行政院國科會專題研究計畫執行進度報告:綠植栽帶對室內外環境懸浮微粒傳輸及人體呼吸道沉積 之影響研究 (1/2)
Date Issued
2004
Date
2004
Author(s)
DOI
922313B002107
Abstract
The main objective of this two-year project
is to study the effect of vegetative canopies on
airborne particle transport in a naturally
ventilated space and its deposition implication
in the human respiratory system. In the first year,
wind-driven airborne particles around
vegetative canopies are tracked to investigate
the transport trajectories and deposition patterns
in vegetative canopies by combining a 3-D
Eulerian wind flow model as well as a 3-D
Lagrangian particle-tracking model. The former
conducts large eddy simulation of the turbulent
flows in vegetative canopies, and the latter
performs raindrop trajectory calculations by
releasing a large number of particles into the
computational domain. The wind speed model
is verified with available wind tunnel
measurement. Numerical scenario simulations
are carried out for various ventilation strategy,
windbreak porosity, and meteorological factors
(wind speed and direction) to study building
airflow pattern and particle deposition around
vegetative canopies. The relative relationship
among three mechanism of particle deposition,
i.e., sedimentation, Brownian diffusion and
inertial impaction, are investigated.
In the second year, road dusts collected from
urban and suburban areas situated in northern
Taiwan are used in an environmental chamber
test to verify the 3-D numerical model. In
addition, a field study of measuring the count
and mass concentration of airborne dusts
upwind and downwind of vegetative canopies is
also carried out in the busy roads of Metropolis
Taipei. The entrapment of particles by
vegetative canopies is discussed. Results
obtained from this research are expected to offer
designers a control strategy for removal of
concentrations of airborne road dust from
vegetative canopies. The study develops a
multiple-path model considering three
deposition mechanisms, including
sedimentation, Brownian diffusion and inertial
impaction, to simulate particle deposition in the
human lung. Two kinds of the human lung
geometry, the typical-path lung model and the
five-lobe symmetric lung model, are considered.
The difference of deposition among four
different breathing types (at rest, light, moderate,
and heavy exercise) is compared.
Traffic-induced particles in Metropolis Taipei
are taken as an example.
This report demonstrates the results of the
first-year project. A common multi-room style
in is selected to simulate the flow patterns of
different kinds of building ventilation strategy,
including complex ventilation, two side
ventilation, piston ventilation, cross ventilation,
and short-cut ventilation。It is concluded that
piston ventilation can provide most effective air
exchange and the downward-side windows are
the key point of ventilation efficiency.
Subjects
Vegetative canopy
Airborne particle transport
particle deposition
Human respiratory system
Ecological engineering
Publisher
臺北市：國立臺灣大學生物環境系統工程學系暨研究所
Type
report
File(s)![Thumbnail Image]()
Loading...
Name
922313B002107.pdf
Size
68.37 KB
Format
Adobe PDF
Checksum
(MD5):c291b95af12aac2e6f5982ecfb9a3af8