Is plastic dust different from mineral dust? Results from idealized wind tunnel experiments.
- 1Department of Micrometeorology, University of Bayreuth, Bayreuth, Germany
- 2Department of Physical Chemistry II, University of Bayreuth, Bayreuth, Germany
- 3Bayreuth Center of Ecology and Environmental Research, University of Bayreuth, Bayreuth, Germany
Atmospheric transport has been shown to effectively disperse microplastic
particulate matter to virtually every environment on the planet. Despite this
efficient long-range transport, only few studies have examined the fundamental
mechanisms of the atmospheric transport of microplastics. Here, we present the
results of wind tunnel experiments, examining the detachment behavior of plastic
particles ranging from 38 to 125 µm in diameter from flat substrates.
Detachment was achieved solely by aerodynamic forces of the turbulent airflow.
The detachment behavior of spheric microplastic particles (Polyethylene) and
spheric glass microparticles (Borosilicate) of nominally the same diameter
(63-75 µm) are contrasted across substrates with hydrophilic to hydrophobic
surface coatings. We further examine the effect of particle-particle collisions on
the detachment behavior of both Polyethylene and glass spheres. The critical
friction velocity (u*,th), which is defined as the value at which 50% of all
microparticles detach, ranged from 0.1 to 0.3 ms −1. Particle-particle collisions
reduced the u*,th of glass, but not that for PE. Results were compared with
predictions of a Jonhson-Kendall-Roberts model. The relation of diameter to
u*,th compared well between results and prediction for Polyethylene spheres.
Glass spheres were predicted to detach at smaller u*,th than polyethylene
spheres, but detached at higher u*,th. Here, we argue that capillary forces
increased the adhesion, which is not covered by the model. The combination of
particle and substrate hydrophobicity influenced the relative humidity, at which
capillary forces increased u*,th.
How to cite: Esders, E., Sittl, S., Krammel, I., Babel, W., Papastavrou, G., and Babel, W.: Is plastic dust different from mineral dust? Results from idealized wind tunnel experiments., EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-12251, https://doi.org/10.5194/egusphere-egu23-12251, 2023.
