total particle concentration in ambient air. The observed NCA concentrations varied significantly depending on the traffic rate and wind direction. The emission factors of NCA for traffic were 2.4·1015 (kgfuel)−1 in a roadside environment, 2.6·1015 (kgfuel)−1 in a street canyon, and 2.9·1015 (kgfuel)−1 in an on-road study throughout Europe. Interestingly, these emissions were not associated with all vehicles. In engine laboratory experiments, the emission factor of exhaust NCA varied from a relatively low value of 1.6·1012 (kgfuel)−1 to a high value of 4.3·1015 (kgfuel)−1. These NCA emissions directly affect particle concentrations and human exposure to nanosized aerosol in urban areas, and potentially may act as nanosized condensation nuclei for the condensation of atmospheric low-volatile organic compounds.
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Kalafut-Pettibone, A. J., J. Wang, W. E. Eichinger, A. Clarke, S. A. Vay, D. R. Blake i C. O. Stanier. "Size-resolved aerosol emission factors and new particle formation/growth activity occurring in Mexico City during the MILAGRO 2006 Campaign". Atmospheric Chemistry and Physics Discussions 11, nr 2 (24.02.2011): 6651–705. http://dx.doi.org/10.5194/acpd-11-6651-2011.
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Abstract. Measurements of the aerosol size distribution from 11 nm to 2.5 microns were made in Mexico City in March, 2006, during the MILAGRO field campaign. Observations at the T0 research site could often be characterized by morning conditions with high particle mass concentrations, low mixing heights, and highly correlated particle number and CO2 concentrations, indicative that particle number is controlled by primary emissions. Average size-resolved and total number- and volume-based emission factors for combustion sources impacting T0 have been determined using a comparison of peak sizes in number and CO2 concentration peaks. The number emission and volume emission factors for particles from 11 nm to 494 nm are 1.23 × 1015 particles, and 7.54 × 1011 cubic microns per kg of carbon, respectively. Uncertainty on the number emission factor is approximately a factor of 1.5. The mode of the number emission factor was between 25 and 32 nm, while the mode of the volume factor was between 0.25 and 0.32 microns. These emission factors are reported as log normal model parameters and are compared with multiple emission factors from the literature. In Mexico City in the afternoon, the CO2 concentration drops during ventilation of the polluted layer, and the coupling between CO2 and particle number breaks down, especially during new particle formation events when particle number is no longer controlled by primary emissions. Using measurements of particle number and CO2 taken aboard the NASA DC-8, this emission factor was applied to the MCMA plume; the primary emission factor predicts less than 50% of the total particle number and the surplus particle count is not correlated with photochemical age. Primary particle volume and number in the size range 0.1–2 μm are similarly too low to predict the observed volume distribution. Contrary to the case for number, the apparent secondary volume increases with photochemical age. The size distribution of the apparent increase, with a mode at ~250 nm, is reported.
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Cheung, H. C., L. Morawska i Z. D. Ristovski. "Observation of new particle formation in subtropical urban environment". Atmospheric Chemistry and Physics Discussions 10, nr 10 (1.10.2010): 22623–52. http://dx.doi.org/10.5194/acpd-10-22623-2010.
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Abstract. The aim of this study was to characterise the new particle formation events in subtropical urban environment Southern Hemisphere. The study measured the number concentration of particles and its size distribution in Brisbane, Australia during 2009. The variation of particle number concentration and nucleation burst events were studied and the particle growth rate was characterised which was first reported in urban environment of Australia. The annual average NUFP, NAitken and Nnuc were 9.3×103, 3.7×103 and 5.6×103 cm−3, respectively. Weak seasonal variation in number concentration was observed. Local vehicle emission was major contributor of the pollution observed in the morning which was dominated by the Aitken mode particles, while particle formed by secondary formation process was contributed to the particle number concentration in the afternoon. 65 nucleation burst events were identified during the study period. Nucleation burst events were classified into two groups with and without particle growth after the burst of nucleation mode particles observed. Average particle growth rate of the nucleation events was 4.6 nm hr−1 (ranged from 1.79–7.78 nm hr−1). Case studies of the nucleation burst events were characterised including i) the nucleation burst with particle growth which was associated with the particle precursor emitted from local vehicle emission, ii) the nucleation burst without particle growth which was due to the transport of industrial emissions from the coast to Brisbane city, and iii) interplay between the above two cases which demonstrated the impact of the vehicle and industrial emissions on the variation of particle number concentration and its size distribution during the same day.
