Exposures to respirable air particles in urban microenvironments and effects of background levels on cardiorespiratory symptoms

Au-Yeung, Ho-Kong Christopher. 2006. Exposures to respirable air particles in urban microenvironments and effects of background levels on cardiorespiratory symptoms. PhD Thesis, Cardiff University.

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Abstract

Epidemiological evidence has shown that increased levels of respirable particulate air pollution leads to adverse cardiorespiratory health effects although the exact mechanism of damage is unknown. In the UK the largest single source of respirable air particulates is road transport. Currently the background levels of respirable air particulates are measured by stationary monitoring stations. However, traffic volumes often vary considerably within a city and hotspots of densely trafficked areas may give rise to microenvironments with increased respirable particulate levels. The primary objective of this thesis was to investigate whether a high density of local motor traffic would give rise to microenvironments with increased levels of respirable air particulates. A selection of streets in Cardiff city were allocated into exposed and control group according to traffic volumes. Levels of respirable air particulates were measured for each residential location both indoor and outdoor, and individual residents provided blood, urine, and hair samples for the analysis of trace elements, which may serve as biomarkers of exposure to air particulates from motor vehicles. Results showed that for both indoor and outdoor respirable air particulate concentrations, the levels were found to be higher in exposed areas than controls, and there was a moderately high correlation between indoor and outdoor concentrations. However, the study failed to demonstrate any differential uptake of trace elements as reflected by the lack of differences in the levels of biomarkers in the biological samples of subjects residing in different exposure areas. A separate study was carried out to investigate whether short-term changes in respirable air particulate levels would lead to acute exacerbation of disease symptoms in individuals with asthma, chronic respiratory diseases excluding asthma, and chronic cardiac diseases. Subjects were recruited through specialist hospital outpatient clinics located in South Wales and disease specific questionnaires were sent out during different episodes of respirable particulate air pollution. Results showed that symptoms of most subjects were not affected by short-term changes in air particulate levels, although individuals with more severe asthma and cardiac disease appeared to have benefited relatively more from lower levels of respirable air particulates than those with less severe disease symptoms as well as those suffering from chronic respiratory disease.

Item Type:	Thesis (PhD)
Status:	Unpublished
Schools:	Medicine
Subjects:	R Medicine > R Medicine (General)
ISBN:	9781303204340
Date of First Compliant Deposit:	30 March 2016
Last Modified:	09 Jan 2018 19:58
URI:	https://orca.cardiff.ac.uk/id/eprint/56042

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