| 1. |
- Janhäll, Sara, 1965, et al.
(författare)
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A novel method for determination of size resolved, submicrometer particle traffic emission factors.
- 2005
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Ingår i: Environmental science & technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 39:19, s. 7609-15
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Tidskriftsartikel (refereegranskat)abstract
- A novel approach to determine size-segregated particle number emission factors for traffic is presented. It was proven that using limited data sets (800-2000 samples) statistically significant emission factors from road traffic can be extracted. In this study data from four sites were used for calculating emission factors (rural and urban roadside, urban rooftop, and urban background). The measurements were performed using SMPS/DMPS (scanning or differential particle sizers) from TSI and commercial gas analyzers. Describing the particle concentration as a ratio to an exhaust trace gas, e.g. NOx, the dilution effect will be minimized. This ratio is easily compared among different studies. By knowledge of the emission factor of the chosen trace gas the emission ratio can be converted to an emission factor for particle numbers of defined particle sizes. For the presented method only one measurement site is needed, where the difference between high and low (background) traffic exposure is used. To define high and low traffic exposure, the best result was obtained using high ratio of [NO] to [NO2] and low [NOx], respectively. Emission ratios for 10-100-nm particles at two road sites, one high-speed 90-kmph rural case and one urban, slower, and more congested situation, were determined to (35 +/- 15) x 10(14) and (24 +/- 8) x 10(14) particles per mole NOx, respectively.
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| 2. |
- Janhäll, Sara, 1965, et al.
(författare)
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Size resolved traffic emission factors of submicrometer particles
- 2004
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Ingår i: Atmospheric Environment. - : Elsevier BV. - 1352-2310 .- 1873-2844. ; 38:26, s. 4331-4340
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Tidskriftsartikel (refereegranskat)abstract
- Size resolved emission factors for submicrometer particles related to trace gases have been obtained from measurement data at a suburban road side, with a traffic intensity of 18,000 vehicles per day. Number of particles with diameter 10-368 nm, trace gases (NO, NOx, O-3 and SO2) traffic and meteorology parameters were measured outside of Goteborg, Sweden. Size distributions of small particles at the site are presented and their relation to meteorological and traffic related variables was evaluated. Wind speed correlated negatively with 10-368 nm particles and temperature correlated negatively with the smaller particles (10-60 nm). Nitric oxide was shown to be a better tracer for traffic related ultrafine particles, than traffic intensity itself. The calculated emission factor, with errors at 95% confidence level, for particles in the range 10-368 nm is presented in relation to nitrogen oxides. The emission factors were 268+/-60 and 176+/-37 particles cm(-3) per ppb NO and NOx, respectively. The particle emission factors for 10-100, 10-50, 50-170 and 170-368 nm were 260+/-70, 228+/-52, 41+/-11 and <1 particle cm(-3) per ppb NO, respectively. The size distribution of the emissions is given by number of particles normalised by the width of the size bin, i.e. in units of dNd log Dp(-1) ppb(-1). The maximum normalised emission factor was 450 cm(-3) per ppb NO for 20 nm particles. The shape of the size distribution of emissions revealed one sharp peak at 20 nm, with a small shoulder at 70 nm. (C) 2004 Elsevier Ltd. All rights reserved.
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| 3. |
- Järlskog, Ida, 1991-, et al.
(författare)
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Differentiating and Quantifying Carbonaceous (Tire, Bitumen, and Road Marking Wear) and Non-carbonaceous (Metals, Minerals, and Glass Beads) Non-exhaust Particles in Road Dust Samples from a Traffic Environment
- 2022
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Ingår i: Water, Air and Soil Pollution. - : Springer. - 0049-6979 .- 1573-2932. ; 233:9
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Tidskriftsartikel (refereegranskat)abstract
- Tires, bitumen, and road markings are important sources of traffic-derived carbonaceous wear particles and microplastic (MP) pollution. In this study, we further developed a machine-learning algorithm coupled to an automated scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDX) analytical approach to classify and quantify the relative number of the following subclasses contained in environmental road dust: tire wear particles (TWP), bitumen wear particles (BiWP), road markings, reflecting glass beads, metallics, minerals, and biogenic/organics. The method is non-destructive, rapid, repeatable, and enables information about the size, shape, and elemental composition of particles 2-125 mu m. The results showed that the method enabled differentiation between TWP and BiWP for particles > 20 mu m with satisfying results. Furthermore, the relative number concentration of the subclasses was similar in both analyzed size fractions (2-20 mu m and 20-125 mu m), with minerals as the most dominant subclass (2-20 mu m x = 78%, 20-125 mu m x = 74%) followed by tire and bitumen wear particles, TBiWP, (2-20 mu m x = 19%, 20-125 mu m x = 22%). Road marking wear, glass beads, and metal wear contributed to x = 1%, x = 0.1%, and x = 1% in the 2-20-mu m fraction and to x = 0.5%, x = 0.2%, and x = 0.4% in the 20-125-mu m fraction. The present results show that road dust appreciably consists of TWP and BiWP within both the coarse and the fine size fraction. The study delivers quantitative evidence of the importance of tires, bitumen, road marking, and glass beads besides minerals and metals to wear particles and MP pollution in traffic environments based on environmental (real-world) samples
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| 4. |
- Järlskog, Ida, 1991, et al.
