May 23, 2006
Tony Puangthongthub presents the final oral defense of his doctoral dissertation on Friday, May 26, 2006 at 1PM in room 2005 of the Michael Hooker Research Center. Details are as follows.Bayesian Maximum Entropy Space/Time Analysis of Ambient Particulate Matter and Mortality in Thailand

Several epidemiological studies have confirmed the associations and estimated the risk of cardiovascular and pulmonary mortality due to exposure to daily PM10. However the effect due to the error introduced by techniques previously used to interpolate PM10 in characterizing the strength of the associations remain in question. Therefore we incorporate the Bayesian Maximum Entropy (BME) method of modern spatiotemporal Geostatistics in the exposure assessment to investigate the effect of that daily PM10 has on cardiovascular and respiratory mortality in different regions of Thailand. The BME method is used to characterize and construct accurate spatiotemporal maps of PM10. This work rigorously takes into account the uncertainty associated with monitoring measurements as well as the natural space/time variability of PM10 field. The BME maps show that the PM10 field across Thailand exhibits considerable space/time variability. These maps suggest that the PM10 daily average concentration did not comply with the PM10 standard, which was supported by the maps of PM10 daily maximum concentration, and confirmed by BME maps of non-attainment areas. Furthermore, BME analysis targeted districts in Northeast region as sites where new monitoring stations should be added in order to improve the monitoring network of Thailand.

These maps provided the most accurate estimate of PM10 exposure obtained to date for each district location and day for which cardiovascular and respiratory mortality was reported in Thailand during 1998-2003. The strength of the associations was then investigated through a analysis using a case-crossover design. The observed associations were stronger for pulmonary mortality than for cardio mortality. High odds ratios observed in Bangkok and central region were possibly due to industrialization, construction, and traffic emission sources while positive associations found in other regions could be related to sources from agricultural biomass burning, forest fire, wind-blown dust, and sea spray. A study showed that mortality risk reported in a single city study may be biased. Our work overcomes this problem using a composite space/time analysis that consider all of the 925 primary districts making up Thailand and all deaths from cardiopulmonary causes reported during 1998-2003.

Furthermore, a holistochastic human exposure framework propagated mapping and epidemiologic uncertainty to model the lower-bound and upper-bound estimates of the number of deaths from cardiovascular and respiratory causes that resulted from acute health response to short term exposure to PM10 across Thailand. An Elasticity uncertainty analysis suggests that the uncertainty in the assessment of the number of deaths caused by PM10 can be improved by adding monitoring stations in the Northeastern region, and by improving the epidemiologic study in the Northern region.

Advisor: Marc Serre
Reader: Douglas Crawford-Brown
Richard Kamens
David Leith
Dana Loomis
Karin Yeatts, EPID

For further information please contact Rebecca Riggsbee Lloyd by email at Rebecca_Lloyd@unc.edu

 

RELATED PAGES
CONTACT INFORMATION
Gillings Admissions: 233 Rosenau Hall, (919) 445-1170
Student Affairs: 263 Rosenau Hall, (919) 966-2499
Dean's Office: 170 Rosenau Hall, (919) 966-3215
Business and Administration: 170 Rosenau Hall, (919) 966-3215
Academic Affairs: 307 Rosenau Hall, (919) 843-8044
Inclusive Excellence: 207B Rosenau Hall, (919) 966-7430
Room Reservations
Facilities


135 Dauer Drive
Chapel Hill, NC 27599-7400