Figure 3 provides an overview of the average diurnal
characteristics of hourly BC concentrations. Average hourly
BC during the four seasons showed a similar diurnal pattern
with two peaks, which appeared at 22:00–00:00 UT and 8:00–10:00 UT. consistent with peaks usually observed
during traffic rush hours at urban sites, implying contributions
from meteorological conditions such as inversion and
mixing height, and other possible sources of vehicle exhausts
and popular domestic cooking or heating in local
towns and the surrounding areas. In general, the diurnal
profile of summer was comparatively flat while those of
other seasons showed much more variation. Compared with
spring and autumn, the morning peak of BC showed an
advance in summer and a delay in winter. The afternoon
peak of BC was somewhat opposite to the morning peak,
especially in winter. One possible explanation for these
small time movements of BC peaks may be the launch of
daybreak or dusk, to a certain extent which affects pollutant
dispersion, and people’s activity in different seasons.
Figure 3 provides an overview of the average diurnalcharacteristics of hourly BC concentrations. Average hourlyBC during the four seasons showed a similar diurnal patternwith two peaks, which appeared at 22:00–00:00 UT and 8:00–10:00 UT. consistent with peaks usually observedduring traffic rush hours at urban sites, implying contributionsfrom meteorological conditions such as inversion andmixing height, and other possible sources of vehicle exhaustsand popular domestic cooking or heating in localtowns and the surrounding areas. In general, the diurnalprofile of summer was comparatively flat while those ofother seasons showed much more variation. Compared withspring and autumn, the morning peak of BC showed anadvance in summer and a delay in winter. The afternoonpeak of BC was somewhat opposite to the morning peak,especially in winter. One possible explanation for thesesmall time movements of BC peaks may be the launch ofdaybreak or dusk, to a certain extent which affects pollutantdispersion, and people’s activity in different seasons.
การแปล กรุณารอสักครู่..