都會區大氣中超細粒徑微粒之特性探討(I)
Other Title
Characterization of Ultrafine Particles in Urban Atmosphere (I)
Date Issued
2000-07-31
Date
2000-07-31
Author(s)
王秋森
DOI
892320B002110
Abstract
The objective of this study was to
measure the mass and number concentration,
and chemical composition of ambient
ultrafine particles (defined in this study as
the particles with aerodynamic diameter <
0.18 mm) in an urban environment. In
addition, a fluorogenic probe was used to
determine the concentrations of reactive
oxygen species (ROS) on particles in
various particle size fractions.
The results showed that the hourly
average number concentration for particles
in the size range of 0.016 to 0.177 µm in a
courtyard was in the range of 8.6 × 104 ±
3.3 × 104 particles/cm3. The mass
concentration of ultrafine particles at a third-floor
balcony, a first-floor courtyard, a bus
stop, a sidewalk and in an underpass were in
the ranges of 3.5~4.9, 6.5~8.8, 6.4~34.5,
3.4~22.1 and 104.7~137.2 mg/m 3 ,
respectively. The mass fractions of organic
carbon in the total carbon content of
ultrafine particles collected at the first-floor
courtyard and in the underpass were similar
and markedly higher than those at the third-floor
balcony. The data indicated that
samples collected at the first-floor courtyard,
which were mainly contributed from
vehicular exhausts, had higher mass
concentrations of ultrafine particles and the
carbonaceous material was mainly organic
carbon. The results imply that the
vehicular exhaust is one of the most
important emission sources of ultrafine particles in Taipei aerosols. Moreover, for
the same mass concentrations of particles,
the concentration of ROS was found to
increase as the particle size decreased,
except for ultrafine particles. The size
dependency of ROS concentrations is
clearly related to the mechanisms of ROS
generation. Further studies are needed on
the factors that affect the concentration of
ROS on ambient aerosol particles.
Subjects
ultrafine particles
urban aerosol
organic carbon
elemental carbon
ROS
Publisher
臺北市：國立臺灣大學公共衛生學院公共衛生學系
Type
report
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