Title: The investigation of the impact of aerosol on air quality in Hong Kong using the GOCART model
Authors: Zhang, Zhenxi (張禎璽)
Abstract: In the study presented in this thesis we quantify the contribution of aerosols emitted from
different source types and different regions to Hong Kong's air quality using the chemical
transport model GOCART (Georgia Tech/Goddard Global Ozone Chemistry Aerosol
Radiation and Transport). A new algorithm has been developed to isolate the emissions
from different regions. This algorithm can account for the non-linear relationship between
emission fluxes and the resulting concentrations in the GOCART model.
Regarding the contributions of the major aerosol components, sulphur has the largest
influence (68%) on the air quality in Hong Kong, followed by organic carbon (13%). The
influence of dust (11%) and black carbon (5%) is relatively lower and sea salt is the lowest
(3%). The highest AOD could be seen in September, mainly composed of sulphur aerosol
(85%). The high AOD in March and April is caused by sulphur and organic carbon.
Organic carbon has a relative contribution of 39% in March and 30% in April.
For sulphur, black carbon and organic carbon, their anthropogenic emission in every
continent, China and South China are considered. The aerosol produced by anthropogenic
emission in Asia has the greatest contribution to Hong Kong, far greater than the total sum
of other continents. The sulphur aerosol AOD in Hong Kong caused by anthropogenic SO2
emission is larger in spring and autumn than in other seasons. In spring and autumn, the
sulphur aerosol from the northern part of China has bigger contribution to Hong Kong
than other regions. The carbon aerosol (black carbon and organic carbon) AOD in Hong
Kong produced by anthropogenic emission has larger value in spring, autumn and winter
than that in summer. In autumn and winter, the carbon aerosol emitted from the China
except South China has bigger contribution to Hong Kong than that emitted from other
regions.
For dust aerosol, the impact of dust coming from different deserts on air pollution in Hong
Kong is investigated and compared. Regarding the vertical distribution of dust
concentration in Hong Kong, the lower part of the atmosphere, from the ground to 2 km
height, is mainly affected by Gobi dust aerosol with a concentration of about 10 μg/m3. However, in the middle to upper part of the atmosphere (above 5 km), Taklamakan dust
aerosol is dominating. An analysis of the temporal variation reveals that the influence of
Gobi and Sahara dust aerosol on Hong Kong mainly occurred in spring and winter, and
Taklamakan dust in summer.
Notes: CityU Call Number: QC882.42 .Z45 2012; xiii, 132 leaves : ill. (some col.) 30 cm.; Thesis (Ph.D.)--City University of Hong Kong, 2012.; Includes bibliographical references (leaves 123-132)
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