(författare)
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Traffic-related microplastic particles, metals, and organic pollutants in an urban area under reconstruction
- 2021
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Ingår i: Science of the Total Environment. - : Elsevier BV. - 0048-9697 .- 1879-1026. ; 774
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Tidskriftsartikel (refereegranskat)abstract
- In urban environments, particularly areas under reconstruction, metals, organic pollutants (OP), and microplastics (MP), are released in large amounts due to heavy traffic. Road runoff, a major transport route for urban pollutants, contributes significantly to a deteriorated water quality in receiving waters. This study was conducted in Gothenburg, Sweden, and is unique because it simultaneously investigates the occurrence of OP, metals, and MP on roads and in stormwater from an urban area under reconstruction. Correlations between the various pollutants were also explored. The study was carried out by collecting washwater and sweepsand generated from street sweeping, road surface sampling, and flow-proportional stormwater sampling on several occasions. The liquid and solid samples were analyzed for metals, polycyclic aromatic hydrocarbons (PAH), oxy-PAH, aliphatics, aromatics, phthalates, and MP. The occurrence of OP was also analyzed with a non-target screening method of selected samples. Microplastics, i.e. plastic fragments/fibers, paint fragments, tire wear particles (TWP) and bitumen, were analyzed with a method based on density separation with sodium iodide and identification with a stereo microscope, melt-tests, and tactile identification. MP concentrations amounted to 1500 particles/L in stormwater, 51,000 particles/L in washwater, and 2.6 × 106 particles/kg dw in sweepsand. In stormwater, washwater and sweepsand, MP ≥20 μm were found to be dominated by TWP (38%, 83% and 78%, respectively). The results confirm traffic as an important source to MP, OP, and metal emissions. Concentrations exceeding water and sediment quality guidelines for metals (e.g. Cu and Zn), PAH, phthalates, and aliphatic hydrocarbons in the C16–C35 fraction were found in most samples. The results show that the street sweeper collects large amounts of polluted materials and thereby prevents further spread of the pollutants to the receiving stormwater.
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| 5. |
- Shannigrahi, Ardhendu Sekhar, 1965, et al.
(författare)
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n-Alkanoic monocarboxylic acid concentrations in urban and rural aerosols : Seasonal dependence and major sources
- 2014
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Ingår i: Atmospheric research. - : Elsevier BV. - 0169-8095 .- 1873-2895. ; 143, s. 228-237
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Tidskriftsartikel (refereegranskat)abstract
- We report new data on the abundance and distribution of n-monocarboxylic acids (n-MCAs) in fine- and coarse-mode aerosols in rural and urban areas of Sweden, and determine their possible sources. Overall, C6–C16n-MCAs accounted for ~ 0.5–1.2% of the total PM10 (particulate matter ≤ 10 μm) mass. In general, the C12–C16 fraction was the most abundant (> 75%), with the exception of wintertime samples from a rural site, where C6–C11 acids accounted for 65% of the total C6–C16n-MCA mass. Positive matrix factorization analysis revealed four major sources of n-MCAs: traffic emissions, wood combustion, microbial activity, and a fourth factor that was dominated by semi-volatile n-MCAs.Traffic emissions were important in the urban environment in both seasons and at the rural site during winters, and were a major source of C9–C11 acids. Wood combustion was a significant source at urban sites during the winter and also to some extent at the rural site in both seasons. This is consistent with the use of wood for domestic heating but may also be related to meat cooking. Thus, during the winter, traffic, wood combustion and microbial activity were all important sources in the urban environment, while traffic was the dominant source at the rural site. During the summer, there was considerable day-to-day variation in n-MCA concentrations but microbial activity was the dominant source. The semi-volatile low molecular weight C6–C8 acids accounted for a small (~ 5–10%) fraction of the total mass of n-MCAs. This factor is unlikely to be linked to a single source and its influence instead reflects the partitioning of these compounds between the gas and particle phases. This would explain their greater contribution during the winter.
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| 6. |
- Zhu, Jiqing, 1987-, et al.
