| dc.description |
This study used daily air pollution data
(PM2.5, PM10, SO2, NO2, CO, and O3) from nine monitoring
stations inWuhan city to calculate the air quality
index (AQI) from 2013 to 2017. Together with this data,
L-band sounding data, ground meteorological data, and
air mass back trajectories were also used to describe the
dynamics of atmospheric boundary layer (ABL) during
pollution process. Analysis of the results shows that,
even though the city is still polluted, the number of
polluted days was decreasing. Ranking the years in
terms of pollution status shows that the year 2013 was
the most polluted year while the year 2017 was the
cleanest year. Average annual limit of PM10, PM2.5,
and NO2 during these 5 years were 1.3~1.8, 1.5~2.7,
and 1.2~1.5 times higher than the annual average acceptable
limit, respectively. The average ratio of PM2.5/
PM10 for 5 years was 0.67 which signifies that a
significant portion of PM2.5 accounted for the total mass
of PM10. Moreover, the condition of ABL during the
pollution process shows the dominance of strong
ground inversion and weak to calm winds. These conditions
are not favorable for horizontal and vertical
mixing of air pollutants and prevent dilution of pollutants
with clean air. Mean cluster analysis of air mass
back trajectory shows that pollutants of local origin were
more important than the trans-boundary movement of
air pollutants. This indicates that the observed pollution
in Wuhan was more of local origin |
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