Triboemission of FINE and Ultrafine Aerosol Particles: A New Approach for Measurement and Accurate Quantification

Abstract

A dynamic model based on mass balance of fine aerosol particles was developed in order to tackle the problem of accurate quantification of mechanically stimulated particle emission (MSPE) from nanofunctionalized and solid lubricating materials. In contrast to the conventional approach, the model accounts for the effect of air turbulization caused by moving parts of the experimental tribological setup on the enhancement of particle deposition velocity. The increase of the velocity of the moving parts results in an increase of the deposition velocity that leads to a significant underestimation of experimentally measured particle emission rates. The developed model was experimentally verified using natural and artificial nanoparticle aerosols. Finally, the new methodology of particle emission rate quantification was employed for the analysis of fine particle emission produced when the solid lubricating materials were tested against a sliding steel surface. The developed method paves the way for defining a standard method of experimental assessment of nanoparticle triboemission enabling the experimental results obtained in various laboratories to be compared. It also bridges the gap between the phenomenological models and experimental measurements.

Assessment of urban air pollution related to potential nanoparticle emission from photocatalytic pavements

“…This study was a part of a full-scale experiment which purpose was to evaluate photocatalytic activity, durability, environmental benefits and impacts of photocatalytic technology on real scale (Cordero et al, 2020;Jim� enez-Relinque et al, 2019;Nevshupa et al, 2020). A photocatalytic coating was chosen out of various commercial products upon an exhaustive analysis of their properties on both laboratory and pilot-plant technical scale using demonstration photocatalytic platforms (Cordero et al, 2020).…”

“…is becoming an urgent task. However, a major knowledge gap between simulation (Shandilya et al, 2015b) and experimental studies still exists, while the experimental findings present serious discrepancies depending on the method of measurement, location and types of vehicles tested (Nevshupa et al, 2020;Timmers and Achten, 2016). The problem is getting more complex with the advent of nanofunctionalized materials such as photocatalytic asphalts, tiles and pavement coatings, which, in addition to "conventional" aerosol emission, are able to release embedded nanoparticles when subjected to wearing and weathering (Jimenez-Relinque et al, 2020;Shandilya et al, 2015a).…”

New Holistic Conceptual Framework for the Assessment of the Performance of Photocatalytic Pavement

“…The test conditions were as follows: pH-neutral demineralized water as leachant, temperature of 19-25 • C, flow rate of 4.16 × 10 −6 m 3 /s, and L/A ratio of 50 ± 10 L/m 2 . The nanoparticle emissions were analyzed using the experimental system TEMIS-1000, which was designed and constructed in the project, and the original procedure and analytical method to calculate the triboemission rate (Nevshupa et al, 2020a; Figure 3D). The test rig consisted of an aerosol-tight case, which was placed on top of the pavement or the sample of the pavement to be characterized.…”

“…However, the particle generation mechanisms and influencing factors, including the road material, presence of embedded nanomaterials, road maintenance, and cleaning, are not sufficiently understood. Nevshupa et al (2020a) made progress with respect to the more accurate quantification of the nanoparticle aerosol emission rate. They developed a new methodological framework based on the mass balance equation and analysis of the decay of the transient aerosol concentration.…”

“…However, this decrease did not affect the quantification of the emitted particles because different size ranges were used. The number of emitted particles as a function of the experimental conditions was determined by integrating the time series considering the particle deposition velocities using the model developed by Nevshupa et al (2020a):…”