Physico-Chemical Characterization and Oxidative Reactivity Evaluation of Aged Brake Wear Particles

Zhao, Jiayuan; Lewinski, Nastassja A.; Riediker, Michael

doi:10.1080/02786826.2014.998363

Cited by 29 publications

(27 citation statements)

References 52 publications

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“…Several toxicological studies have shown that particles in the nanometer scale are particularly dangerous as they can enter the blood stream through the lungs (Oberdörster 2005, Oostingh 2013. Furthermore, metallic brake wear particles damage tight junctions within the mechanisms that involve oxidative stress (Gasser et al, 2009;Zhao et al, 2015); therefore, the important point is not only the particle mass, but also the particle quality (e.g. chemical composition and biological effect).…”

Section: Discussionmentioning

confidence: 99%

Study of Brake Wear Particle Emissions of a Minivan on a Chassis Dynamometer

Chasapidis

Grigoratos

Zygogianni

et al. 2018

Emiss. Control Sci. Technol.

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Car brakes appears to be a significant atmospheric pollutant source, with a contribution to total non-exhaust traffic related PM10 emissions being estimated at approximately 55% in big cities and urban environments (Bukowiecki et al., 2009). Brake wear particle emissions of a minivan running on a chassis dynamometer were measured using a custom sampling system, positioned close to the braking system, under different initial speeds (30km/h and 50km/h), deceleration rates (0.5m/s 2 , 1.5m/s 2 , 2.5m/s 2) and ambient temperature (0°C, 15°C and 25°C). Braking from 50km/h to full stop, results in 40-100% more particles compared to 30km/h, depending on the deceleration rate. It was also found that only 9-50% of the total particles emitted, are released during the braking phase and therefore the most significant amount is released on the acceleration phase following. High brake pad temperatures, result in a bimodal distribution with the first peak being at 1μm and the second falling at the nanometer scale at 200 nm. The ambient temperature appears to have a negligible effect on the particle generation. Nomenclature a Time at 10th

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Section: Discussionmentioning

confidence: 99%

Study of Brake Wear Particle Emissions of a Minivan on a Chassis Dynamometer

Chasapidis

Grigoratos

Zygogianni

et al. 2018

Emiss. Control Sci. Technol.

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show abstract

“…We investigated the ROS production potential of welding fume particles using the DCFH assay, which has been widely applied for non-specific ROS detection ( Venkatachari et al , 2007 ; Jiang et al , 2008 ; Aranda et al , 2013 ; Zhao et al , 2014 ) and found to be relatively inexpensive and robust. Regarding the reported limitations of this assay in the literature ( Hoet et al , 2013 ; Pal et al , 2014 ), we carefully applied the strategies published in the study by Zhao and Riediker (2014) to achieve better performance of the assay and avoid artefacts, such as to always keep an appropriate control to exclude ROS produced by self-oxidation of the reagents and analyse the standards with samples at the same time point.…”

Section: Discussionmentioning

confidence: 99%

Characterization of Tungsten Inert Gas (TIG) Welding Fume Generated by Apprentice Welders

Graczyk

Lewinski

Zhao

et al. 2015

ANNHYG

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Tungsten inert gas welding (TIG) represents one of the most widely used metal joining processes in industry. Its propensity to generate a greater portion of welding fume particles at the nanoscale poses a potential occupational health hazard for workers. However, current literature lacks comprehensive characterization of TIG welding fume particles. Even less is known about welding fumes generated by welding apprentices with little experience in welding. We characterized TIG welding fume generated by apprentice welders (N = 20) in a ventilated exposure cabin. Exposure assessment was conducted for each apprentice welder at the breathing zone (BZ) inside of the welding helmet and at a near-field (NF) location, 60cm away from the welding task. We characterized particulate matter (PM4), particle number concentration and particle size, particle morphology, chemical composition, reactive oxygen species (ROS) production potential, and gaseous components. The mean particle number concentration at the BZ was 1.69E+06 particles cm−3, with a mean geometric mean diameter of 45nm. On average across all subjects, 92% of the particle counts at the BZ were below 100nm. We observed elevated concentrations of tungsten, which was most likely due to electrode consumption. Mean ROS production potential of TIG welding fumes at the BZ exceeded average concentrations previously found in traffic-polluted air. Furthermore, ROS production potential was significantly higher for apprentices that burned their metal during their welding task. We recommend that future exposure assessments take into consideration welding performance as a potential exposure modifier for apprentice welders or welders with minimal training.

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“…Regarding TEM, it is one of the most complete characterization tools for nanostructured systems [145,146]. Sample preparation can be tricky, and one of the methods is preparing a suspension of wear particles in ethanol (with a preceding set of steps), from which a single drop is deposited onto the TEM gold [90] or Cu [147] grid. Gold is preferable since provides X-ray emission lines which can be easily separated from the genuine ones, coming from the specimen.…”

Section: Characterizing Wear Debrismentioning

confidence: 99%

Experimental Characterization Protocols for Wear Products from Disc Brake Materials

et al. 2020

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The increasing interest in the emission from the disc brake system poses new challenges for the characterization approaches used to investigate the particles emitted from the wearing out of the relevant tribological systems. This interest stems from different factors. In the first place, a thorough characterization of brake wear particles is important for a complete understanding of the active tribological mechanisms, under different testing and servicing conditions. This information is an important prerequisite not only for the general improvement of brake systems, but also to guide the development of new materials for discs and brake pads, responding better to the specific requirements, including not only performance, but also the emission behavior. In this review paper, the main material characterization protocols used for the analyses of the brake wear products, with particular regard for the airborne fraction, are presented. Reliable results require investigating the fine and ultrafine particles as concerns their composition together with their structural and microstructural aspects. For this reason, in general, multi-analytical protocols are very much recommended.

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Physico-Chemical Characterization and Oxidative Reactivity Evaluation of Aged Brake Wear Particles

Cited by 29 publications

References 52 publications

Study of Brake Wear Particle Emissions of a Minivan on a Chassis Dynamometer

Study of Brake Wear Particle Emissions of a Minivan on a Chassis Dynamometer

Characterization of Tungsten Inert Gas (TIG) Welding Fume Generated by Apprentice Welders

Experimental Characterization Protocols for Wear Products from Disc Brake Materials

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