K. W. Tham

Home exposures to environmental tobacco smoke and allergic symptoms among young children in Singapore.

Background: Research relating environmental tobacco smoke (ETS) exposures have focused on childhood asthma. There have been fewer studies with conflicting results performed on associations of ETS exposures with allergic symptoms. We are interested to see if ETS exposures in the homes are associated with allergic symptoms among preschool children in Singapore where public smoking is banned. Methods: A cross-sectional study adopting an expanded and modified ISAAC (International Study on Asthma and Allergies in Childhood) questionnaire for the evaluation of asthma and allergies was conducted on 6,794 children attending 120 randomly selected child care centers. Specific information on demographics and ETS exposures was obtained. Adjusted prevalence ratios (PRs) and 95% confidence intervals (CIs) were determined using Poisson multivariate regression with a log-link function and robust variance estimates as recommended for cross-sectional studies. Results: The response proportion was 70.0%, and 4,759 children from 97 centers participated. After adjusting for covariates, it was found that home ETS exposure was associated with increased risks of current symptoms of rhinitis (PR 1.23; 95% CI 1.01–1.50) and rhinoconjunctivitis (PR 1.79; 95% CI 1.26–2.54). These associations followed dose-response trends with respect to number of cigarettes smoked or smokers in the homes. Home ETS exposures were also associated with higher PRs of wheeze, nocturnal cough and doctor-diagnosed asthma. Compared with paternal smoking, higher risks of the above outcomes were found for maternal smoking. Conclusion: Home ETS exposure is a risk factor associated with rhinitis and asthma among preschool children.

Local Discomfort Caused by Draft Perception in a Space Served by Displacement Ventilation System in the Tropics

This paper reports a subjective study in a field environmental chamber (FEC) served by a displacement ventilation (DV) system. Sixty tropically acclimatised subjects, 30 males and 30 females, were engaged in sedentary office work for 3h. The subjects were exposed to three vertical air temperature gradients (nominally 1, 3 and 5K·m 1) between 0.1 and 1.1m heights and three room air temperatures (20, 23 and 26°C) at 0.6m height. The object of this work was to investigate effects of temperature gradient and room air temperature on local discomfort due to air movement at different thermal sensations. The results indicated that vertical temperature gradient had an insignificant impact on draft perception. Draft perceptions at foot, calf, thigh and arm were affected by both overall and local thermal sensations. A cold sensation would increase the risk of draft complaints and a warm sensation would increase the percentage dissatisfied due to insufficient air movement.

The Fuzzy Industry Maturity Grid and its Application to the Singapore Property Sector

This paper introduces the fuzzy industry maturity grid as an extension of the industry maturity grid for diagnosing an economic sector or an industry, to identify fast-growing sectors and to map out growth strategies for sectors showing signs of maturity. By incorporating fuzzy set theory and aggregation models in decision-making, the conventional industry maturity grid is enhanced from a qualiative analysis to a semi-quantitative method which captures an experts knowledge of the sector or industry, inclusive of his judgement. It does this via using a linguistic scale describing the characteristics under each of the three main dimensions of the IMG to form fuzzy sets; a hierarchical aggregation of information based on fuzzy aggregation operators; and a conceptual hypercube to determine the rank and ranking size of the perscribed strategies. The application of the fuzzy industry maturity grid is illustrated with an example on the Singapore property sector.