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CZERWINSKI, J., J. L. PÉTERMANN, A. ULRICH, G. MUELLER i A. WICHSER. "Particle emissions of a TDI-engine with different lubrication oils". Combustion Engines 121, nr 2 (1.05.2005): 46–55. http://dx.doi.org/10.19206/ce-117405.
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Due to increasing concern about health effects of fine and ultra-fine particles (nanoparticles) from combustion engines, the diesel particle filter technology (DPF) was extensively introduced to heavy duty and passenger cars in the last years. In this respect, a very important parameter is the irreversible plugging of the DPF with non-combustible ashes. The quality of lubrication oil, especially the ash content has a certain influence on regeneration intervals of diesel particle filters. In the present study, the effects of different lubrication oils on particle mass and nano-particle size distribution were investigated. The test engine was a modern diesel engine without particle filter system. A main goal was to find out, how different lubrication oils influence the particulate emissions and the contribution of oil to total particle emissions. Moreover, first results of a tracing study will be discussed. The comparison of a non-doped lubrication oil with a doped oil should enlighten the contribution of the oil to the particle formation. It has been shown that beside sulphur content the particle emission is also effected by the composition (e.g. additive packages) of the oils.
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Pielecha, Jacek, Kinga Skobiej, Maciej Gis i Wojciech Gis. "Particle Number Emission from Vehicles of Various Drives in the RDE Tests". Energies 15, nr 17 (5.09.2022): 6471. http://dx.doi.org/10.3390/en15176471.
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In this study, the authors assessed the road emissions of several passenger cars using specialised instrumentation, of the PEMS type, to measure particle number emissions in real traffic conditions. The tests were performed on a RDE test route developed and compliant with EU guidelines. The results of the tests were discussed in terms of the direct (created in the internal combustion engine) emission of particulate matter in various road conditions. Additionally, an index was determined that characterizes the number of particles according to their diameter in relation to the content of particles in the air. A characteristic of combustion engines (gasoline, diesel) is that during a cold start of the engine, the concentration of the number of particles with diameters around 100 nm increases more than 200 times (for hybrids—300 times). On this basis, it can be concluded that particle emissions with diameters smaller than 23 nm are significant in motor vehicles powered by combustion engines, regardless of whether they are conventional or hybrid vehicles. The share of particles with diameters less than 5 nm is 66% (for diesel engines) and 40% (for gasoline engines) of all the particles.
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Yuan, Du, Guang Shun Yi i Gan Moog Chow. "Effects of size and surface on luminescence properties of submicron upconversion NaYF4:Yb,Er particles". Journal of Materials Research 24, nr 6 (czerwiec 2009): 2042–50. http://dx.doi.org/10.1557/jmr.2009.0258.
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Bulk NaYF4:Yb,Er particles (∼1.4 μm particle size) were synthesized using a hydrothermal method. As-synthesized particles were subsequently ball milled to three average particle sizes, namely, ∼260 nm, 160 nm, and 100 nm. The x-ray diffraction pattern showed an hcp phase for as-synthesized and ball-milled particles with a predominant (100) peak. Room temperature emission spectra showed no size dependent peak shifts or peak broadening. The intensities of both green and red emissions decreased with increasing milling time. Segregation of Er ions was detected on the surfaces of milled particle that reduced the sensitizer-activator transition probability, resulting in decreased emission intensities. The green-to-red emission ratio was correlated to the surface enrichment of Er, which affected the cross-relaxation of luminescence dynamics.
