THESIS
2014
iv leaves, v-xi, 98 pages : illustrations (chiefly color), color maps ; 30 cm
Abstract
Hong Kong has one of the highest population densities among the world's mega-cities. Seven
and a half million inhabitants live on a group of islands that total 1,000 km
2. Tall and bulky high-rise buildings with very limited open spaces in between, uniform building heights and
large podium structures have reduced the urban air ventilation at pedestrian level. PM
2.5, a well-known traffic-related pollutant, is currently one of the main causes of street level air quality pollution in the urban areas of Hong Kong. High pollution levels are often observed in
urban street canyons. These street level air quality problems have evident negative effects on
the health of pedestrians.
However, the location limited street level pollution data observed by the three available
Roadside Air Quality...[
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Hong Kong has one of the highest population densities among the world's mega-cities. Seven
and a half million inhabitants live on a group of islands that total 1,000 km
2. Tall and bulky high-rise buildings with very limited open spaces in between, uniform building heights and
large podium structures have reduced the urban air ventilation at pedestrian level. PM
2.5, a well-known traffic-related pollutant, is currently one of the main causes of street level air quality pollution in the urban areas of Hong Kong. High pollution levels are often observed in
urban street canyons. These street level air quality problems have evident negative effects on
the health of pedestrians.
However, the location limited street level pollution data observed by the three available
Roadside Air Quality Monitoring Stations (RAQMSs) make it difficult to spatially
understand the street level pollution on an urban scale. To overcome this limitation, the
Atmospheric Dispersion Modelling System - Urban (ADMS-Urban), which employs the Danish Operational Street Pollution Model, was used to spatially calculate the street level PM
2.5 concentrations over urban areas in Causeway Bay on Hong Kong Island, one of the
most polluted areas in Hong Kong that has limited observational data.
The ADMS-Urban was applied to spatially calculate the PM
2.5 concentrations at a three-metre height level. The results showed that the system was able to produce similar diurnal pollution patterns when compared with the observations from the RAQMS in Causeway Bay, and
capture the spatial variation when validated with the measurements collected by the Dusttrak .
instrument along the entire tram route on Hong Kong Island. The validated model was then used to obtain the spatial distribution of pollution at the pedestrian level on an urban street
scale. Furthermore, the urban building morphology effects on street level PM
2.5
concentrations under different wind directions were explored using the validated
ADMS-Urban. The results suggested that approximately 20% of the urban area in Causeway
Bay on Hong Kong Island would have higher street level PM
2.5 concentrations if the building height increased.
Future studies using the validated model system with other prediction systems that provide
simulations for the model input parameters are needed to establish a street level pollution
forecasting system on an urban street scale.
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