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Multi-scale comparison of the fine particle removal capacity of urban forests and wetlands

View Article: PubMed Central - PubMed

ABSTRACT

As fine particle (FP) pollution is harmful to humans, previous studies have focused on the mechanisms of FP removal by forests. The current study aims to compare the FP removal capacities of urban forests and wetlands on the leaf, canopy, and landscape scales. Water washing and scanning electron microscopy are used to calculate particle accumulation on leaves, and models are used to estimate vegetation collection, sedimentation, and dry deposition. Results showed that, on the leaf scale, forest species are able to accumulate more FP on their leaf surface than aquatic species in wetlands. On the canopy scale, horizontal vegetation collection is the major process involved in FP removal, and the contribution of vertical sedimentation/emission can be ignored. Coniferous tree species also showed stronger FP collection ability than broadleaf species. In the landscape scale, deposition on the forest occurs to a greater extent than that on wetlands, and dry deposition is the major process of FP removal on rain-free days. In conclusion, when planning an urban green system, planting an urban forest should be the first option for FP mitigation.

No MeSH data available.


SEM photomicrographs of six common trees (a: adaxial leave surface of species, b: abaxial leaf surface of species; at ×370 SE – ×500 SE).
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f5: SEM photomicrographs of six common trees (a: adaxial leave surface of species, b: abaxial leaf surface of species; at ×370 SE – ×500 SE).

Mentions: The structure of the leaf surface plays an important role in its ability to capture particles. Thus, different leaf structures may contribute to the heterogeneity of particle accumulation between different species. SEM photomicrographs of aquatic plants (Fig. 4) and common tree species (Fig. 5) show heterogeneity. Aquatic plants present simple grooves on their leaf surface, while tree leaves present more complicated structures, such as leaf hairs, protrusions, and raphe. Structural differences between species are also evident on their adaxial and abaxial surfaces (Figs 4 and 5).


Multi-scale comparison of the fine particle removal capacity of urban forests and wetlands
SEM photomicrographs of six common trees (a: adaxial leave surface of species, b: abaxial leaf surface of species; at ×370 SE – ×500 SE).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5385566&req=5

f5: SEM photomicrographs of six common trees (a: adaxial leave surface of species, b: abaxial leaf surface of species; at ×370 SE – ×500 SE).
Mentions: The structure of the leaf surface plays an important role in its ability to capture particles. Thus, different leaf structures may contribute to the heterogeneity of particle accumulation between different species. SEM photomicrographs of aquatic plants (Fig. 4) and common tree species (Fig. 5) show heterogeneity. Aquatic plants present simple grooves on their leaf surface, while tree leaves present more complicated structures, such as leaf hairs, protrusions, and raphe. Structural differences between species are also evident on their adaxial and abaxial surfaces (Figs 4 and 5).

View Article: PubMed Central - PubMed

ABSTRACT

As fine particle (FP) pollution is harmful to humans, previous studies have focused on the mechanisms of FP removal by forests. The current study aims to compare the FP removal capacities of urban forests and wetlands on the leaf, canopy, and landscape scales. Water washing and scanning electron microscopy are used to calculate particle accumulation on leaves, and models are used to estimate vegetation collection, sedimentation, and dry deposition. Results showed that, on the leaf scale, forest species are able to accumulate more FP on their leaf surface than aquatic species in wetlands. On the canopy scale, horizontal vegetation collection is the major process involved in FP removal, and the contribution of vertical sedimentation/emission can be ignored. Coniferous tree species also showed stronger FP collection ability than broadleaf species. In the landscape scale, deposition on the forest occurs to a greater extent than that on wetlands, and dry deposition is the major process of FP removal on rain-free days. In conclusion, when planning an urban green system, planting an urban forest should be the first option for FP mitigation.

No MeSH data available.