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Wong, H. W., i R. C. Miake-Lye. "Parametric studies of contrail ice particle formation in jet regime using one-dimensional microphysical modeling". Atmospheric Chemistry and Physics Discussions 9, nr 5 (22.10.2009): 22337–63. http://dx.doi.org/10.5194/acpd-9-22337-2009.
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Abstract. Condensation trails (contrails) formed from water vapor emissions behind aircraft engines are the most uncertain components of the aviation impacts on climate change. To gain improved knowledge of contrail and contrail-induced cirrus cloud formation, understanding of contrail ice particle formation immediately after aircraft engines is needed. Despite many efforts spent in modeling the microphysics of ice crystal formation in jet regime (with a plume age <5 s), systematic understanding of parametric effects of variables affecting contrail ice particle formation is still limited. In this work, we apply a one-dimensional modeling approach to study contrail ice particle formation in near-field aircraft plumes up to 1000 m downstream of an aircraft engine in the soot-rich regime (soot number emission index >1×1015 (kg-fuel)−1) at cruise. The effects of ion-mediated nucleation, ambient relative humidity, fuel sulfur content, and initial soot emissions were investigated. Our simulation results suggest that ice particles are mainly formed by water condensation on emitted soot particles. The growth of ice coated soot particles is driven by water vapor emissions in the first 1000 m and by ambient relative humidity afterwards. The presence of chemi-ions does not significantly contribute to the formation of ice particles, and the effect of fuel sulfur content is small over the range typical of standard jet fuels. The initial properties of soot emissions play the most critical role, and our calculations suggest that higher number concentration and smaller size of contrail particle nuclei may be able to effectively suppress the formation of contrail ice particles, providing a possible approach for contrail mitigation.
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Pirjola, L., A. Pajunoja, J. Walden, J. P. Jalkanen, T. Rönkkö, A. Kousa i T. Koskentalo. "Mobile measurements of ship emissions in two harbour areas in Finland". Atmospheric Measurement Techniques Discussions 6, nr 4 (5.08.2013): 7149–84. http://dx.doi.org/10.5194/amtd-6-7149-2013.
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Abstract. Four measurement campaigns by a mobile laboratory van were performed in two different environments; inside the harbour areas in the city center of Helsinki and along the narrow shipping channel near the city of Turku, Finland, during the winter and summer conditions in 2010–2011. The characteristics of gaseous (CO, CO2, SO2, NO, NO2, NOx) and particulate (number and volume size distributions as well as PM2.5) emissions for 11 ships regularly operating on the Baltic Sea were studied to determine the emission parameters. The highest particle concentrations were 1.5 × 106 and 1.6 × 105 cm−3 in Helsinki and Turku, respectively, and the particle number size distributions had two modes. The dominating mode was peaking at 20–30 nm and the accumulation mode at 80–100 nm. The majority of the particle mass was volatile since after heating the sample to 265 °C, the particle volume of the studied ships decreased by around 70%. The emission factors for NOx varied in the range of 25–100 g (kg fuel)−1, for SO2 in the range of 2.5–17.0 g (kg fuel)−1, for particle number in the range of (0.32–2.26) × 1016 particles (kg fuel)−1, and for PM2.5 between 1.0–4.9 g (kg fuel)−1. The ships equipped with SCR had lowest NOx emissions whereas the ships with DWI and HAM had lowest SO2 emissions but highest particulate emissions. For all ships the averaged fuel sulphur contents (FSCs) were less than 1% (by mass) but none of those was below 0.1% which will be the new EU directive from 1 January 2015 in the SOx Emission Control Areas, indicating big challenges for ships operating on the Baltic Sea.
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Mentel, Th F., J. Wildt, A. Kiendler-Scharr, E. Kleist, R. Tillmann, M. Dal Maso, R. Fisseha i in. "Photochemical production of aerosols from real plant emissions". Atmospheric Chemistry and Physics Discussions 9, nr 1 (29.01.2009): 3041–94. http://dx.doi.org/10.5194/acpd-9-3041-2009.
