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postgraduate thesis: The outdoor horizontal and vertical variations of respirable suspendedparticulate concentrations within a densely urban environment in HongKong: application of a box and plumedispersion model (airGIS/OSPM)

TitleThe outdoor horizontal and vertical variations of respirable suspendedparticulate concentrations within a densely urban environment in HongKong: application of a box and plumedispersion model (airGIS/OSPM)
Authors
Advisors
Issue Date2011
PublisherThe University of Hong Kong (Pokfulam, Hong Kong)
Abstract
Background There have been many multicity studies assessing health effects of the population’s exposure to PM10. They assume that there is homogeneous exposure to PM10 and the monitoring locations are representative of the population’s exposure. In a densely urban environment, like Hong Kong, street canyons are common and could alter PM10 exposure. The horizontal and vertical dispersion of PM10 in the urban environment is complex due to the interactions of street geometric, metrological and pollution source conditions. The airGIS/OSPM is a box and plume mathematical model which was designed to model this complex dispersion of PM10. Objectives This study aims to utilize the airGIS/OSPM to assess how the health impact is affected by the misclassifications of within city air pollution exposure. This helps assessing the feasibility of using the airGIS/OSPM in health studies. Methods The airGIS/OSPM was used for an urban area of Hong Kong, in the north west of Kowloon Peninsular for a period from 1998 to spring 2011. PM10 concentration’s were estimated at field measurement points, an EPD roadside monitoring site, and subjects in a subset of the elderly healthcare center cohort and for all building addresses in the modeled area. The airGIS/OSPM was validated by conducting a PM10 measurement campaign over the winter of 2010 to 2011. Also validation was conducted using the measurements of the Mong Kok EPD roadside monitoring station. A pilot study using the time stratified case-crossover analysis was conducted to explore the effects of using the airGIS/OSPM to express the subjects’ short-term outdoor residential exposure to PM10 on all cause mortality. AirGIS/OSPM PM10 estimates were compared with ambient concentrations obtained from the EPD monitoring network. The population mean exposure was calculated using the airGIS/OSPM estimated PM10 concentration at all building address points from 2007 to 2009 at the ground level and at middle building height level. The airGIS/OSPM estimate was used to identify spatial variation of PM10 within the study area. Results The airGIS/OSPM estimated well the measured PM10 concentration from the field measurement campaign and the EPD Mong Kok station. The airGIS/OSPM estimate and the ambient measure for EHC subject exposure both found an odds ratio for all cause mortality there was no difference from unity between case and control times. The airGIS/OSPM derived mean PM10 concentration at the middle height of each building was 54.8μg/m3 while that at the all EPD was 54.4μg/m3. At ground level the airGIS/OSPM PM10 estimate was 58.35μg/m3 while that at the EPD was 54.41μg/m3. Conclusion The misclassification of PM10 was negligible at the middle of buildings, but for people regularly working in ground level microenvironments are often exposed to PM10 concentrations that are higher than those measured at EPD monitors. It is feasible to use the airGIS/OSPM model to estimate PM10 exposure. The small spatial variation in exposure means the airGIS/OSPM may not be appropriate in assessing the short-term PM10 exposure, but due to the larger effect size it might be important in long-term exposure assessment.
DegreeMaster of Philosophy
SubjectAir - Pollution - Health aspects - Mathematical models. - China - Hong Kong
Dept/ProgramCommunity Medicine

 

DC FieldValueLanguage
dc.contributor.advisorWong, CM-
dc.contributor.advisorLam, TH-
dc.contributor.advisorLai, HK-
dc.contributor.authorChapman, Peter Stuart.-
dc.date.issued2011-
dc.description.abstractBackground There have been many multicity studies assessing health effects of the population’s exposure to PM10. They assume that there is homogeneous exposure to PM10 and the monitoring locations are representative of the population’s exposure. In a densely urban environment, like Hong Kong, street canyons are common and could alter PM10 exposure. The horizontal and vertical dispersion of PM10 in the urban environment is complex due to the interactions of street geometric, metrological and pollution source conditions. The airGIS/OSPM is a box and plume mathematical model which was designed to model this complex dispersion of PM10. Objectives This study aims to utilize the airGIS/OSPM to assess how the health impact is affected by the misclassifications of within city air pollution exposure. This helps assessing the feasibility of using the airGIS/OSPM in health studies. Methods The airGIS/OSPM was used for an urban area of Hong Kong, in the north west of Kowloon Peninsular for a period from 1998 to spring 2011. PM10 concentration’s were estimated at field measurement points, an EPD roadside monitoring site, and subjects in a subset of the elderly healthcare center cohort and for all building addresses in the modeled area. The airGIS/OSPM was validated by conducting a PM10 measurement campaign over the winter of 2010 to 2011. Also validation was conducted using the measurements of the Mong Kok EPD roadside monitoring station. A pilot study using the time stratified case-crossover analysis was conducted to explore the effects of using the airGIS/OSPM to express the subjects’ short-term outdoor residential exposure to PM10 on all cause mortality. AirGIS/OSPM PM10 estimates were compared with ambient concentrations obtained from the EPD monitoring network. The population mean exposure was calculated using the airGIS/OSPM estimated PM10 concentration at all building address points from 2007 to 2009 at the ground level and at middle building height level. The airGIS/OSPM estimate was used to identify spatial variation of PM10 within the study area. Results The airGIS/OSPM estimated well the measured PM10 concentration from the field measurement campaign and the EPD Mong Kok station. The airGIS/OSPM estimate and the ambient measure for EHC subject exposure both found an odds ratio for all cause mortality there was no difference from unity between case and control times. The airGIS/OSPM derived mean PM10 concentration at the middle height of each building was 54.8μg/m3 while that at the all EPD was 54.4μg/m3. At ground level the airGIS/OSPM PM10 estimate was 58.35μg/m3 while that at the EPD was 54.41μg/m3. Conclusion The misclassification of PM10 was negligible at the middle of buildings, but for people regularly working in ground level microenvironments are often exposed to PM10 concentrations that are higher than those measured at EPD monitors. It is feasible to use the airGIS/OSPM model to estimate PM10 exposure. The small spatial variation in exposure means the airGIS/OSPM may not be appropriate in assessing the short-term PM10 exposure, but due to the larger effect size it might be important in long-term exposure assessment.-
dc.languageeng-
dc.publisherThe University of Hong Kong (Pokfulam, Hong Kong)-
dc.relation.ispartofHKU Theses Online (HKUTO)-
dc.rightsThe author retains all proprietary rights, (such as patent rights) and the right to use in future works.-
dc.rightsCreative Commons: Attribution 3.0 Hong Kong License-
dc.source.urihttp://hub.hku.hk/bib/B47869847-
dc.subject.lcshAir - Pollution - Health aspects - Mathematical models. - China - Hong Kong-
dc.titleThe outdoor horizontal and vertical variations of respirable suspendedparticulate concentrations within a densely urban environment in HongKong: application of a box and plumedispersion model (airGIS/OSPM)-
dc.typePG_Thesis-
dc.identifier.hkulb4786984-
dc.description.thesisnameMaster of Philosophy-
dc.description.thesislevelmaster's-
dc.description.thesisdisciplineCommunity Medicine-
dc.description.naturepublished_or_final_version-
dc.identifier.doi10.5353/th_b4786984-
dc.date.hkucongregation2012-

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