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The effects of leaf size and microroughness on the branch-scale collection efficiency of ultrafine particles

Publication ,  Journal Article
Huang, CW; Lin, MY; Khlystov, A; Katul, GG
Published in: Journal of Geophysical Research
January 1, 2015

Wind tunnel experiments were performed to explore how leaf size and leaf microroughness impact the collection efficiency of ultrafine particles (UFP) at the branch scale. A porous media model previously used to characterize UFP deposition onto conifers (Pinus taeda and Juniperus chinensis) was employed to interpret these wind tunnel measurements for four different broadleaf species (Ilex cornuta, Quercus alba, Magnolia grandiflora, and Lonicera fragrantissima) and three wind speed (0.3-0.9 ms-1) conditions. Among the four broadleaf species considered, Ilex cornuta with its partially folded shape and sharp edges was the most efficient at collecting UFP followed by the other three flat-shaped broadleaf species. The findings here suggest that a connection must exist between UFP collection and leaf dimension and roughness. This connection is shown to be primarily due to the thickness of a quasi-laminar boundary layer pinned to the leaf surface assuming the flow over a leaf resembles that of a flat plate. A scaling analysis that utilizes a three-sublayer depositional model for a flat plate of finite size and roughness embedded within the quasi-laminar boundary layer illustrates these connections. The analysis shows that a longer leaf dimension allows for thicker quasi-laminar boundary layers to develop. A thicker quasi-laminar boundary layer depth in turn increases the overall resistance to UFP deposition due to an increase in the diffusional path length thereby reducing the leaf-scale UFP collection efficiency. It is suggested that the effects of leaf microroughness are less relevant to the UFP collection efficiency than are the leaf dimensions for the four broadleaf species explored here.

Duke Scholars

Published In

Journal of Geophysical Research

DOI

EISSN

2156-2202

ISSN

0148-0227

Publication Date

January 1, 2015

Volume

120

Issue

8

Start / End Page

3370 / 3385

Related Subject Headings

  • Meteorology & Atmospheric Sciences
 

Citation

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MLA
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Huang, C. W., Lin, M. Y., Khlystov, A., & Katul, G. G. (2015). The effects of leaf size and microroughness on the branch-scale collection efficiency of ultrafine particles. Journal of Geophysical Research, 120(8), 3370–3385. https://doi.org/10.1002/2014JD022458
Huang, C. W., M. Y. Lin, A. Khlystov, and G. G. Katul. “The effects of leaf size and microroughness on the branch-scale collection efficiency of ultrafine particles.” Journal of Geophysical Research 120, no. 8 (January 1, 2015): 3370–85. https://doi.org/10.1002/2014JD022458.
Huang CW, Lin MY, Khlystov A, Katul GG. The effects of leaf size and microroughness on the branch-scale collection efficiency of ultrafine particles. Journal of Geophysical Research. 2015 Jan 1;120(8):3370–85.
Huang, C. W., et al. “The effects of leaf size and microroughness on the branch-scale collection efficiency of ultrafine particles.” Journal of Geophysical Research, vol. 120, no. 8, Jan. 2015, pp. 3370–85. Scopus, doi:10.1002/2014JD022458.
Huang CW, Lin MY, Khlystov A, Katul GG. The effects of leaf size and microroughness on the branch-scale collection efficiency of ultrafine particles. Journal of Geophysical Research. 2015 Jan 1;120(8):3370–3385.

Published In

Journal of Geophysical Research

DOI

EISSN

2156-2202

ISSN

0148-0227

Publication Date

January 1, 2015

Volume

120

Issue

8

Start / End Page

3370 / 3385

Related Subject Headings

  • Meteorology & Atmospheric Sciences