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Abstract. By emission of volatile organic compounds (VOC) which on oxidation form secondary organic aerosols (SOA) the vegetation is coupled to atmosphere and climate. New particle formation from tree emissions was investigated in a new setup: a plant chamber coupled to a reaction chamber for oxidizing the plant emissions and for forming SOA. The boreal tree species birch, pine, and spruce were studied and α-pinene was used as reference compound. Under the experimental conditions OH radicals were essential for inducing new particle formation, although O3 (≤80 ppb) was always present and a part of the monoterpenes and the sesquiterpenes reacted already with ozone before OH was generated. Formation rates of 3 nm particles were linearly related to the carbon mixing ratios of the VOC, as were the maximum observed volume and the condensational growth rates. The threshold of new particle formation was lower for the tree emissions than for α-pinene. It was lowest for birch with the largest fraction of oxygenated VOC (OVOC) suggesting that OVOC may play a pivotal role in new particle formation. Incremental mass yields were ≈5% for pine, spruce and α-pinene, and ≈10% for birch. α-Pinene was a good model compound to describe the yield and the growth of SOA particles from coniferous emissions. The mass fractional yields agreed well with observations for boreal forests. Despite our somewhat enhanced VOC and OH concentrations our results may thus be up-scaled to eco-system level. Using the mass fractional yields observed for the tree emissions and weighting them with the abundance of the respective trees in boreal forests we calculate SOA mass concentrations which agree within 6% with field observations. For a future VOC increase of 50% we predict a particle mass increase due to SOA of 19% assuming today's mass contribution of pre-existing aerosol.
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Kalafut-Pettibone, A. J., J. Wang, W. E. Eichinger, A. Clarke, S. A. Vay, D. R. Blake i C. O. Stanier. "Size-resolved aerosol emission factors and new particle formation/growth activity occurring in Mexico City during the MILAGRO 2006 Campaign". Atmospheric Chemistry and Physics 11, nr 17 (1.09.2011): 8861–81. http://dx.doi.org/10.5194/acp-11-8861-2011.
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Abstract. Measurements of the aerosol size distribution from 11 nm to 2.5 microns were made in Mexico City in March 2006, during the MILAGRO (Megacity Initiative: Local and Global Research Observations) field campaign. Observations at the urban supersite, referred to as T0, could often be characterized by morning conditions with high particle mass concentrations, low mixing heights, and highly correlated particle number and CO2 concentrations, indicative that particle number is controlled by primary emissions. Average size-resolved and total number- and volume-based emission factors for combustion sources impacting T0 have been determined using a comparison of peak sizes in particle number and CO2 concentration. Peaks are determined by subtracting the measured concentration from a calculated baseline concentration time series. The number emission and volume emission factors for particles from 11 nm to 494 nm are 1.56 × 1015 particles, and 9.48 × 1011 cubic microns per kg of carbon, respectively. The uncertainty of the number emission factor is approximately plus or minus 50 %. The mode of the number emission factor was between 25 and 32 nm, while the mode of the volume factor was between 0.25 and 0.32 microns. These emission factors are reported as log normal model parameters and are compared with multiple emission factors from the literature. In Mexico City in the afternoon, the CO2 concentration drops during ventilation of the polluted layer, and the coupling between CO2 and particle number breaks down, especially during new particle formation events when particle number is no longer controlled by primary emissions. Using measurements of particle number and CO2 taken aboard the NASA DC-8, the determined primary emission factor was applied to the Mexico City Metropolitan Area (MCMA) plume to quantify the degree of secondary particle formation in the plume; the primary emission factor accounts for less than 50 % of the total particle number and the surplus particle count is not correlated with photochemical age. Primary particle volume and number in the size range 0.1–2 μm are similarly too low to explain the observed volume distribution. Contrary to the case for number, the apparent secondary volume increases with photochemical age. The size distribution of the apparent increase, with a mode at ~250 nm, is reported.