(författare)
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Extending the Black diagram of bitumen to three dimensions
- 2022
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Ingår i: Construction and Building Materials. - : Elsevier BV. - 0950-0618 .- 1879-0526. ; 349
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Tidskriftsartikel (refereegranskat)abstract
- The ordinary Black diagram of bitumen has only two dimensions. Thus, it does not differentiate the complex shear modulus and phase angle measured under different temperature and frequency conditions. This study proposes to extend the Black diagram to three dimensions by adding a temperature axis. It leads to the combination of multiple necessary ordinary plots in the same three-dimensional (3D) space. In this 3D space, the location, shape, and eventually colour of the plot (either curve or surface) can together indicate the unique temperature-dependency and time-dependency of the bituminous binder's rheological properties, even the interplay between them. Hence, polymer-modified bitumen is distinguished from neat bitumen and harder bitumen is distinguished from softer bitumen. Furthermore, the additional temperature axis in the 3D Black diagram also enables direct visualisation and precise quantitative evaluations of bitumen properties by various current technical criteria in the same space, avoiding the inconvenient use of multiple ordinary plots. This may lead to the development of a practical tool towards more effective and efficient evaluation of rheological properties of bitumen.
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| 7. |
- Kjellsdotter Ivert, Linea, 1980-
(författare)
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Towards a sustainable circular system of textiles in the Nordics
- 2022
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The SATIN project focuses on increasing circularity of EOL textile in the Nordic region and has a strong focus on supply chain management (SCM). SCM relates to balancing the supply and demand of materials to achieve efficiency in the material flow of EOL textiles and related information, and monetary flows as well as collaboration between actors in the EOL textile value chain. The purpose of the SATIN project is to develop and test solutions that can address the EOL textile collection and sorting challenges by taking a SCM perspective. In the project we have 1) Mapped and identified challenges and opportunities in the current system by interviewing main actors in the value chain of EOL textiles in Norway, Sweden, Denmark, and Finland, 2) Analyzed nine pilot studies of different collection methods, 3) Estimated volumes of recyclable textiles and their fiber composition and compared this supply with the current and upcoming sorting and recycling capacity (demand) in each country and in the whole Nordic area. Our results show there are large similarities between the actors in the Nordic countries when it comes to challenges and opportunities in the value chain of EOL textiles. Main challenges can be connected to lack of scale, low profit, no demand, and lack of data whereas opportunities are seen in collaboration, centralization and understanding/finding a market for EOL textiles. Connected to collection methods it was found that it is difficult to compare different methods because there are so many factors at play. However, it became clear that regardless of the collection method, the role of the consumer is very important in scaling up collection. Connected to recyclables our results show that the upcoming automatic sorting and recycling capacity in the Nordic region will be sufficient to deal with the total recyclable fraction, except for some of the synthetic fibers. However, there are imbalances within each country raising a need for collaboration among countries.
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| 8. |
- Tušar, M., et al.
(författare)
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Investigation of the performance of conventional and polymer modified bitumen
- 2011
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Work in SPENS (Sustainable Pavements for European New member States) project was divided into six working groups within each of them surveys were carried out in two or three tasks. In the frame of Task 4.1, we established the advantages and disadvantages of different types of paving grade and modified bitumen. Seven binders were included in the study. The binders were used to make asphalt concrete (AC) with either limestone aggregate or siliceous aggregate, stone mastic asphalt (SMA) and porous asphalt (PA) with siliceous aggregate. The binder test methods included in the study have been the standard test methods, the moduli obtained from the dynamic shear rheometer and the stiffness determined with a bending beam rheometer. Asphalt samples were tested on the wheel tracking, stiffness at different temperatures, water sensitivity and the Marshall stability at different temperatures.The relations between asphalt mechanical properties and the mechanical and visco-elastic properties of the binder have been studied. The multivariate data analysis has been done with modern orthogonal projection methods, i.e. with the partial least squares (PLS) algorithm.
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| 9. |
- Wang, Haopeng, et al.
(författare)
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The role of thermodynamics and kinetics in rubber–bitumen systems : a theoretical overview
- 2021
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Ingår i: The international journal of pavement engineering. - : Taylor and Francis Ltd.. - 1029-8436 .- 1477-268X. ; 22:14, s. 1785-1800
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Tidskriftsartikel (refereegranskat)abstract
- Waste tire rubber has been incorporated into asphalt modification for decades due to its various benefits. There are two main mechanisms during bitumen–rubber interaction: rubber swelling and chemical degradation. This study surveys these two processes from the viewpoint of polymer science. The kinetics of rubber dissolution and thermodynamics of rubber swelling are discussed to provide a fundamental understanding of the interaction process and to demonstrate how optimisation of material selection and processing procedures can lead to the desired binder properties. Factors including the interaction conditions and raw material characteristics are analysed based on the previous theories and compared with experimental results. © 2020, © 2020 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.
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